Version 3.11.0-113.0.dev Merge 2692a110f03d1fa915ef2a259b948aa2dfd31958 into dev

diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/forwarding_listener.dart b/pkg/_fe_analyzer_shared/lib/src/parser/forwarding_listener.dart
index 3c8f88c..b88555e 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/forwarding_listener.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/forwarding_listener.dart

@@ -2669,6 +2669,24 @@
   void endConstDotShorthand(Token token) {
     listener?.beginConstDotShorthand(token);
   }
+
+  @override
+  void beginPrimaryConstructorBody(Token token) {
+    listener?.beginPrimaryConstructorBody(token);
+  }
+
+  @override
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    listener?.endPrimaryConstructorBody(
+      beginToken,
+      beginInitializers,
+      endToken,
+    );
+  }
 }
 
 class NullListener extends ForwardingListener {

diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/listener.dart b/pkg/_fe_analyzer_shared/lib/src/parser/listener.dart
index 7d51650..d5152c2 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/listener.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/listener.dart

@@ -356,6 +356,21 @@
     bool forExtensionType,
   ) {}
 
+  void beginPrimaryConstructorBody(Token token) {}
+
+  // Handles the `this` body block for a primary constructor. Substructures:
+  /// - metadata
+  /// - initializers
+  /// - async marker
+  /// - body
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    logEvent("endPrimaryConstructorBody");
+  }
+
   void beginCombinators(Token token) {}
 
   void endCombinators(int count) {

diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart b/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
index 83aee6e..f765781 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart

@@ -3715,6 +3715,24 @@
     return token;
   }
 
+  Token parsePrimaryConstructorBody(Token token) {
+    Token beginToken = token;
+    listener.beginPrimaryConstructorBody(token);
+
+    Token? beforeInitializers = token;
+    token = parseInitializersOpt(beforeInitializers);
+
+    token = parseAsyncModifierOpt(token);
+    token = parseFunctionBody(
+      token,
+      /* ofFunctionExpression = */ false,
+      /* allowAbstract = */ inPlainSync,
+    );
+
+    listener.endPrimaryConstructorBody(beginToken, beforeInitializers, token);
+    return token;
+  }
+
   /// Parses an extension type declaration after
   ///
   ///    'extension' 'type'
@@ -5361,6 +5379,22 @@
           return token;
         }
         // Fall through to continue parsing `operator` as an identifier.
+      } else if (identical(value, 'this')) {
+        Token next2 = next.next!;
+        if (next2.isA(TokenType.COLON) ||
+            next2.isA(TokenType.SEMICOLON) ||
+            next2.isA(TokenType.OPEN_CURLY_BRACKET)) {
+          if (!_isDeclaringConstructorsFeatureEnabled) {
+            reportExperimentNotEnabled(
+              ExperimentalFlag.declaringConstructors,
+              next,
+              next,
+            );
+          }
+          token = parsePrimaryConstructorBody(next);
+          listener.endMember();
+          return token;
+        }
       } else if (!next.isIdentifier ||
           (identical(value, 'typedef') &&
               token == beforeStart &&

diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/fix_all_in_workspace.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/fix_all_in_workspace.dart
index d757902..3c46fef 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/fix_all_in_workspace.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/fix_all_in_workspace.dart

@@ -58,29 +58,35 @@
     var workspace = DartChangeWorkspace(await server.currentSessions);
     var processor = BulkFixProcessor(server.instrumentationService, workspace);
 
-    var result = await processor.fixErrors(
-      server.contextManager.analysisContexts,
-    );
-    var errorMessage = result.errorMessage;
-    if (errorMessage != null) {
-      return error(ErrorCodes.RequestFailed, errorMessage);
-    }
+    progress.begin('Computing fixes…');
+    try {
+      var result = await processor.fixErrors(
+        server.contextManager.analysisContexts,
+      );
 
-    var changeBuilder = result.builder!;
-    var change = changeBuilder.sourceChange;
-    if (change.edits.isEmpty) {
-      return success(null);
-    }
+      var errorMessage = result.errorMessage;
+      if (errorMessage != null) {
+        return error(ErrorCodes.RequestFailed, errorMessage);
+      }
 
-    var edit = createWorkspaceEdit(
-      server,
-      clientCapabilities,
-      change,
-      annotateChanges: requireConfirmation
-          ? ChangeAnnotations.requireConfirmation
-          : ChangeAnnotations.include,
-    );
-    return sendWorkspaceEditToClient(edit);
+      var changeBuilder = result.builder!;
+      var change = changeBuilder.sourceChange;
+      if (change.edits.isEmpty) {
+        return success(null);
+      }
+
+      var edit = createWorkspaceEdit(
+        server,
+        clientCapabilities,
+        change,
+        annotateChanges: requireConfirmation
+            ? ChangeAnnotations.requireConfirmation
+            : ChangeAnnotations.include,
+      );
+      return sendWorkspaceEditToClient(edit);
+    } finally {
+      progress.end();
+    }
   }
 }
 

diff --git a/pkg/analysis_server/test/lsp/commands/fix_all_in_workspace_test.dart b/pkg/analysis_server/test/lsp/commands/fix_all_in_workspace_test.dart
index 2e49cb3..b3950d1 100644
--- a/pkg/analysis_server/test/lsp/commands/fix_all_in_workspace_test.dart
+++ b/pkg/analysis_server/test/lsp/commands/fix_all_in_workspace_test.dart

@@ -10,6 +10,7 @@
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../tool/lsp_spec/matchers.dart';
+import '../request_helpers_mixin.dart';
 import '../server_abstract.dart';
 
 void main() {
@@ -20,7 +21,8 @@
 }
 
 abstract class AbstractFixAllInWorkspaceTest
-    extends AbstractLspAnalysisServerTest {
+    extends AbstractLspAnalysisServerTest
+    with LspProgressNotificationsMixin {
   String get commandId;
   String get commandName;
   bool get expectRequiresConfirmation;
@@ -229,6 +231,28 @@
 ''');
   }
 
+  Future<void> test_progressNotifications_supported() async {
+    // Advertise that we (the client) support progress.
+    setWorkDoneProgressSupport();
+
+    // Expect (during the test) a progress token to be created, started, ended.
+    expect(progressUpdates, emitsInOrder(['CREATE', 'BEGIN', 'END']));
+
+    await initialize();
+    await executeCommand(Command(command: commandId, title: 'UNUSED'));
+  }
+
+  Future<void> test_progressNotifications_unsupported() async {
+    // Advertise that we do not support progress.
+    setWorkDoneProgressSupport(false);
+
+    // Expect no progress updates at all.
+    expect(progressUpdates, neverEmits(anything));
+
+    await initialize();
+    await executeCommand(Command(command: commandId, title: 'UNUSED'));
+  }
+
   Future<void> test_serverAdvertisesCommand() async {
     await initialize();
     expect(

diff --git a/pkg/analysis_server/test/lsp/server_abstract.dart b/pkg/analysis_server/test/lsp/server_abstract.dart
index c83079f..4cb4848 100644
--- a/pkg/analysis_server/test/lsp/server_abstract.dart
+++ b/pkg/analysis_server/test/lsp/server_abstract.dart

@@ -771,9 +771,9 @@
     setTextDocumentDynamicRegistration('synchronization');
   }
 
-  void setWorkDoneProgressSupport() {
+  void setWorkDoneProgressSupport([bool supported = true]) {
     windowCapabilities = extendWindowCapabilities(windowCapabilities, {
-      'workDoneProgress': true,
+      'workDoneProgress': supported,
     });
   }
 
@@ -826,7 +826,7 @@
   /// initialize.
   ServerCapabilities? _serverCapabilities;
 
-  final validProgressTokens = <ProgressToken>{};
+  final _validProgressTokens = <ProgressToken>{};
 
   /// Default initialization options to be used if [initialize] is not provided
   /// options explicitly.
@@ -1574,7 +1574,7 @@
       request.params as Map<String, Object?>,
     );
     if (params.token != clientProvidedTestWorkDoneToken &&
-        !validProgressTokens.contains(params.token)) {
+        !_validProgressTokens.contains(params.token)) {
       throw Exception(
         'Server sent a progress notification for a token '
         'that has not been created: ${params.token}',
@@ -1582,7 +1582,7 @@
     }
 
     if (WorkDoneProgressEnd.canParse(params.value, nullLspJsonReporter)) {
-      validProgressTokens.remove(params.token);
+      _validProgressTokens.remove(params.token);
     }
 
     if (params.token == analyzingProgressToken) {
@@ -1605,10 +1605,10 @@
     var params = WorkDoneProgressCreateParams.fromJson(
       request.params as Map<String, Object?>,
     );
-    if (validProgressTokens.contains(params.token)) {
+    if (_validProgressTokens.contains(params.token)) {
       throw Exception('Server tried to create already-active progress token');
     }
-    validProgressTokens.add(params.token);
+    _validProgressTokens.add(params.token);
   }
 
   /// Checks whether a notification is likely an error from the server (for

diff --git a/pkg/analysis_server/tool/code_completion/completion_metrics.dart b/pkg/analysis_server/tool/code_completion/completion_metrics.dart
index a3ad607..7a43d54 100644
--- a/pkg/analysis_server/tool/code_completion/completion_metrics.dart
+++ b/pkg/analysis_server/tool/code_completion/completion_metrics.dart

@@ -153,7 +153,7 @@
     )
     ..addFlag('help', abbr: 'h', help: 'Print this help message.')
     ..addOption(
-      CompletionMetricsOptions.OVERLAY,
+      CompletionMetricsOptions.overlayOption,
       allowed: [
         OverlayMode.none.flag,
         OverlayMode.removeRestOfFile.flag,
@@ -167,7 +167,7 @@
           'complete at the start of the token without modifying the file.',
     )
     ..addOption(
-      CompletionMetricsOptions.PREFIX_LENGTH,
+      CompletionMetricsOptions.prefixLengthOption,
       defaultsTo: '0',
       help:
           'The number of characters to include in the prefix. Each '
@@ -175,14 +175,14 @@
           'start of the token being completed.',
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_MISSED_COMPLETION_DETAILS,
+      CompletionMetricsQualityOptions._printMissedCompletionDetails,
       help:
           'Print detailed information every time a completion request fails '
           'to produce a suggestions matching the expected suggestion.',
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_MISSED_COMPLETION_SUMMARY,
+      CompletionMetricsQualityOptions._printMissedCompletionSummary,
       help:
           'Print summary information about the times that a completion '
           'request failed to produce a suggestions matching the expected '
@@ -190,7 +190,7 @@
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_MISSING_INFORMATION,
+      CompletionMetricsQualityOptions._printMissingInformation,
       help:
           'Print information about places where no completion location was '
           'computed and about information that is missing in the completion '
@@ -198,7 +198,7 @@
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_MRR_BY_LOCATION,
+      CompletionMetricsQualityOptions._printMrrByLocation,
       help:
           'Print information about the mrr score achieved at each completion '
           'location. This can help focus efforts to improve the overall '
@@ -207,7 +207,7 @@
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_SHADOWED_COMPLETION_DETAILS,
+      CompletionMetricsQualityOptions._printShadowedCompletionDetails,
       help:
           'Print detailed information every time a completion request '
           'produces a suggestion whose name matches the expected suggestion '
@@ -215,14 +215,14 @@
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsOptions.PRINT_SLOWEST_RESULTS,
+      CompletionMetricsOptions.printSlowestResultsFlag,
       help:
           'Print information about the completion requests that were the '
           'slowest to return suggestions.',
       negatable: false,
     )
     ..addFlag(
-      CompletionMetricsQualityOptions.PRINT_WORST_RESULTS,
+      CompletionMetricsQualityOptions._printWorstResults,
       help:
           'Print information about the completion requests that had the '
           'worst mrr scores.',
@@ -691,34 +691,34 @@
   /// A flag that causes detailed information to be printed every time a
   /// completion request fails to produce a suggestions matching the expected
   /// suggestion.
-  static const String PRINT_MISSED_COMPLETION_DETAILS =
+  static const String _printMissedCompletionDetails =
       'print-missed-completion-details';
 
   /// A flag that causes summary information to be printed about the times that
   /// a completion request failed to produce a suggestions matching the expected
   /// suggestion.
-  static const String PRINT_MISSED_COMPLETION_SUMMARY =
+  static const String _printMissedCompletionSummary =
       'print-missed-completion-summary';
 
   /// A flag that causes information to be printed about places where no
   /// completion location was computed and about information that's missing in
   /// the completion tables.
-  static const String PRINT_MISSING_INFORMATION = 'print-missing-information';
+  static const String _printMissingInformation = 'print-missing-information';
 
   /// A flag that causes information to be printed about the mrr score achieved
   /// at each completion location.
-  static const String PRINT_MRR_BY_LOCATION = 'print-mrr-by-location';
+  static const String _printMrrByLocation = 'print-mrr-by-location';
 
   /// A flag that causes detailed information to be printed every time a
   /// completion request produce a suggestions whose name matches the expected
   /// suggestion but that is referencing a different element (one that's
   /// shadowed by the correct element).
-  static const String PRINT_SHADOWED_COMPLETION_DETAILS =
+  static const String _printShadowedCompletionDetails =
       'print-shadowed-completion-details';
 
   /// A flag that causes information to be printed about the completion requests
   /// that had the worst mrr scores.
-  static const String PRINT_WORST_RESULTS = 'print-worst-results';
+  static const String _printWorstResults = 'print-worst-results';
 
   /// A flag indicating whether information should be printed every time a
   /// completion request fails to produce a suggestions matching the expected
@@ -749,15 +749,18 @@
   final bool printWorstResults;
 
   CompletionMetricsQualityOptions(super.results)
-    : printMissedCompletionDetails =
-          results[PRINT_MISSED_COMPLETION_DETAILS] as bool,
-      printMissedCompletionSummary =
-          results[PRINT_MISSED_COMPLETION_SUMMARY] as bool,
-      printMissingInformation = results[PRINT_MISSING_INFORMATION] as bool,
-      printMrrByLocation = results[PRINT_MRR_BY_LOCATION] as bool,
-      printShadowedCompletionDetails =
-          results[PRINT_SHADOWED_COMPLETION_DETAILS] as bool,
-      printWorstResults = results[PRINT_WORST_RESULTS] as bool;
+    : printMissedCompletionDetails = results.flag(
+        _printMissedCompletionDetails,
+      ),
+      printMissedCompletionSummary = results.flag(
+        _printMissedCompletionSummary,
+      ),
+      printMissingInformation = results.flag(_printMissingInformation),
+      printMrrByLocation = results.flag(_printMrrByLocation),
+      printShadowedCompletionDetails = results.flag(
+        _printShadowedCompletionDetails,
+      ),
+      printWorstResults = results.flag(_printWorstResults);
 }
 
 /// This is the main metrics computer class for code completions. After the

diff --git a/pkg/analysis_server/tool/code_completion/completion_metrics_base.dart b/pkg/analysis_server/tool/code_completion/completion_metrics_base.dart
index 9731e76..6797729 100644
--- a/pkg/analysis_server/tool/code_completion/completion_metrics_base.dart
+++ b/pkg/analysis_server/tool/code_completion/completion_metrics_base.dart

@@ -190,17 +190,17 @@
 /// The options specified on the command-line.
 class CompletionMetricsOptions {
   /// An option to control whether and how overlays should be produced.
-  static const String OVERLAY = 'overlay';
+  static const String overlayOption = 'overlay';
 
   /// An option controlling how long of a prefix should be used.
   ///
   /// This affects the offset of the completion request, and how much content is
   /// removed in each of the overlay modes.
-  static const String PREFIX_LENGTH = 'prefix-length';
+  static const String prefixLengthOption = 'prefix-length';
 
   /// A flag that causes information to be printed about the completion requests
   /// that were the slowest to return suggestions.
-  static const String PRINT_SLOWEST_RESULTS = 'print-slowest-results';
+  static const String printSlowestResultsFlag = 'print-slowest-results';
 
   /// The overlay mode that should be used.
   final OverlayMode overlay;
@@ -212,9 +212,9 @@
   final bool printSlowestResults;
 
   CompletionMetricsOptions(ArgResults results)
-    : overlay = OverlayMode.parseFlag(results[OVERLAY] as String),
-      prefixLength = int.parse(results[PREFIX_LENGTH] as String),
-      printSlowestResults = results[PRINT_SLOWEST_RESULTS] as bool;
+    : overlay = OverlayMode.parseFlag(results.option(overlayOption)!),
+      prefixLength = int.parse(results.option(prefixLengthOption)!),
+      printSlowestResults = results.flag(printSlowestResultsFlag);
 }
 
 enum OverlayMode {

diff --git a/pkg/analysis_server/tool/code_completion/completion_metrics_client.dart b/pkg/analysis_server/tool/code_completion/completion_metrics_client.dart
index a2f316f..5d7c32e 100644
--- a/pkg/analysis_server/tool/code_completion/completion_metrics_client.dart
+++ b/pkg/analysis_server/tool/code_completion/completion_metrics_client.dart

@@ -67,7 +67,7 @@
     )
     ..addFlag('help', abbr: 'h', help: 'Print this help message.')
     ..addOption(
-      CompletionMetricsOptions.OVERLAY,
+      CompletionMetricsOptions.overlayOption,
       allowed: [
         OverlayMode.none.flag,
         OverlayMode.removeRestOfFile.flag,
@@ -81,7 +81,7 @@
           'complete at the start of the token without modifying the file.',
     )
     ..addOption(
-      CompletionMetricsOptions.PREFIX_LENGTH,
+      CompletionMetricsOptions.prefixLengthOption,
       defaultsTo: '0',
       help:
           'The number of characters to include in the prefix. Each '
@@ -89,7 +89,7 @@
           'start of the token being completed.',
     )
     ..addFlag(
-      CompletionMetricsOptions.PRINT_SLOWEST_RESULTS,
+      CompletionMetricsOptions.printSlowestResultsFlag,
       help:
           'Print information about the completion requests that were the '
           'slowest to return suggestions.',

diff --git a/pkg/analysis_server/tool/code_completion/visitors.dart b/pkg/analysis_server/tool/code_completion/visitors.dart
index 986514a..67309c5 100644
--- a/pkg/analysis_server/tool/code_completion/visitors.dart
+++ b/pkg/analysis_server/tool/code_completion/visitors.dart

@@ -130,19 +130,19 @@
 }
 
 class ExpectedCompletionsVisitor extends RecursiveAstVisitor<void> {
-  static const ASYNC_STAR = 'async*';
+  static const _asyncStar = 'async*';
 
-  static const DEFAULT_COLON = 'default:';
+  static const _defaultColon = 'default:';
 
-  static const DEFERRED_AS = 'deferred as';
+  static const _deferredAs = 'deferred as';
 
-  static const EXPORT_STATEMENT = "export '';";
+  static const _exportStatement = "export '';";
 
-  static const IMPORT_STATEMENT = "import '';";
+  static const _importStatement = "import '';";
 
-  static const PART_STATEMENT = "part '';";
-  static const SYNC_STAR = 'sync*';
-  static const YIELD_STAR = 'yield*';
+  static const _partStatement = "part '';";
+  static const _syncStar = 'sync*';
+  static const _yieldStar = 'yield*';
 
   /// The result of resolving the file being visited.
   final ResolvedUnitResult result;
@@ -204,7 +204,7 @@
             entity,
             lineNumber,
             columnNumber,
-            ASYNC_STAR,
+            _asyncStar,
             kind,
             elementKind,
           ),
@@ -216,7 +216,7 @@
             entity,
             lineNumber,
             columnNumber,
-            DEFAULT_COLON,
+            _defaultColon,
             kind,
             elementKind,
           ),
@@ -228,7 +228,7 @@
             entity,
             lineNumber,
             columnNumber,
-            DEFERRED_AS,
+            _deferredAs,
             kind,
             elementKind,
           ),
@@ -240,7 +240,7 @@
             entity,
             lineNumber,
             columnNumber,
-            EXPORT_STATEMENT,
+            _exportStatement,
             kind,
             elementKind,
           ),
@@ -252,7 +252,7 @@
             entity,
             lineNumber,
             columnNumber,
-            IMPORT_STATEMENT,
+            _importStatement,
             kind,
             elementKind,
           ),
@@ -264,7 +264,7 @@
             entity,
             lineNumber,
             columnNumber,
-            PART_STATEMENT,
+            _partStatement,
             kind,
             elementKind,
           ),
@@ -276,7 +276,7 @@
             entity,
             lineNumber,
             columnNumber,
-            SYNC_STAR,
+            _syncStar,
             kind,
             elementKind,
           ),
@@ -288,7 +288,7 @@
             entity,
             lineNumber,
             columnNumber,
-            YIELD_STAR,
+            _yieldStar,
             kind,
             elementKind,
           ),

diff --git a/pkg/analyzer/lib/src/fasta/ast_builder.dart b/pkg/analyzer/lib/src/fasta/ast_builder.dart
index b02d2f5..16de183 100644
--- a/pkg/analyzer/lib/src/fasta/ast_builder.dart
+++ b/pkg/analyzer/lib/src/fasta/ast_builder.dart

@@ -618,6 +618,11 @@
   }
 
   @override
+  void beginPrimaryConstructorBody(Token beginToken) {
+    debugEvent("PrimaryConstructorBody");
+  }
+
+  @override
   void beginSwitchCaseWhenClause(Token when) {
     debugEvent("PatternSwitchCaseGuard");
   }
@@ -3169,6 +3174,23 @@
   }
 
   @override
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    // TODO(declaring-constructors): Implement primary constructor body.
+    // ignore: unused_local_variable
+    var bodyObject = pop();
+    // ignore: unused_local_variable
+    var initializers = (pop() as List<ConstructorInitializerImpl>?) ?? const [];
+    // ignore: unused_local_variable
+    var separator = pop() as Token?;
+    // ignore: unused_local_variable
+    var metadata = pop() as List<AnnotationImpl>?;
+  }
+
+  @override
   void endRecordLiteral(Token leftParenthesis, int count, Token? constKeyword) {
     debugEvent("RecordLiteral");
 

diff --git a/pkg/analyzer_testing/CHANGELOG.md b/pkg/analyzer_testing/CHANGELOG.md
index fa6a0cf..0384c0b 100644
--- a/pkg/analyzer_testing/CHANGELOG.md
+++ b/pkg/analyzer_testing/CHANGELOG.md

@@ -4,6 +4,8 @@
   analysis options file used in testing specifies a `true` value for
   `propagate-linter-exceptions`. This ensures that when tests are run,
   exceptions that occur while processing lint rules will cause the test to fail.
+- Deprecate `PubPackageResolutionTest.addKernelPackageDep`. A mock kernel
+  package can still be written with `PubPackageResolutionTest.newPackage`.
 
 ## 0.1.7
 

diff --git a/pkg/analyzer_testing/lib/src/analysis_rule/pub_package_resolution.dart b/pkg/analyzer_testing/lib/src/analysis_rule/pub_package_resolution.dart
index c1bddc2..9318502 100644
--- a/pkg/analyzer_testing/lib/src/analysis_rule/pub_package_resolution.dart
+++ b/pkg/analyzer_testing/lib/src/analysis_rule/pub_package_resolution.dart

@@ -235,6 +235,10 @@
   /// Adds the 'kernel' package as a dependency to the package-under-test.
   ///
   /// This allows various `package:kernel/` imports to resolve.
+  @Deprecated(
+    'The mock kernel package is deprecated; use '
+    '`PubPackageResolutionTest.newPackage` to make a custom mock',
+  )
   bool get addKernelPackageDep => false;
 
   /// Adds the 'meta' package as a dependency to the package-under-test.

diff --git a/pkg/dart2wasm/lib/closures.dart b/pkg/dart2wasm/lib/closures.dart
index 5f2aaef..f01e77c 100644
--- a/pkg/dart2wasm/lib/closures.dart
+++ b/pkg/dart2wasm/lib/closures.dart

@@ -59,10 +59,12 @@
 /// an entry for each (non-empty) combination of argument names that closures
 /// with this layout can be called with.
 class ClosureRepresentation {
-  /// The struct field index in the vtable struct at which the function
-  /// entries start.
+  /// The number of type arguments.
   final int typeCount;
 
+  /// The maximum number of positional parameters.
+  final int maxPositionalCount;
+
   /// The Wasm struct type for the vtable.
   final w.StructType vtableStruct;
 
@@ -129,6 +131,7 @@
   ClosureRepresentation(
       Translator translator,
       this.typeCount,
+      this.maxPositionalCount,
       this.vtableStruct,
       this.closureStruct,
       this._indexOfCombination,
@@ -136,6 +139,8 @@
 
   bool get isGeneric => typeCount > 0;
 
+  bool get hasNamed => _indexOfCombination != null;
+
   /// Where the vtable entries for function calls start in the vtable struct.
   int get vtableBaseIndex => isGeneric
       ? ClosureLayouter.vtableBaseIndexGeneric
@@ -216,6 +221,10 @@
   // The member currently being visited while collecting function signatures.
   Member? currentMember;
 
+  /// Whether the kernel [Component] uses `Function.apply` and possibly passes
+  /// non-empty map for named arguments.
+  late bool usesFunctionApplyWithNamedArguments;
+
   // For non-generic closures. The entries are:
   // 0: Dynamic call entry
   // 1-...: Entries for calling the closure
@@ -400,8 +409,9 @@
             (translator.component.metadata["vm.procedure-attributes.metadata"]
                     as ProcedureAttributesMetadataRepository)
                 .mapping;
-
   void collect() {
+    usesFunctionApplyWithNamedArguments = false;
+
     // Dynamic module enabled builds use dynamic call entry points for all
     // closure invocations so we don't need to generate any representation
     // info.
@@ -478,12 +488,12 @@
 
   ClosureRepresentation _createRepresentation(
       int typeCount,
-      int positionalCount,
+      int maxPositionalCount,
       List<String> names,
       ClosureRepresentation? parent,
       Map<NameCombination, int>? indexOfCombination,
       Iterable<int> paramCounts) {
-    List<String> nameTags = ["$typeCount", "$positionalCount", ...names];
+    List<String> nameTags = ["$typeCount", "$maxPositionalCount", ...names];
     String vtableName = ["#Vtable", ...nameTags].join("-");
     String closureName = ["#Closure", ...nameTags].join("-");
     w.StructType parentVtableStruct = parent?.vtableStruct ??
@@ -508,7 +518,7 @@
     if (typeCount > 0) {
       // Add or set vtable field for the instantiation function.
       instantiatedRepresentation =
-          getClosureRepresentation(0, positionalCount, names)!;
+          getClosureRepresentation(0, maxPositionalCount, names)!;
       w.RefType inputType = w.RefType.def(closureBaseStruct, nullable: false);
       w.RefType outputType = w.RefType.def(
           instantiatedRepresentation.closureStruct,
@@ -564,6 +574,7 @@
     ClosureRepresentation representation = ClosureRepresentation(
         translator,
         typeCount,
+        maxPositionalCount,
         vtableStruct,
         closureStruct,
         indexOfCombination,
@@ -618,7 +629,7 @@
                     vtableBaseIndexNonGeneric + instantiationTrampolines.length,
                     vtableStruct,
                     vtableBaseIndexGeneric +
-                        (positionalCount + 1) +
+                        (maxPositionalCount + 1) +
                         genericIndex)
                 : translator
                     .getDummyValuesCollectorForModule(module)
@@ -1009,7 +1020,26 @@
   }
 
   @override
+  void visitStaticInvocation(StaticInvocation node) {
+    super.visitStaticInvocation(node);
+    if (node.target == translator.functionApply) {
+      // Function.apply(function, positionalArguments, [namedArguments])
+      if (node.arguments.positional.length > 2) {
+        usesFunctionApplyWithNamedArguments = true;
+      }
+    }
+  }
+
+  @override
+  void visitStaticTearOff(StaticTearOff node) {
+    visitStaticTearOffConstantReference(StaticTearOffConstant(node.target));
+  }
+
+  @override
   void visitStaticTearOffConstantReference(StaticTearOffConstant constant) {
+    if (constant.target == translator.functionApply) {
+      usesFunctionApplyWithNamedArguments = true;
+    }
     _visitFunctionNode(constant.function);
   }
 
@@ -1028,9 +1058,23 @@
 
   @override
   void visitDynamicInvocation(DynamicInvocation node) {
-    if (node.name.text == "call") {
-      _visitFunctionInvocation(node.arguments);
-    }
+    // NOTE: One may have two different kinds of calls here:
+    // ```
+    //   dynamic x;
+    //   x(namedArg: 1);
+    //   x.foo(namedArg: 1);
+    // ```
+    // It may appear as we only have to handle the first case, namely
+    // `node.name.text == "call"`, but the second case can also be a
+    // dynamic closure callsite via call-through-field:
+    // ```
+    //   class Foo {
+    //     void Function({int? namedArg}) get foo => ...;
+    //   }
+    // ```
+    // then a `x.foo(namedArg: 1)` will be executed at runtime via
+    // `var tmp = x.foo; tmp(namedArg: 1)`.
+    _visitFunctionInvocation(node.arguments);
     super.visitDynamicInvocation(node);
   }
 }

diff --git a/pkg/dart2wasm/lib/constants.dart b/pkg/dart2wasm/lib/constants.dart
index fed4b73..89de802 100644
--- a/pkg/dart2wasm/lib/constants.dart
+++ b/pkg/dart2wasm/lib/constants.dart

@@ -1180,12 +1180,12 @@
 
         final b = function.body;
 
-        final closureLocal = function.locals[0];
         final typeArgsListLocal = function.locals[1]; // empty
         final posArgsListLocal = function.locals[2];
         final namedArgsListLocal = function.locals[3];
 
-        b.local_get(closureLocal);
+        constants.instantiateConstant(
+            b, tearOffConstantInfo.constant, translator.topTypeNonNullable);
         constants.instantiateConstant(
             b, typeArgsArrayConstantInfo.constant, typeArgsListLocal.type);
         b.local_get(posArgsListLocal);

diff --git a/pkg/dart2wasm/lib/dispatch_table.dart b/pkg/dart2wasm/lib/dispatch_table.dart
index 9e34a46..2ef07c2 100644
--- a/pkg/dart2wasm/lib/dispatch_table.dart
+++ b/pkg/dart2wasm/lib/dispatch_table.dart

@@ -852,12 +852,17 @@
               fun = wrappedDynamicSubmoduleImports[fun] ??=
                   _wrapDynamicSubmoduleFunction(target, fun);
             }
-            _definedWasmTable.setElement(i, fun);
+            _definedWasmTable.moduleBuilder.elements
+                .activeFunctionSegmentBuilderFor(_definedWasmTable)
+                .setFunctionAt(i, fun);
           } else {
             // This will generate the imported table if it doesn't already
             // exist.
-            (getWasmTable(targetModuleBuilder) as w.ImportedTable)
-                .setElements[i] = fun;
+            final importedTable =
+                getWasmTable(targetModuleBuilder) as w.ImportedTable;
+            targetModuleBuilder.elements
+                .activeFunctionSegmentBuilderFor(importedTable)
+                .setFunctionAt(i, fun);
           }
         }
       }

diff --git a/pkg/dart2wasm/lib/dynamic_modules.dart b/pkg/dart2wasm/lib/dynamic_modules.dart
index be0e2ac..0a9e37c 100644
--- a/pkg/dart2wasm/lib/dynamic_modules.dart
+++ b/pkg/dart2wasm/lib/dynamic_modules.dart

@@ -677,7 +677,8 @@
     overridableFunctions.putIfAbsent(index, () {
       if (!isSubmodule) {
         final mainFunction = translator.mainModule.functions.define(type, name);
-        translator.mainModule.functions.declare(mainFunction);
+        translator.mainModule.elements.declarativeSegmentBuilder
+            .declare(mainFunction);
         buildMain(mainFunction);
         return mainFunction;
       }
@@ -685,7 +686,7 @@
       if (skipSubmodule) return null;
 
       final submoduleFunction = submodule.functions.define(type, name);
-      submodule.functions.declare(submoduleFunction);
+      submodule.elements.declarativeSegmentBuilder.declare(submoduleFunction);
       buildSubmodule(submoduleFunction);
       return submoduleFunction;
     });
@@ -1067,7 +1068,7 @@
 
     // Declare the function so it can be used as a ref_func in a constant
     // context.
-    b.moduleBuilder.functions.declare(checker);
+    b.moduleBuilder.elements.declarativeSegmentBuilder.declare(checker);
 
     // Invoke the 'canonicalize' function with the value and checker.
     b.local_get(valueLocal);
@@ -1101,7 +1102,7 @@
 
     // Declare the function so it can be used as a ref_func in a constant
     // context.
-    b.moduleBuilder.functions.declare(checker);
+    b.moduleBuilder.elements.declarativeSegmentBuilder.declare(checker);
 
     // Invoke the canonicalizer function with the value and checker.
     b.local_get(valueLocal);

diff --git a/pkg/dart2wasm/lib/intrinsics.dart b/pkg/dart2wasm/lib/intrinsics.dart
index 3736abe..89740b6 100644
--- a/pkg/dart2wasm/lib/intrinsics.dart
+++ b/pkg/dart2wasm/lib/intrinsics.dart

@@ -2021,7 +2021,7 @@
         b.end();
         b.local_set(posArgsLocal);
 
-        // Convert named argument map to list, to be passed to shape and type
+        // Convert named argument map to array, to be passed to shape and type
         // checkers and the dynamic call entry.
         final namedArgsListLocal =
             b.addLocal(translator.nullableObjectArrayTypeRef);

diff --git a/pkg/dart2wasm/lib/kernel_nodes.dart b/pkg/dart2wasm/lib/kernel_nodes.dart
index e9455ea..2bd4566 100644
--- a/pkg/dart2wasm/lib/kernel_nodes.dart
+++ b/pkg/dart2wasm/lib/kernel_nodes.dart

@@ -276,6 +276,8 @@
       index.getTopLevelProcedure("dart:core", "_runtimeTypeEquals");
   late final Procedure runtimeTypeHashCode =
       index.getTopLevelProcedure("dart:core", "_runtimeTypeHashCode");
+  late final Procedure? functionApply =
+      index.tryGetProcedure('dart:core', 'Function', 'apply');
 
   // dart:core invocation/exception procedures
   late final Procedure invocationGetterFactory =

diff --git a/pkg/dart2wasm/lib/static_dispatch_table.dart b/pkg/dart2wasm/lib/static_dispatch_table.dart
index 6c78019..59f53a1 100644
--- a/pkg/dart2wasm/lib/static_dispatch_table.dart
+++ b/pkg/dart2wasm/lib/static_dispatch_table.dart

@@ -74,11 +74,15 @@
     _table.forEach((fun, index) {
       final targetModule = translator.moduleToBuilder[fun.enclosingModule]!;
       if (translator.isMainModule(targetModule)) {
-        _definedWasmTable.setElement(index, fun);
+        _definedWasmTable.moduleBuilder.elements
+            .activeFunctionSegmentBuilderFor(_definedWasmTable)
+            .setFunctionAt(index, fun);
       } else {
         // This will generate the imported table if it doesn't already exist.
-        (getWasmTable(targetModule) as w.ImportedTable).setElements[index] =
-            fun;
+        final importedTable = getWasmTable(targetModule) as w.ImportedTable;
+        targetModule.elements
+            .activeFunctionSegmentBuilderFor(importedTable)
+            .setFunctionAt(index, fun);
       }
     });
 

diff --git a/pkg/dart2wasm/lib/translator.dart b/pkg/dart2wasm/lib/translator.dart
index 73e708e..8bd8e44 100644
--- a/pkg/dart2wasm/lib/translator.dart
+++ b/pkg/dart2wasm/lib/translator.dart

@@ -1116,6 +1116,33 @@
     });
   }
 
+  final _closureArgumentsDispatchers =
+      <w.ModuleBuilder, Map<ClosureRepresentation, w.BaseFunction>>{};
+  w.BaseFunction getClosureArgumentsDispatcher(
+      w.ModuleBuilder module, ClosureRepresentation r) {
+    // We can only unpack (type, positional, named) argument arrays and forward
+    // to specific vtable entries if we have closed-world knowledge of all used
+    // name combinations.
+    assert(!dynamicModuleSupportEnabled &&
+        !closureLayouter.usesFunctionApplyWithNamedArguments);
+
+    final moduleCache = _closureArgumentsDispatchers[module] ??= {};
+    return moduleCache.putIfAbsent(r, () {
+      final representationString = '${r.typeCount}-'
+          '${r.maxPositionalCount}'
+          '${r.hasNamed ? '-' : ''}'
+          '${r.nameCombinations.join('-')}';
+      final function = module.functions.define(
+          dynamicCallVtableEntryFunctionType,
+          "closure arguments dispatcher representation=$representationString");
+      compilationQueue.add(CompilationTask(
+          function,
+          _ClosureArgumentsToVtableEntryDispatcherGenerator(
+              this, r, function)));
+      return function;
+    });
+  }
+
   ClosureImplementation getClosure(
       FunctionNode functionNode,
       w.BaseFunction target,
@@ -1249,7 +1276,26 @@
         w.RefType.def(representation.vtableStruct, nullable: false),
         mutable: false));
     final ib = vtable.initializer;
-    final dynamicCallEntry = makeDynamicCallEntry();
+
+    // NOTE: In dynamic modules we do not have closed world knowledge of closure
+    // definitions and callsites, so the dynamic call entry cannot dispatch to
+    // representation specific vtable entries.
+    //
+    // Even if we have closed world knowledge, if anywhere in the program
+    // `Function.apply` is used with named arguments, then we don't know which
+    // name-combinations may be used and we want to avoid creating vtable
+    // entries for all possible name combinations. So also in this situation we
+    // cannot dispatch to representation-specific vtable entries.
+    //
+    // If none of the two cases above apply, we can make the dynamic call entry
+    // be a shared stub that dispatches (based on arguments) to the right
+    // representation specific vtable entry. This saves code size as we don't
+    // have 1 dynamic call entry function per closure but rather 1 per closure
+    // shape / representation.
+    final dynamicCallEntry = (dynamicModuleSupportEnabled ||
+            closureLayouter.usesFunctionApplyWithNamedArguments)
+        ? makeDynamicCallEntry()
+        : getClosureArgumentsDispatcher(closureModule, representation);
     ib.ref_func(dynamicCallEntry);
     if (representation.isGeneric) {
       ib.ref_func(representation
@@ -2336,6 +2382,281 @@
   }
 }
 
+class _ClosureArgumentsToVtableEntryDispatcherGenerator
+    implements CodeGenerator {
+  final Translator translator;
+  final ClosureRepresentation representation;
+  final w.FunctionBuilder function;
+
+  _ClosureArgumentsToVtableEntryDispatcherGenerator(
+      this.translator, this.representation, this.function);
+
+  @override
+  void generate(w.InstructionsBuilder b, List<w.Local> paramLocals,
+      w.Label? returnLabel) {
+    assert(returnLabel == null);
+
+    final b = function.body;
+
+    final closureLocal = function.locals[0];
+    final typeArgsLocal = function.locals[1];
+    final posArgsLocal = function.locals[2];
+    final namedArgsLocal = function.locals[3];
+
+    assert(typeArgsLocal.type == translator.typeArrayTypeRef);
+    assert(posArgsLocal.type == translator.nullableObjectArrayTypeRef);
+    assert(namedArgsLocal.type == translator.nullableObjectArrayTypeRef);
+
+    _verifyAssumptions(
+        b, closureLocal, typeArgsLocal, posArgsLocal, namedArgsLocal);
+
+    final vtableStruct = representation.vtableStruct;
+
+    // Downcast closure to this representation's closure type & get
+    // representation-specific vtable.
+    b.comment('Obtaining representation-specific vtable');
+    b.local_get(closureLocal);
+    b.ref_cast(w.RefType(representation.closureStruct, nullable: false));
+    b.struct_get(representation.closureStruct, FieldIndex.closureVtable);
+    final vtableVar = b.addLocal(w.RefType(vtableStruct, nullable: false));
+    b.local_set(vtableVar);
+
+    final typeStack = <w.ValueType>[];
+
+    // Load closure context.
+    b.comment('Loading closure.context');
+    b.local_get(closureLocal);
+    b.struct_get(translator.closureInfo.struct, FieldIndex.closureContext);
+    typeStack.add(w.RefType.struct(nullable: false));
+
+    // Load required type arguments.
+    for (int i = 0; i < representation.typeCount; ++i) {
+      b.comment('Loading type argument $i');
+      b.local_get(typeArgsLocal);
+      b.i32_const(i);
+      b.array_get(translator.typeArrayType);
+      typeStack.add(translator.translateType(translator.typeType));
+    }
+
+    // Load optional parameters.
+    if (representation.hasNamed) {
+      b.comment('Handle optional named parameters');
+      _handleOptionalNamedCase(b, closureLocal, typeArgsLocal, posArgsLocal,
+          namedArgsLocal, vtableVar, vtableStruct, typeStack);
+    } else {
+      b.comment('Handle optional positional parameters');
+      _handleOptionalPositionalCase(b, closureLocal, typeArgsLocal,
+          posArgsLocal, namedArgsLocal, vtableVar, vtableStruct, typeStack);
+    }
+
+    b.end(); // end function
+  }
+
+  void _handleOptionalPositionalCase(
+    w.InstructionsBuilder b,
+    w.Local closureLocal,
+    w.Local typeArgsLocal,
+    w.Local posArgsLocal,
+    w.Local namedArgsLocal,
+    w.Local vtableVar,
+    w.StructType vtableStruct,
+    List<w.ValueType> typeStack,
+  ) {
+    // Possibly variable number of positionals.
+    for (int i = 0; i <= representation.maxPositionalCount; ++i) {
+      b.comment('Check whether all positionals are loaded');
+      b.local_get(posArgsLocal);
+      b.array_len();
+      b.i32_const(i);
+      b.i32_eq();
+      b.if_(typeStack, typeStack);
+      b.comment('All positionals loaded, calling corresponding vtable entry');
+      b.local_get(vtableVar);
+      final index = representation.vtableBaseIndex + i;
+      b.struct_get(vtableStruct, index);
+      b.call_ref((vtableStruct.fields[index].type.unpacked as w.RefType)
+          .heapType as w.FunctionType);
+      b.return_();
+      b.end();
+
+      if (i <= representation.maxPositionalCount) {
+        // Otherwise load more arguments.
+        b.comment('Loading positional $i (optional)');
+        b.local_get(posArgsLocal);
+        b.i32_const(i);
+        b.array_get(translator.nullableObjectArrayType);
+        typeStack.add(translator.topType);
+      }
+    }
+
+    b.unreachable();
+  }
+
+  void _handleOptionalNamedCase(
+    w.InstructionsBuilder b,
+    w.Local closureLocal,
+    w.Local typeArgsLocal,
+    w.Local posArgsLocal,
+    w.Local namedArgsLocal,
+    w.Local vtableVar,
+    w.StructType vtableStruct,
+    List<w.ValueType> typeStack,
+  ) {
+    // All positionals are required, so load them.
+    for (int i = 0; i < representation.maxPositionalCount; ++i) {
+      b.comment('Loading positional $i (required)');
+      b.local_get(posArgsLocal);
+      b.i32_const(i);
+      b.array_get(translator.nullableObjectArrayType);
+      typeStack.add(translator.topType);
+    }
+
+    // Check for each name whether it's there or not.
+    final allCombinations = representation.nameCombinations.toList();
+    final sortedNames = allCombinations.expand((nc) => nc.names).toList()
+      ..sort();
+    final nameIndexVar = b.addLocal(w.NumType.i32);
+
+    void codeGenNamedHandling(
+        List<String> currentNames, List<w.ValueType> typeStack, int nameIndex) {
+      final currentCombination = NameCombination(currentNames);
+      final isValidCombination = currentNames.isEmpty ||
+          allCombinations.any((nc) => nc.compareTo(currentCombination) == 0);
+
+      if (isValidCombination) {
+        b.comment('Check whether all named are loaded');
+        b.local_get(namedArgsLocal);
+        b.array_len();
+        b.local_get(nameIndexVar);
+        b.i32_eq();
+        b.if_(typeStack, typeStack);
+        b.comment('All named loaded, calling corresponding vtable entry');
+        b.comment('(passed named arguments: ${currentNames.join('-')})');
+        final index = representation.fieldIndexForSignature(
+            representation.maxPositionalCount, currentNames);
+        b.local_get(vtableVar);
+        b.struct_get(vtableStruct, index);
+        b.call_ref((vtableStruct.fields[index].type.unpacked as w.RefType)
+            .heapType as w.FunctionType);
+        b.return_();
+        b.end();
+      } else {
+        if (util.compilerAssertsEnabled) {
+          b.comment('Check there are more names passed by the caller,');
+          b.comment('because the currently processed name set');
+          b.comment('(which are: ${currentNames.join('-')}) does not');
+          b.comment(' correspond to a valid name combination.');
+          b.local_get(namedArgsLocal);
+          b.array_len();
+          b.local_get(nameIndexVar);
+          b.i32_eq();
+          b.if_();
+          b.comment('Unsupported name combination.');
+          b.comment('Maybe bug in closure representation building');
+          b.unreachable();
+          b.end();
+        }
+      }
+
+      if (nameIndex == sortedNames.length) {
+        b.comment('More names passed then expected.');
+        b.unreachable();
+        return;
+      }
+
+      final newName = sortedNames[nameIndex];
+      final symbol = translator.symbols.symbolForNamedParameter(newName);
+
+      b.comment('Load next name and see if it corresponds to "$newName"');
+      b.local_get(namedArgsLocal);
+      b.local_get(nameIndexVar);
+      b.array_get(translator.nullableObjectArrayType);
+      translator.constants.instantiateConstant(b, symbol, translator.topType);
+      b.ref_eq();
+
+      b.if_(typeStack, typeStack);
+      {
+        b.comment('Name "$newName" was provided by caller. Loading its value.');
+        b.local_get(namedArgsLocal);
+        b.local_get(nameIndexVar);
+        b.i32_const(1);
+        b.i32_add();
+        b.array_get(translator.nullableObjectArrayType);
+
+        b.comment('Increment index in named argument array.');
+        b.local_get(nameIndexVar);
+        b.i32_const(2);
+        b.i32_add();
+        b.local_set(nameIndexVar);
+
+        codeGenNamedHandling([...currentNames, newName],
+            [...typeStack, translator.topType], nameIndex + 1);
+      }
+      b.end();
+
+      b.comment('Name "$newName" was *not* provided by caller.');
+      codeGenNamedHandling(currentNames, typeStack, nameIndex + 1);
+    }
+
+    codeGenNamedHandling([], typeStack, 0);
+  }
+
+  // This function is purely used for checking assumptions made by the code this
+  // generator is producing.
+  //
+  // Namely, we assume that the caller has
+  //   * populated default type arguments (if needed)
+  //   * checked the shape of arguments & closure matches
+  //   * performed necessary type checks on arguments.
+  void _verifyAssumptions(
+    w.InstructionsBuilder b,
+    w.Local closureLocal,
+    w.Local typeArgsLocal,
+    w.Local posArgsLocal,
+    w.Local namedArgsLocal,
+  ) {
+    if (!util.compilerAssertsEnabled) {
+      return;
+    }
+    b.comment('Verify assumptions of arguments and closure');
+    final functionTypeLocal =
+        b.addLocal(translator.closureLayouter.functionTypeType);
+    b.local_get(closureLocal);
+    b.struct_get(translator.closureLayouter.closureBaseStruct,
+        FieldIndex.closureRuntimeType);
+    b.local_tee(functionTypeLocal);
+
+    // Ensure type arguments were passed.
+    b.local_get(typeArgsLocal);
+    b.array_len();
+    b.i32_const(representation.typeCount);
+    b.i32_ne();
+    b.if_();
+    b.unreachable();
+    b.end();
+
+    // Ensure closure shape is correct.
+    b.local_get(typeArgsLocal);
+    b.local_get(posArgsLocal);
+    b.local_get(namedArgsLocal);
+    translator.callReference(translator.checkClosureShape.reference, b);
+    b.i32_eqz();
+    b.if_();
+    b.unreachable();
+    b.end();
+
+    // Ensure types are correct.
+    if (!translator.options.omitImplicitTypeChecks) {
+      b.local_get(functionTypeLocal);
+      b.local_get(typeArgsLocal);
+      b.local_get(posArgsLocal);
+      b.local_get(namedArgsLocal);
+      translator.callReference(translator.checkClosureType.reference, b);
+      b.drop();
+    }
+  }
+}
+
 class NodeCounter extends VisitorDefault<void> with VisitorVoidMixin {
   final bool omitCovarianceChecks;
   int count = 0;

diff --git a/pkg/dart2wasm/lib/util.dart b/pkg/dart2wasm/lib/util.dart
index 88ea5ff..fabda99 100644
--- a/pkg/dart2wasm/lib/util.dart
+++ b/pkg/dart2wasm/lib/util.dart

@@ -17,6 +17,12 @@
 import 'package:vm/metadata/table_selector.dart'
     show TableSelectorMetadataRepository;
 
+final bool compilerAssertsEnabled = (() {
+  bool compilerAsserts = false;
+  assert(compilerAsserts = true);
+  return compilerAsserts;
+})();
+
 bool hasPragma(CoreTypes coreTypes, Annotatable node, String name) {
   return getPragma(coreTypes, node, name, defaultValue: '') != null;
 }

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat
index 5afbaf4..bac3e34 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use.wat

@@ -15,8 +15,8 @@
   (type $type1 (func 
     (param $var0 i32)
     (result (ref $MyConstClass))))
-  (global $"C370 \"bad\"" (ref $JSStringImpl) <...>)
   (table $static0-0 (export "static0-0") 2 (ref null $type1))
+  (global $"C370 \"bad\"" (ref $JSStringImpl) <...>)
   (func $Error._throwWithCurrentStackTrace (param $var0 (ref $#Top)) <...>)
   (func $"mainImpl <noInline>" (param $var0 i32)
     (local $var1 (ref $MyConstClass))

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat
index 4a7e2f6..84f328a 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module1.wat

@@ -14,8 +14,8 @@
     (field $b (ref $JSStringImpl)))))
   (global $S.h1-nonshared-const (import "S" "h1-nonshared-const") (ref extern))
   (global $S.shared-const (import "S" "shared-const") (ref extern))
-  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $JSStringImpl) <...>)
-  (table $module0.constant-table1 (import "module0" "constant-table1") 1 (ref null $MyConstClass) <...>)
+  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $JSStringImpl))
+  (table $module0.constant-table1 (import "module0" "constant-table1") 1 (ref null $MyConstClass))
   (global $"C488 MyConstClass" (ref $MyConstClass)
     (i32.const 107)
     (i32.const 0)

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat
index 396d683..3bcd37f 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.multi_module_use_module3.wat

@@ -14,8 +14,8 @@
     (field $b (ref $JSStringImpl)))))
   (global $S.shared-const (import "S" "shared-const") (ref extern))
   (global $S.h0-nonshared-const (import "S" "h0-nonshared-const") (ref extern))
-  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $JSStringImpl) <...>)
-  (table $module0.constant-table1 (import "module0" "constant-table1") 1 (ref null $MyConstClass) <...>)
+  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $JSStringImpl))
+  (table $module0.constant-table1 (import "module0" "constant-table1") 1 (ref null $MyConstClass))
   (global $"C492 MyConstClass" (ref $MyConstClass)
     (i32.const 107)
     (i32.const 0)

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant.wat
index 11686f7..8b4a8b2 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant.wat

@@ -6,12 +6,12 @@
     (field $field0 i32)
     (field $field1 (mut i32))
     (field $fun (ref $#Closure-0-1)))))
-  (type $type245 <...>)
-  (type $type248 <...>)
-  (type $type251 <...>)
-  (table $static1-0 (export "static1-0") 1 (ref null $type251))
-  (table $static2-0 (export "static2-0") 1 (ref null $type245))
-  (table $static3-0 (export "static3-0") 1 (ref null $type248))
+  (type $type236 <...>)
+  (type $type239 <...>)
+  (type $type242 <...>)
+  (table $static1-0 (export "static1-0") 1 (ref null $type242))
+  (table $static2-0 (export "static2-0") 1 (ref null $type236))
+  (table $static3-0 (export "static3-0") 1 (ref null $type239))
   (func $print (param $var0 (ref null $#Top)) (result (ref null $#Top)) <...>)
   (func $"modMainUseH0 <noInline>"
     i64.const 0

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat
index 6675b56..ff3b77c 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant_module1.wat

@@ -5,7 +5,7 @@
   (type $_Type <...>)
   (type $Array<_Type> <...>)
   (type $JSStringImpl <...>)
-  (type $type20 <...>)
+  (type $type21 <...>)
   (type $_TopType <...>)
   (type $Array<_NamedParameter> <...>)
   (type $_FunctionType <...>)
@@ -31,7 +31,7 @@
   (global $"C306 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
   (global $"C28 _InterfaceType" (import "module0" "global7") (ref $_InterfaceType))
   (global $S.globalH1Bar< (import "S" "globalH1Bar<") (ref extern))
-  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType) <...>)
+  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType))
   (global $global7 (ref $#Vtable-1-1) <...>)
   (global $global4 (ref $#DummyStruct) <...>)
   (global $"C459 _FunctionType" (ref $_FunctionType) <...>)
@@ -70,42 +70,39 @@
     local.get $var0
     struct.get $#Closure-0-1 $vtable
     struct.get $#Vtable-0-1 $closureCallEntry-0-1
-    call_ref $type20
+    call_ref $type21
     drop
     ref.null none
   )
-  (func $globalH1Foo (param $var0 (ref $_Type)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
+  (func $"globalH1Foo tear-off trampoline" (param $var0 (ref struct)) (param $var1 (ref $_Type)) (param $var2 (ref null $#Top)) (result (ref null $#Top))
     global.get $"C463 \"globalH1Bar<\""
-    local.get $var0
-    global.get $"C464 \">(\""
     local.get $var1
+    global.get $"C464 \">(\""
+    local.get $var2
     global.get $"C21 \")\""
     array.new_fixed $Array<Object?> 5
     call $JSStringImpl._interpolate
     call $print
   )
-  (func $"globalH1Foo tear-off dynamic call entry" (param $var0 (ref $#ClosureBase)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top))
-    local.get $var1
+  (func $"C460 globalH1Foo tear-off (lazy initializer)}" (result (ref $#Closure-1-1))
+    (local $var0 (ref $#Closure-1-1))
+    i32.const 37
     i32.const 0
-    array.get $Array<_Type>
-    local.get $var2
-    i32.const 0
-    array.get $Array<Object?>
-    call $globalH1Foo
-  )
-  (func $"globalH1Foo tear-off trampoline" (param $var0 (ref struct)) (param $var1 (ref $_Type)) (param $var2 (ref null $#Top)) (result (ref null $#Top))
-    local.get $var1
-    local.get $var2
-    call $globalH1Foo
+    global.get $global4
+    global.get $global7
+    global.get $"C459 _FunctionType"
+    struct.new $#Closure-1-1
+    local.tee $var0
+    global.set $"C460 globalH1Foo tear-off"
+    local.get $var0
   )
   (func $dynamic call entry (param $var0 (ref $#ClosureBase)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top)) <...>)
   (func $#dummy function (ref struct) -> (ref null #Top) (param $var0 (ref struct)) (result (ref null $#Top)) <...>)
   (func $instantiation constant trampoline (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top)) <...>)
   (func $"C462 H1 (lazy initializer)}" (result (ref $H1))
-    (local $var0 (ref $#Closure-1-1))
-    (local $var1 (ref $_FunctionType))
-    (local $var2 (ref $#Closure-0-1))
-    (local $var3 (ref $H1))
+    (local $var0 (ref $_FunctionType))
+    (local $var1 (ref $#Closure-0-1))
+    (local $var2 (ref $H1))
     i32.const 105
     i32.const 0
     block $label0 (result (ref $#Closure-0-1))
@@ -116,15 +113,7 @@
       block $label1 (result (ref $#Closure-1-1))
         global.get $"C460 globalH1Foo tear-off"
         br_on_non_null $label1
-        i32.const 37
-        i32.const 0
-        global.get $global4
-        global.get $global7
-        global.get $"C459 _FunctionType"
-        struct.new $#Closure-1-1
-        local.tee $var0
-        global.set $"C460 globalH1Foo tear-off"
-        local.get $var0
+        call $"C460 globalH1Foo tear-off (lazy initializer)}"
       end $label1
       global.get $"C28 _InterfaceType"
       struct.new $#InstantiationContext-1-1
@@ -148,18 +137,18 @@
         i64.const 1
         global.get $"C306 WasmArray<_NamedParameter>[0]"
         struct.new $_FunctionType
-        local.tee $var1
+        local.tee $var0
         table.set $module0.constant-table0
-        local.get $var1
+        local.get $var0
       end $label2
       struct.new $#Closure-0-1
-      local.tee $var2
+      local.tee $var1
       global.set $"C461 InstantiationConstant(globalH1Foo<int>)"
-      local.get $var2
+      local.get $var1
     end $label0
     struct.new $H1
-    local.tee $var3
+    local.tee $var2
     global.set $"C462 H1"
-    local.get $var3
+    local.get $var2
   )
 )
\ No newline at end of file

diff --git a/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat b/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat
index cc2df20..564b714 100644
--- a/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat
+++ b/pkg/dart2wasm/test/ir_tests/deferred.constant_module2.wat

@@ -1,12 +1,10 @@
 (module $module2
   (type $#Top <...>)
   (type $Object <...>)
-  (type $Array<Object?> <...>)
-  (type $JSStringImpl <...>)
   (type $Array<_Type> <...>)
+  (type $JSStringImpl <...>)
   (type $Array<_NamedParameter> <...>)
   (type $_FunctionType <...>)
-  (type $#ClosureBase <...>)
   (type $#Vtable-0-1 <...>)
   (type $#Closure-0-1 <...>)
   (type $H0 (sub final $Object (struct
@@ -21,7 +19,7 @@
   (global $"C62 WasmArray<_Type>[1]" (import "module0" "global3") (ref $Array<_Type>))
   (global $"C306 WasmArray<_NamedParameter>[0]" (import "module0" "global4") (ref $Array<_NamedParameter>))
   (global $S.globalH0Foo (import "S" "globalH0Foo") (ref extern))
-  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType) <...>)
+  (table $module0.constant-table0 (import "module0" "constant-table0") 1 (ref null $_FunctionType))
   (global $global6 (ref $#Vtable-0-1) <...>)
   (global $global3 (ref $#DummyStruct) <...>)
   (global $"C465 globalH0Foo tear-off" (mut (ref null $#Closure-0-1))
@@ -37,10 +35,6 @@
     global.get $"C467 \"globalH0Foo\""
     call $print
   )
-  (func $"globalH0Foo tear-off dynamic call entry" (param $var0 (ref $#ClosureBase)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top))
-    global.get $"C467 \"globalH0Foo\""
-    call $print
-  )
   (func $"globalH0Foo tear-off trampoline" (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top))
     global.get $"C467 \"globalH0Foo\""
     call $print

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure.dart b/pkg/dart2wasm/test/ir_tests/dyn_closure.dart
new file mode 100644
index 0000000..a5fe2d7
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure.dart

@@ -0,0 +1,35 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// typeFilter=Closure-0-2|Vtable-0-2
+// functionFilter=XXX
+// globalFilter=foo|bar
+
+void main() {
+  final objects = <dynamic>[
+    () {},
+    foo,
+    bar,
+    'a',
+    1,
+  ];
+  final emptyClosure = objects[0];
+  final fooClosure = objects[1];
+  final barClosure = objects[2];
+  emptyClosure();
+  fooClosure(1);
+  fooClosure(1, 'b');
+  barClosure(1, 2);
+  barClosure(1, 2);
+}
+
+@pragma('wasm:never-inline')
+void foo(int a, [String? b]) {
+  print('Foo $a $b');
+}
+
+@pragma('wasm:never-inline')
+void bar(int a, [int? b]) {
+  print('Bar $a $b');
+}

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure.wat
new file mode 100644
index 0000000..c578f3e
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure.wat

@@ -0,0 +1,89 @@
+(module $module0
+  (type $#Top <...>)
+  (type $Array<_Type> <...>)
+  (type $Array<Object?> <...>)
+  (type $_InterfaceType <...>)
+  (type $Array<_NamedParameter> <...>)
+  (type $_FunctionType <...>)
+  (rec
+    (type $#Closure-0-0 <...>)
+    (type $type9 <...>)
+    (type $#Vtable-0-0 <...>)
+  )
+  (type $type15 <...>)
+  (type $_TopType <...>)
+  (type $type12 <...>)
+  (type $#Vtable-0-2 (sub final $#Vtable-0-0 (struct
+    (field $dynamiClosureCallEntry (ref $type9))
+    (field $closureCallEntry-0-1 (ref $type12))
+    (field $closureCallEntry-0-2 (ref $type15)))))
+  (type $#Closure-0-2 (sub final $#Closure-0-0 (struct
+    (field $field0 i32)
+    (field $field1 (mut i32))
+    (field $context (ref struct))
+    (field $vtable (ref $#Vtable-0-2))
+    (field $functionType (ref $_FunctionType)))))
+  (type $#DummyStruct <...>)
+  (global $global3 (ref $#DummyStruct) <...>)
+  (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
+  (global $"C15 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C303 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C329 _TopType" (ref $_TopType) <...>)
+  (global $"C333 foo tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"closure arguments dispatcher representation=0-2")
+    (ref.func $"foo tear-off trampoline")
+    (ref.func $"foo tear-off trampoline_303")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (i32.const 10)
+    (i32.const 0)
+    (i32.const 1)
+    (i32.const 131)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (struct.new $_InterfaceType)
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (global $"C337 bar tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"closure arguments dispatcher representation=0-2")
+    (ref.func $"bar tear-off trampoline")
+    (ref.func $"bar tear-off trampoline_306")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (i32.const 10)
+    (i32.const 0)
+    (i32.const 1)
+    (i32.const 124)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (struct.new $_InterfaceType)
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (func $closure arguments dispatcher representation=0-2 (param $var0 (ref $#Closure-0-0)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top)) <...>)
+  (func $foo tear-off trampoline (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $foo tear-off trampoline_303 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off trampoline (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off trampoline_306 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+)
\ No newline at end of file

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.dart b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.dart
new file mode 100644
index 0000000..6145afd
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// typeFilter=Closure-0-2|Vtable-0-2
+// functionFilter=XXX
+// globalFilter=foo|bar
+
+void main() {
+  Function.apply(() {}, []);
+  Function.apply(foo, [1]);
+  Function.apply(foo, [1, 'b']);
+  Function.apply(bar, [1]);
+  Function.apply(bar, [1, 2]);
+}
+
+@pragma('wasm:never-inline')
+void foo(int a, [String? b]) {
+  print('Foo $a $b');
+}
+
+@pragma('wasm:never-inline')
+void bar(int a, [int? b]) {
+  print('Bar $a $b');
+}

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat
new file mode 100644
index 0000000..31b9cc9
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply.wat

@@ -0,0 +1,89 @@
+(module $module0
+  (type $#Top <...>)
+  (type $Array<_Type> <...>)
+  (type $Array<Object?> <...>)
+  (type $_InterfaceType <...>)
+  (type $Array<_NamedParameter> <...>)
+  (type $_FunctionType <...>)
+  (rec
+    (type $#Closure-0-0 <...>)
+    (type $type9 <...>)
+    (type $#Vtable-0-0 <...>)
+  )
+  (type $type15 <...>)
+  (type $_TopType <...>)
+  (type $type12 <...>)
+  (type $#Vtable-0-2 (sub final $#Vtable-0-0 (struct
+    (field $dynamiClosureCallEntry (ref $type9))
+    (field $closureCallEntry-0-1 (ref $type12))
+    (field $closureCallEntry-0-2 (ref $type15)))))
+  (type $#Closure-0-2 (sub final $#Closure-0-0 (struct
+    (field $field0 i32)
+    (field $field1 (mut i32))
+    (field $context (ref struct))
+    (field $vtable (ref $#Vtable-0-2))
+    (field $functionType (ref $_FunctionType)))))
+  (type $#DummyStruct <...>)
+  (global $global3 (ref $#DummyStruct) <...>)
+  (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
+  (global $"C15 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C303 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C329 _TopType" (ref $_TopType) <...>)
+  (global $"C333 foo tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"closure arguments dispatcher representation=0-2")
+    (ref.func $"foo tear-off trampoline")
+    (ref.func $"foo tear-off trampoline_303")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (i32.const 10)
+    (i32.const 0)
+    (i32.const 1)
+    (i32.const 131)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (struct.new $_InterfaceType)
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (global $"C338 bar tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"closure arguments dispatcher representation=0-2")
+    (ref.func $"bar tear-off trampoline")
+    (ref.func $"bar tear-off trampoline_308")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (i32.const 10)
+    (i32.const 0)
+    (i32.const 1)
+    (i32.const 124)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (struct.new $_InterfaceType)
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (func $closure arguments dispatcher representation=0-2 (param $var0 (ref $#Closure-0-0)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top)) <...>)
+  (func $foo tear-off trampoline (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $foo tear-off trampoline_303 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off trampoline (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off trampoline_308 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+)
\ No newline at end of file

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.dart b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.dart
new file mode 100644
index 0000000..e4530b7
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// typeFilter=Closure-0-2|Vtable-0-2
+// functionFilter=XXX
+// globalFilter=foo|bar
+
+void main() {
+  Function.apply(() {}, []);
+  Function.apply(foo, [1]);
+  Function.apply(foo, [1, 'b']);
+  Function.apply(bar, [1]);
+  Function.apply((int a, {int? n}) {}, [1], {#n: 1});
+}
+
+@pragma('wasm:never-inline')
+void foo(int a, [String? b]) {
+  print('Foo $a $b');
+}
+
+@pragma('wasm:never-inline')
+void bar(int a, [int? b]) {
+  print('Bar $a $b');
+}

diff --git a/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat
new file mode 100644
index 0000000..3b95c1c
--- /dev/null
+++ b/pkg/dart2wasm/test/ir_tests/dyn_closure_function_apply_named.wat

@@ -0,0 +1,80 @@
+(module $module0
+  (type $#Top <...>)
+  (type $Array<Object?> <...>)
+  (type $Array<_Type> <...>)
+  (type $_InterfaceType <...>)
+  (type $type6 <...>)
+  (type $Array<_NamedParameter> <...>)
+  (type $_FunctionType <...>)
+  (rec
+    (type $#Closure-0-0 <...>)
+    (type $type3 <...>)
+    (type $#Vtable-0-0 <...>)
+  )
+  (type $#Vtable-0-2 (sub final $#Vtable-0-0 (struct
+    (field $dynamiClosureCallEntry (ref $type3))
+    (field $closureCallEntry-0-2 (ref $type6)))))
+  (type $#Closure-0-2 (sub final $#Closure-0-0 (struct
+    (field $field0 i32)
+    (field $field1 (mut i32))
+    (field $context (ref struct))
+    (field $vtable (ref $#Vtable-0-2))
+    (field $functionType (ref $_FunctionType)))))
+  (type $_TopType <...>)
+  (type $#DummyStruct <...>)
+  (global $global3 (ref $#DummyStruct) <...>)
+  (global $"C1 WasmArray<_Type>[0]" (ref $Array<_Type>) <...>)
+  (global $"C15 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C303 WasmArray<_NamedParameter>[0]" (ref $Array<_NamedParameter>) <...>)
+  (global $"C329 _TopType" (ref $_TopType) <...>)
+  (global $"C333 foo tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"foo tear-off dynamic call entry")
+    (ref.func $"foo tear-off trampoline_307")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (i32.const 10)
+    (i32.const 0)
+    (i32.const 1)
+    (i32.const 131)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (struct.new $_InterfaceType)
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (global $"C335 _InterfaceType" (ref $_InterfaceType) <...>)
+  (global $"C338 bar tear-off" (ref $#Closure-0-2)
+    (i32.const 51)
+    (i32.const 0)
+    (global.get $global3)
+    (ref.func $"bar tear-off dynamic call entry")
+    (ref.func $"bar tear-off trampoline_313")
+    (struct.new $#Vtable-0-2)
+    (i32.const 12)
+    (i32.const 0)
+    (i32.const 0)
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C1 WasmArray<_Type>[0]")
+    (global.get $"C329 _TopType")
+    (global.get $"C15 _InterfaceType")
+    (global.get $"C335 _InterfaceType")
+    (array.new_fixed $Array<_Type> 2)
+    (i64.const 1)
+    (global.get $"C303 WasmArray<_NamedParameter>[0]")
+    (struct.new $_FunctionType)
+    (struct.new $#Closure-0-2))
+  (func $foo tear-off dynamic call entry (param $var0 (ref $#Closure-0-0)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top)) <...>)
+  (func $foo tear-off trampoline_307 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off dynamic call entry (param $var0 (ref $#Closure-0-0)) (param $var1 (ref $Array<_Type>)) (param $var2 (ref $Array<Object?>)) (param $var3 (ref $Array<Object?>)) (result (ref null $#Top)) <...>)
+  (func $bar tear-off trampoline_313 (param $var0 (ref struct)) (param $var1 (ref null $#Top)) (param $var2 (ref null $#Top)) (result (ref null $#Top)) <...>)
+)
\ No newline at end of file

diff --git a/pkg/dart2wasm/test/ir_tests/interop.num.wat b/pkg/dart2wasm/test/ir_tests/interop.num.wat
index c1ed442..3b5944f 100644
--- a/pkg/dart2wasm/test/ir_tests/interop.num.wat
+++ b/pkg/dart2wasm/test/ir_tests/interop.num.wat

@@ -18,6 +18,7 @@
   (func $"dart2wasm._275 (import)" (import "dart2wasm" "_275") (param externref) (result externref))
   (func $"dart2wasm._147 (import)" (import "dart2wasm" "_147") (param externref) (result f64))
   (func $"dart2wasm._148 (import)" (import "dart2wasm" "_148") (param f64) (result externref))
+  (table $dtable1 666 funcref)
   (global $"C66 WasmArray<WasmArray<_Type>>[727]" (ref $Array<WasmArray<_Type>>) <...>)
   (global $"C311 _TopType" (ref $_TopType) <...>)
   (global $"numValueNullable initialized" (mut i32) <...>)
@@ -25,7 +26,7 @@
   (global $"ktrue initialized" (mut i32) <...>)
   (global $ktrue (mut i32) <...>)
   (global $numValue (mut (ref null $#Top)) <...>)
-  (table $dtable2 666 funcref <...>)
+  (elem $dtable1 <...>)
   (func $_TypeUniverse.isSubtype (param $var0 (ref $_Type)) (param $var1 (ref null $_Environment)) (param $var2 (ref $_Type)) (param $var3 (ref null $_Environment)) (result i32) <...>)
   (func $_TypeUniverse._checkSubclassRelationshipViaTable (param $var0 i32) (param $var1 i32) (result i32) <...>)
   (func $_TypeUniverse.substituteTypeArgument (param $var0 (ref $_Type)) (param $var1 (ref $Array<_Type>)) (result (ref $_Type)) <...>)

diff --git a/pkg/front_end/lib/src/source/diet_listener.dart b/pkg/front_end/lib/src/source/diet_listener.dart
index 2fb2dc5..84680e0 100644
--- a/pkg/front_end/lib/src/source/diet_listener.dart
+++ b/pkg/front_end/lib/src/source/diet_listener.dart

@@ -1214,6 +1214,22 @@
   }
 
   @override
+  // Coverage-ignore(suite): Not run.
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    debugEvent("endPrimaryConstructorBody");
+    assert(
+      checkState(beginToken, [/* metadata token */ ValueKinds.TokenOrNull]),
+    );
+    // TODO(declaring-constructors): Implement primary constructor body.
+    pop() as Token?;
+    checkEmpty(beginToken.charOffset);
+  }
+
+  @override
   void endExtensionTypeDeclaration(
     Token beginToken,
     Token? augmentToken,

diff --git a/pkg/front_end/lib/src/source/outline_builder.dart b/pkg/front_end/lib/src/source/outline_builder.dart
index c54bc48..3352eeb 100644
--- a/pkg/front_end/lib/src/source/outline_builder.dart
+++ b/pkg/front_end/lib/src/source/outline_builder.dart

@@ -1961,6 +1961,31 @@
   }
 
   @override
+  // Coverage-ignore(suite): Not run.
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    debugEvent("endPrimaryConstructorBody");
+    assert(
+      checkState(beginToken, [
+        ValueKinds.MethodBody,
+        ValueKinds.AsyncModifier,
+        ValueKinds.MetadataListOrNull,
+      ]),
+    );
+
+    // TODO(declaring-constructors): Implement primary constructor body.
+    // ignore: unused_local_variable
+    MethodBody bodyKind = pop() as MethodBody;
+    // ignore: unused_local_variable
+    AsyncMarker asyncModifier = pop() as AsyncMarker;
+    // ignore: unused_local_variable
+    List<MetadataBuilder>? metadata = pop() as List<MetadataBuilder>?;
+  }
+
+  @override
   void beginTopLevelMethod(
     Token lastConsumed,
     Token? augmentToken,

diff --git a/pkg/front_end/lib/src/util/parser_ast.dart b/pkg/front_end/lib/src/util/parser_ast.dart
index 45a20b2..9faa804 100644
--- a/pkg/front_end/lib/src/util/parser_ast.dart
+++ b/pkg/front_end/lib/src/util/parser_ast.dart

@@ -1533,6 +1533,18 @@
     if (child is EnumFactoryMethodEnd) return child;
     throw "Not found";
   }
+
+  bool isPrimaryConstructorBody() {
+    ParserAstNode child = children![1];
+    if (child is PrimaryConstructorBodyEnd) return true;
+    return false;
+  }
+
+  PrimaryConstructorBodyEnd getPrimaryConstructorBody() {
+    ParserAstNode child = children![1];
+    if (child is PrimaryConstructorBodyEnd) return child;
+    throw "Not found";
+  }
 }
 
 // Coverage-ignore(suite): Not run.

diff --git a/pkg/front_end/lib/src/util/parser_ast_helper.dart b/pkg/front_end/lib/src/util/parser_ast_helper.dart
index e369359..6a0d52c 100644
--- a/pkg/front_end/lib/src/util/parser_ast_helper.dart
+++ b/pkg/front_end/lib/src/util/parser_ast_helper.dart

@@ -549,6 +549,30 @@
   }
 
   @override
+  void beginPrimaryConstructorBody(Token token) {
+    PrimaryConstructorBodyBegin data = new PrimaryConstructorBodyBegin(
+      ParserAstType.BEGIN,
+      token: token,
+    );
+    seen(data);
+  }
+
+  @override
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    PrimaryConstructorBodyEnd data = new PrimaryConstructorBodyEnd(
+      ParserAstType.END,
+      beginToken: beginToken,
+      beginInitializers: beginInitializers,
+      endToken: endToken,
+    );
+    seen(data);
+  }
+
+  @override
   void beginCombinators(Token token) {
     CombinatorsBegin data = new CombinatorsBegin(
       ParserAstType.BEGIN,
@@ -5082,6 +5106,46 @@
   R accept<R>(ParserAstVisitor<R> v) => v.visitNoPrimaryConstructorHandle(this);
 }
 
+class PrimaryConstructorBodyBegin extends ParserAstNode {
+  final Token token;
+
+  PrimaryConstructorBodyBegin(ParserAstType type, {required this.token})
+    : super("PrimaryConstructorBody", type);
+
+  @override
+  Map<String, Object?> get deprecatedArguments => {"token": token};
+
+  @override
+  R accept<R>(ParserAstVisitor<R> v) =>
+      v.visitPrimaryConstructorBodyBegin(this);
+}
+
+class PrimaryConstructorBodyEnd extends ParserAstNode
+    implements BeginAndEndTokenParserAstNode {
+  @override
+  final Token beginToken;
+  final Token? beginInitializers;
+  @override
+  final Token endToken;
+
+  PrimaryConstructorBodyEnd(
+    ParserAstType type, {
+    required this.beginToken,
+    this.beginInitializers,
+    required this.endToken,
+  }) : super("PrimaryConstructorBody", type);
+
+  @override
+  Map<String, Object?> get deprecatedArguments => {
+    "beginToken": beginToken,
+    "beginInitializers": beginInitializers,
+    "endToken": endToken,
+  };
+
+  @override
+  R accept<R>(ParserAstVisitor<R> v) => v.visitPrimaryConstructorBodyEnd(this);
+}
+
 class CombinatorsBegin extends ParserAstNode {
   final Token token;
 
@@ -11379,6 +11443,8 @@
   R visitPrimaryConstructorBegin(PrimaryConstructorBegin node);
   R visitPrimaryConstructorEnd(PrimaryConstructorEnd node);
   R visitNoPrimaryConstructorHandle(NoPrimaryConstructorHandle node);
+  R visitPrimaryConstructorBodyBegin(PrimaryConstructorBodyBegin node);
+  R visitPrimaryConstructorBodyEnd(PrimaryConstructorBodyEnd node);
   R visitCombinatorsBegin(CombinatorsBegin node);
   R visitCombinatorsEnd(CombinatorsEnd node);
   R visitCompilationUnitBegin(CompilationUnitBegin node);
@@ -11918,6 +11984,14 @@
       node.visitChildren(this);
 
   @override
+  void visitPrimaryConstructorBodyBegin(PrimaryConstructorBodyBegin node) =>
+      node.visitChildren(this);
+
+  @override
+  void visitPrimaryConstructorBodyEnd(PrimaryConstructorBodyEnd node) =>
+      node.visitChildren(this);
+
+  @override
   void visitCombinatorsBegin(CombinatorsBegin node) => node.visitChildren(this);
 
   @override
@@ -13385,6 +13459,15 @@
   ) => defaultNode(node);
 
   @override
+  Future<void> visitPrimaryConstructorBodyBegin(
+    PrimaryConstructorBodyBegin node,
+  ) => defaultNode(node);
+
+  @override
+  Future<void> visitPrimaryConstructorBodyEnd(PrimaryConstructorBodyEnd node) =>
+      defaultNode(node);
+
+  @override
   Future<void> visitCombinatorsBegin(CombinatorsBegin node) =>
       defaultNode(node);
 

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart
new file mode 100644
index 0000000..eb93361
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart

@@ -0,0 +1,15 @@
+class C1() {
+  this {}
+}
+
+class C2() {
+  this : assert(1 > 2) {}
+}
+
+class C3() {
+  this;
+}
+
+class C4() {
+  this : assert(1 > 2);
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.expect
new file mode 100644
index 0000000..900ec45
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.expect

@@ -0,0 +1,134 @@
+beginCompilationUnit(class)
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C1, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C2, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C3, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C4, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.intertwined.expect
new file mode 100644
index 0000000..0d49641
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.intertwined.expect

@@ -0,0 +1,264 @@
+parseUnit(class)
+  skipErrorTokens(class)
+  listener: beginCompilationUnit(class)
+  syntheticPreviousToken(class)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, , class, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C1, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C1)
+        parseClass(C1, class, class, null, C1)
+          parsePrimaryConstructorOpt(C1, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C1, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C1)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C1)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt(this)
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(this, false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endPrimaryConstructorBody(this, this, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C2, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C2)
+        parseClass(C2, class, class, null, C2)
+          parsePrimaryConstructorOpt(C2, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C2, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C2)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C2)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endPrimaryConstructorBody(this, this, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C3, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C3)
+        parseClass(C3, class, class, null, C3)
+          parsePrimaryConstructorOpt(C3, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C3, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C3)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C3)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt(this)
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(this, false, true)
+                  listener: handleEmptyFunctionBody(;)
+                listener: endPrimaryConstructorBody(this, this, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C4, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C4)
+        parseClass(C4, class, class, null, C4)
+          parsePrimaryConstructorOpt(C4, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C4, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C4)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C4)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                listener: endPrimaryConstructorBody(this, this, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(class)
+  listener: endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.parser.expect
new file mode 100644
index 0000000..a66ca35
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.parser.expect

@@ -0,0 +1,33 @@
+class C1() {
+this {}
+}
+
+class C2() {
+this : assert(1 > 2) {}
+}
+
+class C3() {
+this;
+}
+
+class C4() {
+this : assert(1 > 2);
+}
+
+
+class[KeywordToken] C1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.scanner.expect
new file mode 100644
index 0000000..a66ca35
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body.dart.scanner.expect

@@ -0,0 +1,33 @@
+class C1() {
+this {}
+}
+
+class C2() {
+this : assert(1 > 2) {}
+}
+
+class C3() {
+this;
+}
+
+class C4() {
+this : assert(1 > 2);
+}
+
+
+class[KeywordToken] C1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart
new file mode 100644
index 0000000..2ab967e
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart

@@ -0,0 +1,15 @@
+class C1() {
+  this() {}
+}
+
+class C2() {
+  this(int x) : assert(1 > 2) {}
+}
+
+class C3() {
+  this();
+}
+
+class C4() {
+  this(int x) : assert(1 > 2);
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.expect
new file mode 100644
index 0000000..d856662
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.expect

@@ -0,0 +1,204 @@
+Problems reported:
+
+parser/declaring_constructors/class_primary_constructor_body_error:2:3: 'this' can't be used as an identifier because it's a keyword.
+  this() {}
+  ^^^^
+
+parser/declaring_constructors/class_primary_constructor_body_error:6:3: 'this' can't be used as an identifier because it's a keyword.
+  this(int x) : assert(1 > 2) {}
+  ^^^^
+
+parser/declaring_constructors/class_primary_constructor_body_error:6:3: The name of a constructor must match the name of the enclosing class.
+  this(int x) : assert(1 > 2) {}
+  ^^^^
+
+parser/declaring_constructors/class_primary_constructor_body_error:10:3: 'this' can't be used as an identifier because it's a keyword.
+  this();
+  ^^^^
+
+parser/declaring_constructors/class_primary_constructor_body_error:14:3: 'this' can't be used as an identifier because it's a keyword.
+  this(int x) : assert(1 > 2);
+  ^^^^
+
+parser/declaring_constructors/class_primary_constructor_body_error:14:3: The name of a constructor must match the name of the enclosing class.
+  this(int x) : assert(1 > 2);
+  ^^^^
+
+beginCompilationUnit(class)
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C1, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C1)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.NonStaticMethod)
+            endFormalParameters(0, (, ), MemberKind.NonStaticMethod)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endClassMethod(null, this, (, null, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C2, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C2)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.NonStaticMethod)
+              beginMetadataStar(int)
+              endMetadataStar(0)
+              beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                handleIdentifier(int, typeReference)
+                handleNoTypeArguments(x)
+                handleType(int, null)
+                handleIdentifier(x, formalParameterDeclaration)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+            handleRecoverableError(ConstructorWithWrongName, this, this)
+          endClassConstructor(null, this, (, :, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C3, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C3)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.NonStaticMethod)
+            endFormalParameters(0, (, ), MemberKind.NonStaticMethod)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endClassMethod(null, this, (, null, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(class)
+  endMetadataStar(0)
+  beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+    handleIdentifier(C4, classOrMixinDeclaration)
+    handleNoTypeVariables(()
+    beginClassDeclaration(class, null, null, null, null, null, null, null, null, C4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, false)
+      handleNoType())
+      handleClassExtends(null, 1)
+      handleClassNoWithClause()
+      handleImplements(null, 0)
+      handleClassHeader(class, class, null)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C4)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.NonStaticMethod)
+              beginMetadataStar(int)
+              endMetadataStar(0)
+              beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                handleIdentifier(int, typeReference)
+                handleNoTypeArguments(x)
+                handleType(int, null)
+                handleIdentifier(x, formalParameterDeclaration)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+            handleRecoverableError(ConstructorWithWrongName, this, this)
+          endClassConstructor(null, this, (, :, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+    endClassDeclaration(class, })
+  endTopLevelDeclaration(})
+endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.intertwined.expect
new file mode 100644
index 0000000..d38204b
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.intertwined.expect

@@ -0,0 +1,344 @@
+parseUnit(class)
+  skipErrorTokens(class)
+  listener: beginCompilationUnit(class)
+  syntheticPreviousToken(class)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, , class, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C1, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C1)
+        parseClass(C1, class, class, null, C1)
+          parsePrimaryConstructorOpt(C1, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C1, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C1)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C1)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.Class, C1, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C1)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(0, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endClassMethod(null, this, (, null, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C2, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C2)
+        parseClass(C2, class, class, null, C2)
+          parsePrimaryConstructorOpt(C2, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C2, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C2)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C2)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.Class, C2, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C2)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(int)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                        listener: handleIdentifier(int, typeReference)
+                        listener: handleNoTypeArguments(x)
+                        listener: handleType(int, null)
+                        ensureIdentifier(int, formalParameterDeclaration)
+                          listener: handleIdentifier(x, formalParameterDeclaration)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                reportRecoverableError(this, ConstructorWithWrongName)
+                  listener: handleRecoverableError(ConstructorWithWrongName, this, this)
+                listener: endClassConstructor(null, this, (, :, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C3, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C3)
+        parseClass(C3, class, class, null, C3)
+          parsePrimaryConstructorOpt(C3, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C3, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C3)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C3)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.Class, C3, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C3)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(0, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                listener: endClassMethod(null, this, (, null, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(class)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(class, }, class, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseClassOrNamedMixinApplication(class, null, null, null, null, null, null, null, null, class)
+        listener: beginClassOrMixinOrNamedMixinApplicationPrelude(class)
+        ensureIdentifier(class, classOrMixinDeclaration)
+          listener: handleIdentifier(C4, classOrMixinDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginClassDeclaration(class, null, null, null, null, null, null, null, null, C4)
+        parseClass(C4, class, class, null, C4)
+          parsePrimaryConstructorOpt(C4, null, false)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(C4, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, false)
+          parseClassHeaderOpt(), class, class)
+            parseClassExtendsOpt(), DeclarationHeaderKind.Class)
+              listener: handleNoType())
+              listener: handleClassExtends(null, 1)
+            parseClassWithClauseOpt())
+              listener: handleClassNoWithClause()
+            parseClassOrMixinOrEnumImplementsOpt())
+              listener: handleImplements(null, 0)
+            listener: handleClassHeader(class, class, null)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.Class, C4)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.Class, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.Class, C4)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.Class, C4, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, C4)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(int)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                        listener: handleIdentifier(int, typeReference)
+                        listener: handleNoTypeArguments(x)
+                        listener: handleType(int, null)
+                        ensureIdentifier(int, formalParameterDeclaration)
+                          listener: handleIdentifier(x, formalParameterDeclaration)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                reportRecoverableError(this, ConstructorWithWrongName)
+                  listener: handleRecoverableError(ConstructorWithWrongName, this, this)
+                listener: endClassConstructor(null, this, (, :, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 1, {, })
+          listener: endClassDeclaration(class, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(class)
+  listener: endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.parser.expect
new file mode 100644
index 0000000..8e768c1
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.parser.expect

@@ -0,0 +1,33 @@
+class C1() {
+this() {}
+}
+
+class C2() {
+this(int x) : assert(1 > 2) {}
+}
+
+class C3() {
+this();
+}
+
+class C4() {
+this(int x) : assert(1 > 2);
+}
+
+
+class[KeywordToken] C1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.scanner.expect
new file mode 100644
index 0000000..8e768c1
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/class_primary_constructor_body_error.dart.scanner.expect

@@ -0,0 +1,33 @@
+class C1() {
+this() {}
+}
+
+class C2() {
+this(int x) : assert(1 > 2) {}
+}
+
+class C3() {
+this();
+}
+
+class C4() {
+this(int x) : assert(1 > 2);
+}
+
+
+class[KeywordToken] C1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+class[KeywordToken] C4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart
new file mode 100644
index 0000000..c0f080a
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart

@@ -0,0 +1,19 @@
+enum const E1() {
+  e;
+  this {}
+}
+
+enum const E2() {
+  e;
+  this : assert(1 > 2) {}
+}
+
+enum const E3() {
+  e;
+  this;
+}
+
+enum const E4() {
+  e;
+  this : assert(1 > 2);
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.expect
new file mode 100644
index 0000000..177aac5
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.expect

@@ -0,0 +1,170 @@
+beginCompilationUnit(enum)
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E1, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(e)
+        endMetadataStar(0)
+        handleIdentifier(e, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(;)
+        beginConstructorReference(e)
+          handleNoTypeArguments(;)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+        endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+        handleNoArguments(e)
+        handleEnumElement({, null)
+        handleEnumElements(;, 1)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 1, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E2, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(e)
+        endMetadataStar(0)
+        handleIdentifier(e, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(;)
+        beginConstructorReference(e)
+          handleNoTypeArguments(;)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+        endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+        handleNoArguments(e)
+        handleEnumElement({, null)
+        handleEnumElements(;, 1)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 1, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E3, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(e)
+        endMetadataStar(0)
+        handleIdentifier(e, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(;)
+        beginConstructorReference(e)
+          handleNoTypeArguments(;)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+        endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+        handleNoArguments(e)
+        handleEnumElement({, null)
+        handleEnumElements(;, 1)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 1, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E4, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(e)
+        endMetadataStar(0)
+        handleIdentifier(e, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(;)
+        beginConstructorReference(e)
+          handleNoTypeArguments(;)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+        endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+        handleNoArguments(e)
+        handleEnumElement({, null)
+        handleEnumElements(;, 1)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 1, })
+  endTopLevelDeclaration(})
+endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.intertwined.expect
new file mode 100644
index 0000000..86fadf0
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.intertwined.expect

@@ -0,0 +1,300 @@
+parseUnit(enum)
+  skipErrorTokens(enum)
+  listener: beginCompilationUnit(enum)
+  syntheticPreviousToken(enum)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, , enum, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E1, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E1)
+        parsePrimaryConstructorOpt(E1, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E1, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(e)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            listener: handleIdentifier(e, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(;)
+          listener: beginConstructorReference(e)
+          listener: handleNoTypeArguments(;)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+          listener: endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(e)
+          listener: handleEnumElement({, null)
+        listener: handleEnumElements(;, 1)
+        notEofOrType(CLOSE_CURLY_BRACKET, this)
+        parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Enum, E1)
+          parseMetadataStar(;)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          listener: beginMember()
+          parsePrimaryConstructorBody(this)
+            listener: beginPrimaryConstructorBody(this)
+            parseInitializersOpt(this)
+              listener: handleNoInitializers()
+            parseAsyncModifierOpt(this)
+              listener: handleAsyncModifier(null, null)
+              inPlainSync()
+            inPlainSync()
+            parseFunctionBody(this, false, true)
+              listener: beginBlockFunctionBody({)
+              notEofOrType(CLOSE_CURLY_BRACKET, })
+              listener: endBlockFunctionBody(0, {, })
+            listener: endPrimaryConstructorBody(this, this, })
+          listener: endMember()
+        notEofOrType(CLOSE_CURLY_BRACKET, })
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 1, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E2, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E2)
+        parsePrimaryConstructorOpt(E2, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E2, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(e)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            listener: handleIdentifier(e, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(;)
+          listener: beginConstructorReference(e)
+          listener: handleNoTypeArguments(;)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+          listener: endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(e)
+          listener: handleEnumElement({, null)
+        listener: handleEnumElements(;, 1)
+        notEofOrType(CLOSE_CURLY_BRACKET, this)
+        parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Enum, E2)
+          parseMetadataStar(;)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          listener: beginMember()
+          parsePrimaryConstructorBody(this)
+            listener: beginPrimaryConstructorBody(this)
+            parseInitializersOpt(this)
+              parseInitializers(:)
+                listener: beginInitializers(:)
+                parseInitializer(:)
+                  listener: beginInitializer(assert)
+                  parseAssert(:, Assert.Initializer)
+                    listener: beginAssert(assert, Assert.Initializer)
+                    parseExpression(()
+                      looksLikeOuterPatternEquals(()
+                        skipOuterPattern(()
+                      parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                        parseUnaryExpression((, true, ConstantPatternContext.none)
+                          parsePrimary((, expression, ConstantPatternContext.none)
+                            parseLiteralInt(()
+                              listener: handleLiteralInt(1)
+                        listener: beginBinaryExpression(>)
+                        parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                          parseUnaryExpression(>, true, ConstantPatternContext.none)
+                            parsePrimary(>, expression, ConstantPatternContext.none)
+                              parseLiteralInt(>)
+                                listener: handleLiteralInt(2)
+                        listener: endBinaryExpression(>, 2)
+                    listener: endAssert(assert, Assert.Initializer, (, null, ))
+                  listener: endInitializer())
+                listener: endInitializers(1, :, ))
+            parseAsyncModifierOpt())
+              listener: handleAsyncModifier(null, null)
+              inPlainSync()
+            inPlainSync()
+            parseFunctionBody(), false, true)
+              listener: beginBlockFunctionBody({)
+              notEofOrType(CLOSE_CURLY_BRACKET, })
+              listener: endBlockFunctionBody(0, {, })
+            listener: endPrimaryConstructorBody(this, this, })
+          listener: endMember()
+        notEofOrType(CLOSE_CURLY_BRACKET, })
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 1, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E3, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E3)
+        parsePrimaryConstructorOpt(E3, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E3, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(e)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            listener: handleIdentifier(e, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(;)
+          listener: beginConstructorReference(e)
+          listener: handleNoTypeArguments(;)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+          listener: endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(e)
+          listener: handleEnumElement({, null)
+        listener: handleEnumElements(;, 1)
+        notEofOrType(CLOSE_CURLY_BRACKET, this)
+        parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Enum, E3)
+          parseMetadataStar(;)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          listener: beginMember()
+          parsePrimaryConstructorBody(this)
+            listener: beginPrimaryConstructorBody(this)
+            parseInitializersOpt(this)
+              listener: handleNoInitializers()
+            parseAsyncModifierOpt(this)
+              listener: handleAsyncModifier(null, null)
+              inPlainSync()
+            inPlainSync()
+            parseFunctionBody(this, false, true)
+              listener: handleEmptyFunctionBody(;)
+            listener: endPrimaryConstructorBody(this, this, ;)
+          listener: endMember()
+        notEofOrType(CLOSE_CURLY_BRACKET, })
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 1, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E4, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E4)
+        parsePrimaryConstructorOpt(E4, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E4, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(e)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            listener: handleIdentifier(e, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(;)
+          listener: beginConstructorReference(e)
+          listener: handleNoTypeArguments(;)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(e)
+          listener: endConstructorReference(e, null, e, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(e)
+          listener: handleEnumElement({, null)
+        listener: handleEnumElements(;, 1)
+        notEofOrType(CLOSE_CURLY_BRACKET, this)
+        parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Enum, E4)
+          parseMetadataStar(;)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          listener: beginMember()
+          parsePrimaryConstructorBody(this)
+            listener: beginPrimaryConstructorBody(this)
+            parseInitializersOpt(this)
+              parseInitializers(:)
+                listener: beginInitializers(:)
+                parseInitializer(:)
+                  listener: beginInitializer(assert)
+                  parseAssert(:, Assert.Initializer)
+                    listener: beginAssert(assert, Assert.Initializer)
+                    parseExpression(()
+                      looksLikeOuterPatternEquals(()
+                        skipOuterPattern(()
+                      parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                        parseUnaryExpression((, true, ConstantPatternContext.none)
+                          parsePrimary((, expression, ConstantPatternContext.none)
+                            parseLiteralInt(()
+                              listener: handleLiteralInt(1)
+                        listener: beginBinaryExpression(>)
+                        parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                          parseUnaryExpression(>, true, ConstantPatternContext.none)
+                            parsePrimary(>, expression, ConstantPatternContext.none)
+                              parseLiteralInt(>)
+                                listener: handleLiteralInt(2)
+                        listener: endBinaryExpression(>, 2)
+                    listener: endAssert(assert, Assert.Initializer, (, null, ))
+                  listener: endInitializer())
+                listener: endInitializers(1, :, ))
+            parseAsyncModifierOpt())
+              listener: handleAsyncModifier(null, null)
+              inPlainSync()
+            inPlainSync()
+            parseFunctionBody(), false, true)
+              listener: handleEmptyFunctionBody(;)
+            listener: endPrimaryConstructorBody(this, this, ;)
+          listener: endMember()
+        notEofOrType(CLOSE_CURLY_BRACKET, })
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 1, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(enum)
+  listener: endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.parser.expect
new file mode 100644
index 0000000..b4e1efd
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.parser.expect

@@ -0,0 +1,41 @@
+enum const E1() {
+e;
+this {}
+}
+
+enum const E2() {
+e;
+this : assert(1 > 2) {}
+}
+
+enum const E3() {
+e;
+this;
+}
+
+enum const E4() {
+e;
+this : assert(1 > 2);
+}
+
+
+enum[KeywordToken] const[KeywordToken] E1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.scanner.expect
new file mode 100644
index 0000000..b4e1efd
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body.dart.scanner.expect

@@ -0,0 +1,41 @@
+enum const E1() {
+e;
+this {}
+}
+
+enum const E2() {
+e;
+this : assert(1 > 2) {}
+}
+
+enum const E3() {
+e;
+this;
+}
+
+enum const E4() {
+e;
+this : assert(1 > 2);
+}
+
+
+enum[KeywordToken] const[KeywordToken] E1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+e[StringToken];[SimpleToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart
new file mode 100644
index 0000000..9853cc7
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart

@@ -0,0 +1,23 @@
+enum const E1() {
+  this() {}
+}
+
+enum const E2() {
+  this(int x) : assert(1 > 2) {}
+}
+
+enum const E3() {
+  this();
+}
+
+enum const E4() {
+  this(int x) : assert(1 > 2);
+}
+
+enum const E5() { // missing constants
+  this : assert(1 > 2);
+}
+
+enum const E6() { // missing constants
+  this {}
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.expect
new file mode 100644
index 0000000..5044ac0
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.expect

@@ -0,0 +1,257 @@
+Problems reported:
+
+parser/declaring_constructors/enum_primary_constructor_body_error:2:3: 'this' can't be used as an identifier because it's a keyword.
+  this() {}
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:2:10: Expected '}' before this.
+  this() {}
+         ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:6:3: 'this' can't be used as an identifier because it's a keyword.
+  this(int x) : assert(1 > 2) {}
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:6:12: Expected ',' before this.
+  this(int x) : assert(1 > 2) {}
+           ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:6:15: Expected '}' before this.
+  this(int x) : assert(1 > 2) {}
+              ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:10:3: 'this' can't be used as an identifier because it's a keyword.
+  this();
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:14:3: 'this' can't be used as an identifier because it's a keyword.
+  this(int x) : assert(1 > 2);
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:14:12: Expected ',' before this.
+  this(int x) : assert(1 > 2);
+           ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:14:15: Expected '}' before this.
+  this(int x) : assert(1 > 2);
+              ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:18:3: 'this' can't be used as an identifier because it's a keyword.
+  this : assert(1 > 2);
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:18:8: Expected '}' before this.
+  this : assert(1 > 2);
+       ^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:22:3: 'this' can't be used as an identifier because it's a keyword.
+  this {}
+  ^^^^
+
+parser/declaring_constructors/enum_primary_constructor_body_error:22:8: Expected '}' before this.
+  this {}
+       ^
+
+beginCompilationUnit(enum)
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E1, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(()
+        beginConstructorReference(this)
+          handleNoTypeArguments(()
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        beginArguments(()
+        endArguments(0, (, ))
+        handleEnumElement({, null)
+        handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], {, {)
+        handleEnumElements(}, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E2, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(()
+        beginConstructorReference(this)
+          handleNoTypeArguments(()
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        beginArguments(()
+          handleIdentifier(int, expression)
+          handleNoTypeArguments(x)
+          handleNoArguments(x)
+          handleSend(int, int)
+          handleRecoverableError(Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], x, x)
+          handleIdentifier(x, expression)
+          handleNoTypeArguments())
+          handleNoArguments())
+          handleSend(x, x)
+        endArguments(2, (, ))
+        handleEnumElement({, null)
+        handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        handleEnumElements(}, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E3, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(()
+        beginConstructorReference(this)
+          handleNoTypeArguments(()
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        beginArguments(()
+        endArguments(0, (, ))
+        handleEnumElement({, null)
+        handleEnumElements(;, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E4, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(()
+        beginConstructorReference(this)
+          handleNoTypeArguments(()
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        beginArguments(()
+          handleIdentifier(int, expression)
+          handleNoTypeArguments(x)
+          handleNoArguments(x)
+          handleSend(int, int)
+          handleRecoverableError(Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], x, x)
+          handleIdentifier(x, expression)
+          handleNoTypeArguments())
+          handleNoArguments())
+          handleSend(x, x)
+        endArguments(2, (, ))
+        handleEnumElement({, null)
+        handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        handleEnumElements(}, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E5, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E5)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference(:)
+        beginConstructorReference(this)
+          handleNoTypeArguments(:)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        handleNoArguments(this)
+        handleEnumElement({, null)
+        handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        handleEnumElements(}, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(enum)
+  endMetadataStar(0)
+  beginEnumDeclarationPrelude(enum)
+    handleIdentifier(E6, enumDeclaration)
+    handleNoTypeVariables(()
+    beginEnumDeclaration(enum, null, enum, E6)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+        endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, const, false, false)
+      handleEnumNoWithClause()
+      handleImplements(null, 0)
+      handleEnumHeader(null, enum, {)
+      beginEnumBody({)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+        handleIdentifier(this, enumValueDeclaration)
+        handleNoTypeNameInConstructorReference({)
+        beginConstructorReference(this)
+          handleNoTypeArguments({)
+          handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+        endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+        handleNoArguments(this)
+        handleEnumElement({, null)
+        handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], {, {)
+        handleEnumElements(}, 1)
+      endEnumBody({, })
+    endEnumDeclaration(enum, enum, {, 0, })
+  endTopLevelDeclaration(})
+endCompilationUnit(6, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.intertwined.expect
new file mode 100644
index 0000000..447685c
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.intertwined.expect

@@ -0,0 +1,343 @@
+parseUnit(enum)
+  skipErrorTokens(enum)
+  listener: beginCompilationUnit(enum)
+  syntheticPreviousToken(enum)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, , enum, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E1, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E1)
+        parsePrimaryConstructorOpt(E1, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E1, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(()
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments(()
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          parseConstructorInvocationArguments(this)
+            parseArgumentsRest(()
+              listener: beginArguments(()
+              listener: endArguments(0, (, ))
+          listener: handleEnumElement({, null)
+        reportRecoverableError({, Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}])
+          listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], {, {)
+        listener: handleEnumElements(}, 1)
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E2, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E2)
+        parsePrimaryConstructorOpt(E2, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E2, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(()
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments(()
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          parseConstructorInvocationArguments(this)
+            parseArgumentsRest(()
+              listener: beginArguments(()
+              allowedToShortcutParseExpression()
+              parseExpression(()
+                looksLikeOuterPatternEquals(()
+                  skipOuterPattern(()
+                    skipObjectPatternRest(int)
+                parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                  parseUnaryExpression((, true, ConstantPatternContext.none)
+                    parsePrimary((, expression, ConstantPatternContext.none)
+                      parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                        parseSend((, expression, ConstantPatternContext.none)
+                          ensureIdentifier((, expression)
+                            listener: handleIdentifier(int, expression)
+                          listener: handleNoTypeArguments(x)
+                          parseArgumentsOpt(int)
+                            listener: handleNoArguments(x)
+                          listener: handleSend(int, int)
+              rewriteAndRecover(int, Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], ,)
+                reportRecoverableError(x, Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}])
+                  listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], x, x)
+                rewriter()
+              allowedToShortcutParseExpression()
+              listener: handleIdentifier(x, expression)
+              listener: handleNoTypeArguments())
+              listener: handleNoArguments())
+              listener: handleSend(x, x)
+              listener: endArguments(2, (, ))
+          listener: handleEnumElement({, null)
+        reportRecoverableError(:, Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}])
+          listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        listener: handleEnumElements(}, 1)
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E3, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E3)
+        parsePrimaryConstructorOpt(E3, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E3, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(()
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments(()
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          parseConstructorInvocationArguments(this)
+            parseArgumentsRest(()
+              listener: beginArguments(()
+              listener: endArguments(0, (, ))
+          listener: handleEnumElement({, null)
+        listener: handleEnumElements(;, 1)
+        notEofOrType(CLOSE_CURLY_BRACKET, })
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E4, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E4)
+        parsePrimaryConstructorOpt(E4, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E4, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(()
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments(()
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          parseConstructorInvocationArguments(this)
+            parseArgumentsRest(()
+              listener: beginArguments(()
+              allowedToShortcutParseExpression()
+              parseExpression(()
+                looksLikeOuterPatternEquals(()
+                  skipOuterPattern(()
+                    skipObjectPatternRest(int)
+                parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                  parseUnaryExpression((, true, ConstantPatternContext.none)
+                    parsePrimary((, expression, ConstantPatternContext.none)
+                      parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                        parseSend((, expression, ConstantPatternContext.none)
+                          ensureIdentifier((, expression)
+                            listener: handleIdentifier(int, expression)
+                          listener: handleNoTypeArguments(x)
+                          parseArgumentsOpt(int)
+                            listener: handleNoArguments(x)
+                          listener: handleSend(int, int)
+              rewriteAndRecover(int, Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], ,)
+                reportRecoverableError(x, Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}])
+                  listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected ',' before this., null, {string: ,}], x, x)
+                rewriter()
+              allowedToShortcutParseExpression()
+              listener: handleIdentifier(x, expression)
+              listener: handleNoTypeArguments())
+              listener: handleNoArguments())
+              listener: handleSend(x, x)
+              listener: endArguments(2, (, ))
+          listener: handleEnumElement({, null)
+        reportRecoverableError(:, Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}])
+          listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        listener: handleEnumElements(}, 1)
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E5, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E5)
+        parsePrimaryConstructorOpt(E5, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E5, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference(:)
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments(:)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(this)
+          listener: handleEnumElement({, null)
+        reportRecoverableError(:, Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}])
+          listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], :, :)
+        listener: handleEnumElements(}, 1)
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(enum)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(enum, }, enum, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseEnum(enum, null, enum)
+        listener: beginEnumDeclarationPrelude(enum)
+        ensureIdentifier(const, enumDeclaration)
+          listener: handleIdentifier(E6, enumDeclaration)
+        listener: handleNoTypeVariables(()
+        listener: beginEnumDeclaration(enum, null, enum, E6)
+        parsePrimaryConstructorOpt(E6, const, false)
+          listener: beginPrimaryConstructor(()
+          parseFormalParameters(E6, MemberKind.PrimaryConstructor)
+            parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+              listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+              listener: endFormalParameters(0, (, ), MemberKind.PrimaryConstructor)
+          listener: endPrimaryConstructor((, const, false, false)
+        parseEnumHeaderOpt(), enum)
+          parseEnumWithClauseOpt())
+            listener: handleEnumNoWithClause()
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+        listener: handleEnumHeader(null, enum, {)
+        listener: beginEnumBody({)
+        parseEnumElement({)
+          parseMetadataStar({)
+            listener: beginMetadataStar(this)
+            listener: endMetadataStar(0)
+          ensureIdentifier({, enumValueDeclaration)
+            reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+              listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            listener: handleIdentifier(this, enumValueDeclaration)
+          listener: handleNoTypeNameInConstructorReference({)
+          listener: beginConstructorReference(this)
+          listener: handleNoTypeArguments({)
+          listener: handleNoConstructorReferenceContinuationAfterTypeArguments(this)
+          listener: endConstructorReference(this, null, this, ConstructorReferenceContext.Const)
+          listener: handleNoArguments(this)
+          listener: handleEnumElement({, null)
+        reportRecoverableError({, Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}])
+          listener: handleRecoverableError(Message[Template(ExpectedButGot), Expected '}' before this., null, {string: }}], {, {)
+        listener: handleEnumElements(}, 1)
+        listener: endEnumBody({, })
+        listener: endEnumDeclaration(enum, enum, {, 0, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(enum)
+  listener: endCompilationUnit(6, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.parser.expect
new file mode 100644
index 0000000..dae1e1f
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.parser.expect

@@ -0,0 +1,51 @@
+NOTICE: Stream was rewritten by parser!
+
+enum const E1() {
+this() {}
+}
+
+enum const E2() {
+this(int ,x) : assert(1 > 2) {}
+}
+
+enum const E3() {
+this();
+}
+
+enum const E4() {
+this(int ,x) : assert(1 > 2);
+}
+
+enum const E5() {
+this : assert(1 > 2);
+}
+
+enum const E6() {
+this {}
+}
+
+
+enum[KeywordToken] const[KeywordToken] E1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] ,[SyntheticToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] ,[SyntheticToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E5[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E6[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.scanner.expect
new file mode 100644
index 0000000..a26c6e3
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/enum_primary_constructor_body_error.dart.scanner.expect

@@ -0,0 +1,49 @@
+enum const E1() {
+this() {}
+}
+
+enum const E2() {
+this(int x) : assert(1 > 2) {}
+}
+
+enum const E3() {
+this();
+}
+
+enum const E4() {
+this(int x) : assert(1 > 2);
+}
+
+enum const E5() {
+this : assert(1 > 2);
+}
+
+enum const E6() {
+this {}
+}
+
+
+enum[KeywordToken] const[KeywordToken] E1[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E2[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E3[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E4[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E5[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+
+enum[KeywordToken] const[KeywordToken] E6[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart
new file mode 100644
index 0000000..634e4a6
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart

@@ -0,0 +1,15 @@
+extension type E1(int x) {
+  this {}
+}
+
+extension type E2(int x) {
+  this : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+  this;
+}
+
+extension type E4(int x) {
+  this : assert(1 > 2);
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.expect
new file mode 100644
index 0000000..8c3ed0a
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.expect

@@ -0,0 +1,150 @@
+beginCompilationUnit(extension)
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endPrimaryConstructorBody(this, this, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginPrimaryConstructorBody(this)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+          endPrimaryConstructorBody(this, this, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.intertwined.expect
new file mode 100644
index 0000000..0476cda
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.intertwined.expect

@@ -0,0 +1,276 @@
+parseUnit(extension)
+  skipErrorTokens(extension)
+  listener: beginCompilationUnit(extension)
+  syntheticPreviousToken(extension)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, , extension, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E1)
+          parsePrimaryConstructorOpt(E1, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E1, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E1)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E1)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt(this)
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(this, false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endPrimaryConstructorBody(this, this, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E2)
+          parsePrimaryConstructorOpt(E2, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E2, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E2)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E2)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endPrimaryConstructorBody(this, this, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E3)
+          parsePrimaryConstructorOpt(E3, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E3, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E3)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E3)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt(this)
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(this, false, true)
+                  listener: handleEmptyFunctionBody(;)
+                listener: endPrimaryConstructorBody(this, this, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E4)
+          parsePrimaryConstructorOpt(E4, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E4, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E4)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E4)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parsePrimaryConstructorBody(this)
+                listener: beginPrimaryConstructorBody(this)
+                parseInitializersOpt(this)
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                listener: endPrimaryConstructorBody(this, this, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(extension)
+  listener: endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.parser.expect
new file mode 100644
index 0000000..7ea6456
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.parser.expect

@@ -0,0 +1,33 @@
+extension type E1(int x) {
+this {}
+}
+
+extension type E2(int x) {
+this : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+this;
+}
+
+extension type E4(int x) {
+this : assert(1 > 2);
+}
+
+
+extension[KeywordToken] type[StringToken] E1[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E2[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E3[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E4[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.scanner.expect
new file mode 100644
index 0000000..7ea6456
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body.dart.scanner.expect

@@ -0,0 +1,33 @@
+extension type E1(int x) {
+this {}
+}
+
+extension type E2(int x) {
+this : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+this;
+}
+
+extension type E4(int x) {
+this : assert(1 > 2);
+}
+
+
+extension[KeywordToken] type[StringToken] E1[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E2[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E3[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken];[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E4[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart
new file mode 100644
index 0000000..ef6f47b
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart

@@ -0,0 +1,15 @@
+extension type E1(int x) {
+  this(this.x) {}
+}
+
+extension type E2(int x) {
+  this(this.x)  : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+  this(this.x) ;
+}
+
+extension type E4(int x) {
+  this(this.x)  : assert(1 > 2);
+}

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.expect
new file mode 100644
index 0000000..ec736b2
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.expect

@@ -0,0 +1,235 @@
+Problems reported:
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:2:3: 'this' can't be used as an identifier because it's a keyword.
+  this(this.x) {}
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:6:3: 'this' can't be used as an identifier because it's a keyword.
+  this(this.x)  : assert(1 > 2) {}
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:6:3: The name of a constructor must match the name of the enclosing class.
+  this(this.x)  : assert(1 > 2) {}
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:10:3: 'this' can't be used as an identifier because it's a keyword.
+  this(this.x) ;
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:10:3: Extension types can't declare abstract members.
+  this(this.x) ;
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:14:3: 'this' can't be used as an identifier because it's a keyword.
+  this(this.x)  : assert(1 > 2);
+  ^^^^
+
+parser/declaring_constructors/extension_type_primary_constructor_body_error:14:3: The name of a constructor must match the name of the enclosing class.
+  this(this.x)  : assert(1 > 2);
+  ^^^^
+
+beginCompilationUnit(extension)
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E1)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E1)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+              beginMetadataStar(this)
+              endMetadataStar(0)
+              beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                handleNoType(()
+                handleIdentifier(x, fieldInitializer)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+          endExtensionTypeMethod(null, this, (, null, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E2)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E2)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+              beginMetadataStar(this)
+              endMetadataStar(0)
+              beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                handleNoType(()
+                handleIdentifier(x, fieldInitializer)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            beginBlockFunctionBody({)
+            endBlockFunctionBody(0, {, })
+            handleRecoverableError(ConstructorWithWrongName, this, this)
+          endExtensionTypeConstructor(null, this, (, :, })
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E3)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E3)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+              beginMetadataStar(this)
+              endMetadataStar(0)
+              beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                handleNoType(()
+                handleIdentifier(x, fieldInitializer)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+            handleNoInitializers()
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+            handleRecoverableError(ExtensionTypeDeclaresAbstractMember, this, this)
+          endExtensionTypeMethod(null, this, (, null, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+  beginMetadataStar(extension)
+  endMetadataStar(0)
+  beginExtensionDeclarationPrelude(extension)
+    handleNoTypeVariables(()
+    beginExtensionTypeDeclaration(null, extension, E4)
+      beginPrimaryConstructor(()
+        beginFormalParameters((, MemberKind.PrimaryConstructor)
+          beginMetadataStar(int)
+          endMetadataStar(0)
+          beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+            handleIdentifier(int, typeReference)
+            handleNoTypeArguments(x)
+            handleType(int, null)
+            handleIdentifier(x, formalParameterDeclaration)
+            handleFormalParameterWithoutValue())
+          endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+        endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+      endPrimaryConstructor((, null, false, true)
+      handleImplements(null, 0)
+      beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+        beginMetadataStar(this)
+        endMetadataStar(0)
+        beginMember()
+          beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E4)
+            handleNoType({)
+            handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+            handleIdentifier(this, methodDeclaration)
+            handleNoTypeVariables(()
+            beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+              beginMetadataStar(this)
+              endMetadataStar(0)
+              beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                handleNoType(()
+                handleIdentifier(x, fieldInitializer)
+                handleFormalParameterWithoutValue())
+              endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+            endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+            beginInitializers(:)
+              beginInitializer(assert)
+                beginAssert(assert, Assert.Initializer)
+                  handleLiteralInt(1)
+                  beginBinaryExpression(>)
+                    handleLiteralInt(2)
+                  endBinaryExpression(>, 2)
+                endAssert(assert, Assert.Initializer, (, null, ))
+              endInitializer())
+            endInitializers(1, :, ))
+            handleAsyncModifier(null, null)
+            handleEmptyFunctionBody(;)
+            handleRecoverableError(ConstructorWithWrongName, this, this)
+          endExtensionTypeConstructor(null, this, (, :, ;)
+        endMember()
+      endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+    endExtensionTypeDeclaration(extension, null, extension, type, })
+  endTopLevelDeclaration(})
+endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.intertwined.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.intertwined.expect
new file mode 100644
index 0000000..8166699
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.intertwined.expect

@@ -0,0 +1,374 @@
+parseUnit(extension)
+  skipErrorTokens(extension)
+  listener: beginCompilationUnit(extension)
+  syntheticPreviousToken(extension)
+  parseTopLevelDeclarationImpl(, DirectiveContext(DirectiveState.Unknown))
+    parseMetadataStar()
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, , extension, null, null, null, null, DirectiveContext(DirectiveState.Unknown))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E1)
+          parsePrimaryConstructorOpt(E1, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E1, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E1)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E1)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.ExtensionType, E1, false)
+                listener: beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E1)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.ExtensionTypeNonStaticMethod)
+                  parseFormalParameters(this, MemberKind.ExtensionTypeNonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(this)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                        listener: handleNoType(()
+                        ensureIdentifier(., fieldInitializer)
+                          listener: handleIdentifier(x, fieldInitializer)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                listener: endExtensionTypeMethod(null, this, (, null, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E2)
+          parsePrimaryConstructorOpt(E2, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E2, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E2)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E2)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.ExtensionType, E2, false)
+                listener: beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E2)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.ExtensionTypeNonStaticMethod)
+                  parseFormalParameters(this, MemberKind.ExtensionTypeNonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(this)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                        listener: handleNoType(()
+                        ensureIdentifier(., fieldInitializer)
+                          listener: handleIdentifier(x, fieldInitializer)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+                parseInitializersOpt())
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(0, {, })
+                reportRecoverableError(this, ConstructorWithWrongName)
+                  listener: handleRecoverableError(ConstructorWithWrongName, this, this)
+                listener: endExtensionTypeConstructor(null, this, (, :, })
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E3)
+          parsePrimaryConstructorOpt(E3, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E3, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E3)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E3)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.ExtensionType, E3, false)
+                listener: beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E3)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.ExtensionTypeNonStaticMethod)
+                  parseFormalParameters(this, MemberKind.ExtensionTypeNonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(this)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                        listener: handleNoType(()
+                        ensureIdentifier(., fieldInitializer)
+                          listener: handleIdentifier(x, fieldInitializer)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                reportRecoverableError(this, ExtensionTypeDeclaresAbstractMember)
+                  listener: handleRecoverableError(ExtensionTypeDeclaresAbstractMember, this, this)
+                listener: endExtensionTypeMethod(null, this, (, null, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  parseTopLevelDeclarationImpl(}, DirectiveContext(DirectiveState.Declarations))
+    parseMetadataStar(})
+      listener: beginMetadataStar(extension)
+      listener: endMetadataStar(0)
+    parseTopLevelKeywordDeclaration(extension, }, extension, null, null, null, null, DirectiveContext(DirectiveState.Declarations))
+      parseExtension(extension, null, extension)
+        listener: beginExtensionDeclarationPrelude(extension)
+        parseExtensionTypeDeclaration(extension, type, null, extension, type)
+          listener: handleNoTypeVariables(()
+          listener: beginExtensionTypeDeclaration(null, extension, E4)
+          parsePrimaryConstructorOpt(E4, null, true)
+            listener: beginPrimaryConstructor(()
+            parseFormalParameters(E4, MemberKind.PrimaryConstructor)
+              parseFormalParametersRest((, MemberKind.PrimaryConstructor)
+                listener: beginFormalParameters((, MemberKind.PrimaryConstructor)
+                parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                  parseMetadataStar(()
+                    listener: beginMetadataStar(int)
+                    listener: endMetadataStar(0)
+                  listener: beginFormalParameter(int, MemberKind.PrimaryConstructor, null, null, null)
+                  listener: handleIdentifier(int, typeReference)
+                  listener: handleNoTypeArguments(x)
+                  listener: handleType(int, null)
+                  ensureIdentifier(int, formalParameterDeclaration)
+                    listener: handleIdentifier(x, formalParameterDeclaration)
+                  listener: handleFormalParameterWithoutValue())
+                  listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.PrimaryConstructor)
+                listener: endFormalParameters(1, (, ), MemberKind.PrimaryConstructor)
+            listener: endPrimaryConstructor((, null, false, true)
+          parseClassOrMixinOrEnumImplementsOpt())
+            listener: handleImplements(null, 0)
+          parseClassOrMixinOrExtensionBody(), DeclarationKind.ExtensionType, E4)
+            listener: beginClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, {)
+            notEofOrType(CLOSE_CURLY_BRACKET, this)
+            parseClassOrMixinOrExtensionOrEnumMemberImpl({, DeclarationKind.ExtensionType, E4)
+              parseMetadataStar({)
+                listener: beginMetadataStar(this)
+                listener: endMetadataStar(0)
+              listener: beginMember()
+              parseMethod({, null, null, null, null, null, null, null, {, NoType(), null, this, DeclarationKind.ExtensionType, E4, false)
+                listener: beginMethod(DeclarationKind.ExtensionType, null, null, null, null, null, null, this, E4)
+                listener: handleNoType({)
+                ensureIdentifierPotentiallyRecovered({, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.ExtensionTypeNonStaticMethod)
+                  parseFormalParameters(this, MemberKind.ExtensionTypeNonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.ExtensionTypeNonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(this)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(this, MemberKind.ExtensionTypeNonStaticMethod, null, null, null)
+                        listener: handleNoType(()
+                        ensureIdentifier(., fieldInitializer)
+                          listener: handleIdentifier(x, fieldInitializer)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, this, null, ., x, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionTypeNonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.ExtensionTypeNonStaticMethod)
+                parseInitializersOpt())
+                  parseInitializers(:)
+                    listener: beginInitializers(:)
+                    parseInitializer(:)
+                      listener: beginInitializer(assert)
+                      parseAssert(:, Assert.Initializer)
+                        listener: beginAssert(assert, Assert.Initializer)
+                        parseExpression(()
+                          looksLikeOuterPatternEquals(()
+                            skipOuterPattern(()
+                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression((, true, ConstantPatternContext.none)
+                              parsePrimary((, expression, ConstantPatternContext.none)
+                                parseLiteralInt(()
+                                  listener: handleLiteralInt(1)
+                            listener: beginBinaryExpression(>)
+                            parsePrecedenceExpression(>, 9, true, ConstantPatternContext.none)
+                              parseUnaryExpression(>, true, ConstantPatternContext.none)
+                                parsePrimary(>, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(>)
+                                    listener: handleLiteralInt(2)
+                            listener: endBinaryExpression(>, 2)
+                        listener: endAssert(assert, Assert.Initializer, (, null, ))
+                      listener: endInitializer())
+                    listener: endInitializers(1, :, ))
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
+                  inPlainSync()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: handleEmptyFunctionBody(;)
+                reportRecoverableError(this, ConstructorWithWrongName)
+                  listener: handleRecoverableError(ConstructorWithWrongName, this, this)
+                listener: endExtensionTypeConstructor(null, this, (, :, ;)
+              listener: endMember()
+            notEofOrType(CLOSE_CURLY_BRACKET, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.ExtensionType, 1, {, })
+          listener: endExtensionTypeDeclaration(extension, null, extension, type, })
+  listener: endTopLevelDeclaration(})
+  reportAllErrorTokens(extension)
+  listener: endCompilationUnit(4, )

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.parser.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.parser.expect
new file mode 100644
index 0000000..5246fe9
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.parser.expect

@@ -0,0 +1,33 @@
+extension type E1(int x) {
+this(this.x) {}
+}
+
+extension type E2(int x) {
+this(this.x) : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+this(this.x) ;
+}
+
+extension type E4(int x) {
+this(this.x) : assert(1 > 2);
+}
+
+
+extension[KeywordToken] type[StringToken] E1[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E2[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E3[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] ;[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E4[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.scanner.expect b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.scanner.expect
new file mode 100644
index 0000000..5246fe9
--- /dev/null
+++ b/pkg/front_end/parser_testcases/declaring_constructors/extension_type_primary_constructor_body_error.dart.scanner.expect

@@ -0,0 +1,33 @@
+extension type E1(int x) {
+this(this.x) {}
+}
+
+extension type E2(int x) {
+this(this.x) : assert(1 > 2) {}
+}
+
+extension type E3(int x) {
+this(this.x) ;
+}
+
+extension type E4(int x) {
+this(this.x) : assert(1 > 2);
+}
+
+
+extension[KeywordToken] type[StringToken] E1[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E2[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken] {[BeginToken]}[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E3[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] ;[SimpleToken]
+}[SimpleToken]
+
+extension[KeywordToken] type[StringToken] E4[StringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+this[KeywordToken]([BeginToken]this[KeywordToken].[SimpleToken]x[StringToken])[SimpleToken] :[SimpleToken] assert[KeywordToken]([BeginToken]1[StringToken] >[SimpleToken] 2[StringToken])[SimpleToken];[SimpleToken]
+}[SimpleToken]
+[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_fields.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_fields.dart.intertwined.expect
index 5e92672..e0fa28e 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_fields.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_fields.dart.intertwined.expect

@@ -1669,29 +1669,28 @@
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
               listener: beginMember()
-              recoverFromInvalidMember(int, ;, null, null, null, null, null, null, null, ;, SimpleType(), null, DeclarationKind.Class, WrapperClass)
-                parseFields(;, null, null, null, null, null, null, null, ;, SimpleType(), this, DeclarationKind.Class, WrapperClass, false)
-                  listener: beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, ;)
-                  listener: handleIdentifier(int, typeReference)
-                  listener: handleNoTypeArguments(this)
-                  listener: handleType(int, null)
-                  ensureIdentifierPotentiallyRecovered(int, fieldDeclaration, false)
-                    reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
-                      listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
-                    listener: handleIdentifier(this, fieldDeclaration)
-                  parseFieldInitializerOpt(this, this, null, null, null, null, null, DeclarationKind.Class, WrapperClass)
-                    listener: beginFieldInitializer(=)
-                    parseExpression(=)
-                      looksLikeOuterPatternEquals(=)
-                        skipOuterPattern(=)
-                      parsePrecedenceExpression(=, 1, true, ConstantPatternContext.none)
-                        parseUnaryExpression(=, true, ConstantPatternContext.none)
-                          parsePrimary(=, expression, ConstantPatternContext.none)
-                            parseLiteralInt(=)
-                              listener: handleLiteralInt(42)
-                    listener: endFieldInitializer(=, 42)
-                  listener: endClassFields(null, null, null, null, null, null, null, 1, int, ;)
-                listener: endMember()
+              parseFields(;, null, null, null, null, null, null, null, ;, SimpleType(), this, DeclarationKind.Class, WrapperClass, false)
+                listener: beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, ;)
+                listener: handleIdentifier(int, typeReference)
+                listener: handleNoTypeArguments(this)
+                listener: handleType(int, null)
+                ensureIdentifierPotentiallyRecovered(int, fieldDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, fieldDeclaration)
+                parseFieldInitializerOpt(this, this, null, null, null, null, null, DeclarationKind.Class, WrapperClass)
+                  listener: beginFieldInitializer(=)
+                  parseExpression(=)
+                    looksLikeOuterPatternEquals(=)
+                      skipOuterPattern(=)
+                    parsePrecedenceExpression(=, 1, true, ConstantPatternContext.none)
+                      parseUnaryExpression(=, true, ConstantPatternContext.none)
+                        parsePrimary(=, expression, ConstantPatternContext.none)
+                          parseLiteralInt(=)
+                            listener: handleLiteralInt(42)
+                  listener: endFieldInitializer(=, 42)
+                listener: endClassFields(null, null, null, null, null, null, null, 1, int, ;)
+              listener: endMember()
             notEofOrType(CLOSE_CURLY_BRACKET, int)
             parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Class, WrapperClass)
               parseMetadataStar(;)

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect
index 77ffd9b..0fff1e6 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect

@@ -348,14 +348,6 @@
   int this(int x) {
       ^^^^
 
-parser/error_recovery/keyword_named_class_methods:298:7: Expected ';' after this.
-  int this(int x) {
-      ^^^^
-
-parser/error_recovery/keyword_named_class_methods:298:11: Expected an identifier, but got '('.
-  int this(int x) {
-          ^
-
 parser/error_recovery/keyword_named_class_methods:303:7: 'throw' can't be used as an identifier because it's a keyword.
   int throw(int x) {
       ^^^^^
@@ -4105,23 +4097,12 @@
         beginMetadataStar(int)
         endMetadataStar(0)
         beginMember()
-          beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, })
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, WrapperClass)
             handleIdentifier(int, typeReference)
             handleNoTypeArguments(this)
             handleType(int, null)
             handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
-            handleIdentifier(this, fieldDeclaration)
-            handleNoFieldInitializer(()
-            handleRecoverableError(Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}], this, this)
-          endClassFields(null, null, null, null, null, null, null, 1, int, ;)
-        endMember()
-        beginMetadataStar(()
-        endMetadataStar(0)
-        beginMember()
-          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, (, WrapperClass)
-            handleNoType(;)
-            handleRecoverableError(Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}], (, ()
-            handleIdentifier(, methodDeclaration)
+            handleIdentifier(this, methodDeclaration)
             handleNoTypeVariables(()
             beginFormalParameters((, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
@@ -4170,7 +4151,7 @@
                 endBinaryExpression(+, 1)
               endReturnStatement(true, return, ;)
             endBlockFunctionBody(2, {, })
-          endClassMethod(null, , (, null, })
+          endClassMethod(null, int, (, null, })
         endMember()
         beginMetadataStar(int)
         endMetadataStar(0)
@@ -4778,7 +4759,7 @@
             endBlockFunctionBody(2, {, })
           endClassMethod(null, int, (, null, })
         endMember()
-      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 71, {, })
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 70, {, })
     endClassDeclaration(class, })
   endTopLevelDeclaration(})
 endCompilationUnit(1, )

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect
index 00bd591..eafcd09 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect

@@ -8915,163 +8915,138 @@
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
               listener: beginMember()
-              recoverFromInvalidMember(int, }, null, null, null, null, null, null, null, }, SimpleType(), null, DeclarationKind.Class, WrapperClass)
-                parseFields(}, null, null, null, null, null, null, null, }, SimpleType(), this, DeclarationKind.Class, WrapperClass, false)
-                  listener: beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, })
-                  listener: handleIdentifier(int, typeReference)
-                  listener: handleNoTypeArguments(this)
-                  listener: handleType(int, null)
-                  ensureIdentifierPotentiallyRecovered(int, fieldDeclaration, false)
-                    reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
-                      listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
-                    listener: handleIdentifier(this, fieldDeclaration)
-                  parseFieldInitializerOpt(this, this, null, null, null, null, null, DeclarationKind.Class, WrapperClass)
-                    listener: handleNoFieldInitializer(()
-                  ensureSemicolon(this)
-                    reportRecoverableError(this, Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}])
-                      listener: handleRecoverableError(Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}], this, this)
-                    rewriter()
-                  listener: endClassFields(null, null, null, null, null, null, null, 1, int, ;)
-                listener: endMember()
-            notEofOrType(CLOSE_CURLY_BRACKET, ()
-            parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Class, WrapperClass)
-              parseMetadataStar(;)
-                listener: beginMetadataStar(()
-                listener: endMetadataStar(0)
-              listener: beginMember()
-              recoverFromInvalidMember(;, ;, null, null, null, null, null, null, null, ;, NoType(), null, DeclarationKind.Class, WrapperClass)
-                parseMethod(;, null, null, null, null, null, null, null, ;, NoType(), null, (, DeclarationKind.Class, WrapperClass, false)
-                  listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, (, WrapperClass)
-                  listener: handleNoType(;)
-                  ensureIdentifierPotentiallyRecovered(;, methodDeclaration, false)
-                    insertSyntheticIdentifier(;, methodDeclaration, message: null, messageOnToken: null)
-                      reportRecoverableError((, Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}])
-                        listener: handleRecoverableError(Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}], (, ()
-                      rewriter()
-                    listener: handleIdentifier(, methodDeclaration)
-                  parseQualifiedRestOpt(, methodDeclarationContinuation)
-                  parseMethodTypeVar()
-                    listener: handleNoTypeVariables(()
-                  parseGetterOrFormalParameters(, (, false, MemberKind.NonStaticMethod)
-                    parseFormalParameters(, MemberKind.NonStaticMethod)
-                      parseFormalParametersRest((, MemberKind.NonStaticMethod)
-                        listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                        parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
-                          parseMetadataStar(()
-                            listener: beginMetadataStar(int)
-                            listener: endMetadataStar(0)
-                          listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
-                          listener: handleIdentifier(int, typeReference)
-                          listener: handleNoTypeArguments(x)
-                          listener: handleType(int, null)
-                          ensureIdentifier(int, formalParameterDeclaration)
-                            listener: handleIdentifier(x, formalParameterDeclaration)
-                          listener: handleFormalParameterWithoutValue())
-                          listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
-                        listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
-                  parseInitializersOpt())
-                    listener: handleNoInitializers()
-                  parseAsyncModifierOpt())
-                    listener: handleAsyncModifier(null, null)
-                    inPlainSync()
+              parseMethod(}, null, null, null, null, null, null, null, }, SimpleType(), null, this, DeclarationKind.Class, WrapperClass, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, WrapperClass)
+                listener: handleIdentifier(int, typeReference)
+                listener: handleNoTypeArguments(this)
+                listener: handleType(int, null)
+                ensureIdentifierPotentiallyRecovered(int, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(int)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                        listener: handleIdentifier(int, typeReference)
+                        listener: handleNoTypeArguments(x)
+                        listener: handleType(int, null)
+                        ensureIdentifier(int, formalParameterDeclaration)
+                          listener: handleIdentifier(x, formalParameterDeclaration)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
                   inPlainSync()
-                  parseFunctionBody(), false, true)
-                    listener: beginBlockFunctionBody({)
-                    notEofOrType(CLOSE_CURLY_BRACKET, if)
-                    parseStatement({)
-                      parseStatementX({)
-                        parseIfStatement({)
-                          listener: beginIfStatement(if)
-                          ensureParenthesizedCondition(if, allowCase: false)
-                            parseExpressionInParenthesisRest((, allowCase: false)
-                              parseExpression(()
-                                parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
-                                  parseUnaryExpression((, true, ConstantPatternContext.none)
-                                    parsePrimary((, expression, ConstantPatternContext.none)
-                                      parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
-                                        parseSend((, expression, ConstantPatternContext.none)
-                                          ensureIdentifier((, expression)
-                                            listener: handleIdentifier(x, expression)
-                                          listener: handleNoTypeArguments(==)
-                                          parseArgumentsOpt(x)
-                                            listener: handleNoArguments(==)
-                                          listener: handleSend(x, x)
-                                  listener: beginBinaryExpression(==)
-                                  parsePrecedenceExpression(==, 8, true, ConstantPatternContext.none)
-                                    parseUnaryExpression(==, true, ConstantPatternContext.none)
-                                      parsePrimary(==, expression, ConstantPatternContext.none)
-                                        parseLiteralInt(==)
-                                          listener: handleLiteralInt(0)
-                                  listener: endBinaryExpression(==, 0)
-                              ensureCloseParen(0, ()
-                              listener: handleParenthesizedCondition((, null, null)
-                          listener: beginThenStatement(return)
-                          parseStatement())
-                            parseStatementX())
-                              parseReturnStatement())
-                                listener: beginReturnStatement(return)
-                                parseExpression(return)
-                                  parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
-                                    parseUnaryExpression(return, true, ConstantPatternContext.none)
-                                      parsePrimary(return, expression, ConstantPatternContext.none)
-                                        parseLiteralInt(return)
-                                          listener: handleLiteralInt(42)
-                                ensureSemicolon(42)
-                                listener: endReturnStatement(true, return, ;)
-                                inGenerator()
-                          listener: endThenStatement(return, ;)
-                          listener: endIfStatement(if, null, ;)
-                    notEofOrType(CLOSE_CURLY_BRACKET, return)
-                    parseStatement(;)
-                      parseStatementX(;)
-                        parseReturnStatement(;)
-                          listener: beginReturnStatement(return)
-                          parseExpression(return)
-                            parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
-                              parseUnaryExpression(return, true, ConstantPatternContext.none)
-                                parsePrimary(return, expression, ConstantPatternContext.none)
-                                  parseThisExpression(return, expression)
-                                    listener: handleThisExpression(this, expression)
-                                    listener: handleNoTypeArguments(()
-                                    parseArguments(this)
-                                      parseArgumentsRest(()
-                                        listener: beginArguments(()
-                                        allowedToShortcutParseExpression()
-                                        parseExpression(()
-                                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
-                                            parseUnaryExpression((, true, ConstantPatternContext.none)
-                                              parsePrimary((, expression, ConstantPatternContext.none)
-                                                parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
-                                                  parseSend((, expression, ConstantPatternContext.none)
-                                                    ensureIdentifier((, expression)
-                                                      listener: handleIdentifier(x, expression)
-                                                    listener: handleNoTypeArguments(-)
-                                                    parseArgumentsOpt(x)
-                                                      listener: handleNoArguments(-)
-                                                    listener: handleSend(x, x)
-                                            listener: beginBinaryExpression(-)
-                                            parsePrecedenceExpression(-, 14, true, ConstantPatternContext.none)
-                                              parseUnaryExpression(-, true, ConstantPatternContext.none)
-                                                parsePrimary(-, expression, ConstantPatternContext.none)
-                                                  parseLiteralInt(-)
-                                                    listener: handleLiteralInt(1)
-                                            listener: endBinaryExpression(-, 1)
-                                        listener: endArguments(1, (, ))
-                                    listener: handleSend(this, ))
-                              listener: beginBinaryExpression(+)
-                              parsePrecedenceExpression(+, 14, true, ConstantPatternContext.none)
-                                parseUnaryExpression(+, true, ConstantPatternContext.none)
-                                  parsePrimary(+, expression, ConstantPatternContext.none)
-                                    parseLiteralInt(+)
-                                      listener: handleLiteralInt(1)
-                              listener: endBinaryExpression(+, 1)
-                          ensureSemicolon(1)
-                          listener: endReturnStatement(true, return, ;)
-                          inGenerator()
-                    notEofOrType(CLOSE_CURLY_BRACKET, })
-                    listener: endBlockFunctionBody(2, {, })
-                  listener: endClassMethod(null, , (, null, })
-                listener: endMember()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, if)
+                  parseStatement({)
+                    parseStatementX({)
+                      parseIfStatement({)
+                        listener: beginIfStatement(if)
+                        ensureParenthesizedCondition(if, allowCase: false)
+                          parseExpressionInParenthesisRest((, allowCase: false)
+                            parseExpression(()
+                              parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                                parseUnaryExpression((, true, ConstantPatternContext.none)
+                                  parsePrimary((, expression, ConstantPatternContext.none)
+                                    parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                                      parseSend((, expression, ConstantPatternContext.none)
+                                        ensureIdentifier((, expression)
+                                          listener: handleIdentifier(x, expression)
+                                        listener: handleNoTypeArguments(==)
+                                        parseArgumentsOpt(x)
+                                          listener: handleNoArguments(==)
+                                        listener: handleSend(x, x)
+                                listener: beginBinaryExpression(==)
+                                parsePrecedenceExpression(==, 8, true, ConstantPatternContext.none)
+                                  parseUnaryExpression(==, true, ConstantPatternContext.none)
+                                    parsePrimary(==, expression, ConstantPatternContext.none)
+                                      parseLiteralInt(==)
+                                        listener: handleLiteralInt(0)
+                                listener: endBinaryExpression(==, 0)
+                            ensureCloseParen(0, ()
+                            listener: handleParenthesizedCondition((, null, null)
+                        listener: beginThenStatement(return)
+                        parseStatement())
+                          parseStatementX())
+                            parseReturnStatement())
+                              listener: beginReturnStatement(return)
+                              parseExpression(return)
+                                parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
+                                  parseUnaryExpression(return, true, ConstantPatternContext.none)
+                                    parsePrimary(return, expression, ConstantPatternContext.none)
+                                      parseLiteralInt(return)
+                                        listener: handleLiteralInt(42)
+                              ensureSemicolon(42)
+                              listener: endReturnStatement(true, return, ;)
+                              inGenerator()
+                        listener: endThenStatement(return, ;)
+                        listener: endIfStatement(if, null, ;)
+                  notEofOrType(CLOSE_CURLY_BRACKET, return)
+                  parseStatement(;)
+                    parseStatementX(;)
+                      parseReturnStatement(;)
+                        listener: beginReturnStatement(return)
+                        parseExpression(return)
+                          parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression(return, true, ConstantPatternContext.none)
+                              parsePrimary(return, expression, ConstantPatternContext.none)
+                                parseThisExpression(return, expression)
+                                  listener: handleThisExpression(this, expression)
+                                  listener: handleNoTypeArguments(()
+                                  parseArguments(this)
+                                    parseArgumentsRest(()
+                                      listener: beginArguments(()
+                                      allowedToShortcutParseExpression()
+                                      parseExpression(()
+                                        parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                                          parseUnaryExpression((, true, ConstantPatternContext.none)
+                                            parsePrimary((, expression, ConstantPatternContext.none)
+                                              parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                                                parseSend((, expression, ConstantPatternContext.none)
+                                                  ensureIdentifier((, expression)
+                                                    listener: handleIdentifier(x, expression)
+                                                  listener: handleNoTypeArguments(-)
+                                                  parseArgumentsOpt(x)
+                                                    listener: handleNoArguments(-)
+                                                  listener: handleSend(x, x)
+                                          listener: beginBinaryExpression(-)
+                                          parsePrecedenceExpression(-, 14, true, ConstantPatternContext.none)
+                                            parseUnaryExpression(-, true, ConstantPatternContext.none)
+                                              parsePrimary(-, expression, ConstantPatternContext.none)
+                                                parseLiteralInt(-)
+                                                  listener: handleLiteralInt(1)
+                                          listener: endBinaryExpression(-, 1)
+                                      listener: endArguments(1, (, ))
+                                  listener: handleSend(this, ))
+                            listener: beginBinaryExpression(+)
+                            parsePrecedenceExpression(+, 14, true, ConstantPatternContext.none)
+                              parseUnaryExpression(+, true, ConstantPatternContext.none)
+                                parsePrimary(+, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(+)
+                                    listener: handleLiteralInt(1)
+                            listener: endBinaryExpression(+, 1)
+                        ensureSemicolon(1)
+                        listener: endReturnStatement(true, return, ;)
+                        inGenerator()
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(2, {, })
+                listener: endClassMethod(null, int, (, null, })
+              listener: endMember()
             notEofOrType(CLOSE_CURLY_BRACKET, int)
             parseClassOrMixinOrExtensionOrEnumMemberImpl(}, DeclarationKind.Class, WrapperClass)
               parseMetadataStar(})
@@ -10613,7 +10588,7 @@
                 listener: endClassMethod(null, int, (, null, })
               listener: endMember()
             notEofOrType(CLOSE_CURLY_BRACKET, })
-            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 71, {, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 70, {, })
           listener: endClassDeclaration(class, })
   listener: endTopLevelDeclaration(})
   reportAllErrorTokens(class)

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.parser.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.parser.expect
index 6295405..4e77265 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.parser.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.parser.expect

@@ -296,7 +296,7 @@
 return sync(x-1) + 1;
 }
 
-int this;*synthetic*(int x) {
+int this(int x) {
 if (x == 0) return 42;
 return this(x-1) + 1;
 }
@@ -644,7 +644,7 @@
 return[KeywordToken] sync[KeywordToken]([BeginToken]x[StringToken]-[SimpleToken]1[StringToken])[SimpleToken] +[SimpleToken] 1[StringToken];[SimpleToken]
 }[SimpleToken]
 
-int[StringToken] this[KeywordToken];[SyntheticToken][SyntheticStringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+int[StringToken] this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
 if[KeywordToken] ([BeginToken]x[StringToken] ==[SimpleToken] 0[StringToken])[SimpleToken] return[KeywordToken] 42[StringToken];[SimpleToken]
 return[KeywordToken] this[KeywordToken]([BeginToken]x[StringToken]-[SimpleToken]1[StringToken])[SimpleToken] +[SimpleToken] 1[StringToken];[SimpleToken]
 }[SimpleToken]

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.expect
index 93c9258..319fa07 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.expect

@@ -336,14 +336,6 @@
   int this(int x) {
       ^^^^
 
-parser/error_recovery/keyword_named_class_methods_2:297:7: Expected ';' after this.
-  int this(int x) {
-      ^^^^
-
-parser/error_recovery/keyword_named_class_methods_2:297:11: Expected an identifier, but got '('.
-  int this(int x) {
-          ^
-
 parser/error_recovery/keyword_named_class_methods_2:302:7: 'throw' can't be used as an identifier because it's a keyword.
   int throw(int x) {
       ^^^^^
@@ -4081,23 +4073,12 @@
         beginMetadataStar(int)
         endMetadataStar(0)
         beginMember()
-          beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, })
+          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, WrapperClass)
             handleIdentifier(int, typeReference)
             handleNoTypeArguments(this)
             handleType(int, null)
             handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
-            handleIdentifier(this, fieldDeclaration)
-            handleNoFieldInitializer(()
-            handleRecoverableError(Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}], this, this)
-          endClassFields(null, null, null, null, null, null, null, 1, int, ;)
-        endMember()
-        beginMetadataStar(()
-        endMetadataStar(0)
-        beginMember()
-          beginMethod(DeclarationKind.Class, null, null, null, null, null, null, (, WrapperClass)
-            handleNoType(;)
-            handleRecoverableError(Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}], (, ()
-            handleIdentifier(, methodDeclaration)
+            handleIdentifier(this, methodDeclaration)
             handleNoTypeVariables(()
             beginFormalParameters((, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
@@ -4146,7 +4127,7 @@
                 endBinaryExpression(+, 1)
               endReturnStatement(true, return, ;)
             endBlockFunctionBody(2, {, })
-          endClassMethod(null, , (, null, })
+          endClassMethod(null, int, (, null, })
         endMember()
         beginMetadataStar(int)
         endMetadataStar(0)
@@ -4754,7 +4735,7 @@
             endBlockFunctionBody(2, {, })
           endClassMethod(null, int, (, null, })
         endMember()
-      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 71, {, })
+      endClassOrMixinOrExtensionBody(DeclarationKind.Class, 70, {, })
     endClassDeclaration(class, })
   endTopLevelDeclaration(})
 endCompilationUnit(1, )

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.intertwined.expect
index fb96c2b..c857c73 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.intertwined.expect

@@ -9518,173 +9518,148 @@
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
               listener: beginMember()
-              recoverFromInvalidMember(int, }, null, null, null, null, null, null, null, }, SimpleType(), null, DeclarationKind.Class, WrapperClass)
-                parseFields(}, null, null, null, null, null, null, null, }, SimpleType(), this, DeclarationKind.Class, WrapperClass, false)
-                  listener: beginFields(DeclarationKind.Class, null, null, null, null, null, null, null, })
-                  listener: handleIdentifier(int, typeReference)
-                  listener: handleNoTypeArguments(this)
-                  listener: handleType(int, null)
-                  ensureIdentifierPotentiallyRecovered(int, fieldDeclaration, false)
-                    reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
-                      listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
-                    listener: handleIdentifier(this, fieldDeclaration)
-                  parseFieldInitializerOpt(this, this, null, null, null, null, null, DeclarationKind.Class, WrapperClass)
-                    listener: handleNoFieldInitializer(()
-                  ensureSemicolon(this)
-                    reportRecoverableError(this, Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}])
-                      listener: handleRecoverableError(Message[Template(ExpectedAfterButGot), Expected ';' after this., null, {string: ;}], this, this)
-                    rewriter()
-                  listener: endClassFields(null, null, null, null, null, null, null, 1, int, ;)
-                listener: endMember()
-            notEofOrType(CLOSE_CURLY_BRACKET, ()
-            parseClassOrMixinOrExtensionOrEnumMemberImpl(;, DeclarationKind.Class, WrapperClass)
-              parseMetadataStar(;)
-                listener: beginMetadataStar(()
-                listener: endMetadataStar(0)
-              listener: beginMember()
-              recoverFromInvalidMember(;, ;, null, null, null, null, null, null, null, ;, NoType(), null, DeclarationKind.Class, WrapperClass)
-                parseMethod(;, null, null, null, null, null, null, null, ;, NoType(), null, (, DeclarationKind.Class, WrapperClass, false)
-                  listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, (, WrapperClass)
-                  listener: handleNoType(;)
-                  ensureIdentifierPotentiallyRecovered(;, methodDeclaration, false)
-                    insertSyntheticIdentifier(;, methodDeclaration, message: null, messageOnToken: null)
-                      reportRecoverableError((, Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}])
-                        listener: handleRecoverableError(Message[Template(ExpectedIdentifier), Expected an identifier, but got '('., Try inserting an identifier before '('., {lexeme: (}], (, ()
-                      rewriter()
-                    listener: handleIdentifier(, methodDeclaration)
-                  parseQualifiedRestOpt(, methodDeclarationContinuation)
-                  parseMethodTypeVar()
-                    listener: handleNoTypeVariables(()
-                  parseGetterOrFormalParameters(, (, false, MemberKind.NonStaticMethod)
-                    parseFormalParameters(, MemberKind.NonStaticMethod)
-                      parseFormalParametersRest((, MemberKind.NonStaticMethod)
-                        listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                        parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
-                          parseMetadataStar(()
-                            listener: beginMetadataStar(int)
-                            listener: endMetadataStar(0)
-                          listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
-                          listener: handleIdentifier(int, typeReference)
-                          listener: handleNoTypeArguments(x)
-                          listener: handleType(int, null)
-                          ensureIdentifier(int, formalParameterDeclaration)
-                            listener: handleIdentifier(x, formalParameterDeclaration)
-                          listener: handleFormalParameterWithoutValue())
-                          listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
-                        listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
-                  parseInitializersOpt())
-                    listener: handleNoInitializers()
-                  parseAsyncModifierOpt())
-                    listener: handleAsyncModifier(null, null)
-                    inPlainSync()
+              parseMethod(}, null, null, null, null, null, null, null, }, SimpleType(), null, this, DeclarationKind.Class, WrapperClass, false)
+                listener: beginMethod(DeclarationKind.Class, null, null, null, null, null, null, this, WrapperClass)
+                listener: handleIdentifier(int, typeReference)
+                listener: handleNoTypeArguments(this)
+                listener: handleType(int, null)
+                ensureIdentifierPotentiallyRecovered(int, methodDeclaration, false)
+                  reportRecoverableErrorWithToken(this, Template(ExpectedIdentifierButGotKeyword))
+                    listener: handleRecoverableError(Message[Template(ExpectedIdentifierButGotKeyword), 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
+                  listener: handleIdentifier(this, methodDeclaration)
+                parseQualifiedRestOpt(this, methodDeclarationContinuation)
+                parseMethodTypeVar(this)
+                  listener: handleNoTypeVariables(()
+                parseGetterOrFormalParameters(this, this, false, MemberKind.NonStaticMethod)
+                  parseFormalParameters(this, MemberKind.NonStaticMethod)
+                    parseFormalParametersRest((, MemberKind.NonStaticMethod)
+                      listener: beginFormalParameters((, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                        parseMetadataStar(()
+                          listener: beginMetadataStar(int)
+                          listener: endMetadataStar(0)
+                        listener: beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
+                        listener: handleIdentifier(int, typeReference)
+                        listener: handleNoTypeArguments(x)
+                        listener: handleType(int, null)
+                        ensureIdentifier(int, formalParameterDeclaration)
+                          listener: handleIdentifier(x, formalParameterDeclaration)
+                        listener: handleFormalParameterWithoutValue())
+                        listener: endFormalParameter(null, null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
+                parseInitializersOpt())
+                  listener: handleNoInitializers()
+                parseAsyncModifierOpt())
+                  listener: handleAsyncModifier(null, null)
                   inPlainSync()
-                  parseFunctionBody(), false, true)
-                    listener: beginBlockFunctionBody({)
-                    notEofOrType(CLOSE_CURLY_BRACKET, if)
-                    parseStatement({)
-                      parseStatementX({)
-                        parseIfStatement({)
-                          listener: beginIfStatement(if)
-                          ensureParenthesizedCondition(if, allowCase: true)
-                            parseExpressionInParenthesisRest((, allowCase: true)
-                              parseExpression(()
-                                looksLikeOuterPatternEquals(()
-                                  skipOuterPattern(()
-                                    skipObjectPatternRest(x)
-                                parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
-                                  parseUnaryExpression((, true, ConstantPatternContext.none)
-                                    parsePrimary((, expression, ConstantPatternContext.none)
-                                      parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
-                                        parseSend((, expression, ConstantPatternContext.none)
-                                          ensureIdentifier((, expression)
-                                            listener: handleIdentifier(x, expression)
-                                          listener: handleNoTypeArguments(==)
-                                          parseArgumentsOpt(x)
-                                            listener: handleNoArguments(==)
-                                          listener: handleSend(x, x)
-                                  listener: beginBinaryExpression(==)
-                                  parsePrecedenceExpression(==, 8, true, ConstantPatternContext.none)
-                                    parseUnaryExpression(==, true, ConstantPatternContext.none)
-                                      parsePrimary(==, expression, ConstantPatternContext.none)
-                                        parseLiteralInt(==)
-                                          listener: handleLiteralInt(0)
-                                  listener: endBinaryExpression(==, 0)
-                              ensureCloseParen(0, ()
-                              listener: handleParenthesizedCondition((, null, null)
-                          listener: beginThenStatement(return)
-                          parseStatement())
-                            parseStatementX())
-                              parseReturnStatement())
-                                listener: beginReturnStatement(return)
-                                parseExpression(return)
-                                  looksLikeOuterPatternEquals(return)
-                                    skipOuterPattern(return)
-                                  parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
-                                    parseUnaryExpression(return, true, ConstantPatternContext.none)
-                                      parsePrimary(return, expression, ConstantPatternContext.none)
-                                        parseLiteralInt(return)
-                                          listener: handleLiteralInt(42)
-                                ensureSemicolon(42)
-                                listener: endReturnStatement(true, return, ;)
-                                inGenerator()
-                          listener: endThenStatement(return, ;)
-                          listener: endIfStatement(if, null, ;)
-                    notEofOrType(CLOSE_CURLY_BRACKET, return)
-                    parseStatement(;)
-                      parseStatementX(;)
-                        parseReturnStatement(;)
-                          listener: beginReturnStatement(return)
-                          parseExpression(return)
-                            looksLikeOuterPatternEquals(return)
-                              skipOuterPattern(return)
-                            parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
-                              parseUnaryExpression(return, true, ConstantPatternContext.none)
-                                parsePrimary(return, expression, ConstantPatternContext.none)
-                                  parseThisExpression(return, expression)
-                                    listener: handleThisExpression(this, expression)
-                                    listener: handleNoTypeArguments(()
-                                    parseArguments(this)
-                                      parseArgumentsRest(()
-                                        listener: beginArguments(()
-                                        allowedToShortcutParseExpression()
-                                        parseExpression(()
-                                          looksLikeOuterPatternEquals(()
-                                            skipOuterPattern(()
-                                              skipObjectPatternRest(x)
-                                          parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
-                                            parseUnaryExpression((, true, ConstantPatternContext.none)
-                                              parsePrimary((, expression, ConstantPatternContext.none)
-                                                parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
-                                                  parseSend((, expression, ConstantPatternContext.none)
-                                                    ensureIdentifier((, expression)
-                                                      listener: handleIdentifier(x, expression)
-                                                    listener: handleNoTypeArguments(-)
-                                                    parseArgumentsOpt(x)
-                                                      listener: handleNoArguments(-)
-                                                    listener: handleSend(x, x)
-                                            listener: beginBinaryExpression(-)
-                                            parsePrecedenceExpression(-, 14, true, ConstantPatternContext.none)
-                                              parseUnaryExpression(-, true, ConstantPatternContext.none)
-                                                parsePrimary(-, expression, ConstantPatternContext.none)
-                                                  parseLiteralInt(-)
-                                                    listener: handleLiteralInt(1)
-                                            listener: endBinaryExpression(-, 1)
-                                        listener: endArguments(1, (, ))
-                                    listener: handleSend(this, ))
-                              listener: beginBinaryExpression(+)
-                              parsePrecedenceExpression(+, 14, true, ConstantPatternContext.none)
-                                parseUnaryExpression(+, true, ConstantPatternContext.none)
-                                  parsePrimary(+, expression, ConstantPatternContext.none)
-                                    parseLiteralInt(+)
-                                      listener: handleLiteralInt(1)
-                              listener: endBinaryExpression(+, 1)
-                          ensureSemicolon(1)
-                          listener: endReturnStatement(true, return, ;)
-                          inGenerator()
-                    notEofOrType(CLOSE_CURLY_BRACKET, })
-                    listener: endBlockFunctionBody(2, {, })
-                  listener: endClassMethod(null, , (, null, })
-                listener: endMember()
+                inPlainSync()
+                parseFunctionBody(), false, true)
+                  listener: beginBlockFunctionBody({)
+                  notEofOrType(CLOSE_CURLY_BRACKET, if)
+                  parseStatement({)
+                    parseStatementX({)
+                      parseIfStatement({)
+                        listener: beginIfStatement(if)
+                        ensureParenthesizedCondition(if, allowCase: true)
+                          parseExpressionInParenthesisRest((, allowCase: true)
+                            parseExpression(()
+                              looksLikeOuterPatternEquals(()
+                                skipOuterPattern(()
+                                  skipObjectPatternRest(x)
+                              parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                                parseUnaryExpression((, true, ConstantPatternContext.none)
+                                  parsePrimary((, expression, ConstantPatternContext.none)
+                                    parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                                      parseSend((, expression, ConstantPatternContext.none)
+                                        ensureIdentifier((, expression)
+                                          listener: handleIdentifier(x, expression)
+                                        listener: handleNoTypeArguments(==)
+                                        parseArgumentsOpt(x)
+                                          listener: handleNoArguments(==)
+                                        listener: handleSend(x, x)
+                                listener: beginBinaryExpression(==)
+                                parsePrecedenceExpression(==, 8, true, ConstantPatternContext.none)
+                                  parseUnaryExpression(==, true, ConstantPatternContext.none)
+                                    parsePrimary(==, expression, ConstantPatternContext.none)
+                                      parseLiteralInt(==)
+                                        listener: handleLiteralInt(0)
+                                listener: endBinaryExpression(==, 0)
+                            ensureCloseParen(0, ()
+                            listener: handleParenthesizedCondition((, null, null)
+                        listener: beginThenStatement(return)
+                        parseStatement())
+                          parseStatementX())
+                            parseReturnStatement())
+                              listener: beginReturnStatement(return)
+                              parseExpression(return)
+                                looksLikeOuterPatternEquals(return)
+                                  skipOuterPattern(return)
+                                parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
+                                  parseUnaryExpression(return, true, ConstantPatternContext.none)
+                                    parsePrimary(return, expression, ConstantPatternContext.none)
+                                      parseLiteralInt(return)
+                                        listener: handleLiteralInt(42)
+                              ensureSemicolon(42)
+                              listener: endReturnStatement(true, return, ;)
+                              inGenerator()
+                        listener: endThenStatement(return, ;)
+                        listener: endIfStatement(if, null, ;)
+                  notEofOrType(CLOSE_CURLY_BRACKET, return)
+                  parseStatement(;)
+                    parseStatementX(;)
+                      parseReturnStatement(;)
+                        listener: beginReturnStatement(return)
+                        parseExpression(return)
+                          looksLikeOuterPatternEquals(return)
+                            skipOuterPattern(return)
+                          parsePrecedenceExpression(return, 1, true, ConstantPatternContext.none)
+                            parseUnaryExpression(return, true, ConstantPatternContext.none)
+                              parsePrimary(return, expression, ConstantPatternContext.none)
+                                parseThisExpression(return, expression)
+                                  listener: handleThisExpression(this, expression)
+                                  listener: handleNoTypeArguments(()
+                                  parseArguments(this)
+                                    parseArgumentsRest(()
+                                      listener: beginArguments(()
+                                      allowedToShortcutParseExpression()
+                                      parseExpression(()
+                                        looksLikeOuterPatternEquals(()
+                                          skipOuterPattern(()
+                                            skipObjectPatternRest(x)
+                                        parsePrecedenceExpression((, 1, true, ConstantPatternContext.none)
+                                          parseUnaryExpression((, true, ConstantPatternContext.none)
+                                            parsePrimary((, expression, ConstantPatternContext.none)
+                                              parseSendOrFunctionLiteral((, expression, ConstantPatternContext.none)
+                                                parseSend((, expression, ConstantPatternContext.none)
+                                                  ensureIdentifier((, expression)
+                                                    listener: handleIdentifier(x, expression)
+                                                  listener: handleNoTypeArguments(-)
+                                                  parseArgumentsOpt(x)
+                                                    listener: handleNoArguments(-)
+                                                  listener: handleSend(x, x)
+                                          listener: beginBinaryExpression(-)
+                                          parsePrecedenceExpression(-, 14, true, ConstantPatternContext.none)
+                                            parseUnaryExpression(-, true, ConstantPatternContext.none)
+                                              parsePrimary(-, expression, ConstantPatternContext.none)
+                                                parseLiteralInt(-)
+                                                  listener: handleLiteralInt(1)
+                                          listener: endBinaryExpression(-, 1)
+                                      listener: endArguments(1, (, ))
+                                  listener: handleSend(this, ))
+                            listener: beginBinaryExpression(+)
+                            parsePrecedenceExpression(+, 14, true, ConstantPatternContext.none)
+                              parseUnaryExpression(+, true, ConstantPatternContext.none)
+                                parsePrimary(+, expression, ConstantPatternContext.none)
+                                  parseLiteralInt(+)
+                                    listener: handleLiteralInt(1)
+                            listener: endBinaryExpression(+, 1)
+                        ensureSemicolon(1)
+                        listener: endReturnStatement(true, return, ;)
+                        inGenerator()
+                  notEofOrType(CLOSE_CURLY_BRACKET, })
+                  listener: endBlockFunctionBody(2, {, })
+                listener: endClassMethod(null, int, (, null, })
+              listener: endMember()
             notEofOrType(CLOSE_CURLY_BRACKET, int)
             parseClassOrMixinOrExtensionOrEnumMemberImpl(}, DeclarationKind.Class, WrapperClass)
               parseMetadataStar(})
@@ -11333,7 +11308,7 @@
                 listener: endClassMethod(null, int, (, null, })
               listener: endMember()
             notEofOrType(CLOSE_CURLY_BRACKET, })
-            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 71, {, })
+            listener: endClassOrMixinOrExtensionBody(DeclarationKind.Class, 70, {, })
           listener: endClassDeclaration(class, })
   listener: endTopLevelDeclaration(})
   reportAllErrorTokens(class)

diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.parser.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.parser.expect
index 777511a..02b4683 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.parser.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods_2.dart.parser.expect

@@ -296,7 +296,7 @@
 return sync(x-1) + 1;
 }
 
-int this;*synthetic*(int x) {
+int this(int x) {
 if (x == 0) return 42;
 return this(x-1) + 1;
 }
@@ -644,7 +644,7 @@
 return[KeywordToken] sync[KeywordToken]([BeginToken]x[StringToken]-[SimpleToken]1[StringToken])[SimpleToken] +[SimpleToken] 1[StringToken];[SimpleToken]
 }[SimpleToken]
 
-int[StringToken] this[KeywordToken];[SyntheticToken][SyntheticStringToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
+int[StringToken] this[KeywordToken]([BeginToken]int[StringToken] x[StringToken])[SimpleToken] {[BeginToken]
 if[KeywordToken] ([BeginToken]x[StringToken] ==[SimpleToken] 0[StringToken])[SimpleToken] return[KeywordToken] 42[StringToken];[SimpleToken]
 return[KeywordToken] this[KeywordToken]([BeginToken]x[StringToken]-[SimpleToken]1[StringToken])[SimpleToken] +[SimpleToken] 1[StringToken];[SimpleToken]
 }[SimpleToken]

diff --git a/pkg/front_end/test/parser/parser_ast_test.dart b/pkg/front_end/test/parser/parser_ast_test.dart
index d001c0b..0995e2c 100644
--- a/pkg/front_end/test/parser/parser_ast_test.dart
+++ b/pkg/front_end/test/parser/parser_ast_test.dart

@@ -704,6 +704,15 @@
           decl.endToken.offset + decl.endToken.length,
         ),
       ];
+    } else if (item.isPrimaryConstructorBody()) {
+      PrimaryConstructorBodyEnd decl = item.getPrimaryConstructorBody();
+      return [
+        getCutContent(
+          data,
+          decl.beginToken.offset,
+          decl.endToken.offset + decl.endToken.length,
+        ),
+      ];
     } else {
       if (item.type == ParserAstType.BEGIN) return const [];
       if (item.type == ParserAstType.HANDLE) return const [];

diff --git a/pkg/front_end/test/parser_test_listener.dart b/pkg/front_end/test/parser_test_listener.dart
index a8d0faf..e6a144a 100644
--- a/pkg/front_end/test/parser_test_listener.dart
+++ b/pkg/front_end/test/parser_test_listener.dart

@@ -597,6 +597,34 @@
   }
 
   @override
+  void beginPrimaryConstructorBody(Token token) {
+    seen(token);
+    doPrint(
+      'beginPrimaryConstructorBody('
+      '$token)',
+    );
+    indent++;
+  }
+
+  @override
+  void endPrimaryConstructorBody(
+    Token beginToken,
+    Token? beginInitializers,
+    Token endToken,
+  ) {
+    indent--;
+    seen(beginToken);
+    seen(beginInitializers);
+    seen(endToken);
+    doPrint(
+      'endPrimaryConstructorBody('
+      '$beginToken, '
+      '$beginInitializers, '
+      '$endToken)',
+    );
+  }
+
+  @override
   void beginCombinators(Token token) {
     seen(token);
     doPrint(

diff --git a/pkg/front_end/test/parser_test_parser.dart b/pkg/front_end/test/parser_test_parser.dart
index 34ddf6f..22912ff 100644
--- a/pkg/front_end/test/parser_test_parser.dart
+++ b/pkg/front_end/test/parser_test_parser.dart

@@ -1236,6 +1236,18 @@
   }
 
   @override
+  Token parsePrimaryConstructorBody(Token token) {
+    doPrint(
+      'parsePrimaryConstructorBody('
+      '$token)',
+    );
+    indent++;
+    var result = super.parsePrimaryConstructorBody(token);
+    indent--;
+    return result;
+  }
+
+  @override
   Token parseExtensionTypeDeclaration(
     Token beginToken,
     Token token,

diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.expect
index d16ec61..2d3100c 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.expect

@@ -2,45 +2,91 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Expected a class member, but got 'this'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: 'this' can't be used as an identifier because it's a keyword.
+// Try renaming this to be an identifier that isn't a keyword.
 //         this.y = 2;
 //         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:13: Error: Expected a class member, but got '.'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: A method declaration needs an explicit list of parameters.
+// Try adding a parameter list to the method declaration.
 //         this.y = 2;
-//             ^
+//         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Only factory constructor can specify '=' redirection.
+// Try making this a factory constructor, or remove the redirection.
 //         this.y = 2;
-//              ^
+//                ^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: 'y' is already declared in this scope.
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected an identifier, but got '2'.
+// Try inserting an identifier before '2'.
 //         this.y = 2;
-//              ^
-// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: Previous declaration of 'y'.
-//   final int y;
-//             ^
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected ';' after this.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: The name of a constructor must match the name of the enclosing class.
+//         this.y = 2;
+//         ^^^^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected a class member, but got '2'.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:19: Error: Expected a class member, but got ';'.
+//         this.y = 2;
+//                   ^
 //
 // pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
 //         this.x = 1;
 //                ^
 //
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected a function body or '=>'.
+// Try adding {}.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+// Try removing the return type.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'x' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:6:13: Context: 'x' is defined here.
+//   final int x;
+//             ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'y' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: 'y' is defined here.
+//   final int y;
+//             ^
+//
 import self as self;
 import "dart:core" as core;
 
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
+  erroneous constructor y() → self::E
+    : self::E::y = null, self::E::x = null, super core::Object::•()
+    invalid-expression "pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+Try removing the return type.
+        this.y = 2;
+                 ^";
   erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
     ;
   constructor named() → self::E
-    : self::E::x = 5, final dynamic #t2 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:13:20: Error: Can't use 'y' because it is declared more than once.
-              this.y = 6;
-                   ^"
+    : self::E::x = 5, self::E::y = 6, super core::Object::•()
     ;
 }
 static method main() → dynamic {}

diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect
index d16ec61..2d3100c 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.modular.expect

@@ -2,45 +2,91 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Expected a class member, but got 'this'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: 'this' can't be used as an identifier because it's a keyword.
+// Try renaming this to be an identifier that isn't a keyword.
 //         this.y = 2;
 //         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:13: Error: Expected a class member, but got '.'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: A method declaration needs an explicit list of parameters.
+// Try adding a parameter list to the method declaration.
 //         this.y = 2;
-//             ^
+//         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Only factory constructor can specify '=' redirection.
+// Try making this a factory constructor, or remove the redirection.
 //         this.y = 2;
-//              ^
+//                ^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: 'y' is already declared in this scope.
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected an identifier, but got '2'.
+// Try inserting an identifier before '2'.
 //         this.y = 2;
-//              ^
-// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: Previous declaration of 'y'.
-//   final int y;
-//             ^
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected ';' after this.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: The name of a constructor must match the name of the enclosing class.
+//         this.y = 2;
+//         ^^^^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected a class member, but got '2'.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:19: Error: Expected a class member, but got ';'.
+//         this.y = 2;
+//                   ^
 //
 // pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
 //         this.x = 1;
 //                ^
 //
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected a function body or '=>'.
+// Try adding {}.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+// Try removing the return type.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'x' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:6:13: Context: 'x' is defined here.
+//   final int x;
+//             ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'y' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: 'y' is defined here.
+//   final int y;
+//             ^
+//
 import self as self;
 import "dart:core" as core;
 
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
+  erroneous constructor y() → self::E
+    : self::E::y = null, self::E::x = null, super core::Object::•()
+    invalid-expression "pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+Try removing the return type.
+        this.y = 2;
+                 ^";
   erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
     ;
   constructor named() → self::E
-    : self::E::x = 5, final dynamic #t2 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:13:20: Error: Can't use 'y' because it is declared more than once.
-              this.y = 6;
-                   ^"
+    : self::E::x = 5, self::E::y = 6, super core::Object::•()
     ;
 }
 static method main() → dynamic {}

diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.outline.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.outline.expect
index 21d01c4..00476c2 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.outline.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.outline.expect

@@ -2,25 +2,41 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Expected a class member, but got 'this'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: 'this' can't be used as an identifier because it's a keyword.
+// Try renaming this to be an identifier that isn't a keyword.
 //         this.y = 2;
 //         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:13: Error: Expected a class member, but got '.'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: A method declaration needs an explicit list of parameters.
+// Try adding a parameter list to the method declaration.
 //         this.y = 2;
-//             ^
+//         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Only factory constructor can specify '=' redirection.
+// Try making this a factory constructor, or remove the redirection.
 //         this.y = 2;
-//              ^
+//                ^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: 'y' is already declared in this scope.
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected an identifier, but got '2'.
+// Try inserting an identifier before '2'.
 //         this.y = 2;
-//              ^
-// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: Previous declaration of 'y'.
-//   final int y;
-//             ^
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected ';' after this.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: The name of a constructor must match the name of the enclosing class.
+//         this.y = 2;
+//         ^^^^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected a class member, but got '2'.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:19: Error: Expected a class member, but got ';'.
+//         this.y = 2;
+//                   ^
 //
 import self as self;
 import "dart:core" as core;
@@ -28,6 +44,8 @@
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
+  constructor y() → self::E
+    ;
   constructor •() → self::E
     ;
   constructor named() → self::E

diff --git a/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect b/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect
index d16ec61..2d3100c 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.strong.transformed.expect

@@ -2,45 +2,91 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Expected a class member, but got 'this'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: 'this' can't be used as an identifier because it's a keyword.
+// Try renaming this to be an identifier that isn't a keyword.
 //         this.y = 2;
 //         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:13: Error: Expected a class member, but got '.'.
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: A method declaration needs an explicit list of parameters.
+// Try adding a parameter list to the method declaration.
 //         this.y = 2;
-//             ^
+//         ^^^^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Only factory constructor can specify '=' redirection.
+// Try making this a factory constructor, or remove the redirection.
 //         this.y = 2;
-//              ^
+//                ^
 //
-// pkg/front_end/testcases/general/issue43363.dart:10:14: Error: 'y' is already declared in this scope.
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected an identifier, but got '2'.
+// Try inserting an identifier before '2'.
 //         this.y = 2;
-//              ^
-// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: Previous declaration of 'y'.
-//   final int y;
-//             ^
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected ';' after this.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: The name of a constructor must match the name of the enclosing class.
+//         this.y = 2;
+//         ^^^^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Expected a class member, but got '2'.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:19: Error: Expected a class member, but got ';'.
+//         this.y = 2;
+//                   ^
 //
 // pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
 //         this.x = 1;
 //                ^
 //
+// pkg/front_end/testcases/general/issue43363.dart:10:16: Error: Expected a function body or '=>'.
+// Try adding {}.
+//         this.y = 2;
+//                ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+// Try removing the return type.
+//         this.y = 2;
+//                  ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'x' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:6:13: Context: 'x' is defined here.
+//   final int x;
+//             ^
+//
+// pkg/front_end/testcases/general/issue43363.dart:10:9: Error: Final field 'y' is not initialized by this constructor.
+// Try to initialize the field using an initializing formal or a field initializer.
+//         this.y = 2;
+//         ^
+// pkg/front_end/testcases/general/issue43363.dart:7:13: Context: 'y' is defined here.
+//   final int y;
+//             ^
+//
 import self as self;
 import "dart:core" as core;
 
 class E extends core::Object {
   final field core::int x;
   final field core::int y;
+  erroneous constructor y() → self::E
+    : self::E::y = null, self::E::x = null, super core::Object::•()
+    invalid-expression "pkg/front_end/testcases/general/issue43363.dart:10:18: Error: Constructors can't have a return type.
+Try removing the return type.
+        this.y = 2;
+                 ^";
   erroneous constructor •() → self::E
     : final dynamic #t1 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:9:16: Error: A redirecting constructor can't have other initializers.
         this.x = 1;
                ^", this self::E::named()
     ;
   constructor named() → self::E
-    : self::E::x = 5, final dynamic #t2 = invalid-expression "pkg/front_end/testcases/general/issue43363.dart:13:20: Error: Can't use 'y' because it is declared more than once.
-              this.y = 6;
-                   ^"
+    : self::E::x = 5, self::E::y = 6, super core::Object::•()
     ;
 }
 static method main() → dynamic {}

diff --git a/pkg/front_end/testcases/general/issue43363.dart.textual_outline.expect b/pkg/front_end/testcases/general/issue43363.dart.textual_outline.expect
index 789eed9..b80822e 100644
--- a/pkg/front_end/testcases/general/issue43363.dart.textual_outline.expect
+++ b/pkg/front_end/testcases/general/issue43363.dart.textual_outline.expect

@@ -2,8 +2,8 @@
   final int x;
   final int y;
   E() : this.named(), this.x = 1;
-  this.
-  y = 2;
+  this.y ()= ;
+  2;
   E.named() : this.x = 5, this.y = 6;
 }
 

diff --git a/pkg/linter/lib/src/rules/parameter_assignments.dart b/pkg/linter/lib/src/rules/parameter_assignments.dart
index d9c4eb3..2805fac 100644
--- a/pkg/linter/lib/src/rules/parameter_assignments.dart
+++ b/pkg/linter/lib/src/rules/parameter_assignments.dart

@@ -42,6 +42,8 @@
     var visitor = _Visitor(this);
     registry.addFunctionDeclaration(this, visitor);
     registry.addMethodDeclaration(this, visitor);
+    registry.addFunctionExpression(this, visitor);
+    registry.addConstructorDeclaration(this, visitor);
   }
 }
 
@@ -152,6 +154,11 @@
   _Visitor(this.rule);
 
   @override
+  void visitConstructorDeclaration(ConstructorDeclaration node) {
+    _checkParameters(node.parameters, node.body);
+  }
+
+  @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
     _checkParameters(
       node.functionExpression.parameters,
@@ -160,6 +167,13 @@
   }
 
   @override
+  void visitFunctionExpression(FunctionExpression node) {
+    if (node.parent is! FunctionDeclaration) {
+      _checkParameters(node.parameters, node.body);
+    }
+  }
+
+  @override
   void visitMethodDeclaration(MethodDeclaration node) {
     _checkParameters(node.parameters, node.body);
   }

diff --git a/pkg/linter/test/rules/erase_dart_type_extension_types_test.dart b/pkg/linter/test/rules/erase_dart_type_extension_types_test.dart
index 3ea96a3..41e90fb 100644
--- a/pkg/linter/test/rules/erase_dart_type_extension_types_test.dart
+++ b/pkg/linter/test/rules/erase_dart_type_extension_types_test.dart

@@ -15,10 +15,21 @@
 @reflectiveTest
 class EraseDartTypeExtensionTypesTest extends LintRuleTest {
   @override
-  bool get addKernelPackageDep => true;
+  String get lintRule => LintNames.erase_dart_type_extension_types;
 
   @override
-  String get lintRule => LintNames.erase_dart_type_extension_types;
+  void setUp() {
+    newPackage('kernel').addFile('lib/ast.dart', r'''
+library kernel.ast;
+
+abstract class Node {}
+
+class DartType extends Node {}
+
+class InterfaceType extends DartType {}
+''');
+    super.setUp();
+  }
 
   test_isDartType() async {
     await assertDiagnostics(

diff --git a/pkg/linter/test/rules/parameter_assignments_test.dart b/pkg/linter/test/rules/parameter_assignments_test.dart
index e596d0a..e896a75 100644
--- a/pkg/linter/test/rules/parameter_assignments_test.dart
+++ b/pkg/linter/test/rules/parameter_assignments_test.dart

@@ -17,6 +17,43 @@
   @override
   String get lintRule => LintNames.parameter_assignments;
 
+  test_anonymousFunction_assignment() async {
+    await assertDiagnostics(
+      r'''
+void main() {
+  (int i) {
+    i = 42;
+  }(0);
+}
+''',
+      [lint(30, 6)],
+    );
+  }
+
+  test_anonymousFunction_assignment_arrowBody() async {
+    await assertDiagnostics(
+      r'''
+void main() {
+  (int i) => i = 42;
+}
+''',
+      [lint(27, 6)],
+    );
+  }
+
+  test_anonymousFunction_assignment_notInvoked() async {
+    await assertDiagnostics(
+      r'''
+void main() {
+  (int i) {
+    i = 42;
+  };
+}
+''',
+      [lint(30, 6)],
+    );
+  }
+
   test_assignment_inIfElseBranches() async {
     await assertDiagnostics(
       r'''
@@ -70,7 +107,6 @@
     );
   }
 
-  @FailingTest(reason: 'Closures not implemented')
   test_closure_assignment() async {
     await assertDiagnostics(
       r'''
@@ -95,6 +131,19 @@
     );
   }
 
+  test_constructor_assignment() async {
+    await assertDiagnostics(
+      r'''
+class Foo {
+  Foo(int x) {
+    x = 4;
+  }
+}
+''',
+      [lint(31, 5)],
+    );
+  }
+
   test_function_assignment() async {
     await assertDiagnostics(
       r'''

diff --git a/pkg/wasm_builder/lib/src/builder/builder.dart b/pkg/wasm_builder/lib/src/builder/builder.dart
index 6a380e1..6e154b5 100644
--- a/pkg/wasm_builder/lib/src/builder/builder.dart
+++ b/pkg/wasm_builder/lib/src/builder/builder.dart

@@ -11,6 +11,7 @@
 export 'global.dart' show GlobalBuilder;
 export 'functions.dart' show FunctionsBuilder;
 export 'function.dart' show FunctionBuilder;
+export 'elements.dart' show ElementsBuilder;
 export 'memories.dart' show MemoriesBuilder;
 export 'module.dart' show ModuleBuilder;
 export 'tables.dart' show TablesBuilder;

diff --git a/pkg/wasm_builder/lib/src/builder/elements.dart b/pkg/wasm_builder/lib/src/builder/elements.dart
new file mode 100644
index 0000000..a3082f9
--- /dev/null
+++ b/pkg/wasm_builder/lib/src/builder/elements.dart

@@ -0,0 +1,107 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:math' as math;
+
+import '../ir/ir.dart' as ir;
+import 'builder.dart';
+
+/// Builder for the elements section of a wasm module.
+class ElementsBuilder with Builder<ir.Elements> {
+  final ModuleBuilder _moduleBuilder;
+  final _functionTableBuilders = <ir.Table, ActiveFunctionSegmentBuilder>{};
+
+  late final declarativeSegmentBuilder =
+      DeclarativeSegmentBuilder(_moduleBuilder);
+
+  ElementsBuilder(this._moduleBuilder);
+
+  ActiveFunctionSegmentBuilder activeFunctionSegmentBuilderFor(ir.Table table) {
+    assert(table.type.isSubtypeOf(ir.RefType.func(nullable: true)));
+    assert(table.enclosingModule == _moduleBuilder.module);
+    return _functionTableBuilders.putIfAbsent(
+        table, () => ActiveFunctionSegmentBuilder(table));
+  }
+
+  @override
+  ir.Elements forceBuild() {
+    final segments = <ir.ElementSegment>[];
+    for (final b in _functionTableBuilders.values) {
+      segments.addAll(b.build());
+    }
+    if (declarativeSegmentBuilder._declaredFunctions.isNotEmpty) {
+      segments.add(declarativeSegmentBuilder.build());
+    }
+    return ir.Elements(segments);
+  }
+}
+
+class DeclarativeSegmentBuilder with Builder<ir.DeclarativeElementSegment> {
+  final ModuleBuilder _moduleBuilder;
+  final _declaredFunctions = <ir.BaseFunction>{};
+
+  DeclarativeSegmentBuilder(this._moduleBuilder);
+
+  /// Pre-declare [function] in a declared segment which allows using that
+  /// function in `ref.func` constant instructions.
+  void declare(ir.BaseFunction function) {
+    assert(function.enclosingModule == _moduleBuilder.module);
+    _declaredFunctions.add(function);
+  }
+
+  @override
+  ir.DeclarativeElementSegment forceBuild() =>
+      ir.DeclarativeElementSegment(_declaredFunctions.toList());
+}
+
+class ActiveFunctionSegmentBuilder with Builder<List<ir.ActiveElementSegment>> {
+  final ir.Table table;
+  final Map<int, ir.BaseFunction> _functions = {};
+
+  ActiveFunctionSegmentBuilder(this.table);
+
+  void setFunctionAt(int index, ir.BaseFunction function) {
+    assert(function.enclosingModule == table.enclosingModule);
+    assert(table.maxSize == null || index < table.maxSize!,
+        'Index $index greater than max table size ${table.maxSize}');
+    _functions[index] = function;
+    table.minSize = math.max(table.minSize, index + 1);
+  }
+
+  @override
+  List<ir.ActiveElementSegment> forceBuild() {
+    final entries = _functions.entries.toList()
+      ..sort((a, b) => a.key.compareTo(b.key));
+
+    final segments = <ir.ActiveElementSegment>[];
+    if (const ir.RefType.func(nullable: false).isSubtypeOf(table.type)) {
+      ir.ActiveFunctionElementSegment? current;
+      int lastIndex = -2;
+      for (final entry in entries) {
+        final index = entry.key;
+        final function = entry.value;
+        if (index != lastIndex + 1) {
+          current = ir.ActiveFunctionElementSegment(table, index);
+          segments.add(current);
+        }
+        current!.entries.add(function);
+        lastIndex = index;
+      }
+    } else {
+      ir.ActiveExpressionElementSegment? current;
+      int lastIndex = -2;
+      for (final entry in entries) {
+        final index = entry.key;
+        final function = entry.value;
+        if (index != lastIndex + 1) {
+          current = ir.ActiveExpressionElementSegment(table, table.type, index);
+          segments.add(current);
+        }
+        current!.expressions.add([ir.RefFunc(function), ir.End()]);
+        lastIndex = index;
+      }
+    }
+    return segments;
+  }
+}

diff --git a/pkg/wasm_builder/lib/src/builder/functions.dart b/pkg/wasm_builder/lib/src/builder/functions.dart
index 6e957d5a..0999e08 100644
--- a/pkg/wasm_builder/lib/src/builder/functions.dart
+++ b/pkg/wasm_builder/lib/src/builder/functions.dart

@@ -11,7 +11,6 @@
   final ModuleBuilder _moduleBuilder;
   final _functionBuilders = <FunctionBuilder>[];
   final _importedFunctions = <ir.ImportedFunction>[];
-  final _declaredFunctions = <ir.BaseFunction>{};
 
   FunctionsBuilder(this._moduleBuilder);
 
@@ -45,17 +44,10 @@
     return function;
   }
 
-  /// Declare [function] as a module element so it can be used in a constant
-  /// context.
-  void declare(ir.BaseFunction function) {
-    assert(function.enclosingModule == _moduleBuilder.module);
-    _declaredFunctions.add(function);
-  }
-
   @override
   ir.Functions forceBuild() {
     final built = finalizeImportsAndBuilders<ir.DefinedFunction>(
         _importedFunctions, _functionBuilders);
-    return ir.Functions(_importedFunctions, built, [..._declaredFunctions]);
+    return ir.Functions(_importedFunctions, built);
   }
 }

diff --git a/pkg/wasm_builder/lib/src/builder/module.dart b/pkg/wasm_builder/lib/src/builder/module.dart
index 088db5c..668d195 100644
--- a/pkg/wasm_builder/lib/src/builder/module.dart
+++ b/pkg/wasm_builder/lib/src/builder/module.dart

@@ -26,7 +26,8 @@
   final List<int> watchPoints;
   late final TypesBuilder types;
   late final functions = FunctionsBuilder(this);
-  late final tables = TablesBuilder(module);
+  late final elements = ElementsBuilder(this);
+  late final tables = TablesBuilder(this);
   late final memories = MemoriesBuilder(module);
   late final tags = TagsBuilder(module);
   final dataSegments = DataSegmentsBuilder();
@@ -54,6 +55,7 @@
   ir.Module forceBuild() {
     final finalFunctions = functions.build();
     final finalTables = tables.build();
+    final finalElements = elements.build();
     final finalMemories = memories.build();
     final finalGlobals = globals.build();
     final finalTags = tags.build();
@@ -70,6 +72,7 @@
           finalFunctions,
           _startFunction,
           finalTables,
+          finalElements,
           finalTags,
           finalMemories,
           exports.build(),

diff --git a/pkg/wasm_builder/lib/src/builder/table.dart b/pkg/wasm_builder/lib/src/builder/table.dart
index 3c30615..caea162 100644
--- a/pkg/wasm_builder/lib/src/builder/table.dart
+++ b/pkg/wasm_builder/lib/src/builder/table.dart

@@ -7,25 +7,13 @@
 
 /// A table defined in a module.
 class TableBuilder extends ir.Table with IndexableBuilder<ir.DefinedTable> {
-  final List<ir.BaseFunction?> elements;
+  final ModuleBuilder moduleBuilder;
 
-  TableBuilder(super.enclosingModule, super.index, super.type, super.minSize,
-      super.maxSize)
-      : elements = List.filled(minSize, null, growable: true);
-
-  void setElement(int index, ir.BaseFunction function) {
-    assert(type.isSubtypeOf(ir.RefType.func(nullable: true)),
-        "Elements are only supported for funcref tables");
-    assert(maxSize == null || index < maxSize!,
-        'Index $index greater than max table size $maxSize');
-    assert(function.enclosingModule == enclosingModule);
-    if (index >= elements.length) {
-      elements.length = index + 1;
-    }
-    elements[index] = function;
-  }
+  TableBuilder(this.moduleBuilder, ir.FinalizableIndex index, ir.RefType type,
+      int minSize, int? maxSize)
+      : super(moduleBuilder.module, index, type, minSize, maxSize);
 
   @override
   ir.DefinedTable forceBuild() => ir.DefinedTable(
-      enclosingModule, elements, finalizableIndex, type, minSize, maxSize);
+      enclosingModule, finalizableIndex, type, minSize, maxSize);
 }

diff --git a/pkg/wasm_builder/lib/src/builder/tables.dart b/pkg/wasm_builder/lib/src/builder/tables.dart
index 4cb9dd8..793141d 100644
--- a/pkg/wasm_builder/lib/src/builder/tables.dart
+++ b/pkg/wasm_builder/lib/src/builder/tables.dart

@@ -8,16 +8,16 @@
 
 /// The interface for the tables in a module.
 class TablesBuilder with Builder<ir.Tables> {
-  final ir.Module _module;
+  final ModuleBuilder _moduleBuilder;
   final _tableBuilders = <TableBuilder>[];
   final _importedTables = <ir.ImportedTable>[];
 
-  TablesBuilder(this._module);
+  TablesBuilder(this._moduleBuilder);
 
   /// Defines a new table in this module.
   TableBuilder define(ir.RefType type, int minSize, [int? maxSize]) {
-    final table =
-        TableBuilder(_module, ir.FinalizableIndex(), type, minSize, maxSize);
+    final table = TableBuilder(
+        _moduleBuilder, ir.FinalizableIndex(), type, minSize, maxSize);
     _tableBuilders.add(table);
     return table;
   }
@@ -26,8 +26,8 @@
   ir.ImportedTable import(
       String module, String name, ir.RefType type, int minSize,
       [int? maxSize]) {
-    final table = ir.ImportedTable(
-        _module, module, name, ir.FinalizableIndex(), type, minSize, maxSize);
+    final table = ir.ImportedTable(_moduleBuilder.module, module, name,
+        ir.FinalizableIndex(), type, minSize, maxSize);
     _importedTables.add(table);
     return table;
   }

diff --git a/pkg/wasm_builder/lib/src/ir/element.dart b/pkg/wasm_builder/lib/src/ir/element.dart
new file mode 100644
index 0000000..4e172dd
--- /dev/null
+++ b/pkg/wasm_builder/lib/src/ir/element.dart

@@ -0,0 +1,199 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import '../serialize/serialize.dart';
+import 'ir.dart';
+
+sealed class ElementSegment implements Serializable {}
+
+sealed class ActiveElementSegment extends ElementSegment {
+  final Table table;
+  final int startIndex;
+
+  ActiveElementSegment(this.table, this.startIndex);
+}
+
+/// Initializes a specific table with function references.
+///
+/// NOTE: Can only be used if the table type is `RefType.func(nullable: true)`.
+final class ActiveFunctionElementSegment extends ActiveElementSegment {
+  final List<BaseFunction> entries;
+
+  ActiveFunctionElementSegment(super.table, super.startIndex,
+      [List<BaseFunction>? entries])
+      : entries = entries ?? [];
+
+  @override
+  void serialize(Serializer s) {
+    final useTable0Encoding = table.index == 0;
+    if (useTable0Encoding) {
+      s.writeByte(0x00);
+    } else {
+      s.writeByte(0x02);
+      s.writeUnsigned(table.index);
+    }
+    s.serializeTableOffset(startIndex);
+
+    if (!useTable0Encoding) {
+      s.writeByte(_ElemKind.refFunc);
+    }
+
+    s.writeUnsigned(entries.length);
+    for (var entry in entries) {
+      s.writeUnsigned(entry.index);
+    }
+  }
+
+  static ActiveFunctionElementSegment deserialize(
+    Deserializer d,
+    Module module,
+    Types types,
+    Functions functions,
+    Tables tables,
+    Globals globals,
+  ) {
+    const int tableIndex = 0;
+    final byte = d.readByte();
+    assert(byte == 0x00 || byte == 0x02);
+
+    final offset = d.deserializeTableOffset(types, functions, globals);
+
+    if (byte == 0x02) {
+      final elemKind = d.readByte();
+      if (elemKind != _ElemKind.refFunc) {
+        throw UnimplementedError('Unsupported element kind.');
+      }
+    }
+
+    final table = tables[tableIndex];
+    final tableElement = ActiveFunctionElementSegment(table, offset);
+    final count = d.readUnsigned();
+    for (int i = 0; i < count; i++) {
+      tableElement.entries.add(functions[d.readUnsigned()]);
+    }
+    return tableElement;
+  }
+}
+
+/// Initializes a specific table with initialization expressions.
+final class ActiveExpressionElementSegment extends ActiveElementSegment {
+  final RefType type;
+  final List<List<Instruction>> expressions = [];
+
+  ActiveExpressionElementSegment(super.table, this.type, super.startIndex);
+
+  @override
+  void serialize(Serializer s) {
+    final useTableTable0RefNullFuncEncoding =
+        table.index == 0 && type == RefType.func(nullable: true);
+    if (useTableTable0RefNullFuncEncoding) {
+      s.writeByte(0x04);
+    } else {
+      s.writeByte(0x06);
+      s.writeUnsigned(table.index);
+    }
+    s.serializeTableOffset(startIndex);
+    if (!useTableTable0RefNullFuncEncoding) {
+      s.write(type);
+    }
+    s.writeUnsigned(expressions.length);
+    for (final expression in expressions) {
+      for (final instruction in expression) {
+        instruction.serialize(s);
+      }
+    }
+  }
+
+  static ActiveExpressionElementSegment deserialize(
+    Deserializer d,
+    Module module,
+    Types types,
+    Functions functions,
+    Tables tables,
+    Globals globals,
+  ) {
+    final kind = d.readByte();
+    assert(kind == 0x04 || kind == 0x06);
+
+    final useTableTable0RefNullFuncEncoding = kind == 0x04;
+    final tableIndex = useTableTable0RefNullFuncEncoding ? 0 : d.readUnsigned();
+    final offset = d.deserializeTableOffset(types, functions, globals);
+    final type = useTableTable0RefNullFuncEncoding
+        ? RefType.func(nullable: true)
+        : RefType.deserialize(d, types.defined);
+
+    final table = tables[tableIndex];
+    final tableElement = ActiveExpressionElementSegment(table, type, offset);
+    final count = d.readUnsigned();
+    for (int i = 0; i < count; i++) {
+      final instructions = <Instruction>[];
+      while (true) {
+        final instruction =
+            Instruction.deserializeConst(d, types, functions, globals);
+        instructions.add(instruction);
+        if (instruction is End) break;
+      }
+      tableElement.expressions.add(instructions);
+    }
+    return tableElement;
+  }
+}
+
+final class DeclarativeElementSegment implements ElementSegment {
+  final List<BaseFunction> entries;
+
+  DeclarativeElementSegment(this.entries);
+
+  @override
+  void serialize(Serializer s) {
+    if (entries.isEmpty) return;
+    s.writeByte(0x03);
+    s.writeByte(_ElemKind.refFunc);
+
+    s.writeUnsigned(entries.length);
+    for (final entry in entries) {
+      s.writeUnsigned(entry.index);
+    }
+  }
+
+  static DeclarativeElementSegment deserialize(
+      Deserializer d, Functions functions) {
+    if (d.readByte() != 0x03) {
+      throw StateError('Expected declarative segment to start with 0x03.');
+    }
+
+    final elemkind = d.readByte();
+    if (elemkind != _ElemKind.refFunc) {
+      throw UnsupportedError('Unsupported element kind: $elemkind');
+    }
+
+    final declaredFunctions = d.readList((d) => functions[d.readUnsigned()]);
+    return DeclarativeElementSegment(declaredFunctions);
+  }
+}
+
+abstract class _ElemKind {
+  static const refFunc = 0;
+}
+
+extension on Serializer {
+  void serializeTableOffset(int offset) {
+    I32Const(offset).serialize(this);
+    End().serialize(this);
+  }
+}
+
+extension on Deserializer {
+  int deserializeTableOffset(
+      Types types, Functions functions, Globals globals) {
+    final i0 = Instruction.deserializeConst(this, types, functions, globals);
+    final i1 = Instruction.deserializeConst(this, types, functions, globals);
+    if (i0 is! I32Const || i1 is! End) {
+      throw StateError('Expected offset to be encoded as '
+          '`(i32.const <value>) (end)`. '
+          'Got instead: (${i0.name}) (${i1.name})');
+    }
+    return i0.value;
+  }
+}

diff --git a/pkg/wasm_builder/lib/src/ir/elements.dart b/pkg/wasm_builder/lib/src/ir/elements.dart
new file mode 100644
index 0000000..8dde374
--- /dev/null
+++ b/pkg/wasm_builder/lib/src/ir/elements.dart

@@ -0,0 +1,11 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'ir.dart';
+
+class Elements {
+  final List<ElementSegment> segments;
+
+  Elements(this.segments);
+}

diff --git a/pkg/wasm_builder/lib/src/ir/functions.dart b/pkg/wasm_builder/lib/src/ir/functions.dart
index 6ea06ddc..1f15e45 100644
--- a/pkg/wasm_builder/lib/src/ir/functions.dart
+++ b/pkg/wasm_builder/lib/src/ir/functions.dart

@@ -12,12 +12,7 @@
   /// Defined functions.
   final List<DefinedFunction> defined;
 
-  /// Declared functions.
-  late final List<BaseFunction> declared;
-
-  Functions(this.imported, this.defined, this.declared);
-
-  Functions.withoutDeclared(this.imported, this.defined);
+  Functions(this.imported, this.defined);
 
   BaseFunction operator [](int index) => index < imported.length
       ? imported[index]

diff --git a/pkg/wasm_builder/lib/src/ir/ir.dart b/pkg/wasm_builder/lib/src/ir/ir.dart
index b6cf0a2..481c4a7 100644
--- a/pkg/wasm_builder/lib/src/ir/ir.dart
+++ b/pkg/wasm_builder/lib/src/ir/ir.dart

@@ -21,6 +21,14 @@
 export 'memory.dart' show DefinedMemory, ImportedMemory, Memory, MemoryExport;
 export 'module.dart' show Module;
 export 'tables.dart' show Tables;
+export 'elements.dart' show Elements;
+export 'element.dart'
+    show
+        ElementSegment,
+        ActiveElementSegment,
+        ActiveFunctionElementSegment,
+        ActiveExpressionElementSegment,
+        DeclarativeElementSegment;
 export 'table.dart' show DefinedTable, ImportedTable, Table, TableExport;
 export 'tags.dart' show DefinedTag, ImportedTag, Tag, Tags, TagExport;
 export 'types.dart' show Types;

diff --git a/pkg/wasm_builder/lib/src/ir/module.dart b/pkg/wasm_builder/lib/src/ir/module.dart
index 29cda4c..8ea4981 100644
--- a/pkg/wasm_builder/lib/src/ir/module.dart
+++ b/pkg/wasm_builder/lib/src/ir/module.dart

@@ -26,6 +26,7 @@
   late final Functions _functions;
   late final BaseFunction? _start;
   late final Tables _tables;
+  late final Elements _elements;
   late final Tags _tags;
   late final Memories _memories;
   late final Exports _exports;
@@ -43,6 +44,7 @@
     Functions functions,
     BaseFunction? start,
     Tables tables,
+    Elements elements,
     Tags tags,
     Memories memories,
     Exports exports,
@@ -60,6 +62,7 @@
     _functions = functions;
     _start = start;
     _tables = tables;
+    _elements = elements;
     _tags = tags;
     _memories = memories;
     _exports = exports;
@@ -75,6 +78,7 @@
   Functions get functions => _functions;
   BaseFunction? get start => _start;
   Tables get tables => _tables;
+  Elements get elements => _elements;
   Tags get tags => _tags;
   Memories get memories => _memories;
   Exports get exports => _exports;
@@ -103,9 +107,7 @@
     GlobalSection(globals.defined, watchPoints).serialize(s);
     ExportSection(exports.exported, watchPoints).serialize(s);
     StartSection(start, watchPoints).serialize(s);
-    ElementSection(
-            tables.defined, tables.imported, functions.declared, watchPoints)
-        .serialize(s);
+    ElementSection(elements, watchPoints).serialize(s);
     DataCountSection(dataSegments.defined, watchPoints).serialize(s);
     CodeSection(functions.defined, watchPoints).serialize(s);
     DataSection(dataSegments.defined, watchPoints).serialize(s);
@@ -198,10 +200,7 @@
         StartSection.deserialize(startFunctionSections?.single, functions);
 
     final elementSections = sections[ElementSection.sectionId];
-    // As side-effect initializes [Table.elements]
-    // As side-effect initializes [ImprotedTable.setElements]
-    // As side-effect initializes [Functions.declaredFunctions]
-    ElementSection.deserialize(
+    final elements = ElementSection.deserialize(
         elementSections?.single, module, types, functions, tables, globals);
 
     final dataCountSections = sections[DataCountSection.sectionId];
@@ -230,6 +229,7 @@
         functions,
         start,
         tables,
+        elements,
         tags,
         memories,
         exports,

diff --git a/pkg/wasm_builder/lib/src/ir/table.dart b/pkg/wasm_builder/lib/src/ir/table.dart
index dc760d8..23d35b5 100644
--- a/pkg/wasm_builder/lib/src/ir/table.dart
+++ b/pkg/wasm_builder/lib/src/ir/table.dart

@@ -41,14 +41,10 @@
 
 /// A table defined in a module.
 class DefinedTable extends Table {
-  final List<BaseFunction?> elements;
+  DefinedTable(super.enclosingModule, super.finalizableIndex, super.type,
+      super.minSize, super.maxSize);
 
-  DefinedTable(super.enclosingModule, this.elements, super.finalizableIndex,
-      super.type, super.minSize, super.maxSize);
-
-  void printTo(IrPrinter p, {bool includeElements = true}) {
-    // NOTE: This format differs from what V8's `wami` will print.
-    // It makes it easier to see the exact values of the table.
+  void printTo(IrPrinter p) {
     p.write('(table ');
     p.writeTableReference(this, alwaysPrint: true);
     String? exportName;
@@ -65,23 +61,6 @@
 
     p.write(' $minSize ');
     p.writeValueType(type);
-    if (includeElements) {
-      if (elements.any((e) => e != null)) {
-        p.writeln();
-        p.withIndent(() {
-          for (int i = 0; i < elements.length; ++i) {
-            final function = elements[i];
-            if (function != null) {
-              p.write('(def $i ');
-              p.writeFunctionReference(function);
-              p.writeln(')');
-            }
-          }
-        });
-      }
-    } else {
-      p.write(' <...>');
-    }
     p.write(')');
   }
 }
@@ -93,9 +72,6 @@
   @override
   final String name;
 
-  /// Functions to be inserted via the elements section.
-  final Map<int, BaseFunction> setElements = {};
-
   ImportedTable(super.enclosingModule, this.module, this.name,
       super.finalizableIndex, super.type, super.minSize, super.maxSize);
 
@@ -107,29 +83,13 @@
     super.serialize(s);
   }
 
-  void printTo(IrPrinter p, {bool includeElements = true}) {
-    // NOTE: This format differs from what V8's `wami` will print.
-    // It makes it easier to see the exact values of the table.
+  void printTo(IrPrinter p) {
     p.write('(table ');
     p.writeTableReference(this, alwaysPrint: true);
     p.write(' ');
     p.writeImport(module, name);
     p.write(' $minSize ');
     p.writeValueType(type);
-    if (includeElements) {
-      if (setElements.isNotEmpty) {
-        p.writeln();
-        p.withIndent(() {
-          setElements.forEach((int i, function) {
-            p.write('(set $i ');
-            p.writeFunctionReference(function);
-            p.writeln(')');
-          });
-        });
-      }
-    } else {
-      p.write(' <...>');
-    }
     p.write(')');
   }
 }

diff --git a/pkg/wasm_builder/lib/src/serialize/printer.dart b/pkg/wasm_builder/lib/src/serialize/printer.dart
index 49e1136..bf511db 100644
--- a/pkg/wasm_builder/lib/src/serialize/printer.dart
+++ b/pkg/wasm_builder/lib/src/serialize/printer.dart

@@ -26,6 +26,9 @@
   final _types = <ir.DefType, String>{};
   final _tags = <ir.Tag, String>{};
   final _tables = <ir.Table, String>{};
+  final _elementSegments = <ir.ElementSegment>{};
+  final _activeElementSegments = <ir.Table, Map<int, String>>{};
+  final _declarativeElements = <ir.DeclarativeElementSegment, String>{};
   final _globals = <ir.Global, String>{};
   final _functions = <ir.BaseFunction, String>{};
   final _dataSegments = <ir.BaseDataSegment, String>{};
@@ -81,9 +84,84 @@
   void enqueueTable(ir.Table table) {
     if (!_tables.containsKey(table)) {
       _tables[table] = '';
-      _generateTable(table,
-          includeElements: settings.printTableElements(
-              tableNamer.nameTable(table, activateOnReferenceCallback: false)));
+      _generateTable(table);
+
+      for (final segment in _module.elements.segments) {
+        if (segment is ir.ActiveElementSegment && segment.table == table) {
+          enqueueElementSegment(segment);
+        }
+      }
+    }
+  }
+
+  void enqueueElementSegment(ir.ElementSegment segment) {
+    if (_elementSegments.add(segment)) {
+      switch (segment) {
+        case ir.ActiveFunctionElementSegment(
+            startIndex: final start,
+            table: final table,
+            entries: final entries
+          ):
+          final printedEntries =
+              _activeElementSegments.putIfAbsent(table, () => {});
+          if (settings.printTableElements(tableNamer.nameTable(segment.table,
+              activateOnReferenceCallback: false))) {
+            for (int i = 0; i < entries.length; ++i) {
+              final index = start + i;
+              final ip = newIrPrinter();
+              ip.write('(');
+              ir.RefFunc(entries[i]).printTo(ip);
+              ip.write(')');
+              printedEntries[index] = ip.getText();
+            }
+          }
+
+          break;
+        case ir.ActiveExpressionElementSegment(
+            startIndex: final start,
+            table: final table,
+            expressions: final expressions
+          ):
+          final printedEntries =
+              _activeElementSegments.putIfAbsent(table, () => {});
+          if (settings.printTableElements(tableNamer.nameTable(segment.table,
+              activateOnReferenceCallback: false))) {
+            for (int i = 0; i < expressions.length; ++i) {
+              final index = start + i;
+              final expression = expressions[i];
+              final ip = newIrPrinter();
+              for (int j = 0; j < expression.length; ++j) {
+                ip.write(j > 0 ? ' (' : '(');
+                expression[j].printTo(ip);
+                ip.write(')');
+              }
+              printedEntries[index] = ip.getText();
+            }
+          }
+          break;
+        case ir.DeclarativeElementSegment(entries: final entries):
+          final ip = newIrPrinter();
+          ip.write('(elem declare');
+          if (ip.preferMultiline) {
+            ip.indent();
+          }
+          for (final entry in entries) {
+            if (ip.preferMultiline) {
+              ip.writeln();
+            } else {
+              ip.write(' ');
+            }
+            ip.write('(');
+            ir.RefFunc(entry).printTo(ip);
+            ip.write(')');
+          }
+          if (ip.preferMultiline) {
+            ip.deindent();
+          }
+          ip.write(')');
+          _declarativeElements[segment] = ip.getText();
+          break;
+      }
     }
   }
 
@@ -151,6 +229,13 @@
           mp.writeln();
         }
       }
+      for (final table in _module.tables.defined) {
+        final s = _tables[table];
+        if (s != null) {
+          mp.write(s);
+          mp.writeln();
+        }
+      }
       for (final tag in _module.tags.defined) {
         final s = _tags[tag];
         if (s != null) {
@@ -165,13 +250,30 @@
           mp.writeln();
         }
       }
-      for (final table in _module.tables.defined) {
-        final s = _tables[table];
-        if (s != null) {
-          mp.write(s);
-          mp.writeln();
+      _activeElementSegments.forEach((table, values) {
+        final ip = newIrPrinter();
+        ip.write('(elem ');
+        ip.writeTableReference(table, alwaysPrint: true);
+        if (values.isEmpty) {
+          ip.write(' <...>');
+        } else {
+          ip.withIndent(() {
+            final indices = values.keys.toList()..sort();
+            for (int i = 0; i < indices.length; ++i) {
+              ip.writeln();
+              final index = indices[i];
+              final value = values[index]!;
+              ip.write('(set $index $value)');
+            }
+          });
         }
-      }
+        ip.write(')');
+        mp.writeln(ip.getText());
+      });
+      _declarativeElements.forEach((_, value) {
+        mp.writeln(value);
+      });
+
       for (final fun in _module.functions.defined) {
         final s = _functions[fun];
         if (s != null) {
@@ -197,12 +299,12 @@
     _tags[tag] = p.getText();
   }
 
-  void _generateTable(ir.Table table, {required bool includeElements}) {
+  void _generateTable(ir.Table table) {
     final p = newIrPrinter();
     if (table is ir.DefinedTable) {
-      table.printTo(p, includeElements: includeElements);
+      table.printTo(p);
     } else if (table is ir.ImportedTable) {
-      table.printTo(p, includeElements: includeElements);
+      table.printTo(p);
     } else {
       return;
     }

diff --git a/pkg/wasm_builder/lib/src/serialize/sections.dart b/pkg/wasm_builder/lib/src/serialize/sections.dart
index 3ae4b13..6b73699 100644
--- a/pkg/wasm_builder/lib/src/serialize/sections.dart
+++ b/pkg/wasm_builder/lib/src/serialize/sections.dart

@@ -240,7 +240,7 @@
   static ir.Functions deserialize(Deserializer? d, ir.Module module,
       ir.Types types, List<ir.ImportedFunction> imported) {
     if (d == null) {
-      return ir.Functions.withoutDeclared(imported, []);
+      return ir.Functions(imported, []);
     }
 
     final List<ir.DefinedFunction> defined = [];
@@ -252,7 +252,7 @@
           module, ir.FinalizableIndex()..value = imported.length + i, type);
       defined.add(function);
     }
-    return ir.Functions.withoutDeclared(imported, defined);
+    return ir.Functions(imported, defined);
   }
 }
 
@@ -286,7 +286,6 @@
       final maxSize = limits == 0x01 ? d.readUnsigned() : null;
       final table = ir.DefinedTable(
           module,
-          [],
           ir.FinalizableIndex()..value = imported.length + i,
           type,
           minSize,
@@ -500,188 +499,24 @@
   }
 }
 
-sealed class _Element implements Serializable {}
-
-class _TableElement implements _Element {
-  final ir.Table table;
-  final int startIndex;
-  final List<ir.BaseFunction> entries = [];
-
-  _TableElement(this.table, this.startIndex);
-
-  @override
-  void serialize(Serializer s) {
-    final int kind;
-    if (table.index == 0) {
-      kind = 0x00;
-      s.writeByte(kind);
-    } else {
-      kind = 0x06;
-      s.writeByte(kind);
-      s.writeUnsigned(table.index);
-    }
-
-    ir.I32Const(startIndex).serialize(s);
-    ir.End().serialize(s);
-
-    if (kind == 0x06) {
-      s.write(table.type);
-    }
-    s.writeUnsigned(entries.length);
-    for (var entry in entries) {
-      if (kind == 0x0) {
-        s.writeUnsigned(entry.index);
-      } else {
-        ir.RefFunc(entry).serialize(s);
-        ir.End().serialize(s);
-      }
-    }
-  }
-
-  static _TableElement deserialize(
-    Deserializer d,
-    ir.Module module,
-    ir.Types types,
-    ir.Functions functions,
-    ir.Tables tables,
-    ir.Globals globals,
-  ) {
-    final int tableIndex;
-    final kind = d.readByte();
-    switch (kind) {
-      case 0x00:
-        tableIndex = 0;
-        break;
-      case 0x06:
-        tableIndex = d.readUnsigned();
-        break;
-      default:
-        throw "unsupported element segment kind $kind";
-    }
-
-    final i0 = ir.Instruction.deserializeConst(d, types, functions, globals);
-    final i1 = ir.Instruction.deserializeConst(d, types, functions, globals);
-    if (i0 is! ir.I32Const || i1 is! ir.End) {
-      throw StateError('Expected offset to be encoded as '
-          '`(i32.const <value>) (end)`. '
-          'Got instead: (${i0.name}) (${i1.name})');
-    }
-    final offset = i0.value;
-
-    if (kind == 0x06) {
-      ir.RefType.deserialize(d, types.defined);
-    }
-
-    final table = tables[tableIndex];
-    final tableElement = _TableElement(table, offset);
-    final count = d.readUnsigned();
-    for (int i = 0; i < count; i++) {
-      if (kind == 0x0) {
-        tableElement.entries.add(functions[d.readUnsigned()]);
-      } else {
-        final i0 =
-            ir.Instruction.deserializeConst(d, types, functions, globals);
-        final i1 =
-            ir.Instruction.deserializeConst(d, types, functions, globals);
-        if (i0 is! ir.RefFunc || i1 is! ir.End) {
-          throw StateError('Expected function reference to be encoded as '
-              '`(ref.func <value>) (end)`. '
-              'Got instead: (${i0.name}) (${i1.name})');
-        }
-        tableElement.entries.add(i0.function);
-      }
-    }
-    return tableElement;
-  }
-}
-
-class _DeclaredElement implements _Element {
-  final List<ir.BaseFunction> entries;
-
-  _DeclaredElement(this.entries);
-
-  @override
-  void serialize(Serializer s) {
-    if (entries.isEmpty) return;
-    s.writeByte(0x03);
-    s.writeByte(0x00);
-
-    s.writeUnsigned(entries.length);
-    for (final entry in entries) {
-      s.writeUnsigned(entry.index);
-    }
-  }
-
-  static _DeclaredElement deserialize(Deserializer d, ir.Functions functions) {
-    if (d.readByte() != 0x03) throw 'bad encoding';
-
-    final elemkind = d.readByte();
-    if (elemkind != 0x00) throw "unsupported elemkind";
-
-    final declaredFunctions = d.readList((d) => functions[d.readUnsigned()]);
-    return _DeclaredElement(declaredFunctions);
-  }
-}
-
 class ElementSection extends Section {
   static const int sectionId = 9;
 
-  final List<ir.DefinedTable> definedTables;
-  final List<ir.ImportedTable> importedTables;
-  final List<ir.BaseFunction> declaredFunctions;
+  final ir.Elements elementSegments;
 
-  ElementSection(this.definedTables, this.importedTables,
-      this.declaredFunctions, super.watchPoints);
+  ElementSection(this.elementSegments, super.watchPoints);
 
   @override
   int get id => sectionId;
 
   @override
   void serializeContents(Serializer s) {
-    // Group nonempty element entries into contiguous stretches and serialize
-    // each stretch as an element.
-    List<_Element> elements = [];
-    for (final table in definedTables) {
-      _TableElement? current;
-      for (int i = 0; i < table.elements.length; i++) {
-        ir.BaseFunction? function = table.elements[i];
-        if (function != null) {
-          if (current == null) {
-            current = _TableElement(table, i);
-            elements.add(current);
-          }
-          current.entries.add(function);
-        } else {
-          current = null;
-        }
-      }
-    }
-    for (final table in importedTables) {
-      final entries = [...table.setElements.entries]
-        ..sort((a, b) => a.key.compareTo(b.key));
-
-      _TableElement? current;
-      int lastIndex = -2;
-      for (final entry in entries) {
-        final index = entry.key;
-        final function = entry.value;
-        if (index != lastIndex + 1) {
-          current = _TableElement(table, index);
-          elements.add(current);
-        }
-        current!.entries.add(function);
-        lastIndex = index;
-      }
-    }
-    if (declaredFunctions.isNotEmpty) {
-      elements.add(_DeclaredElement(declaredFunctions));
-    }
-    if (elements.isNotEmpty) {
-      s.writeList(elements);
+    if (elementSegments.segments.isNotEmpty) {
+      s.writeList(elementSegments.segments);
     }
   }
 
-  static void deserialize(
+  static ir.Elements deserialize(
     Deserializer? d,
     ir.Module module,
     ir.Types types,
@@ -690,38 +525,36 @@
     ir.Globals globals,
   ) {
     if (d == null) {
-      functions.declared = [];
-      return;
+      return ir.Elements([]);
     }
-    final declaredFunctions = <ir.BaseFunction>[];
+
+    final segments = <ir.ElementSegment>[];
     final count = d.readUnsigned();
     for (int i = 0; i < count; i++) {
-      if (d.peekByte() == 0x03) {
-        final declaredElement = _DeclaredElement.deserialize(d, functions);
-        declaredFunctions.addAll(declaredElement.entries);
+      final byte = d.peekByte();
+      if (byte == 0x03) {
+        // Declarative segment, only to forward-declare functions.
+        final es = ir.DeclarativeElementSegment.deserialize(d, functions);
+        segments.add(es);
         continue;
       }
-      final tableElement = _TableElement.deserialize(
-          d, module, types, functions, tables, globals);
-      for (int i = 0; i < tableElement.entries.length; i++) {
-        final table = tableElement.table;
-        final offset = tableElement.startIndex;
-        final function = tableElement.entries[i];
-
-        if (table is ir.DefinedTable) {
-          if (table.elements.length <= offset + i) {
-            table.elements.length = offset + i + 1;
-          }
-          table.elements[offset + i] = function;
-        } else if (table is ir.ImportedTable) {
-          table.setElements[offset + i] = function;
-        } else {
-          throw "unsupported table type $table";
-        }
+      if (byte == 0x00 || byte == 0x02) {
+        // Active element, table values are function indices.
+        final es = ir.ActiveFunctionElementSegment.deserialize(
+            d, module, types, functions, tables, globals);
+        segments.add(es);
+        continue;
+      }
+      if (byte == 0x04 || byte == 0x06) {
+        // Active element, table values are expressions.
+        final es = ir.ActiveExpressionElementSegment.deserialize(
+            d, module, types, functions, tables, globals);
+        segments.add(es);
+        continue;
       }
     }
 
-    functions.declared = declaredFunctions;
+    return ir.Elements(segments);
   }
 }
 

diff --git a/sdk/lib/_internal/wasm/lib/type.dart b/sdk/lib/_internal/wasm/lib/type.dart
index 2222c78..f6d62ce 100644
--- a/sdk/lib/_internal/wasm/lib/type.dart
+++ b/sdk/lib/_internal/wasm/lib/type.dart

@@ -1780,10 +1780,6 @@
 /// Checks that argument lists have expected number of arguments for the
 /// closure.
 ///
-/// If the type argument list ([typeArguments]) is empty but the closure has
-/// type parameters, updates [typeArguments] with the default bounds of the
-/// type parameters.
-///
 /// [namedArguments] is a list of `Symbol` and `Object?` pairs.
 @pragma("wasm:entry-point")
 bool _checkClosureShape(

diff --git a/tests/web/wasm/closures/dynamic_call_via_field_test.dart b/tests/web/wasm/closures/dynamic_call_via_field_test.dart
new file mode 100644
index 0000000..6bc4d2d
--- /dev/null
+++ b/tests/web/wasm/closures/dynamic_call_via_field_test.dart

@@ -0,0 +1,21 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:expect/expect.dart';
+
+void main() {
+  final runtimeTrue = int.parse('1') == 1;
+  final dynamic object = runtimeTrue ? A() : 'a';
+
+  // The purpose of this test is to ensure that dar2wasm's closed-world closure
+  // layouter will consider `(foobar: 1)` as a closure call site and therefore
+  // register `foobar` to be a used name combination.
+  Expect.equals('foo<$int>(1)', object.closureGetter<int>(foobar: 1));
+}
+
+class A {
+  void Function<T>() get closureGetter => foo;
+}
+
+String foo<T>({int? foobar}) => "foo<$T>($foobar)";

diff --git a/tests/web/wasm/closures/function_apply_test.dart b/tests/web/wasm/closures/function_apply_test.dart
new file mode 100644
index 0000000..7547272
--- /dev/null
+++ b/tests/web/wasm/closures/function_apply_test.dart

@@ -0,0 +1,29 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+
+main() {
+  // Prevent constant propagation of closure into `Function.apply`.
+  for (final (name, closure) in <(String, Function)>[
+    ('static1', static1),
+    ('static2', static2),
+  ]) {
+    test('$name: 1 missing-b', closure, [1]);
+    test('$name: 1 2', closure, [1, 2]);
+  }
+}
+
+String static1(a, [b = 'missing-b']) => 'static1: $a $b';
+String static2(a, [b = 'missing-b']) => 'static2: $a $b';
+
+void test(String expected, Function function, List positional) {
+  Expect.equals(expected, Function.apply(function, positional));
+  final oneMoreThanAllowed = [
+    for (int i = positional.length; i < 3; ++i) 'extra$i',
+  ];
+  Expect.throwsNoSuchMethodError(
+    () => Function.apply(function, [...positional, ...oneMoreThanAllowed]),
+  );
+}

diff --git a/tools/VERSION b/tools/VERSION
index 1305895..960133e 100644
--- a/tools/VERSION
+++ b/tools/VERSION

@@ -27,5 +27,5 @@
 MAJOR 3
 MINOR 11
 PATCH 0
-PRERELEASE 112
+PRERELEASE 113
 PRERELEASE_PATCH 0