diff --git a/pkg/analyzer/lib/src/dart/analysis/driver.dart b/pkg/analyzer/lib/src/dart/analysis/driver.dart
index d8d2ac7..0c9499c 100644
--- a/pkg/analyzer/lib/src/dart/analysis/driver.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/driver.dart
@@ -335,6 +335,20 @@
   /// not been processed yet, it might be missing.
   Set<String> get knownFiles => _fsState.knownFilePaths;
 
+  /// Return the context in which libraries should be analyzed.
+  LibraryContext get libraryContext {
+    return _libraryContext ??= LibraryContext(
+      testView: _testView.libraryContextTestView,
+      session: currentSession,
+      logger: _logger,
+      byteStore: _byteStore,
+      analysisOptions: _analysisOptions,
+      declaredVariables: declaredVariables,
+      sourceFactory: _sourceFactory,
+      externalSummaries: _externalSummaries,
+    );
+  }
+
   /// Return the path of the folder at the root of the context.
   String get name => analysisContext?.contextRoot.root.path ?? '';
 
@@ -684,7 +698,6 @@
         return UnspecifiedInvalidResult();
       },
       (externalLibrary) async {
-        var libraryContext = _createLibraryContext(null);
         var element = libraryContext.getLibraryElement(externalLibrary.uri);
         return LibraryElementResultImpl(element);
       },
@@ -1301,7 +1314,7 @@
           return _newMissingDartLibraryResult(file, 'dart:async');
         }
 
-        var libraryContext = _createLibraryContext(library!);
+        libraryContext.load2(library!);
 
         LibraryAnalyzer analyzer = LibraryAnalyzer(
             analysisOptions as AnalysisOptionsImpl,
@@ -1373,7 +1386,7 @@
 
     return _logger.run('Compute resolved library $path', () {
       _testView.numOfAnalyzedLibraries++;
-      var libraryContext = _createLibraryContext(library);
+      libraryContext.load2(library);
 
       LibraryAnalyzer analyzer = LibraryAnalyzer(
           analysisOptions as AnalysisOptionsImpl,
@@ -1431,7 +1444,7 @@
 
     return _logger.run('Compute unit element for $path', () {
       _logger.writeln('Work in $name');
-      var libraryContext = _createLibraryContext(library!);
+      libraryContext.load2(library!);
       var element = libraryContext.computeUnitElement(library, file);
       return UnitElementResultImpl(
         currentSession,
@@ -1478,36 +1491,6 @@
     _fileTracker = FileTracker(_logger, _fsState);
   }
 
-  /// Return the context in which the [library] should be analyzed.
-  LibraryContext _createLibraryContext(FileState? library) {
-    {
-      var libraryContext = _libraryContext;
-      if (libraryContext != null) {
-        if (libraryContext.pack()) {
-          clearLibraryContext();
-        }
-      }
-    }
-
-    var libraryContext = _libraryContext;
-    libraryContext ??= _libraryContext = LibraryContext(
-      testView: _testView.libraryContextTestView,
-      session: currentSession,
-      logger: _logger,
-      byteStore: _byteStore,
-      analysisOptions: _analysisOptions,
-      declaredVariables: declaredVariables,
-      sourceFactory: _sourceFactory,
-      externalSummaries: _externalSummaries,
-    );
-
-    if (library != null) {
-      libraryContext.load2(library);
-    }
-
-    return libraryContext;
-  }
-
   /// If this has not been done yet, schedule discovery of all files that are
   /// potentially available, so that they are included in [knownFiles].
   void _discoverAvailableFiles() {
diff --git a/pkg/analyzer/lib/src/dart/analysis/library_context.dart b/pkg/analyzer/lib/src/dart/analysis/library_context.dart
index af4763e..dbdb140 100644
--- a/pkg/analyzer/lib/src/dart/analysis/library_context.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/library_context.dart
@@ -36,8 +36,6 @@
 ///
 /// Currently this is implemented as a wrapper around [AnalysisContext].
 class LibraryContext {
-  static const _maxLinkedDataInBytes = 64 * 1024 * 1024;
-
   final LibraryContextTestView testView;
   final PerformanceLog logger;
   final ByteStore byteStore;
@@ -45,11 +43,6 @@
   final SummaryDataStore? externalSummaries;
   final SummaryDataStore store = SummaryDataStore([]);
 
-  /// The size of the linked data that is loaded by this context.
-  /// When it reaches [_maxLinkedDataInBytes] the whole context is thrown away.
-  /// We use it as an approximation for the heap size of elements.
-  final int _linkedDataInBytes = 0;
-
   late final AnalysisContextImpl analysisContext;
   late LinkedElementFactory elementFactory;
 
@@ -224,15 +217,6 @@
     timerLoad2.stop();
   }
 
-  /// Return `true` if this context grew too large, and should be recreated.
-  ///
-  /// It might have been used to analyze libraries that we don't need anymore,
-  /// and because loading libraries is not very expensive (but not free), the
-  /// simplest way to get rid of the garbage is to throw away everything.
-  bool pack() {
-    return _linkedDataInBytes > _maxLinkedDataInBytes;
-  }
-
   void _createElementFactory() {
     elementFactory = LinkedElementFactory(
       analysisContext,
diff --git a/pkg/front_end/lib/src/fasta/source/outline_builder.dart b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
index 902f60b..63f5779 100644
--- a/pkg/front_end/lib/src/fasta/source/outline_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
@@ -2314,6 +2314,14 @@
       } else {
         // TODO(ahe): Improve this error message.
         addProblem(messageTypedefNotFunction, equals.charOffset, equals.length);
+        aliasedType = new NamedTypeBuilder.fromTypeDeclarationBuilder(
+            new InvalidTypeDeclarationBuilder(
+                "${name}",
+                messageTypedefNotType.withLocation(
+                    uri, equals.charOffset, equals.length)),
+            const NullabilityBuilder.omitted(),
+            instanceTypeVariableAccess:
+                InstanceTypeVariableAccessState.Allowed);
       }
     }
     List<MetadataBuilder>? metadata = pop() as List<MetadataBuilder>?;
diff --git a/pkg/front_end/testcases/general/issue47495.dart b/pkg/front_end/testcases/general/issue47495.dart
new file mode 100644
index 0000000..53c19c1
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue47495.dart
@@ -0,0 +1,15 @@
+// Copyright (c) 2021, 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.
+
+// @dart = 2.9
+
+class S {}
+class M {}
+
+typedef SAlias = S;
+typedef MAlias = M;
+
+class C = SAlias with MAlias;
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue47495.dart.textual_outline.expect b/pkg/front_end/testcases/general/issue47495.dart.textual_outline.expect
new file mode 100644
index 0000000..c7f3471
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue47495.dart.textual_outline.expect
@@ -0,0 +1,7 @@
+// @dart = 2.9
+class S {}
+class M {}
+typedef SAlias = S;
+typedef MAlias = M;
+class C = SAlias with MAlias;
+main() {}
diff --git a/pkg/front_end/testcases/general/issue47495.dart.weak.expect b/pkg/front_end/testcases/general/issue47495.dart.weak.expect
new file mode 100644
index 0000000..1c6fab0
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue47495.dart.weak.expect
@@ -0,0 +1,84 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/issue47495.dart:10:16: Error: Can't create typedef from non-function type.
+// typedef SAlias = S;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:11:16: Error: Can't create typedef from non-function type.
+// typedef MAlias = M;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' can't be mixed in.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'SAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:10:9: Context: The issue arises via this type alias.
+// typedef SAlias = S;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef SAlias = invalid-type;
+typedef MAlias = invalid-type;
+class S extends core::Object {
+  synthetic constructor •() → self::S*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class M extends core::Object {
+  synthetic constructor •() → self::M*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class C extends core::Object {
+  synthetic constructor •() → self::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/general/issue47495.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue47495.dart.weak.outline.expect
new file mode 100644
index 0000000..f366ace
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue47495.dart.weak.outline.expect
@@ -0,0 +1,82 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/issue47495.dart:10:16: Error: Can't create typedef from non-function type.
+// typedef SAlias = S;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:11:16: Error: Can't create typedef from non-function type.
+// typedef MAlias = M;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' can't be mixed in.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'SAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:10:9: Context: The issue arises via this type alias.
+// typedef SAlias = S;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef SAlias = invalid-type;
+typedef MAlias = invalid-type;
+class S extends core::Object {
+  synthetic constructor •() → self::S*
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class M extends core::Object {
+  synthetic constructor •() → self::M*
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class C extends core::Object {
+  synthetic constructor •() → self::C*
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/general/issue47495.dart.weak.transformed.expect b/pkg/front_end/testcases/general/issue47495.dart.weak.transformed.expect
new file mode 100644
index 0000000..1c6fab0
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue47495.dart.weak.transformed.expect
@@ -0,0 +1,84 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/issue47495.dart:10:16: Error: Can't create typedef from non-function type.
+// typedef SAlias = S;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:11:16: Error: Can't create typedef from non-function type.
+// typedef MAlias = M;
+//                ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' can't be mixed in.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'SAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:10:9: Context: The issue arises via this type alias.
+// typedef SAlias = S;
+//         ^
+//
+// pkg/front_end/testcases/general/issue47495.dart:13:7: Error: The type 'MAlias' which is an alias of 'invalid-type' can't be used as supertype.
+// class C = SAlias with MAlias;
+//       ^
+// pkg/front_end/testcases/general/issue47495.dart:11:9: Context: The issue arises via this type alias.
+// typedef MAlias = M;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef SAlias = invalid-type;
+typedef MAlias = invalid-type;
+class S extends core::Object {
+  synthetic constructor •() → self::S*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class M extends core::Object {
+  synthetic constructor •() → self::M*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+class C extends core::Object {
+  synthetic constructor •() → self::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method toString() → core::String*; -> core::Object::toString
+  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/textual_outline.status b/pkg/front_end/testcases/textual_outline.status
index 344af28..decb8b5 100644
--- a/pkg/front_end/testcases/textual_outline.status
+++ b/pkg/front_end/testcases/textual_outline.status
@@ -87,6 +87,7 @@
 general/issue43363: FormatterCrash
 general/issue45490: FormatterCrash
 general/issue45700.crash: FormatterCrash
+general/issue47495: FormatterCrash
 general/many_errors: FormatterCrash
 general/missing_prefix_name: FormatterCrash
 general/new_as_selector: FormatterCrash
diff --git a/runtime/tests/vm/dart/regress_47468_test.dart b/runtime/tests/vm/dart/regress_47468_test.dart
new file mode 100644
index 0000000..1ff1bbe
--- /dev/null
+++ b/runtime/tests/vm/dart/regress_47468_test.dart
@@ -0,0 +1,18 @@
+// Copyright (c) 2021, 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.
+
+// Regression test for https://github.com/dart-lang/sdk/issues/47468.
+// Verifies that the sending empty non-const maps works
+
+// VMOptions=--no-enable-isolate-groups
+
+import 'dart:isolate';
+
+void main() async {
+  final nonConstMap = <int, Object>{};
+  final receivePort = ReceivePort();
+  final sendPort = receivePort.sendPort;
+  sendPort.send(nonConstMap);
+  await receivePort.first;
+}
diff --git a/runtime/tests/vm/dart_2/regress_47468_test.dart b/runtime/tests/vm/dart_2/regress_47468_test.dart
new file mode 100644
index 0000000..b1ccb10
--- /dev/null
+++ b/runtime/tests/vm/dart_2/regress_47468_test.dart
@@ -0,0 +1,20 @@
+// Copyright (c) 2021, 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.
+
+// Regression test for https://github.com/dart-lang/sdk/issues/47468.
+// Verifies that the sending empty non-const maps works
+
+// VMOptions=--no-enable-isolate-groups
+
+// @dart = 2.9
+
+import 'dart:isolate';
+
+void main() async {
+  final nonConstMap = <int, Object>{};
+  final receivePort = ReceivePort();
+  final sendPort = receivePort.sendPort;
+  sendPort.send(nonConstMap);
+  await receivePort.first;
+}
diff --git a/sdk/lib/_internal/vm/lib/compact_hash.dart b/sdk/lib/_internal/vm/lib/compact_hash.dart
index 096f7ef..14fbf46 100644
--- a/sdk/lib/_internal/vm/lib/compact_hash.dart
+++ b/sdk/lib/_internal/vm/lib/compact_hash.dart
@@ -24,15 +24,15 @@
   // least one unoccupied entry.
   // NOTE: When maps are deserialized, their _index and _hashMask is regenerated
   // eagerly by _regenerateIndex.
-  Uint32List _index = _initialIndex;
+  Uint32List _index = _uninitializedIndex;
 
   // Cached in-place mask for the hash pattern component.
-  int _hashMask = 0;
+  int _hashMask = _HashBase._UNINITIALIZED_HASH_MASK;
 
   // Fixed-length list of keys (set) or key/value at even/odd indices (map).
   //
   // Can be either a mutable or immutable list.
-  List _data = _initialData;
+  List _data = _uninitializedData;
 
   // Length of _data that is used (i.e., keys + values for a map).
   int _usedData = 0;
@@ -126,12 +126,15 @@
 // TODO(koda): Consider moving field comments to _HashFieldBase.
 abstract class _HashBase implements _HashVMBase {
   // The number of bits used for each component is determined by table size.
-  // The length of _index is twice the number of entries in _data, and both
-  // are doubled when _data is full. Thus, _index will have a max load factor
-  // of 1/2, which enables one more bit to be used for the hash.
+  // If initialized, the length of _index is (at least) twice the number of
+  // entries in _data, and both are doubled when _data is full. Thus, _index
+  // will have a max load factor of 1/2, which enables one more bit to be used
+  // for the hash.
   // TODO(koda): Consider growing _data by factor sqrt(2), twice as often.
   static const int _INITIAL_INDEX_BITS = 2;
   static const int _INITIAL_INDEX_SIZE = 1 << (_INITIAL_INDEX_BITS + 1);
+  static const int _UNINITIALIZED_INDEX_SIZE = 1;
+  static const int _UNINITIALIZED_HASH_MASK = 0;
 
   // Unused and deleted entries are marked by 0 and 1, respectively.
   static const int _UNUSED_PAIR = 0;
@@ -142,6 +145,11 @@
   // as unsigned words.
   // Keep consistent with IndexSizeToHashMask in runtime/vm/object.h.
   static int _indexSizeToHashMask(int indexSize) {
+    assert(indexSize >= _INITIAL_INDEX_SIZE ||
+        indexSize == _UNINITIALIZED_INDEX_SIZE);
+    if (indexSize == _UNINITIALIZED_INDEX_SIZE) {
+      return _UNINITIALIZED_HASH_MASK;
+    }
     int indexBits = indexSize.bitLength - 2;
     return internal.has63BitSmis
         ? (1 << (32 - indexBits)) - 1
@@ -203,11 +211,11 @@
   bool _equals(e1, e2) => e1 == e2;
 }
 
-final _initialIndex = new Uint32List(1);
+final _uninitializedIndex = new Uint32List(_HashBase._UNINITIALIZED_INDEX_SIZE);
 // Note: not const. Const arrays are made immutable by having a different class
 // than regular arrays that throws on element assignment. We want the data field
 // in maps and sets to be monomorphic.
-final _initialData = new List.filled(0, null);
+final _uninitializedData = new List.filled(0, null);
 
 // VM-internalized implementation of a default-constructed LinkedHashMap.
 @pragma("vm:entry-point")
@@ -219,9 +227,9 @@
         _OperatorEqualsAndHashCode
     implements LinkedHashMap<K, V> {
   _InternalLinkedHashMap() {
-    _index = _initialIndex;
-    _hashMask = 0;
-    _data = _initialData;
+    _index = _uninitializedIndex;
+    _hashMask = _HashBase._UNINITIALIZED_HASH_MASK;
+    _data = _uninitializedData;
     _usedData = 0;
     _deletedKeys = 0;
   }
@@ -324,7 +332,11 @@
 
   void clear() {
     if (!isEmpty) {
-      _init(_HashBase._INITIAL_INDEX_SIZE, _hashMask, null, 0);
+      _index = _uninitializedIndex;
+      _hashMask = _HashBase._UNINITIALIZED_HASH_MASK;
+      _data = _uninitializedData;
+      _usedData = 0;
+      _deletedKeys = 0;
     }
   }
 
@@ -354,8 +366,9 @@
 
   // This method is called by [_rehashObjects] (see above).
   void _regenerateIndex() {
-    _index = _data.length == 0 ? _initialIndex : new Uint32List(_data.length);
-    assert(_hashMask == 0);
+    _index =
+        _data.length == 0 ? _uninitializedIndex : new Uint32List(_data.length);
+    assert(_hashMask == _HashBase._UNINITIALIZED_HASH_MASK);
     _hashMask = _HashBase._indexSizeToHashMask(_index.length);
     final int tmpUsed = _usedData;
     _usedData = 0;
@@ -655,7 +668,11 @@
 
   void clear() {
     if (!isEmpty) {
-      _init(_HashBase._INITIAL_INDEX_SIZE, _hashMask, null, 0);
+      _index = _uninitializedIndex;
+      _hashMask = _HashBase._UNINITIALIZED_HASH_MASK;
+      _data = _uninitializedData;
+      _usedData = 0;
+      _deletedKeys = 0;
     }
   }
 
@@ -773,8 +790,10 @@
 
   // This method is called by [_rehashObjects] (see above).
   void _regenerateIndex() {
-    _index = _data.length == 0 ? _initialIndex : new Uint32List(_data.length);
-    assert(_hashMask == 0);
+    final size =
+        _roundUpToPowerOfTwo(max(_data.length, _HashBase._INITIAL_INDEX_SIZE));
+    _index = _data.length == 0 ? _uninitializedIndex : new Uint32List(size);
+    assert(_hashMask == _HashBase._UNINITIALIZED_HASH_MASK);
     _hashMask = _HashBase._indexSizeToHashMask(_index.length);
     _rehash();
   }
@@ -790,9 +809,9 @@
         _OperatorEqualsAndHashCode
     implements LinkedHashSet<E> {
   _CompactLinkedHashSet() {
-    _index = _initialIndex;
-    _hashMask = 0;
-    _data = _initialData;
+    _index = _uninitializedIndex;
+    _hashMask = _HashBase._UNINITIALIZED_HASH_MASK;
+    _data = _uninitializedData;
     _usedData = 0;
     _deletedKeys = 0;
   }
diff --git a/tools/VERSION b/tools/VERSION
index bbfee5c..c11d373 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 15
 PATCH 0
-PRERELEASE 239
+PRERELEASE 240
 PRERELEASE_PATCH 0
\ No newline at end of file