Address comments

address comments in https://dart-review.googlesource.com/c/sdk/+/72123

Change-Id: I0752369d4e41e72dc772cd63cf62625e2e3988ba
Reviewed-on: https://dart-review.googlesource.com/72500
Commit-Queue: Dan Rubel <danrubel@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
diff --git a/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart b/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
index 5de4f22..c1361b0 100644
--- a/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
+++ b/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
@@ -530,6 +530,7 @@
       correction: "Try adding either a catch or finally clause, or "
           "remove the try statement.");
 
+  /// TODO(danrubel): Consider splitting this into two separate error messages.
   static const ParserErrorCode MISSING_CLASS_BODY = const ParserErrorCode(
       'MISSING_CLASS_BODY',
       "A class or mixin definition must have a body, even if it is empty.",
diff --git a/pkg/analyzer/test/src/fasta/recovery/partial_code/mixin_declaration_test.dart b/pkg/analyzer/test/src/fasta/recovery/partial_code/mixin_declaration_test.dart
index e4ec1a0..e2e5d7b 100644
--- a/pkg/analyzer/test/src/fasta/recovery/partial_code/mixin_declaration_test.dart
+++ b/pkg/analyzer/test/src/fasta/recovery/partial_code/mixin_declaration_test.dart
@@ -38,6 +38,17 @@
           new TestDescriptor('onBody', 'mixin A on {}',
               [ParserErrorCode.EXPECTED_TYPE_NAME], 'mixin A on _s_ {}'),
           new TestDescriptor(
+              'onNameComma',
+              'mixin A on B,',
+              [
+                ParserErrorCode.EXPECTED_TYPE_NAME,
+                ParserErrorCode.MISSING_CLASS_BODY
+              ],
+              'mixin A on B, _s_ {}',
+              failing: ['functionVoid', 'functionNonVoid', 'getter']),
+          new TestDescriptor('onNameCommaBody', 'mixin A on B, {}',
+              [ParserErrorCode.EXPECTED_TYPE_NAME], 'mixin A on B, _s_ {}'),
+          new TestDescriptor(
               'onImplementsNameBody',
               'mixin A on implements B {}',
               [ParserErrorCode.EXPECTED_TYPE_NAME],