improve fasta closing brace recovery

pkg/analyzer/test/generated/parser_test.dart

 // Copyright (c) 2014, 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:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
@@ skipping 4122 matching lines @@
 
   void test_typedefInClass_withReturnType() {
     parseCompilationUnit("class C { typedef int F(int x); }",
         [ParserErrorCode.TYPEDEF_IN_CLASS]);
   }
 
   void test_unexpectedTerminatorForParameterGroup_named() {
     createParser('(a, b})');
     FormalParameterList list = parser.parseFormalParameterList();
     expectNotNullIfNoErrors(list);
-    listener.assertErrorsWithCodes(fe.Scanner.useFasta
-        ? [ScannerErrorCode.EXPECTED_TOKEN]
-        : [ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP]);
+    listener.assertErrorsWithCodes(
+        [ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP]);
   }
 
   void test_unexpectedTerminatorForParameterGroup_optional() {
     createParser('(a, b])');
     FormalParameterList list = parser.parseFormalParameterList();
     expectNotNullIfNoErrors(list);
-    listener.assertErrorsWithCodes(fe.Scanner.useFasta
-        ? [ScannerErrorCode.EXPECTED_TOKEN]
-        : [ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP]);
+    listener.assertErrorsWithCodes(
+        [ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP]);
   }
 
   void test_unexpectedToken_endOfFieldDeclarationStatement() {
     parseStatement("String s = (null));");
     assertErrorsWithCodes([ParserErrorCode.UNEXPECTED_TOKEN]);
   }
 
   @failingTest
   void test_unexpectedToken_invalidPostfixExpression() {
     // Note: this might not be the right error to produce, but some error should
@@ skipping 219 matching lines @@
     expectNotNullIfNoErrors(list);
     listener.assertErrorsWithCodes(
         [ParserErrorCode.WRONG_SEPARATOR_FOR_POSITIONAL_PARAMETER]);
   }
 
   void test_wrongTerminatorForParameterGroup_named() {
     createParser('(a, {b, c])');
     FormalParameterList list = parser.parseFormalParameterList();
     expectNotNullIfNoErrors(list);
     listener.assertErrorsWithCodes(fe.Scanner.useFasta
-        ? [ScannerErrorCode.EXPECTED_TOKEN, ScannerErrorCode.EXPECTED_TOKEN]
+        ? [
+            // fasta scanner generates '(a, {b, c]})' where '}' is synthetic
+            ParserErrorCode.WRONG_TERMINATOR_FOR_PARAMETER_GROUP,
+            ScannerErrorCode.EXPECTED_TOKEN,
+          ]
         : [ParserErrorCode.WRONG_TERMINATOR_FOR_PARAMETER_GROUP]);
   }
 
   void test_wrongTerminatorForParameterGroup_optional() {
     createParser('(a, [b, c})');
     FormalParameterList list = parser.parseFormalParameterList();
     expectNotNullIfNoErrors(list);
-    listener.assertErrorsWithCodes(fe.Scanner.useFasta
-        ? [ScannerErrorCode.EXPECTED_TOKEN, ScannerErrorCode.EXPECTED_TOKEN]
+    listener.assertErrorsWithCodes(usingFastaScanner
+        ? [
+            // fasta scanner generates '(a, [b, c}])' where ']' is synthetic
+            ParserErrorCode.WRONG_TERMINATOR_FOR_PARAMETER_GROUP,
+            ScannerErrorCode.EXPECTED_TOKEN,
+          ]
         : [ParserErrorCode.WRONG_TERMINATOR_FOR_PARAMETER_GROUP]);
   }
 }
 
 @reflectiveTest
 class ExpressionParserTest extends ParserTestCase
     with ExpressionParserTestMixin {}
 
 abstract class ExpressionParserTestMixin implements AbstractParserTestCase {
   void test_namedArgument() {
@@ skipping 10754 matching lines @@
     expectCommentText(typeVariable.documentationComment, '/// Doc');
   }
 
   /**
    * Assert that the given [name] is in declaration context.
    */
   void _assertIsDeclarationName(SimpleIdentifier name) {
     expect(name.inDeclarationContext(), isTrue);
   }
 }