improve fasta closing brace recovery

pkg/analyzer/lib/src/generated/parser.dart

Index: pkg/analyzer/lib/src/generated/parser.dart
diff --git a/pkg/analyzer/lib/src/generated/parser.dart b/pkg/analyzer/lib/src/generated/parser.dart
index 9053bb0463cc7ff2c731d2a2f2c579b3cdac5eca..a18a016b41fb8399164cce1841d1d118501b2787 100644
--- a/pkg/analyzer/lib/src/generated/parser.dart
+++ b/pkg/analyzer/lib/src/generated/parser.dart
@@ -6911,6 +6911,12 @@ class Parser {
                 ['}', ']']);
             rightCurlyBracket = rightSquareBracket;
             rightSquareBracket = null;
+            // Skip over synthetic closer inserted by fasta
+            // since we've already reported an error
+            if (_currentToken.type == TokenType.CLOSE_CURLY_BRACKET &&
+                _currentToken.isSynthetic) {
+              _advance();
+            }
           } else {
             _reportErrorForCurrentToken(
                 ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP,
@@ -6927,6 +6933,12 @@ class Parser {
                 [']', '}']);
             rightSquareBracket = rightCurlyBracket;
             rightCurlyBracket = null;
+            // Skip over synthetic closer inserted by fasta
+            // since we've already reported an error
+            if (_currentToken.type == TokenType.CLOSE_SQUARE_BRACKET &&
+                _currentToken.isSynthetic) {
+              _advance();
+            }
           } else {
             _reportErrorForCurrentToken(
                 ParserErrorCode.UNEXPECTED_TERMINATOR_FOR_PARAMETER_GROUP,