improve fasta export directive 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 2627 matching lines @@
   void test_expectedToken_parseStatement_afterVoid() {
     parseStatement("void}");
     assertErrorsWithCodes(
         [ParserErrorCode.EXPECTED_TOKEN, ParserErrorCode.MISSING_IDENTIFIER]);
   }
 
   void test_expectedToken_semicolonMissingAfterExport() {
     CompilationUnit unit = parseCompilationUnit(
         "export '' class A {}", [ParserErrorCode.EXPECTED_TOKEN]);
     ExportDirective directive = unit.directives[0] as ExportDirective;
+    expect(directive.uri, isNotNull);
+    expect(directive.uri.stringValue, '');
+    expect(directive.uri.beginToken.isSynthetic, false);
+    expect(directive.uri.isSynthetic, false);
     Token semicolon = directive.semicolon;
     expect(semicolon, isNotNull);
     expect(semicolon.isSynthetic, isTrue);
+    ClassDeclaration clazz = unit.declarations[0] as ClassDeclaration;
+    expect(clazz.name.name, 'A');
+  }
+
+  void test_expectedToken_uriAndSemicolonMissingAfterExport() {
+    CompilationUnit unit = parseCompilationUnit("export class A {}", [
+      ParserErrorCode.EXPECTED_STRING_LITERAL,
+      ParserErrorCode.EXPECTED_TOKEN,
+    ]);
+    ExportDirective directive = unit.directives[0] as ExportDirective;
+    expect(directive.uri, isNotNull);
+    expect(directive.uri.stringValue, '');
+    expect(directive.uri.beginToken.isSynthetic, true);
+    expect(directive.uri.isSynthetic, true);
+    Token semicolon = directive.semicolon;
+    expect(semicolon, isNotNull);
+    expect(semicolon.isSynthetic, isTrue);
+    ClassDeclaration clazz = unit.declarations[0] as ClassDeclaration;
+    expect(clazz.name.name, 'A');
   }
 
   void test_expectedToken_semicolonMissingAfterExpression() {
     parseStatement("x");
     assertErrorsWithCodes([ParserErrorCode.EXPECTED_TOKEN]);
   }
 
   void test_expectedToken_semicolonMissingAfterImport() {
     CompilationUnit unit = parseCompilationUnit(
         "import '' class A {}", [ParserErrorCode.EXPECTED_TOKEN]);
@@ skipping 12772 matching lines @@
     expectCommentText(typeVariable.documentationComment, '/// Doc');
   }
 
   /**
    * Assert that the given [name] is in declaration context.
    */
   void _assertIsDeclarationName(SimpleIdentifier name) {
     expect(name.inDeclarationContext(), isTrue);
   }
 }