update invalid hex digit recovery

pkg/front_end/test/scanner_test.dart

 // Copyright (c) 2016, 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:front_end/src/base/errors.dart';
 import 'package:front_end/src/base/jenkins_smi_hash.dart';
 import 'package:front_end/src/scanner/errors.dart';
 import 'package:front_end/src/scanner/reader.dart';
 import 'package:front_end/src/scanner/scanner.dart';
 import 'package:front_end/src/scanner/token.dart';
@@ skipping 1025 matching lines @@
     _assertToken(TokenType.STRING, "'''string'''");
   }
 
   void test_string_multi_slashEnter() {
     _assertToken(TokenType.STRING, "'''\\\n'''");
   }
 
   void test_string_multi_unterminated() {
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "'''string'''", 0, 9),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "'''string", 0),
       ]);
     }
   }
 
   void test_string_multi_unterminated_interpolation_block() {
     List<Token> expectedTokens = [
       new StringToken(TokenType.STRING, "'''", 0),
       new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 3),
       new StringToken(TokenType.IDENTIFIER, "name", 5),
     ];
     var expectedErrors = [
       new TestError(8, ScannerErrorCode.UNTERMINATED_STRING_LITERAL, null),
     ];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticToken(TokenType.CLOSE_CURLY_BRACKET, 9),
         new SyntheticStringToken(TokenType.STRING, "'''", 9, 0),
       ]);
       expectedErrors.addAll([
         new TestError(3, ScannerErrorCode.EXPECTED_TOKEN, ['}']),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "", 9),
       ]);
     }
     ErrorListener listener = new ErrorListener();
     Token token = scanWithListener("'''\${name", listener);
     listener.assertErrors(expectedErrors);
     _checkTokens(token, expectedTokens);
   }
 
   void test_string_multi_unterminated_interpolation_identifier() {
     List<Token> expectedTokens = [
       new StringToken(TokenType.STRING, "'''", 0),
       new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 3),
       new StringToken(TokenType.IDENTIFIER, "name", 4),
     ];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "'''", 8, 0),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "", 8),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 7,
         "'''\$name", expectedTokens);
   }
 
   void test_string_raw_multi_double() {
     _assertToken(TokenType.STRING, "r\"\"\"line1\nline2\"\"\"");
   }
 
   void test_string_raw_multi_single() {
     _assertToken(TokenType.STRING, "r'''string'''");
   }
 
   void test_string_raw_multi_unterminated() {
     String source = "r'''string";
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "r'''string'''", 0, 10),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "r'''string", 0),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 9,
         source, expectedTokens);
   }
 
   void test_string_raw_simple_double() {
     _assertToken(TokenType.STRING, "r\"string\"");
   }
 
   void test_string_raw_simple_single() {
     _assertToken(TokenType.STRING, "r'string'");
   }
 
   void test_string_raw_simple_unterminated_eof() {
     String source = "r'string";
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "r'string'", 0, 8),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "r'string", 0),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 7,
         source, expectedTokens);
   }
 
   void test_string_raw_simple_unterminated_eol() {
     String source = "r'string\n";
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "r'string'", 0, 8),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "r'string", 0),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL,
         usingFasta ? 7 : 8, source, expectedTokens);
@@ skipping 120 matching lines @@
   }
 
   void test_string_simple_single() {
     _assertToken(TokenType.STRING, "'string'");
   }
 
   void test_string_simple_unterminated_eof() {
     String source = "'string";
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "'string'", 0, 7),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "'string", 0),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 6,
         source, expectedTokens);
   }
 
   void test_string_simple_unterminated_eol() {
     String source = "'string\r";
     List<Token> expectedTokens = [];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "'string'", 0, 7),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "'string", 0),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL,
         usingFasta ? 6 : 7, source, expectedTokens);
   }
 
   void test_string_simple_unterminated_interpolation_block() {
     List<Token> expectedTokens = [
       new StringToken(TokenType.STRING, "'", 0),
       new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 1),
       new StringToken(TokenType.IDENTIFIER, "name", 3),
     ];
     List<TestError> expectedErrors = [
       new TestError(6, ScannerErrorCode.UNTERMINATED_STRING_LITERAL, null),
     ];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticToken(TokenType.CLOSE_CURLY_BRACKET, 7),
         new SyntheticStringToken(TokenType.STRING, "'", 7, 0),
       ]);
       expectedErrors.addAll([
         new TestError(1, ScannerErrorCode.EXPECTED_TOKEN, ['}']),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "", 7),
       ]);
     }
     ErrorListener listener = new ErrorListener();
     Token token = scanWithListener("'\${name", listener);
     listener.assertErrors(expectedErrors);
     _checkTokens(token, expectedTokens);
   }
 
   void test_string_simple_unterminated_interpolation_identifier() {
     List<Token> expectedTokens = [
       new StringToken(TokenType.STRING, "'", 0),
       new StringToken(TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 1),
       new StringToken(TokenType.IDENTIFIER, "name", 2),
     ];
     if (usingFasta) {
-      // fasta inserts synthetic closers
+      // Fasta inserts synthetic closers.
       expectedTokens.addAll([
         new SyntheticStringToken(TokenType.STRING, "'", 6, 0),
       ]);
     } else {
       expectedTokens.addAll([
         new StringToken(TokenType.STRING, "", 6),
       ]);
     }
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 5,
         "'\$name", expectedTokens);
@@ skipping 341 matching lines @@
   _TestScanner(CharacterReader reader, [this.listener]) : super.create(reader);
 
   @override
   void reportError(
       ScannerErrorCode errorCode, int offset, List<Object> arguments) {
     if (listener != null) {
       listener.errors.add(new TestError(offset, errorCode, arguments));
     }
   }
 }