Use message.yaml in parser.

pkg/front_end/messages.yaml

 # Copyright (c) 2017, 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.
 
 # Each entry in this map corresponds to a diagnostic message. Ideally, each
 # entry contains three parts:
 #
 # 1. A message template (template).
 #
 # 2. A suggestion for how to correct the problem (tip).
 #
 # 3. Examples that produce the message (one of expression, statement,
 #    declaration, member, script, or bytes).
 #
+# In addition, an entry can contain an analyzer error code (analyzerCode) and a
+# dart2js error code (dart2jsCode).
+#
 # ## Parameter Substitution in Template and Tip
 #
 # The fields `template` and `tip` are subject to parameter substitution. When
 # the compiler reports a problem, it may also specify a map with the following
 # keys to be substituted into the message:
 #
 # `#character` a Unicode character.
 #
 # `#unicode` a Unicode short identifier (U+xxxx). We use this to represent code
 #  units or code points.
 #
 # `#name` a name (a string).
 #
 # `#lexeme` a token. The token's `lexeme` property is used.
 #
 # `#string` a string.
 
 AsciiControlCharacter:
   template: "The control character #unicode can only be used in strings and comments."
+  dart2jsCode: BAD_INPUT_CHARACTER
   expresssion: "\x1b 1"
 
 NonAsciiIdentifier:
   template: "The non-ASCII character '#character' (#unicode) can't be used in identifiers, only in strings and comments."
   tip: "Try using an US-ASCII letter, a digit, '_' (an underscore), or '$' (a dollar sign)."
+  analyzerCode: ILLEGAL_CHARACTER
+  dart2jsCode: BAD_INPUT_CHARACTER
   expresssion: "å"
 
 NonAsciiWhitespace:
   template: "The non-ASCII space character #unicode can only be used in strings and comments."
+  analyzerCode: ILLEGAL_CHARACTER
+  dart2jsCode: BAD_INPUT_CHARACTER
   expresssion: "\u2028 1"
 
 Encoding:
   template: "Unable to decode bytes as UTF-8."
+  dart2jsCode: FASTA_FATAL
   bytes: [255]
 
 EmptyNamedParameterList:
   template: "Named parameter lists cannot be empty."
   tip: "Try adding a named parameter to the list."
+  dart2jsCode: EMPTY_NAMED_PARAMETER_LIST
   script: >
     foo({}) {}
 
     main() {
       foo();
     }
 
 EmptyOptionalParameterList:
   template: "Optional parameter lists cannot be empty."
   tip: "Try adding an optional parameter to the list."
+  dart2jsCode: EMPTY_OPTIONAL_PARAMETER_LIST
   script: >
     foo([]) {}
 
     main() {
       foo();
     }
 
-ExpectedBlockToSkip: ExpectedBody
+ExpectedBlockToSkip:
+  template: "Expected a function body or '=>'."
+  # TODO(ahe): In some scenarios, we can suggest removing the 'static' keyword.
+  tip: "Try adding {}."
+  dart2jsCode: NATIVE_OR_BODY_EXPECTED
+  script: "main();"
 
 ExpectedBody:
   template: "Expected a function body or '=>'."
   # TODO(ahe): In some scenarios, we can suggest removing the 'static' keyword.
   tip: "Try adding {}."
+  dart2jsCode: BODY_EXPECTED
   script: "main();"
 
 ExpectedButGot:
-  template: "Expected '#lexeme' before this."
+  template: "Expected '#string' before this."
   # Consider the second example below: the parser expects a ')' before 'y', but
   # a ',' would also have worked. We don't have enough information to give a
   # good suggestion.
   tip: DONT_KNOW_HOW_TO_FIX,
+  dart2jsCode: MISSING_TOKEN_BEFORE_THIS
   script:
     - "main() => true ? 1;"
     - "main() => foo(x: 1 y: 2);"
 
 ExpectedClassBody:
   template: "Expected a class body, but got '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 ExpectedClassBodyToSkip: ExpectedClassBody
 
 ExpectedDeclaration:
   template: "Expected a declaration, but got '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 ExpectedExpression:
   template: "Expected an expression, but got '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 ExpectedFunctionBody:
   template: "Expected a function body, but got '#lexeme'."
+  dart2jsCode: NATIVE_OR_FATAL
 
 ExpectedHexDigit:
   template: "A hex digit (0-9 or A-F) must follow '0x'."
   # No tip, seems obvious from the error message.
+  analyzerCode: MISSING_HEX_DIGIT
+  dart2jsCode: HEX_DIGIT_EXPECTED
   script: >
     main() {
       var i = 0x;
     }
 
 ExpectedIdentifier:
   template: "'#lexeme' is a reserved word and can't be used here."
   tip: "Try using a different name."
+  dart2jsCode: EXPECTED_IDENTIFIER
   script: "do() {} main() {}"
 
 ExpectedOpenParens:
   template: "Expected '('."
+  dart2jsCode: GENERIC
 
 ExpectedString:
   template: "Expected a String, but got '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 ExpectedType:
   template: "Expected a type, but got '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 ExtraneousModifier:
   template: "Can't have modifier '#lexeme' here."
   tip: "Try removing '#lexeme'."
+  dart2jsCode: EXTRANEOUS_MODIFIER
   script:
     - "var String foo; main(){}"
     - "var set foo; main(){}"
     - "var final foo; main(){}"
     - "var var foo; main(){}"
     - "var const foo; main(){}"
     - "var abstract foo; main(){}"
     - "var static foo; main(){}"
     - "var external foo; main(){}"
     - "get var foo; main(){}"
     - "set var foo; main(){}"
     - "final var foo; main(){}"
     - "var var foo; main(){}"
     - "const var foo; main(){}"
     - "abstract var foo; main(){}"
     - "static var foo; main(){}"
     - "external var foo; main(){}"
 
 ExtraneousModifierReplace:
   template: "Can't have modifier '#lexeme' here."
   tip: "Try replacing modifier '#lexeme' with 'var', 'final', or a type."
+  dart2jsCode: EXTRANEOUS_MODIFIER_REPLACE
   script:
     - "set foo; main(){}"
     - "abstract foo; main(){}"
     - "static foo; main(){}"
     - "external foo; main(){}"
 
 InvalidAwaitFor:
   template: "'await' is only supported in methods with an 'async' or 'async*' body modifier."
   tip: "Try adding 'async' or 'async*' to the method body or removing the 'await' keyword."
+  dart2jsCode: INVALID_AWAIT_FOR
   script: >
     main(o) sync* {
       await for (var e in o) {}
     }
 
 InvalidSyncModifier:
   template: "Invalid modifier 'sync'."
   tip: "Try replacing 'sync' with 'sync*'."
+  dart2jsCode: INVALID_SYNC_MODIFIER
   script: "main() sync {}"
 
 InvalidVoid:
   template: "Type 'void' can't be used here because it isn't a return type."
   tip: "Try removing 'void' keyword or replace it with 'var', 'final', or a type."
+  dart2jsCode: VOID_NOT_ALLOWED
   script:
     - "void x; main() {}"
     - "foo(void x) {} main() { foo(null); }"
 
 MissingExponent:
   template: "Numbers in exponential notation should always contain an exponent (an integer number with an optional sign)."
   tip: "Make sure there is an exponent, and remove any whitespace before it."
+  analyzerCode: MISSING_DIGIT
+  dart2jsCode: EXPONENT_MISSING
   script: >
     main() {
       var i = 1e;
     }
 
 PositionalParameterWithEquals:
   template: "Positional optional parameters can't use ':' to specify a default value."
   tip: "Try replacing ':' with '='."
+  dart2jsCode: POSITIONAL_PARAMETER_WITH_EQUALS
   script: >
     main() {
       foo([a: 1]) => print(a);
       foo(2);
     }
 
 RequiredParameterWithDefault:
   template: "Non-optional parameters can't have a default value."
   tip: "Try removing the default value or making the parameter optional."
+  dart2jsCode: REQUIRED_PARAMETER_WITH_DEFAULT
   script:
     - >
       main() {
         foo(a: 1) => print(a);
         foo(2);
       }
     - >
       main() {
         foo(a = 1) => print(a);
         foo(2);
       }
 
 StackOverflow:
   template: "Stack overflow."
+  dart2jsCode: GENERIC
 
 UnexpectedDollarInString:
   template: "A '$' has special meaning inside a string, and must be followed by an identifier or an expression in curly braces ({})."
   tip: "Try adding a backslash (\\) to escape the '$'."
+  dart2jsCode: MALFORMED_STRING_LITERAL
   script:
     - >
       main() {
         return '$';
       }
     - >
       main() {
         return "$";
       }
     - >
       main() {
         return '''$''';
       }
     - >
       main() {
         return """$""";
       }
 
 UnexpectedToken:
   template: "Unexpected token '#lexeme'."
+  dart2jsCode: FASTA_FATAL
 
 UnmatchedToken:
   template: "Can't find '#string' to match '#lexeme'."
+  dart2jsCode: UNMATCHED_TOKEN
   script:
     - "main("
     - "main(){"
     - "main(){[}"
 
 UnsupportedPrefixPlus:
   template: "'+' is not a prefix operator. "
   tip: "Try removing '+'."
+  dart2jsCode: UNSUPPORTED_PREFIX_PLUS
   script: "main() => +2;  // No longer a valid way to write '2'"
 
 UnterminatedComment:
   template: "Comment starting with '/*' must end with '*/'."
+  analyzerCode: UNTERMINATED_MULTI_LINE_COMMENT
+  dart2jsCode: UNTERMINATED_COMMENT
   script:
     main() {
     }
     /*
 
 UnterminatedString:
   template: "String must end with #string."
+  analyzerCode: UNTERMINATED_STRING_LITERAL
+  dart2jsCode: UNTERMINATED_STRING
   script:
     - >
       main() {
         return '
       ;
       }
     - >
       main() {
         return \"
       ;
@@ skipping 13 matching lines @@
     - >
       main() => \"\"\"
     - >
       main() => r'''
     - >
       main() => r\"\"\"
 
 UnterminatedToken:
   # This is a fall-back message that shouldn't happen.
   template: "Incomplete token."
+  dart2jsCode: UNTERMINATED_TOKEN
 
 Unspecified:
   template: "#string"
+  dart2jsCode: GENERIC
 
 AbstractNotSync:
   template: "Abstract methods can't use 'async', 'async*', or 'sync*'."
+  dart2jsCode: FASTA_IGNORED
 
 AsyncAsIdentifier:
+  analyzerCode: ASYNC_KEYWORD_USED_AS_IDENTIFIER
   template: "'async' can't be used as an identifier in 'async', 'async*', or 'sync*' methods."
+  dart2jsCode: GENERIC
 
 AwaitAsIdentifier:
   template: "'await' can't be used as an identifier in 'async', 'async*', or 'sync*' methods."
+  dart2jsCode: FASTA_IGNORED
 
 AwaitNotAsync:
   template: "'await' can only be used in 'async' or 'async*' methods."
+  dart2jsCode: FASTA_IGNORED
 
 BuiltInIdentifierAsType:
   template: "Can't use '#lexeme' as a type."
+  dart2jsCode: GENERIC
 
 BuiltInIdentifierInDeclaration:
   template: "Can't use '#lexeme' as a name here."
+  dart2jsCode: GENERIC
 
 AwaitForNotAsync:
   template: "Asynchronous for-loop can only be used in 'async' or 'async*' methods."
+  dart2jsCode: FASTA_IGNORED
 
 FactoryNotSync:
   template: "Factories can't use 'async', 'async*', or 'sync*'."
+  dart2jsCode: FASTA_IGNORED
 
 GeneratorReturnsValue:
   template: "'sync*' and 'async*' can't return a value."
+  dart2jsCode: FASTA_IGNORED
 
 InvalidInlineFunctionType:
   template: "Invalid inline function type."
   tip: "Try changing the inline function type (as in 'int f()') to a prefixed function type using the `Function` keyword (as in 'int Function() f')."
+  dart2jsCode: INVALID_INLINE_FUNCTION_TYPE
   declaration: "typedef F = Function(int f(String x)); main() { F f; }"
 
 SetterNotSync:
   template: "Setters can't use 'async', 'async*', or 'sync*'."
+  dart2jsCode: FASTA_IGNORED
 
 YieldAsIdentifier:
   template: "'yield' can't be used as an identifier in 'async', 'async*', or 'sync*' methods."
+  dart2jsCode: FASTA_IGNORED
 
 YieldNotGenerator:
   template: "'yield' can only be used in 'sync*' or 'async*' methods."
+  dart2jsCode: FASTA_IGNORED
 
 OnlyTry:
   template: "Try block should be followed by 'on', 'catch', or 'finally' block."
   tip: "Did you forget to add a 'finally' block?"
   statement: "try {}"
+  dart2jsCode: FASTA_IGNORED