Implement initializer asserts.

pkg/analyzer/lib/src/fasta/ast_builder.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.
 
 library fasta.analyzer.ast_builder;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast_factory.dart' show AstFactory;
 import 'package:analyzer/dart/ast/standard_ast_factory.dart' as standard;
 import 'package:analyzer/dart/ast/token.dart' as analyzer show Token;
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
 import 'package:analyzer/dart/element/element.dart' show Element;
 import 'package:front_end/src/fasta/parser/parser.dart'
-    show FormalParameterType, MemberKind, Parser;
+    show Assert, FormalParameterType, MemberKind, Parser;
 import 'package:front_end/src/fasta/scanner/string_scanner.dart';
 import 'package:front_end/src/fasta/scanner/token.dart' show CommentToken;
 import 'package:front_end/src/scanner/token.dart' as analyzer;
 
 import 'package:front_end/src/fasta/errors.dart' show internalError;
 import 'package:front_end/src/fasta/fasta_codes.dart'
     show FastaMessage, codeExpectedExpression, codeExpectedFunctionBody;
 import 'package:front_end/src/fasta/kernel/kernel_builder.dart'
     show Builder, KernelLibraryBuilder, ProcedureBuilder, Scope;
 import 'package:front_end/src/fasta/parser/identifier_context.dart'
@@ skipping 650 matching lines @@
     debugEvent("Type");
     TypeArgumentList arguments = pop();
     Identifier name = pop();
     // TODO(paulberry,ahe): what if the type doesn't resolve to a class
     // element?  Try to share code with BodyBuilder.builderToFirstExpression.
     KernelClassElement cls = name.staticElement;
     push(ast.typeName(name, arguments)..type = cls?.rawType);
   }
 
   @override
-  void handleAssertStatement(Token assertKeyword, Token leftParenthesis,
+  void endAssert(Token assertKeyword, Assert kind, Token leftParenthesis,
       Token comma, Token rightParenthesis, Token semicolon) {
-    debugEvent("AssertStatement");
+    debugEvent("Assert");
     Expression message = popIfNotNull(comma);
     Expression condition = pop();
     push(ast.assertStatement(assertKeyword, leftParenthesis, condition, comma,
         message, rightParenthesis, semicolon));
   }
 
   void handleAsOperator(Token operator, Token endToken) {
     debugEvent("AsOperator");
     TypeAnnotation type = pop();
     Expression expression = pop();
@@ skipping 1323 matching lines @@
       } else if (identical('var', s)) {
         finalConstOrVarKeyword = token;
       } else if (identical('covariant', s)) {
         covariantKeyword = token;
       } else {
         internalError('Unhandled modifier: $s');
       }
     }
   }
 }