Fix for parsing 'rethrow' statement with Fasta.

pkg/front_end/lib/src/fasta/analyzer/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;
@@ skipping 548 matching lines @@
 
   void handleConditionalExpression(Token question, Token colon) {
     debugEvent("ConditionalExpression");
     Expression elseExpression = pop();
     Expression thenExpression = pop();
     Expression condition = pop();
     push(ast.conditionalExpression(condition, toAnalyzerToken(question),
         thenExpression, toAnalyzerToken(colon), elseExpression));
   }
 
+  @override
+  void endRethrowStatement(Token throwToken, Token endToken) {

[Brian Wilkerson, 2017/03/06 19:47:28]

"throwToken" --> "rethrowToken"?

+    debugEvent("RethrowStatement");
+    RethrowExpression expression =
+        ast.rethrowExpression(toAnalyzerToken(throwToken));
+    // TODO(scheglov) According to the specification, 'rethrow' is a statement.
+    push(ast.expressionStatement(expression, toAnalyzerToken(endToken)));
+  }
+
   void endThrowExpression(Token throwToken, Token endToken) {
     debugEvent("ThrowExpression");
     push(ast.throwExpression(toAnalyzerToken(throwToken), pop()));
   }
 
   @override
   void endOptionalFormalParameters(
       int count, Token beginToken, Token endToken) {
     debugEvent("OptionalFormalParameters");
     push(new _OptionalFormalParameters(popList(count), beginToken, endToken));
@@ skipping 892 matching lines @@
       } else if (identical('static', s)) {
         staticKeyword = token;
       } else if (identical('var', s)) {
         finalConstOrVarKeyword = token;
       } else {
         internalError('Unhandled modifier: $s');
       }
     }
   }
 }