Generate type variable events before parsing return type.

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;
@@ skipping 754 matching lines @@
   void handleValuedFormalParameter(Token equals, Token token) {
     debugEvent("ValuedFormalParameter");
     Expression value = pop();
     push(new _ParameterDefaultValue(equals, value));
   }
 
   @override
   void endFunctionType(Token functionToken, Token semicolon) {
     debugEvent("FunctionType");
     FormalParameterList parameters = pop();
+    TypeAnnotation returnType = pop();
     TypeParameterList typeParameters = pop();
-    TypeAnnotation returnType = pop();
     push(ast.genericFunctionType(
         returnType, functionToken, typeParameters, parameters));
   }
 
   void handleFormalParameterWithoutValue(Token token) {
     debugEvent("FormalParameterWithoutValue");
     push(NullValue.ParameterDefaultValue);
   }
 
   @override
@@ skipping 1252 matching lines @@
       } else if (identical('var', s)) {
         finalConstOrVarKeyword = token;
       } else if (identical('covariant', s)) {
         covariantKeyword = token;
       } else {
         internalError('Unhandled modifier: $s');
       }
     }
   }
 }