Require two type arguments for map literals (issue 4522).

lib/compiler/implementation/js_backend/native_emitter.dart

 // Copyright (c) 2012, 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.
 
 class NativeEmitter {
 
   CodeEmitterTask emitter;
   CodeBuffer nativeBuffer;
 
   // Classes that participate in dynamic dispatch. These are the
@@ skipping 265 matching lines @@
     // The sets could be much smaller if we could make assumptions about the
     // cls tags of other classes (which are constructor names or part of the
     // result of Object.protocls.toString).  For example, if objects that are
     // Dart objects could be easily excluded, then we might be able to simplify
     // the test, replacing dozens of HTMLxxxElement classes with the regexp
     // /HTML.*Element/.
 
     // Temporary variables for common substrings.
     List<String> varNames = <String>[];
     // var -> expression
-    Map<String, String> varDefns = <String>{};
+    Map<String, String> varDefns = <String, String>{};
     // tag -> expression (a string or a variable)
     Map<ClassElement, String> tagDefns = new Map<ClassElement, String>();
 
     String makeExpression(ClassElement classElement) {
       // Expression fragments for this set of cls keys.
       List<String> expressions = <String>[];
       // TODO: Remove if cls is abstract.
       List<String> subtags = [toNativeName(classElement)];
       void walk(ClassElement cls) {
         for (final ClassElement subclass in getDirectSubclasses(cls)) {
@@ skipping 129 matching lines @@
         if (!first) targetBuffer.add(",\n");
         targetBuffer.add(" $name: $function");
         first = false;
       });
       targetBuffer.add("\n});\n\n");
     }
     targetBuffer.add('$nativeBuffer');
     targetBuffer.add('\n');
   }
 }