Better mangling in frog for fixing parts of issue 1837.

frog/member_set.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 MemberSet {
   final String name;
   final List<Member> members;
   final String jsname;
   final bool isVar;
 
@@ skipping 157 matching lines @@
       if (name == ':index') {
         world.gen.corejs.useIndex = true;
       } else if (name == ':setindex') {
         world.gen.corejs.useSetIndex = true;
       }
       return new Value(returnType, '${target.code}.$jsname($argsString)',
           target.span);
     } else {
       if (argsString.length > 0) argsString = ', $argsString';
       world.gen.corejs.useOperator(name);
-      return new Value(returnType, '\$$jsname(${target.code}$argsString)',
+      return new Value(returnType, '$jsname\$(${target.code}$argsString)',
           target.span);
     }
   }
 
   Value invokeOnVar(CallingContext context, Node node, Value target,
       Arguments args) {
     context.counters.dynamicMethodCalls++;
 
     var member = getVarMember(context, node, args);
     return member.invoke(context, node, target, args);
@@ skipping 101 matching lines @@
           returnType = world.varType;
         }
       }
     }
     if (returnType == null) {
       // TODO(jimhug): Warning here for no match anywhere in the world?
       returnType = world.varType;
     }
   }
 }