anchor.diff:          buffer.write('\$${safeName(argumentName)}');
         }
         String suffix = '\$${selector.argumentCount}$buffer';
  -      // We don't mangle the closure invoking function name if no named
  -      // arguments are present because it is generated by string concatenation
  -      // in applyFunction from js_helper.dart. To keep code size down, we
  -      // potentially shorten the prefix though. Also, in the presence of named
  -      // arguments, we can use the usual minification path.
  -      String proposedName;
  +      // We don't mangle the closure invoking function name because it
  +      // is generated by string concatenation in applyFunction from
  +      // js_helper.dart. We potentially shorten the prefix though.
         if (selector.isClosureCall()) {
  -        proposedName = callPrefix;
  -        if (selector.namedArguments.isEmpty) return "$proposedName$suffix";
  +        return "$callPrefix$suffix";
         } else {
  -         proposedName = privateName(selector.library, name);
  +        String proposedName = privateName(selector.library, name);
  +        return getMappedInstanceName('$proposedName$suffix');
         }
  -      return getMappedInstanceName('$proposedName$suffix');
       }
     }
   
  
positive.code:       signature.orderedOptionalParameters.forEach((Element element) {
          buffer.write('\$${safeName(element.name)}');
        });
        return getMappedInstanceName('$methodName$buffer');
      }
      if (name == closureInvocationSelectorName) return methodName;
      return getMappedInstanceName(methodName);
  
negative.code:       name = Elements.reconstructConstructorNameSourceString(element);
      }
      FunctionSignature signature = element.functionSignature;
      // We don't mangle the closure invoking function name because it
      // is generated by string concatenation in applyFunction from
      // js_helper.dart. To keep code size down, we potentially shorten
      // the prefix though.
      String methodName;
      if (name == closureInvocationSelectorName) {
        methodName = '$callPrefix\$${signature.parameterCount}';
  