anchor.diff:  
     /// Extend current method parameters with parameters for the function type
     /// variables.
  -  ///
  -  /// TODO(johnniwinther): Do we need this?
  -  /// If the method has type variables but does not need them, bind to `dynamic`
  -  /// (represented as `null`).
     void _addFunctionTypeVariablesIfNeeded(MemberEntity member) {
       if (member is! FunctionEntity) return;
   
  
positive.code:     }
      bool needsTypeArguments = _rtiNeed.methodNeedsTypeArguments(function);
      bool elideTypeParameters = function.parameterStructure.typeParameters == 0;
      for (TypeVariableType typeVariable
          in _elementEnvironment.getFunctionTypeVariables(function)) {
        HInstruction param;
        bool erased = false;
        if (elideTypeParameters) {
  
negative.code:             localsHandler.getTypeVariableAsLocal(typeVariable), argument);
        });
      }
  
      assert(
          argumentIndex == compiledArguments.length ||
              !_rtiNeed.methodNeedsTypeArguments(function) &&
  