code: public static TypeAnnotationPosition
          methodRefTypeArg(final List<TypePathEntry> location,
                           final JCLambda onLambda,
                           final int type_index,
                           final int pos) {
          return new TypeAnnotationPosition(TargetType.METHOD_REFERENCE_TYPE_ARGUMENT,
                                            pos, Integer.MIN_VALUE, onLambda,
                                            type_index, Integer.MIN_VALUE,
                                            location);
      }
docs: Create a {@code TypeAnnotationPosition} for a method reference
  type argument.
  
  @param location The type path.
  @param onLambda The lambda for this variable.
  @param type_index The index of the type argument.
  @param pos The position from the associated tree node.