anchor.diff:          StringLiteral,
           SuperInitializer,
           TypeParameter,
  +        TypeParameterType,
           VariableDeclaration,
           VariableGet,
           VoidType,
  
positive.code:     function.body = actualBody;
      actualBody?.parent = function;
      if (isPatch) {
        actualOrigin.setRedirectingFactoryBody(target, typeArguments);
      }
    }
  
negative.code:     if (actualBody != null) {
        unexpected("null", "${actualBody.runtimeType}", charOffset, fileUri);
      }
      actualBody = new RedirectingFactoryBody(target, typeArguments);
      function.body = actualBody;
      actualBody?.parent = function;
      if (isPatch) {
  