Why is *a{...} invalid indirect?

invalid indirect of oauth.RequestToken literal (type oauth.RequestToken)

Why is the following line invalid?

func (s *Service) Callback(r *http.Request, req *RequestOauth, resp *Response) error {
	c := endpoints.NewContext(r)
	consumer.HttpClient=urlfetch.Client(c)
	====>requestToken := *oauth.RequestToken{Token:req.Oauth_token, Secret:""}<======
	b, err := TwitterApi(requestToken, req.Oauth_verifier)
	resp.Message=b.Name
	return err
}

func TwitterApi(requestToken *oauth.RequestToken, verificationCode string) (u *UserT, err error) {
	accessToken, err := consumer.AuthorizeToken(requestToken, verificationCode)
	if err != nil {log.Fatal(err)}
	response, err := consumer.Get("https://api.twitter.com/1.1/account/verify_credentials.json", nil, accessToken)
	if err != nil {log.Fatal(err)}
	defer response.Body.Close()
	b, err := ioutil.ReadAll(response.Body)
	err = json.Unmarshal(b, &u)
	return
}

This line:

requestToken := *oauth.RequestToken{Token:req.Oauth_token, Secret:""}

translated literally says "create an instance of oauth.RequestToken, then attempt to dereference it as a pointer." i.e. it is attempting to perform an indirect (pointer) access via a literal struct value.

Instead, you want to create the instance and take its address (&), yielding a pointer-to-RequestToken, *oauth.RequestToken:

requestToken := &oauth.RequestToken{Token:req.Oauth_token, Secret:""}

Alternatively, you could create the token as a local value, then pass it by address to the TwitterApi function:

requestToken := oauth.RequestToken{Token:req.Oauth_token, Secret:""}

b, err := TwitterApi(&requestToken, req.Oauth_verifier)

You'll need to create a pointer to the value you're creating, which is done with & , * does the opposite, it dereferences a pointer. So:

requestToken := &oauth.RequestToken{Token:req.Oauth_token, Secret:""}

Now requestToken is a pointer to a oauth.RequestToken value.

Or you can initialize requestToken as a value:

requestToken := oauth.RequestToken{Token:req.Oauth_token, Secret:""}

Now requestToken is a oauth.RequestToken value.

Then you can pass a pointer to that value to TwitterApi

  b, err := TwitterApi(&requestToken, req.Oauth_verifier)

I may add to the top answer, if we want to explicitly look at a struct value in one line we could do this :

*&yourStruct

Where you get the instance of your struct, look up at its memory address, and access its value.