x/tools/gopls: Find All References on named parameters should show the return values

[jsgoupil]

Is your feature request related to a problem? Please describe.
When using Find All References, I expect to find all references where a variable is used or assigned.
If I am using a named return parameters, then the final return is not included in the references.

x := func() (other string) {
	defer func() {
		fmt.Println("I got: " + other)
	}()

	other = "abc"
	return "def"
}

xx := x()
fmt.Println(xx)

Searching the variable other in the code above will not give me the final def usage.

Describe the solution you'd like
Show me the return line in the References.

[findleyr]

Hmm, this is an interesting idea. Since this is a gopls feature request, I'll transfer to the Go issue tracker.

Something @adonovan and I have discussed is the extension to 'Find References' to find all assignments of a variable (something I often want). This could be part of that analysis.

[adonovan]

The current Hover functionality does almost exactly that: if you position the cursor within an element of a function's return type, it highlights all the corresponding return operands within the function body. And, conversely, if you position the cursor in one of the return operands, it highlights all the others and the corresponding element of the function's return type. It works whether the return variables are named or not.

[adonovan]

There are other places in the grammar that make an implicit reference without an identifier, the most obvious one being that S{x} is an implicit reference to a field of struct S. But things get fuzzy: if return 1 is an assignment to a named result variable, is f(1) not then an assignment to the parameter variable? (And what about aliasing? Given ptr := &x, is *ptr = 1 an assignment to x?)

Making FindAllReferences return implicit references could be quite confusing, and I'm not convinced it's worth doing given that the hover feature I mentioned above provides a simple solution to the immediate problem.

[adonovan]

This seems like an implicit request for microsoft/language-server-protocol#1911, which is to say, the ability to request a variety of "references-like" things that are all presented using the same UI.