Golang x/tools/gopls: show underlying type on hover over alias

gopls version

golang.org/x/tools/gopls v0.17.1

go env

n/a

What did you do?

Note: this is a feature request

Given

// This is a dog.
type Dog struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

type Hound = Dog

// A Puppy is a Dog with an age less than 2.
type Puppy = Dog

I hovered over Hound and Puppy

What did you see happen?

The hover message reads

type Hound = Dog

and respectively

type Puppy = Dog

A puppy is a dog with an age less than 2.

What did you expect to see?

type Hound = Dog

This is a dog.

type Dog struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

and respectively

type Puppy = Dog

A puppy is a dog with an age less than 2.

type Dog struct {
    Name string `json:"name"`
    Age int `json:"age"`
}

I like the semantic that docstrings are inherited if, and only if, the alias provides no docstring of its own.

Editor and settings

n/a

Logs

n/a

Comment From: findleyr

This sounds like a nice improvement. Thanks.

Comment From: adonovan

@jacobzim-stl, did you want to take a crack at implementing the necessary fix? (I heard a rumor from one of my coworkers.)

Comment From: jacobzim-stl

@adonovan I'd love to, unfortunately my bandwidth is a bit limited in the coming weeks. I'll give it an initial shot this weekend. If the implementation gets heavy I might not be able to implement it for a while.

Comment From: gopherbot

Change https://go.dev/cl/644495 mentions this issue: gopls/internal/hover: show underlying type on hover over alias

Comment From: xieyuschen

Hi @jacobzim-stl , I have put the real type definition after the original typeDecl, as the screenshot shows below. I hope it meets your expectations :)

Comment From: jacobzim-stl

Amazing! Thanks @xieyuschen!

Comment From: adonovan

I think this behavior change may have been a mistake; see https://github.com/golang/go/issues/74361#issuecomment-3001485832.