Thanks for the report. Which gopls commit did you build at? I thought this might be related to recent work on AST trimming, but can't reproduce at tip.

Are you able to repro? If so, can you please capture RPC logs, as described here?
https://github.com/golang/vscode-go/blob/master/docs/troubleshooting.md#collect-gopls-information

It was built with go install run from the gopls repo.

Unfortunately I can't reproduce it now, it had been in that state for a while, but after restart of VS Code, I can see documentation for this particular function. I'll watch over it and let you know if this repeats.

I faced a similar issue. But in my case fields of a struct have disappeared. The first commit with this issue is golang/tools@cd1d088. Note that this behavior is inconsistent (see screenshots)

Steps to reproduce

package main

import (
	"github.com/go-pg/pg/v10/orm"
)

func main() {
	orm.NewQuery(nil, nil)
	(&orm.Query{}).New()
}

1. Go to Definition of orm.NewQuery
2. Hover on the return value
3. Query has ho fields

And

1. Go to Definition of method (*orm.Query).New
2. Hover on Query in the line clone := &Query{
3. Query has fields, but they are poorly formatted

gopls@09ab05b (master)

1	2

gopls@v0.6.11

1	2

FWIW, I think these are separate issues.

@ShoshinNikita you issue seems to clearly be a result of AST trimming. I am not so sure about the original issue. Keeping this as a single issue until I understand it better.

Change https://golang.org/cl/320550 mentions this issue: internal/lsp/source: re-parse if needed when collecting identifier info

The CL above should fix the issue reported by @ShoshinNikita, but I'm still not sure what's going on in the original issue: none of the AST trimming should have dropped comments.

So I think we should leave this issue open for a little while in case the problem reoccurs and we can capture logs. Unassigning in the meantime.

@inliquid: Have you encountered this again, after the CL above? If not, let's close this issue as I think it has been resolved.

@stamblerre no, haven't seen this so far.

@findleyr At first, I decided the issue I reported is not completely fixed. But then I understood it is the intended result of AST trimming. Is that correct?

Exported function ast.FilterFile:

Unexported function ast.filterFile:

Thanks for catching that. This must be an edge case that doesn't trigger re-parsing, for some reason.

I'll look into it.

The issue is that in the case of filterFile, we're not finding the hovered declaration at all. The patch of CL 320550 was really too shallow: we need a mechanism for specifying exactly what information is needed to fulfill the hover request, and this mechanism should go through the gopls cache.

I'm experimenting with this now, but it will likely turn out not to be a small change.

Change https://golang.org/cl/333689 mentions this issue: internal/lsp: improve package search in a couple places

Change https://golang.org/cl/333690 mentions this issue: internal/lsp/source: improve logic for finding full syntax in hover

@findleyr I think I found a regression introduced in the last CL (https://golang.org/cl/333690):

1. Open the following code

   package main
   
   import "go/ast"
   
   func main() {
   	var l *ast.BasicLit
   	_ = l.Value
   }

2. Hover on Value - there's no comment

   

3. Press Ctrl + Space 2 times (trigger suggestions and toggle details) - there's a comment

   

4. Go to Value definition and trigger hover - there's a comment

   

Note: it's happening only with packages from std lib and other modules

Updated TestHoverUnexported to reproduce this issue:

func TestHoverUnexported(t *testing.T) {
	const proxy = `
-- golang.org/x/structs@v1.0.0/go.mod --
module golang.org/x/structs

go 1.12

-- golang.org/x/structs@v1.0.0/types.go --
package structs

type Mixed struct {
	// Exported comment
	Exported   int
	unexported string
}

func printMixed(m Mixed) {
	println(m)
}
`
	const mod = `
-- go.mod --
module mod.com

go 1.12

require golang.org/x/structs v1.0.0
-- go.sum --
golang.org/x/structs v1.0.0 h1:Ito/a7hBYZaNKShFrZKjfBA/SIPvmBrcPCBWPx5QeKk=
golang.org/x/structs v1.0.0/go.mod h1:47gkSIdo5AaQaWJS0upVORsxfEr1LL1MWv9dmYF3iq4=
-- main.go --
package main

import "golang.org/x/structs"

func main() {
	var m structs.Mixed
	_ = m.Exported
}
`

	// TODO: use a nested workspace folder here.
	WithOptions(
		ProxyFiles(proxy),
	).Run(t, mod, func(t *testing.T, env *Env) {
		env.OpenFile("main.go")
		mixedPos := env.RegexpSearch("main.go", "Mixed")
		got, _ := env.Hover("main.go", mixedPos)
		if !strings.Contains(got.Value, "unexported") {
			t.Errorf("Workspace hover: missing expected field 'unexported'. Got:\n%q", got.Value)
		}

		cacheFile, _ := env.GoToDefinition("main.go", mixedPos)
		argPos := env.RegexpSearch(cacheFile, "printMixed.*(Mixed)")
		got, _ = env.Hover(cacheFile, argPos)
		if !strings.Contains(got.Value, "unexported") {
			t.Errorf("Non-workspace hover: missing expected field 'unexported'. Got:\n%q", got.Value)
		}

		exportedFieldPos := env.RegexpSearch("main.go", "Exported")
		got, _ = env.Hover("main.go", exportedFieldPos)
		if !strings.Contains(got.Value, "comment") {
			t.Errorf("Workspace hover: missing comment for field 'Exported'. Got:\n%q", got.Value)
		}
	})
}

The regression is caused by this code:

// Always use the full declaration here if we have it, because the
// dependent code doesn't rely on pointer identity. This is fragile.
if d, _ := fullDecl.(*ast.GenDecl); d != nil {
	node = d
}

We can't find a comment (see function findFieldComment) because fields of fullDecl have completely different token positions. For example:

1. We try to find a comment for field with pos 2318327
2. node before update: &ast.GenDecl{Doc:(*ast.CommentGroup)(0xc002ba5c50), TokPos:2317438, Tok:84, ...}
3. node after update: &ast.GenDecl{Doc:(*ast.CommentGroup)(0xc00d5d7cf8), TokPos:36467060, Tok:84, ...}
4. Fields of "new" node has the following positions: 36467816, 36467859, 36467949

@ShoshinNikita thank you for that investigation!

Moving this to v0.8.0.

Change https://go.dev/cl/384697 mentions this issue: internal/lsp/source: adjust object position when formatting full AST