x/tools/gopls: Extend hover ability to get the type of selected expression

[xzbdmw]

gopls version

golang.org/x/tools/gopls v0.0.0-20240816163142-66adacf20fc4
golang.org/x/tools/gopls@v0.0.0-20240816163142-66adacf20fc4 h1:iSreTB1mHFYjQkoNmGjFjKRGkrhedt4wmfg
47nKSo28=
github.com/BurntSushi/toml@v1.2.1 h1:9F2/+DoOYIOksmaJFPw1tGFy1eDnIJXg+UHjuD8lTak=
github.com/google/go-cmp@v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
golang.org/x/exp/typeparams@v0.0.0-20221212164502-fae10dda9338 h1:2O2DON6y3XMJiQRAS1UWU+54aec2uopH
3x7MAiqGW6Y=
golang.org/x/mod@v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
golang.org/x/sync@v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
golang.org/x/telemetry@v0.0.0-20240712210958-268b4a8ec2d7 h1:nU8/tAV/21mkPrCjACUeSibjhynTovgRMXc32
+Y1Aec=
golang.org/x/text@v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
golang.org/x/tools@v0.24.1-0.20240816163142-66adacf20fc4 h1:PoPnfVMls3TamN2+Zq6FsI1uSjUOqW1mt6AXfY
w3kdw=
golang.org/x/vuln@v1.0.4 h1:SP0mPeg2PmGCu03V+61EcQiOjmpri2XijexKdzv8Z1I=
honnef.co/go/tools@v0.4.7 h1:9MDAWxMoSnB6QoSqiVr7P5mtkT9pOc1kSxchzPCnqJs=
mvdan.cc/gofumpt@v0.6.0 h1:G3QvahNDmpD+Aek/bNOLrFR2XC6ZAdo62dZu65gmwGo=
mvdan.cc/xurls/v2@v2.5.0 h1:lyBNOm8Wo71UknhUs4QTFUNNMyxy2JEIaKKo0RWOh+8=
go: go1.22.4

go env

GO111MODULE='auto'
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/xzb/Library/Caches/go-build'
GOENV='/Users/xzb/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/xzb/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/xzb/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.22.4'
GCCGO='gccgo'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/Users/xzb/Project/go/tools/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/gv/r110hgbx1gbgzp95kf_q71x40000gn/T/go-build4205968761=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

As the title says, get the type info of seleted range.
in Goland
https://github.com/user-attachments/assets/7eea395f-490f-420f-8c8e-d1897f679f0e

in rust-analyzer
documentation

iShot_2024-08-25_10.07.24.mp4

What did you see happen?

We can't hover in selection state to get type information

What did you expect to see?

Get the type info of seleted range.
related:rust-lang/rust-analyzer#9693

Editor and settings

No response

Logs

No response

[gabyhelp]

Related Issues and Documentation

• x/tools/gopls: add method documentation & jump to page source to hovered type. #66721 (closed)
• x/tools/gopls: jump to definition for inlay hints #64632
• x/tools/gopls: add inlay hints #52343 (closed)
• x/tools/gopls: InvalidRangeExpr when using GOEXPERIMENT=rangefunc on iter.Seq #65667 (closed)
• x/tools/gopls: hover stops working #64778 (closed)
• x/tools/gopls: extract function action doesn't work if the first line is a comment #54816 (closed)
• x/tools/gopls: hover over some tokens in template files oops #50031 (closed)
• x/tools/gopls: hover doc doesn't show the receiver variable name #62190 (closed)
• x/tools/gopls: space in package path leads to invalid hover markdown #68026
• x/tools/gopls: empty hover response should be null, not a zero struct #37570 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[findleyr]

Thanks.

We've talked about such a feature in the past, but have always been limited by the fact that textDocument/hover accepts a position, not a range (https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#hoverParams).

Looks like rust-analyzer added a hoverRange extension. I wonder how many clients support this?

CC @adonovan, who I believe has thought about this exact feature.

[adonovan]

See:

• Pass the current selection for a Hover Request microsoft/language-server-protocol#377
• new feature: describe (type of) selected expression microsoft/language-server-protocol#1466

As soon as LSP supports a range in a hover request, we should add support for it to gopls.

[gopherbot]

Change https://go.dev/cl/609656 mentions this issue: gopls/internal/golang: hover: show type of selected expr

[xzbdmw]

https://go.dev/cl/609656

It already works in neovim, amazing 🚀

[findleyr]

@xzbdmw are you using the built in neovim lsp client, or some LSP plugin?

Send screenshots, please :)

@adonovan should we follow the Rust team's lead and just ship first and ask questions later? :)

[adonovan]

@adonovan should we follow the Rust team's lead and just ship first and ask questions later? :)

I nudged the 377 issue last night and I think the dominoes may be close to toppling.

[xzbdmw]

are you using the built in neovim lsp client

Yes, by adding range param to requst of TextDocument/Hover, something like

local range = require("vim.lsp.buf").range_from_selection(0, mode)
local param = vim.lsp.util.make_position_params(0, nil)
param.range = range
vim.lsp.buf_request(0, "textDocument/hover", param, handler)

screenshot:

iShot_2024-08-31_11.11.43.mp4