x/tools/gopls: InlayHint(constantValues): don't exclude booleans

[rothelius]

gopls version

Build info

golang.org/x/tools/gopls v0.20.0
golang.org/x/tools/gopls@v0.20.0 h1:fxOYZXKl6IsOTKIh6IgjDbIDHlr5btOtOUkrGOgFDB4=
github.com/BurntSushi/toml@v1.5.0 h1:W5quZX/G/csjUnuI8SUYlsHs9M38FC7znL0lIO+DvMg=
github.com/fatih/camelcase@v1.0.0 h1:hxNvNX/xYBp0ovncs8WyWZrOrpBNub/JfaMvbURyft8=
github.com/fatih/gomodifytags@v1.17.1-0.20250423142747-f3939df9aa3c h1:dDSgAjoOMp8da3egfz0t2S+t8RGOpEmEXZubcGuc0Bg=
github.com/fatih/structtag@v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
github.com/fsnotify/fsnotify@v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
github.com/google/go-cmp@v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
golang.org/x/exp/typeparams@v0.0.0-20250620022241-b7579e27df2b h1:KdrhdYPDUvJTvrDK9gdjfFd6JTk8vA1WJoldYSi0kHo=
golang.org/x/mod@v0.26.0 h1:EGMPT//Ezu+ylkCijjPc+f4Aih7sZvaAr+O3EHBxvZg=
golang.org/x/sync@v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
golang.org/x/sys@v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
golang.org/x/telemetry@v0.0.0-20250710130107-8d8967aff50b h1:DU+gwOBXU+6bO0sEyO7o/NeMlxZxCZEvI7v+J4a1zRQ=
golang.org/x/text@v0.27.0 h1:4fGWRpyh641NLlecmyl4LOe6yDdfaYNrGb2zdfo4JV4=
golang.org/x/tools@v0.35.1-0.20250728180453-01a3475a31bc h1:ZRKyKRJl/YEWl9ScZwd6Ua6xSt7DE6tHp1I3ucMroGM=
golang.org/x/vuln@v1.1.4 h1:Ju8QsuyhX3Hk8ma3CesTbO8vfJD9EvUBgHvkxHBzj0I=
honnef.co/go/tools@v0.7.0-0.dev.0.20250523013057-bbc2f4dd71ea h1:fj8r9irJSpolAGUdZBxJIRY3lLc4jH2Dt4lwnWyWwpw=
mvdan.cc/gofumpt@v0.8.0 h1:nZUCeC2ViFaerTcYKstMmfysj6uhQrA2vJe+2vwGU6k=
mvdan.cc/xurls/v2@v2.6.0 h1:3NTZpeTxYVWNSokW3MKeyVkz/j7uYXYiMtXRUfmjbgI=
go: go1.25.0

go env

set AR=ar
set CC=gcc
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_ENABLED=1
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set CXX=g++
set GCCGO=gccgo
set GO111MODULE=
set GOAMD64=v1
set GOARCH=amd64
set GOAUTH=netrc
set GOBIN=
set GOCACHE=C:\Users\telic\AppData\Local\go-build
set GOCACHEPROG=
set GODEBUG=gotypesalias=1
set GOENV=C:\Users\telic\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=aliastypeparams
set GOFIPS140=off
set GOFLAGS=
set GOGCCFLAGS=-m64 -mthreads -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=C:\Users\telic\AppData\Local\Temp\go-build1324528744=/tmp/go-build -gno-record-gcc-switches
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMOD=C:\Code\go\bftv\go.mod
set GOMODCACHE=C:\Users\telic\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\telic\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Program Files\Go
set GOSUMDB=sum.golang.org
set GOTELEMETRY=on
set GOTELEMETRYDIR=C:\Users\telic\AppData\Roaming\go\telemetry
set GOTMPDIR=
set GOTOOLCHAIN=auto
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.25.0
set GOWORK=C:\Code\go\go.work
set PKG_CONFIG=pkg-config

What did you do?

Wrote a bool-typed constant, e.g:
const smallInt = unsafe.Sizeof(int(0)) == 4

What did you see happen?

Despite inlay hints for constant values enabled, no such hint.

What did you expect to see?

A // false inlay hint.

The inlay hint code does explicitly exclude bools, but it seems this is more due to the fact that true and false are not *ast.BasicLits (which blocks other simple constants) than owing to its usefulness.

Editor and settings

VSCode

Logs

No response

[gabyhelp]

Related Issues

• x/tools/gopls: add inlay hints #52343 (closed)
• x/tools/gopls: jump to definition for inlay hints #64632
• x/tools/gopls: broken hovering in the builtin file #68026 (closed)
• x/tools/gopls: Missing defaultLibrary semantic token modifier for builtin constants #70219 (closed)
• x/tools/gopls: Semantic Highlighting for builtin `true` and `false` broken in 0.17.0 #70934 (closed)
• x/tools/gopls: using hints results in error saying hints already specified when not #57470 (closed)
• x/tools/gopls: Unexpected line comment insertion after line break #74618 (closed)
• x/tools/gopls: #52425 (closed)
• x/tools/gopls: run completion using partial type checking of current package #68063
• x/tools/gopls: Incorrect result of `unsafe.Sizeof` for time.Time type. #59757 (closed)

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

[adonovan]

The documentation at https://go.dev/gopls/features/passive#inlay-hint is wrong. It says:

For a constant expression (perhaps using iota), a hint provides its computed value (constantValues).

But according to the code, the intent is to provide a hint only at the declaration of a constant, and only if either (1) there is no right-hand side value, as in one below:

const (
    zero = iota
    one
    ...
)

or (2) when there is a right-hand side expression, but it is a non-literal, and its type is not boolean, as in two below:

const two = 1 + 1

I don't know why booleans were excluded; it was like this since the feature was added in https://go.dev/cl/411101, and neither its code review nor attached issues sheds any light. (Perhaps booleans were excluded because they are more likely to depend on the build configuration, e.g. GOOS=="darwin"? That's just a guess.) I can't see any obvious reason not to include booleans.

We should also update the documentation to reflect the code.