x/tools/gopls: "invalid type" completion for make(map) in struct field assign

[skewb1k]

gopls version

Build info

golang.org/x/tools/gopls v0.0.0-20250825151158-e8ff82cb4556
golang.org/x/tools/gopls@v0.0.0-20250825151158-e8ff82cb4556
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@v0.0.0-20250718183923-645b1fa84792 h1:54/e+WfmhvjR2Zuz8Q7dzLGxIBM+s5WZpvo1QfVDGB8=
golang.org/x/mod@v0.27.0 h1:kb+q2PyFnEADO2IEF935ehFUXlWiNjJWtRNgBLSfbxQ=
golang.org/x/sync@v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
golang.org/x/sys@v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
golang.org/x/telemetry@v0.0.0-20250807160809-1a19826ec488 h1:3doPGa+Gg4snce233aCWnbZVFsyFMo/dR40KK/6skyE=
golang.org/x/text@v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
golang.org/x/tools@v0.35.0 => ../
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

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/skewb1k/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/skewb1k/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2136758201=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/skewb1k/dev/go-tools/gopls/go.mod'
GOMODCACHE='/home/skewb1k/.local/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/skewb1k/.local/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/lib/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/skewb1k/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.25.0'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

1. Create a Go file with the following code:

package main

func main() {
	_ = struct {
		Foo map[string]int
	}{
		Foo: make(map|),
	}
}

2. Place the cursor at | position.
3. Trigger completion.

What did you see happen?

map[invalid type]invalid type completion item.

What did you expect to see?

map[string]int

Editor and settings

NVIM v0.12.0-dev, using the builtin LSP client.

Logs

No response

[xieyuschen]

Hi @skewb1k , could you explain what does invalid type inside map[invalid type]invalid type mean?
Besides, if you trigger completion Foo: | here, it will give you the correct completion items.

[skewb1k]

@xieyuschen you didn't follow the reproduction steps. Start by typing make(map (the trailing paren doesn't matter).
What you showed works, and make(|) works too. But make(map[string]|) also gives map[string]invalid type, so this looks like a flaw in how typechecker handles make.

[xieyuschen]

@skewb1k , thanks for your explanation, i have reproduced map[string]invalid type, but haven't reproduced map[invalid type]invalid type.
But I believe i have understood your question now, and will try to find a time to tackle it.

gopls -v version
Build info
----------
golang.org/x/tools/gopls v0.36.1-0.20250825151158-e8ff82cb4556