What version of Go are you using (go version)?

$ go version
go version devel go1.18-b7529c3 Tue Nov 9 06:27:04 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

N/A

What operating system and processor architecture are you using (go env)?

Custom VSCode devcontainer, Dockerfile based on golang:latest, but running a Go build of the latest master branch.

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/vscode/.cache/go-build"
GOENV="/home/vscode/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/master/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/master/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.18-b7529c3 Tue Nov 9 06:27:04 2021 +0000"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/workspace/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3516386950=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Some functions that take type parameters, are ignored / not documented by godoc http server. Notably I found generic functions that return a value or slice of Type are omitted in the documentation output. While functions which receive an argument of a generic Type are represented in the documentation.

I've created a small Github repo to easily reproduce. It contains a source.go file with generic functions, and a Dockerfile that build the latest golang/go:master with x/tools/cmd/godoc@master:

1. git clone https://github.com/muhlemmer/godoc_generics_issue.git
2. docker build -t ggi .
3. docker run -p 6060:6060 ggi
4. Browse to http://localhost:6060/pkg/github.com/muhlemmer/godoc_generics_issue/

What did you expect to see?

All exported functions, with or without type parameters to be documented.

What did you see instead?

This function is documented:

func Print[T proto.Message](s []T) {
	for _, v := range s {
		fmt.Println(v)
	}
}

This functions are missing:

func Slice[T any]() []T {
	return nil
}

func Single[T any]() *T {
	return nil
}