x/exp/slices: Clone returns nil for an empty non-nil slice

[ainar-g]

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

$ go version
go version devel go1.18-5337e53dfa Sun Nov 14 17:38:42 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

Yes.

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

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/ainar/.cache/go-build"
GOENV="/home/ainar/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/ainar/go/pkg/mod"
GONOPROXY="REMOVED"
GONOSUMDB="REMOVED"
GOOS="linux"
GOPATH="/home/ainar/go"
GOPRIVATE="REMOVED"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/ainar/go/tip"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/ainar/go/tip/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.18-5337e53dfa Sun Nov 14 17:38:42 2021 +0000"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3251505622=/tmp/go-build -gno-record-gcc-switches"

What did you do?

package main

import (
	"fmt"

	"golang.org/x/exp/slices"
)

func main() {
	fmt.Printf("%#v\n", slices.Clone([]int(nil)))
	fmt.Printf("%#v\n", slices.Clone([]int{}))
	fmt.Printf("%#v\n", slices.Clone([]int{1}))
}

What did you expect to see?

[]int(nil)
[]int{}
[]int{1}

What did you see instead?

[]int(nil)
[]int(nil)
[]int{1}

[gopherbot]

Change https://golang.org/cl/365174 mentions this issue: slices: preserve nil/non-nil in Clone

[ainar-g]

I confirm that the fix works, thanks!