x/tools: shadow analyzer does not consider variables declared in for-range statement #44986
Description
What version of Go are you using (go version)?
$ go version go version go1.16.2 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="" GOARCH="amd64" GOBIN="" GOCACHE="/home/john/.cache/go-build" GOENV="/home/john/.config/go/env" GOEXE="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOINSECURE="" GOMODCACHE="/home/john/go/pkg/mod" GONOPROXY="" GONOSUMDB="" GOOS="linux" GOPATH="/home/john/go" GOPRIVATE="" GOPROXY="https://proxy.golang.org,direct" GOROOT="/usr/local/go" GOSUMDB="sum.golang.org" GOTMPDIR="" GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64" GOVCS="" GOVERSION="go1.16.2" GCCGO="gccgo" AR="ar" CC="gcc" CXX="g++" CGO_ENABLED="1" GOMOD="/dev/null" 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-build3861764262=/tmp/go-build -gno-record-gcc-switches"
What did you do?
Installed and ran the shadow analyzer on a file witht the contents below:
$ go get -u -v golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow
$ cat tt.go
package main
import (
"fmt"
)
func main() {
n := 10
total := 0
for _, n := range []int{1, 2, 3} {
total += n
}
fmt.Printf("total is %d, n is %d\n", total, n)
}
$ shadow tt.go
$
No warning was generated
What did you expect to see?
A message similar to:
/home/john/tt.go:10:9: declaration of "n" shadows declaration at line 8
What did you see instead?
No output from the shadow tool.