cmd/compile: internal compiler error: walkExpr: switch 1 unknown op RECOVER

[ahazhangxin]

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

$ go version
go version go1.18 darwin/amd64

Does this issue reproduce with the latest release?

it is already the latest version

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

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/zhangxin/Library/Caches/go-build"
GOENV="/Users/zhangxin/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/zhangxin/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/zhangxin/go"
GOPROXY="https://goproxy.io,direct"
GOROOT="/usr/local/Cellar/go/1.18/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.18/libexec/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.18"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
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 -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/dg/2q4522bs3959p0x7tbn61_kw0000gn/T/go-build3463372418=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

go func() { defer func() { if r := recover(); r != nil { glog.Errorf("error=%v", r) } }() }

it seems fixed in https://go-review.googlesource.com/c/go/+/342350/
but in this version it appears again

What did you expect to see?

compiles correctly

What did you see instead?

walk . RECOVER INTER-interface {} tc(1) # hello_dao.go:50:21 hello_dao.go:50:21: internal compiler error: walkExpr: switch 1 unknown op RECOVER

[mvdan]

Could you please provide a full program to reproduce this crash?

[ahazhangxin]

package main

import (
	"runtime"
	"sync"

	"github.com/golang/glog"
)

var prefetchOnce sync.Once

func testRecover() {
	if "darwin" != runtime.GOOS {
		prefetchOnce.Do(func() {
			go func() {
				defer func() {
					err := recover()
					if err != nil {
						//fmt.Println(err)
						glog.Errorf("error=%v", err)
					}
				}()
			}()
		})
	}
}

func main() {
	testRecover()
}

when i use go build test.go

# command-line-arguments
walk
.   RECOVER INTER-interface {} tc(1) # test.go:17:20
./test.go:17:20: internal compiler error: walkExpr: switch 1 unknown op RECOVER

Please file a bug report including a short program that triggers the error.
https://go.dev/issue/new

[hopehook]

A simple demo:

package main

func main() {
	testRecover()

}

func testRecover() {
	if false {
		func() {
			defer func() {
				_ = recover()
			}()
		}()
	}
}

[gopherbot]

Change https://go.dev/cl/394079 mentions this issue: cmd/compile: fix panic with nested dead hidden closures

[cuonglm]

Not sure this is qualified for backporting, since when the runtime.GOOS checking is likely to happen so often in user code. A workaround can be moving the code for specific OS to separated file, instead of checking for runtime.GOOS.

cc @mdempsky @cherrymui

[mvdan]

I do think this should be backported if possible, as it's a regression with a seemingly small fix.

[ianlancetaylor]

@gopherbot Please open backport to 1.18

This is an internal compiler error on valid code.

[gopherbot]

Backport issue(s) opened: #51846 (for 1.18).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.