cmd/go: "go run -compiler=gccgo main.go" doesn't work well with go1.19rc2

[zigo101]

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

$ go version
go version go1.19rc2 linux/amd64

$ gccgo --version
gccgo (Debian 10.2.1-6) 10.2.1 20210110

Does this issue reproduce with the latest release?

Not for 1.18.x, just for 1.19rc2

What did you do?

go run -compiler=gccgo main.go

What did you expect to see?

Run well.

What did you see instead?

Errors:

../software/go/src/runtime/chan.go:21:2: cannot find package
../software/go/src/runtime/error.go:7:8: cannot find package
...

Running gccgo solely is also okay.

[ianlancetaylor]

I can't recreate this. Can you see when it stopped working? Thanks.

[zigo101]

At least since 1.19beta1.

1.18.4 is ok.

My gccgo version is 10, which is the newest version on debian.

My go env:

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/myname/.cache/go-build"
GOENV="/home/myname/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/myname/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/myname/go"
GOPRIVATE=""
GOPROXY=""
GOROOT="/home/myname/software/go"
GOSUMDB="on"
GOTMPDIR=""
GOTOOLDIR="/home/myname/software/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18.4"
GCCGO="/usr/bin/gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3655385898=/tmp/go-build -gno-record-gcc-switches"

[ianlancetaylor]

I can't recreate the problem with 1.19beta1 either. I'm sorry, I don't know what is happening here. Do you have GOROOT set in the environment?

[zigo101]

No. I only set /home/myname/software/go/bin in PATH.

[zigo101]

I just built the go1.19rc2 tag and the tip. The problem exists in the go1.19rc2 tag version but is fixed in tip.
I haven't enough time to bisect which revision fixed this problem.
If the tip will be merged into 1.19, then this issue may be closed now.

[ianlancetaylor]

OK, still not sure why it worked for me, but I may have made a mistake somewhere. Glad it is working for you. This may be #53815.