cmd/compile: invalid field name *** in struct initializer

[Reasno]

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

go 1.18beta1

$ go version
go1.18beta1 darwin/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="/Users/donew/Library/Caches/go-build"
GOENV="/Users/donew/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/donew/src/go/pkg/mod"
GONOPROXY="glab.tagtic.cn"
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/donew/src/go"
GOPRIVATE=""
GOPROXY="https://goproxy.cn,direct"
GOROOT="/Users/donew/src/go/go1.18beta1"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/Users/donew/src/go/go1.18beta1/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.18beta1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/donew/Downloads/go118bug/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 -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/92/6vv251ls5_lgh6kmm9xq_wh80000gn/T/go-build1725229051=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

when I was playing with generics I discovered a subtle (possible) compiler bug. go1.18beta1 vet and go1.18beta1 build gives me no complaint but the go1.18beta1 test failed out of no good reason.

The offending code is isolated in https://github.com/Reasno/go1.18beta1bug.

The code with generic:

package bar

type Data[K comparable, V any] struct {
	field int
}

type Dataset[K comparable, V any] struct{}

func (m *Dataset[K, V]) GetData() *Data[K, V] {
	d := &Data[K, V]{field: 1}
	return d
}

var DefaultDataset = Dataset[string, any]{}

func GetData() *Data[string, any] {
	return DefaultDataset.GetData()
}

and the test file:

package bar_test

import (
	bar "github.com/reasno/go1.18beta1bug"
	"testing"
)

func Test(t *testing.T) {
	bar.GetData()
}

What did you expect to see?

The go1.18beta1 test compilation should be green.

What did you see instead?

go1.18beta1 test rants: ../main.go:10:24: invalid field name bar.field in struct initializer

[randall77]

This seems to be fixed at tip. Can you try that to verify, or we should have beta2 out in a few days which should also have this fixed.

[mknyszek]

Because this seems to be fixed, not marking as a release blocker. Waiting for info from OP to verify that it's fixed at tip.

[Reasno]

I compiled go from git master and the issue remains

$ go version
go version devel go1.18-9ff0039848 Fri Jan 28 02:40:34 2022 +0000 darwin/amd64
$ go test
# github.com/reasno/go1.18beta1bug_test [github.com/reasno/go1.18beta1bug.test]
./main.go:10:24: invalid field name bar.field in struct initializer
FAIL    github.com/reasno/go1.18beta1bug [build failed]

[randall77]

I can't get it to fail at tip (@9ff00398489d9eb1822b3de028cd6ccf5674ebb3) but I can at 1.18beta1.

Just to be clear I have a directory issue50848 with three items in it:

go.mod:

module issue50848

go 1.18

issue50848_test.go:

package issue50848_test

import (
	"testing"

	"issue50848/bar"
)

func Test(t *testing.T) {
	bar.GetData()
}

and a directory bar with one file in it, bar.go:

package bar

type Data[K comparable, V any] struct {
	field int
}

type Dataset[K comparable, V any] struct{}

func (m *Dataset[K, V]) GetData() *Data[K, V] {
	d := &Data[K, V]{field: 1}
	return d
}

var DefaultDataset = Dataset[string, any]{}

func GetData() *Data[string, any] {
	return DefaultDataset.GetData()
}

Which gives:

issue50848 % ~/go1.18beta1/bin/go test
# issue50848_test [issue50848.test]
./bar/bar.go:10:24: invalid field name bar.field in struct initializer
FAIL	issue50848 [build failed]
issue50848 % ~/sandbox/ro/bin/go test 
PASS
ok  	issue50848	0.004s

(~/sandbox/ro is synced and make.bash'd at the commit listed above.)

[Reasno]

go version devel go1.18-9ff0039848 Fri Jan 28 02:40:34 2022 +0000 darwin/amd64

Looks like you are right.

My IDE has GOROOT="~/src/go/go1.18beta1"set even though the binary I used is the latest. In a fresh terminal, I can confirm the bug is fixed at tip.

Thanks for the hard work.