cmd/compile: interface conversion with generics reports "types from different scopes" [1.18 backport] #53883
Description
What version of Go are you using (go version)?
$ go version go version go1.18.4 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/USER/.cache/go-build" GOENV="/home/USER/.config/go/env" GOEXE="" GOEXPERIMENT="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOINSECURE="" GOMODCACHE="/home/USER/gows/pkg/mod" GONOPROXY="athome.fractalqb.de" GONOSUMDB="athome.fractalqb.de" GOOS="linux" GOPATH="/home/USER/gows" GOPRIVATE="athome.fractalqb.de" GOPROXY="https://proxy.golang.org,direct" GOROOT="/home/USER/bin/go1.18.4" GOSUMDB="sum.golang.org" GOTMPDIR="" GOTOOLDIR="/home/USER/bin/go1.18.4/pkg/tool/linux_amd64" GOVCS="" GOVERSION="go1.18.4" GCCGO="gccgo" GOAMD64="v1" AR="ar" CC="gcc" CXX="g++" CGO_ENABLED="1" GOMOD="/home/USER/gows/src/git.fractalqb.de/proto/different-scopes-1.18.3/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 -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build131321195=/tmp/go-build -gno-record-gcc-switches"
What did you do?
- Compile this code
package main
import (
"fmt"
"github.com/fractalqb/change"
"github.com/fractalqb/change/chgsql"
)
var id change.Val[uint64]
func main() {
v := chgsql.Nullable[uint64](&id, 0)
fmt.Println(v)
}
- Run the program
$ ./different-scopes
panic: interface conversion: change.Changeable[go.shape.uint64_0] is *change.Val[uint64], not *change.Val[uint64] (types from different scopes)
goroutine 1 [running]:
github.com/fractalqb/change/chgsql.Nullable[...](...)
/home/USERgows/pkg/mod/github.com/fractalqb/change@v0.4.1/chgsql/type.go:27
main.main()
/home/USER/gows/src/git.fractalqb.de/proto/different-scopes-1.18.3/main.go:16 +0x2e
What did you expect to see?
When running the program I expect the output to be: <nil>
When compiling and running with Go 1.18.2 it works as expected. Please also read my remarks on #52027
What did you see instead?
As already mentioned above. Running the Program (compiled with 1.8.4) gives me the output:
panic: interface conversion: change.Changeable[go.shape.uint64_0] is *change.Val[uint64], not *change.Val[uint64] (types from different scopes)
goroutine 1 [running]:
github.com/fractalqb/change/chgsql.Nullable[...](...)
/home/USERgows/pkg/mod/github.com/fractalqb/change@v0.4.1/chgsql/type.go:27
main.main()
/home/USER/gows/src/git.fractalqb.de/proto/different-scopes-1.18.3/main.go:16 +0x2e