cmd/compile: internal compiler error: assertion failed

[fogfish]

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

$ go version
go version go1.18.3 darwin/amd64

Does this issue reproduce with the latest release?

Yes

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

The issue is reproducible at

• darwin/amd64
• linux/amd64

go env Output

$ go env
GO111MODULE=""

GOARCH="amd64"

GOBIN=""

GOCACHE="/Users/kolesnik/Library/Caches/go-build"

GOENV="/Users/kolesnik/Library/Application Support/go/env"

GOEXE=""

GOEXPERIMENT=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="darwin"

GOINSECURE=""

GOMODCACHE="/Users/kolesnik/devel/go/pkg/mod"

GONOPROXY=""

GONOSUMDB=""

GOOS="darwin"

GOPATH="/Users/kolesnik/devel/go"

GOPRIVATE=""

GOPROXY="https://proxy.golang.org,direct"

GOROOT="/usr/local/go"

GOSUMDB="sum.golang.org"

GOTMPDIR=""

GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"

GOVCS=""

GOVERSION="go1.18.3"

GCCGO="gccgo"

GOAMD64="v1"

AR="ar"

CC="clang"

CXX="clang++"

CGO_ENABLED="1"

GOMOD="/Users/kolesnik/devel/go/src/github.com/fogfish/dynamo/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/gj/dt8b38qd4xx60g9y89d5mfj40000gn/T/go-build2387231264=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

assertion failed error appears while trying to run go test ./... or go vet ./... on the library that uses various generic abstraction. It has started to fail at 1.18.3 release but works perfectly with 1.18.1 and also building the library with go build ./... works with 1.18.3.

You can reproduce an error with following commands

git clone https://github.com/fogfish/dynamo
cd dynamo
go test ./...

What did you expect to see?

Successful compilation.

What did you see instead?

go test ./...
# github.com/fogfish/dynamo/internal/ddb [github.com/fogfish/dynamo/internal/ddb.test]
/Users/kolesnik/devel/go/pkg/mod/github.com/fogfish/golem@v0.8.5/pure/hseq/hseq.go:99:11: internal compiler error: assertion failed

The error report fails to compile dependency but building that decencies in other context also works fine.

Something fishy is going on... any advice is welcome how to debug this issue!

[cherrymui]

Reproduced at tip. Here is the error message

/Users/cherryyz/gopkg/pkg/mod/github.com/fogfish/golem@v0.8.5/pure/hseq/hseq.go:99:11: internal compiler error: assertion failed

goroutine 1 [running]:
runtime/debug.Stack()
	/Users/cherryyz/src/go-tmp/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x138ceb8?, 0xc0?}, {0x193e93e, 0x10}, {0x0, 0x0, 0x0})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/base/print.go:227 +0x1d7
cmd/compile/internal/base.Fatalf(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/base.Assert(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/base/print.go:239
cmd/compile/internal/noder.assert(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:27
cmd/compile/internal/noder.convertUsingDictionary(0xc00138ceb8, 0xc000455250?, {0x1805371?, 0x0?}, {0x1aa9690, 0xc001361440}, {0x1aa9ae0?, 0xc00139e640}, 0xc00132bb20)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:1487 +0x837
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1aa9ae0, 0xc00139e640})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:1330 +0x39e
cmd/compile/internal/ir.editNodes(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*ReturnStmt).editChildren(0xc00138f2d0?, 0xc000e904b0)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/node_gen.go:962 +0xa2
cmd/compile/internal/ir.EditChildren(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1aaacd8, 0xc00139e550})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:1230 +0x11b
cmd/compile/internal/ir.editNodes(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*Func).editChildren(0xc000455510?, 0xc000e904b0?)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/func.go:152 +0x74
cmd/compile/internal/ir.EditChildren(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1aa9e78, 0xc0013643c0})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:1230 +0x11b
cmd/compile/internal/noder.(*genInst).dictPass(0x1fcab00, 0xc00138ceb8)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:1400 +0x150
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x1fcab00)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:78 +0x1cc
cmd/compile/internal/noder.BuildInstantiations(...)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/stencil.go:44
cmd/compile/internal/noder.(*irgen).generate(0xc000690300, {0xc000372ff0, 0x6, 0x200d760?})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/irgen.go:333 +0x3d1
cmd/compile/internal/noder.check2({0xc000372ff0, 0x6, 0x6})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/irgen.go:87 +0x14d
cmd/compile/internal/noder.LoadPackage({0xc0000be100, 0x6, 0x6})
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/noder/noder.go:84 +0x49c
cmd/compile/internal/gc.Main(0x1966cf8)
	/Users/cherryyz/src/go-tmp/src/cmd/compile/internal/gc/main.go:189 +0xbbd
main.main()
	/Users/cherryyz/src/go-tmp/src/cmd/compile/main.go:57 +0xdd

It appears to be from instantiating a generic function. cc @randall77

[wdvxdr1123]

Here is a simple repro.
https://go.dev/play/p/cjrTt3JyRTZ?v=gotip

package main

type Interface[T any] interface {
}

func F[T any]() Interface[T] {
	var i int
	return i
}

func main() {
	F[int]()
}

[gopherbot]

Change https://go.dev/cl/410655 mentions this issue: cmd/compile: don't use dictionary convert to shaped empty interface

[randall77]

@gopherbot please open a backport issue to 1.18.

[gopherbot]

Backport issue(s) opened: #53274 (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.

[ecryth]

I also got the same error. MWE of the code I was working with:

package main

import "fmt"

type Interface[K any] interface {
	Name() string
}

type interfaceImpl[K any] struct {
	name string
}

func (i interfaceImpl[K]) Name() string {
	return i.name
}

type Type[T any, K any] struct {
	interfaceImpl[K]
}

func main() {
	a := Type[int, int]{
		interfaceImpl[int]{name: "hello"},
	}
	printName(a)
}

func printName[T any](k Type[T, int]) {
	fmt.Println(k.Name())
}

[wdvxdr1123]

@arvidfm I believe this is an another issue because of different stack backtrace. I open a new issue and will mail a fix soon.