cmd/compile: internal compiler error: assertion failed

[Clemens-H]

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

$ go version
go version go1.19rc1 linux/amd64

and

go version devel go1.19-c1a4e0fe01 Fri Jul 8 23:41:37 2022 +0000 linux/amd64

Does this issue reproduce with the latest release?

No, it works fine with 1.18.3.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/clemens/.cache/go-build"
GOENV="/home/clemens/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/clemens/src/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/clemens/src/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/clemens/sdk/gotip"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/clemens/sdk/gotip/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.19-c1a4e0fe01 Fri Jul 8 23:41:37 2022 +0000"
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 -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build2895368460=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Tried to compile some generics heavy code.

What did you expect to see?

A working program.

What did you see instead?

An internal compiler error.

I could not identify a small example using the referenced location.

I attach three traces here.

/home/clemens/Programs/Go/comp/sum.go:33:19: internal compiler error: assertion failed

goroutine 1 [running]:
runtime/debug.Stack()
        /home/clemens/sdk/gotip/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x11627f8?, 0xc0?}, {0xd428bb, 0x10}, {0x0, 0x0, 0x0})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:227 +0x1d7
cmd/compile/internal/base.Fatalf(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/base.Assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:239
cmd/compile/internal/noder.assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:27
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeafba8, 0xc0015ada90})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1367 +0x28c
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*AssignListStmt).editChildren(0xc0011df020, 0xc000ca4660)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:85 +0xc2
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xead928, 0xc0011df020})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*Func).editChildren(0xc0004ef510?, 0xc000ca4660?)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/func.go:152 +0x74
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeae618, 0xc000e63540})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/noder.(*genInst).dictPass(0x13cee40, 0xc0011627f8)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1426 +0x150
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x13cee40)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:78 +0x1cc
cmd/compile/internal/noder.BuildInstantiations(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:44
cmd/compile/internal/noder.(*irgen).generate(0xc000172240, {0xc000152780, 0x14, 0x203000?})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:333 +0x3d1
cmd/compile/internal/noder.check2({0xc000152780, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:87 +0x14d
cmd/compile/internal/noder.LoadPackage({0xc000122100, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/noder.go:82 +0x48f
cmd/compile/internal/gc.Main(0xd6b110)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/gc/main.go:189 +0xbbd
main.main()
        /home/clemens/sdk/gotip/src/cmd/compile/main.go:57 +0xdd

/home/clemens/Programs/Go/comp/sum.go:33:19: internal compiler error: assertion failed

goroutine 1 [running]:
runtime/debug.Stack()
        /home/clemens/sdk/gotip/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x16374e8?, 0xc0?}, {0xd428bb, 0x10}, {0x0, 0x0, 0x0})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:227 +0x1d7
cmd/compile/internal/base.Fatalf(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/base.Assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:239
cmd/compile/internal/noder.assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:27
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeafba8, 0xc00164e550})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1367 +0x28c
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*AssignListStmt).editChildren(0xc001641980, 0xc0019d3590)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:85 +0xc2
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xead928, 0xc001641980})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*Func).editChildren(0xc000d674f0?, 0xc0019d3590?)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/func.go:152 +0x74
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeae618, 0xc001603540})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/noder.(*genInst).dictPass(0x13cee40, 0xc0016374e8)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1426 +0x150
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x13cee40)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:78 +0x1cc
cmd/compile/internal/noder.BuildInstantiations(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:44
cmd/compile/internal/noder.(*irgen).generate(0xc000172240, {0xc000152820, 0x14, 0x1411b00?})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:333 +0x3d1
cmd/compile/internal/noder.check2({0xc000152820, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:87 +0x14d
cmd/compile/internal/noder.LoadPackage({0xc000122100, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/noder.go:82 +0x48f
cmd/compile/internal/gc.Main(0xd6b110)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/gc/main.go:189 +0xbbd
main.main()
        /home/clemens/sdk/gotip/src/cmd/compile/main.go:57 +0xdd

/home/clemens/Programs/Go/comp/sum.go:33:19: internal compiler error: assertion failed

goroutine 1 [running]:
runtime/debug.Stack()
        /home/clemens/sdk/gotip/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x15e92d8?, 0xc0?}, {0xd428bb, 0x10}, {0x0, 0x0, 0x0})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:227 +0x1d7
cmd/compile/internal/base.Fatalf(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/base.Assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/base/print.go:239
cmd/compile/internal/noder.assert(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:27
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeafba8, 0xc001600550})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1367 +0x28c
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*AssignListStmt).editChildren(0xc0015edb00, 0xc0011724e0)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:85 +0xc2
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xead928, 0xc0015edb00})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/ir.editNodes(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1388
cmd/compile/internal/ir.(*Func).editChildren(0xc0000ff510?, 0xc0011724e0?)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/func.go:152 +0x74
cmd/compile/internal/ir.EditChildren(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0xeae618, 0xc0015ad540})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1256 +0x11b
cmd/compile/internal/noder.(*genInst).dictPass(0x13cee40, 0xc0015e92d8)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1426 +0x150
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x13cee40)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:78 +0x1cc
cmd/compile/internal/noder.BuildInstantiations(...)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:44
cmd/compile/internal/noder.(*irgen).generate(0xc000146240, {0xc000000820, 0x14, 0x1411b00?})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:333 +0x3d1
cmd/compile/internal/noder.check2({0xc000000820, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:87 +0x14d
cmd/compile/internal/noder.LoadPackage({0xc000022340, 0x14, 0x14})
        /home/clemens/sdk/gotip/src/cmd/compile/internal/noder/noder.go:82 +0x48f
cmd/compile/internal/gc.Main(0xd6b110)
        /home/clemens/sdk/gotip/src/cmd/compile/internal/gc/main.go:189 +0xbbd
main.main()
        /home/clemens/sdk/gotip/src/cmd/compile/main.go:57 +0xdd

[ianlancetaylor]

Can you share a copy of the code that you are compiling? Thanks.

[Clemens-H]

I am sharing two files here (had to change the suffix to upload), but I couldn't come up with a minimal example just using SumFloats and Abs. Line 33 in sum.go is where Abs is called from SumFloats.

sum.go.txt
abs.go.txt

[wdvxdr1123]

Here is a small repro

package main

type Value[T any] interface {
}

func use[T any](v Value[T]) {
	_, _ = v.(int)
}

func main() {
	use(Value[int](nil))
}

[gopherbot]

Change https://go.dev/cl/416736 mentions this issue: cmd/compile: fix type assert in dict pass

[wdvxdr1123]

I can reproduce on go 1.18.4.
@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.