cmd/compile: internal error: DwarfFixupTable has orphaned fixup when wrapping iter.Seq2[K, ZeroSize] into iter.Seq[K]

[johejo]

Go version

go version go1.27-devel_996b985008 Wed Apr 8 14:21:41 2026 -0700 darwin/arm64

Output of go env in your module/workspace:

AR='ar'
CC='cc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='c++'
GCCGO='gccgo'
GO111MODULE=''
GOARCH='arm64'
GOARM64='v8.0'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/Users/mitsuoheijo/Library/Caches/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/Users/mitsuoheijo/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/bq/s3vkkxm17jq79lx5qy3856zh0000gn/T/go-build2761551716=/tmp/go-build -gno-record-gcc-switches -fno-common'
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMOD='/Users/mitsuoheijo/repos/github.com/golang/go/src/go.mod'
GOMODCACHE='/Users/mitsuoheijo/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/mitsuoheijo/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Users/mitsuoheijo/repos/github.com/golang/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/mitsuoheijo/Library/Application Support/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/Users/mitsuoheijo/repos/github.com/golang/go/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.27-devel_996b985008 Wed Apr 8 14:21:41 2026 -0700'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

https://go.dev/play/p/aBf7_2IDaTe?v=gotip

package main

import "iter"

func pairs() iter.Seq2[int, struct{}] {
	return func(yield func(int, struct{}) bool) {
		yield(1, struct{}{})
	}
}

func keys() iter.Seq[int] {
	return func(yield func(int) bool) {
		for k := range pairs() {
			if !yield(k) {
				return
			}
		}
	}
}

func main() {
	for range keys() {
	}
}

What did you see happen?

./prog.go:7:8: internal error: DwarfFixupTable has orphaned fixup on  targeting main.keys.func1-range1 relidx=9 dclidx=1

What did you expect to see?

build succeeds

bisected 70dc75b
related d7b6fb4

cc @derekparker

[gabyhelp]

Related Issues

• cmd/compile: ICE compiling rangefunc for < 1.23 in combination with Cgo #67497 (closed)
• cmd/compile: range over rune literal causes internal compiler error #64471 (closed)
• cmd/compile: internal compiler error: 'F-range1': panic during short circuit while compiling F-range1 #78408 (closed)
• cmd/compile: internal compiler error: panic with range over integer value #67141 (closed)
• cmd/compile: internal compiler error: unexpected type: <nil> (<nil>) in for-range #67027 (closed)
• cmd/compile: internal compiler error using float in range #67785 (closed)
• debug/dwarf: slice bounds out of range in SeekPC #55948 (closed)
• cmd/link: index out of range at cmd/link/internal/ld.decodetypeKind #62156 (closed)
• debug/elf: index out of range in DWARF #75130 (closed)
• Latest tip version of all.bash fails on macOS #24165 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[derekparker]

I will look into this today.

[gopherbot]

Change https://go.dev/cl/764720 mentions this issue: cmd/compile: improve filtering in preInliningDcls

[dr2chase]

@golang/compiler

[eikemeier]

Even simpler (go.dev/play/p/5v7iLAF_DxQ):

package main

func main() {
	for range func(yield func(struct{}) bool) {
		yield(struct{}{})
	} {
		println()
	}
}

./prog.go:5:8: internal error: DwarfFixupTable has orphaned fixup on  targeting main.main-range1 relidx=6 dclidx=0

[derekparker]

@eikemeier are you able to test my patch above and verify it fixes on your reproducer as well?

[eikemeier]

@eikemeier are you able to test my patch above and verify it fixes on your reproducer as well?

Yes, it does. I want to file a bug report and costructed a minimal reproducible example, but then found this issue and though I'll add it, since it is smaller. Also, in your test, you shouldn't need

func keys() iter.Seq[int] {
	return func(yield func(int) bool) {
		for k := range pairs() {
			if !yield(k) {
				return
			}
		}
	}
}

It should be enough to do

func main() {
	for k := range pairs() {
		println(k)
	}
}

Thanks for the good work, BTW.