cmd/compile: range over func internal compiler error with named bool type in yield

[rothelius]

Go version

go version go1.23.4 darwin/amd64

Output of go env in your module/workspace:

GO111MODULE='on'
GOARCH='amd64'
GOBIN=''
GOCACHE='/Users/fabianr/Library/Caches/go-build'
GOENV='/Users/fabianr/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT='aliastypeparams'
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/fabianr/e/be/gamelogic/gohome/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/fabianr/e/be/gamelogic/gohome'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_amd64'
GOVCS=''
GOVERSION='go1.23.4'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/fabianr/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/5y/2cd0ydxn7nl7sz2nnk3d91xc0000gn/T/go-build3384530003=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

Ran this playground code.

What did you see happen?

./prog.go:7:2: internal compiler error: func() (#r bool) is not assignable to func() main.Bool

What did you expect to see?

Either no error, or an error that isn't an internal compiler error.

[gabyhelp]

Related Issues

• cmd/compile: internal compiler error: found illegal assignment FUNC-func() T₁ -> main.T₁; #48137 (closed)
• cmd/compile: internal compiler error: got untyped bool for autotmp #17551 (closed)
• cmd/compile: ICE compiling rangefunc for < 1.23 in combination with Cgo #67497 (closed)
• cmd/compile: internal compiler error: found illegal assignment #49875 (closed)
• "internal compiler error: assertion failed" with generic code #53834 (closed)
• cmd/compile: internal compiler error with zero-size types #65808 (closed)
• cmd/compile: unreachable code causes internal compiler error #65680 (closed)
• cmd/compile: internal compiler error using float in range #67785 (closed)
• cmd/compile: range over rune literal causes internal compiler error #64471 (closed)
• cmd/compile: internal compiler error: 'XXXXXX': not lowered: v128, Load INTER PTR SSA #43112 (closed)

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

[randall77]

Unified IR is having trouble with this code, because there's an argument/formal mismatch it doesn't think typechecks.

Something like:

type Bool bool
var iter func(func() Bool) = ... // user's iter function
var yield1 func() bool = ... // the loop body closure
iter(yield1)

I think the frontend should either declare the yield function with a return type that matches the user's iteration function's arg's return type, or disallow named booleans as the return type.
I would lean towards the latter, as the spec only lists bool, not a named bool, as the return type.

@griesemer

[griesemer]

@randall77 Agreed. I will take care of this.

[gopherbot]

Change https://go.dev/cl/640599 mentions this issue: go/types, types2: require iterator yield to return bool (work-around)