go: [dev.typeparams] internal compiler error: cannot export = (22) node

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

$ gotip version 
go version devel go1.18-1b193598b3a Tue Aug 3 02:42:15 2021 +0000 linux/amd64

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

go env Output

$ gotip env   
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/enikolov/.cache/go-build"
GOENV="/home/enikolov/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/enikolov/.asdf/installs/golang/1.16.6/packages/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/enikolov/.asdf/installs/golang/1.16.6/packages"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/enikolov/sdk/gotip"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/enikolov/sdk/gotip/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.18-1b193598b3a Tue Aug 3 02:42:15 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/enikolov/dev/golang-design/go2generics/go.mod"
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-build3230277771=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I tried to compile the following program

package main

func Do[T any]() {
	_ = func() string {
		return ""
	}
}

func main() {

}

using

gotip run -gcflags=all=-G=3 main.go

What did you expect to see?

I expected it to compile

What did you see instead?

# command-line-arguments
main.go:5:3: internal compiler error: cannot export = (22) node
        ==> please file an issue and assign to gri@

goroutine 1 [running]:
runtime/debug.Stack()
        /home/enikolov/sdk/gotip/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x4913b0, 0xc0}, {0xd0be24, 0x47}, {0xc000455418, 0x2, 0x2})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/base/print.go:227 +0x154
cmd/compile/internal/base.Fatalf(...)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/typecheck.(*exportWriter).expr(0xc00049d7a0, {0xe575f0, 0xc0004913b0})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:2056 +0x19c5
cmd/compile/internal/typecheck.(*exportWriter).exprList(0xc00049d7a0, {0xc000488340, 0x1, 0x604639})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1618 +0x76
cmd/compile/internal/typecheck.(*exportWriter).stmt(0xc00049d7a0, {0xe59468, 0xc000490460})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1512 +0x83f
cmd/compile/internal/typecheck.(*exportWriter).node(0xc000455546, {0xe59468, 0xc000490460})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1438 +0x65
cmd/compile/internal/typecheck.(*exportWriter).stmtList(0xc00049d7a0, {0xc000488310, 0x1, 0xc000455596})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1431 +0x76
cmd/compile/internal/typecheck.(*exportWriter).expr(0xc00049d7a0, {0xe57c30, 0xc000490280})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1732 +0x1efa
cmd/compile/internal/typecheck.(*exportWriter).stmt(0xc00049d7a0, {0xe575f0, 0xc0004904b0})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1484 +0x22d
cmd/compile/internal/typecheck.(*exportWriter).node(0x30, {0xe575f0, 0xc0004904b0})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1438 +0x65
cmd/compile/internal/typecheck.(*exportWriter).stmtList(0xc00049d7a0, {0xc0004881a0, 0x1, 0xcb7140})
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1431 +0x76
cmd/compile/internal/typecheck.(*exportWriter).funcBody(0xc00049d7a0, 0xc00048a2c0)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1426 +0x5b
cmd/compile/internal/typecheck.(*iexporter).doInline(0xc0003ac370, 0xc00049a5b0)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:619 +0xc5
cmd/compile/internal/typecheck.(*exportWriter).funcExt(0xc00049cd20, 0xc00049a5b0)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:1363 +0x1b6
cmd/compile/internal/typecheck.(*iexporter).doDecl(0xc0003ac370, 0xc00049a5b0)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:503 +0x1d7
cmd/compile/internal/typecheck.WriteExports({0xe3f160, 0xc0000a7530}, 0x1)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/typecheck/iexport.go:300 +0x2eb
cmd/compile/internal/noder.WriteExports(0xc00007e330)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/noder/export.go:40 +0x7a
cmd/compile/internal/gc.dumpCompilerObj(0xc00007e330)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/gc/obj.go:107 +0x28
cmd/compile/internal/gc.dumpobj1({0x7ffd056a0007, 0x24}, 0x3)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/gc/obj.go:63 +0x185
cmd/compile/internal/gc.dumpobj()
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/gc/obj.go:44 +0x36
cmd/compile/internal/gc.Main(0xd13510)
        /home/enikolov/sdk/gotip/src/cmd/compile/internal/gc/main.go:321 +0x10d6
main.main()
        /home/enikolov/sdk/gotip/src/cmd/compile/main.go:55 +0xdd

About this issue

Original URL
State: closed
Created 3 years ago
Comments: 16 (8 by maintainers)

Commits related to this issue

[dev.typeparams] cmd/compile: make sure closures inside generic funcs are not compiled Closures inside generic functions were being added to the g.target.Decls list during noding, just like other clo... — committed to golang/go by danscales 3 years ago
[dev.typeparams] cmd/compile: call transformArgs before early typecheckaste in noder In the cases where we do an early call to typecheckaste() in noder to expose CONVIFACE nodes, we need a preceding ... — committed to golang/go by danscales 3 years ago

Most upvoted comments

Change https://golang.org/cl/345411 mentions this issue: cmd/compile: fix reference to generic type needed by crawler

gopherbot on Aug 26, 2021

Yes, thanks for the original case and the new case! I’m aware of the issue of the new case, which relates to the use of multiple return values in generic calls. The original case is mainly related to closures in generic functions, so they are largely unrelated. I’ll leave the issue open for the second case, which I’m still working on the cleanest way to fix.

danscales on Aug 6, 2021

@randall77 Yeah, I think the problem is that in irgen.funcDecl, we set fn.Inl.Body = fn.Body. Thus later, fn.Body is changed during walk, cause fn.Inl.Body also changed.

I think irgen need to do something like unified IR exapandInline does.

cuonglm on Aug 6, 2021