compiler: internal compiler error: assertion failed when using concrete nested type in interface constraint

[pmalek]

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

$ gotip version
go version devel go1.18-90860e0 Sat Jan 8 00:24:25 2022 +0000 darwin/amd64

Does this issue reproduce with the latest release?

Only tip as mentioned above.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/pmalek/Library/Caches/go-build"
GOENV="/Users/pmalek/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/pmalek/.gvm/pkgsets/go1.18beta1/global/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/pmalek/.gvm/pkgsets/go1.18beta1/global"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/Users/pmalek/sdk/gotip"
GOSUMDB="off"
GOTMPDIR=""
GOTOOLDIR="/Users/pmalek/sdk/gotip/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="devel go1.18-90860e0 Sat Jan 8 00:24:25 2022 +0000"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/pmalek/code/own/go/csv/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/78/xm1r7h7s7lqdp36w81v765500000gn/T/go-build2797857967=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Playground link

package main

type Entry struct {
	Data int
}

type EntryT interface {
	Entry
}

func main() {
	foo([]Entry{})
}

func foo[T EntryT](entries []T) {
	for _, e := range entries {
		_ = e.Data // without this line the code compiles fine
	}
}

What did you expect to see?

No error

What did you see instead?

# csv
./calculate.go:149:14: internal compiler error: assertion failed

goroutine 1 [running]:
runtime/debug.Stack()
        /Users/pmalek/sdk/gotip/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x8297a0?, 0xc0?}, {0x192059c, 0x10}, {0x0, 0x0, 0x0})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/base/print.go:227 +0x1ca
cmd/compile/internal/base.Fatalf(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/base.Assert(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/base/print.go:239
cmd/compile/internal/noder.assert(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:28
cmd/compile/internal/noder.transformDot(0xc000881140?, 0x0)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/transform.go:645 +0x151
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1a90f80, 0xc0008297a0})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1258 +0x815
cmd/compile/internal/ir.(*AssignStmt).editChildren(0xc00089ef00, 0xc0008bc100)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:163 +0xc8
cmd/compile/internal/ir.EditChildren(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1a8eeb0, 0xc00089ef00})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1218 +0x74
cmd/compile/internal/ir.editNodes(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1521
cmd/compile/internal/ir.(*RangeStmt).editChildren(0xc00088f3b0, 0xc0008bc100)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1000 +0x236
cmd/compile/internal/ir.EditChildren(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1a90b98, 0xc00088f3b0})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1218 +0x74
cmd/compile/internal/ir.editNodes(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/node_gen.go:1521
cmd/compile/internal/ir.(*Func).editChildren(0xc0000e94c8?, 0xc0008bc100?)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/func.go:153 +0x74
cmd/compile/internal/ir.EditChildren(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/ir/visit.go:185
cmd/compile/internal/noder.(*genInst).dictPass.func1({0x1a8fbf8, 0xc000898b00})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1218 +0x74
cmd/compile/internal/noder.(*genInst).dictPass(0x1f8daa0, 0xc000881140)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:1350 +0x126
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x1f8daa0, 0x1)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:84 +0x26b
cmd/compile/internal/noder.BuildInstantiations(...)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/stencil.go:47
cmd/compile/internal/noder.(*irgen).generate(0xc0003723c0, {0xc000139780, 0x7, 0x203000?})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:331 +0x3db
cmd/compile/internal/noder.check2({0xc000139780, 0x7, 0x7})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/irgen.go:92 +0x16d
cmd/compile/internal/noder.LoadPackage({0xc00013e100, 0x7, 0x0?})
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/noder/noder.go:90 +0x335
cmd/compile/internal/gc.Main(0x1948848)
        /Users/pmalek/sdk/gotip/src/cmd/compile/internal/gc/main.go:191 +0xb13
main.main()
        /Users/pmalek/sdk/gotip/src/cmd/compile/main.go:55 +0xdd

[ALTree]

Thanks for reporting this.

cc @danscales @randall77

[danscales]

This is a dup of #50417 (field reference to a type param that has a constraint which is a single concrete type). I'm working on the compiler side of #50417 now.