go/types, cmd/compile/internal/types2: type parameter inference fails for constraints that succeed individually #66751
Description
Go version
go version go1.22.1 linux/amd64
Output of go env in your module/workspace:
GO111MODULE='' GOARCH='amd64' GOBIN='' GOCACHE='/home/firelizzard/.cache/go-build' GOENV='/home/firelizzard/.config/go/env' GOEXE='' GOEXPERIMENT='' GOFLAGS='' GOHOSTARCH='amd64' GOHOSTOS='linux' GOINSECURE='' GOMODCACHE='/home/firelizzard/go/pkg/mod' GONOPROXY='' GONOSUMDB='' GOOS='linux' GOPATH='/home/firelizzard/go' GOPRIVATE='' GOPROXY='https://proxy.golang.org,direct' GOROOT='/usr/lib/go' GOSUMDB='sum.golang.org' GOTMPDIR='' GOTOOLCHAIN='local' GOTOOLDIR='/usr/lib/go/pkg/tool/linux_amd64' GOVCS='' GOVERSION='go1.22.1' GCCGO='/usr/bin/gccgo' GOAMD64='v1' AR='ar' CC='x86_64-pc-linux-gnu-gcc' CXX='x86_64-pc-linux-gnu-g++' CGO_ENABLED='1' GOMOD='/home/firelizzard/src/yaegi/go-script/go.mod' 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 -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3476193043=/tmp/go-build -gno-record-gcc-switches'What did you do?
https://go.dev/play/p/fVSkvTEgYx_1
package main type ptrTo[A any] interface{ ~*A } type hasFoo[A any] interface{ foo(A) } type both[A, B any] interface { ptrTo[A] hasFoo[B] } type fooer[A any] struct{} func (f *fooer[A]) foo(A) {} func withPtr[A ptrTo[B], B any]() {} func withFoo[A hasFoo[B], B any]() {} func withBoth[A both[B, C], B, C any]() {} func main() { withPtr[*fooer[int]]() // Ok withFoo[*fooer[int]]() // Ok withBoth[*fooer[int]]() // Error: cannot infer C }What did you see happen?
Inference succeeds on all three calls.
What did you expect to see?
Inference succeeds on the first two but fails on the third. If inference of B for withPtr or withFoo failed, it would make sense. But inference succeeds on both of those so it's surprising and confusing that it fails for withBoth.
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