From 477ad7dd5151a2cb54fb68aa84ccbe9bb96ffbee Mon Sep 17 00:00:00 2001 From: Cuong Manh Le Date: Thu, 20 Jun 2024 22:58:24 +0700 Subject: [PATCH] cmd/compile: support generic alias type Type parameters on aliases are now allowed after #46477 accepted. Updates #46477 Fixes #68054 Change-Id: Ic2e3b6f960a898163f47666e3a6bfe43b8cc22e2 Reviewed-on: https://go-review.googlesource.com/c/go/+/593715 Reviewed-by: Robert Griesemer Reviewed-by: Matthew Dempsky LUCI-TryBot-Result: Go LUCI Auto-Submit: Robert Griesemer --- src/cmd/compile/internal/noder/writer.go | 13 ++++++++++++- test/fixedbugs/issue68054.go | 23 +++++++++++++++++++++++ 2 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue68054.go diff --git a/src/cmd/compile/internal/noder/writer.go b/src/cmd/compile/internal/noder/writer.go index 9b33fb7c6d..fe8f8f2a35 100644 --- a/src/cmd/compile/internal/noder/writer.go +++ b/src/cmd/compile/internal/noder/writer.go @@ -543,7 +543,7 @@ func (pw *pkgWriter) typIdx(typ types2.Type, dict *writerDict) typeInfo { case *types2.Alias: w.Code(pkgbits.TypeNamed) - w.namedType(typ.Obj(), nil) + w.namedType(splitAlias(typ)) case *types2.TypeParam: w.derived = true @@ -2958,6 +2958,9 @@ func objTypeParams(obj types2.Object) *types2.TypeParamList { if !obj.IsAlias() { return obj.Type().(*types2.Named).TypeParams() } + if alias, ok := obj.Type().(*types2.Alias); ok { + return alias.TypeParams() + } } return nil } @@ -2974,6 +2977,14 @@ func splitNamed(typ *types2.Named) (*types2.TypeName, *types2.TypeList) { return typ.Obj(), typ.TypeArgs() } +// splitAlias is like splitNamed, but for an alias type. +func splitAlias(typ *types2.Alias) (*types2.TypeName, *types2.TypeList) { + orig := typ.Origin() + base.Assertf(typ.Obj() == orig.Obj(), "alias type %v has object %v, but %v has object %v", typ, typ.Obj(), orig, orig.Obj()) + + return typ.Obj(), typ.TypeArgs() +} + func asPragmaFlag(p syntax.Pragma) ir.PragmaFlag { if p == nil { return 0 diff --git a/test/fixedbugs/issue68054.go b/test/fixedbugs/issue68054.go new file mode 100644 index 0000000000..5409fc9081 --- /dev/null +++ b/test/fixedbugs/issue68054.go @@ -0,0 +1,23 @@ +// compile -goexperiment aliastypeparams + +// Copyright 2024 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package p + +type Seq[V any] = func(yield func(V) bool) + +func f[E any](seq Seq[E]) { + return +} + +func g() { + f(Seq[int](nil)) +} + +type T[P any] struct{} + +type A[P any] = T[P] + +var _ A[int] -- 2.48.1