From: zhouguangyuan <zhouguangyuan.xian@gmail.com>
Date: Fri, 29 Oct 2021 07:24:28 +0000 (+0800)
Subject: go/types: fix TypeName.IsAlias for type parameter names
X-Git-Tag: go1.18beta1~643
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=80bedb848092c993182f79a946d54776dc251549;p=gostls13.git

go/types: fix TypeName.IsAlias for type parameter names

Fixes #49213

Change-Id: I2bfc151b74b0d14efbd00e5d28584f4180126c5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/359656
Trust: Robert Griesemer <gri@golang.org>
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
---

diff --git a/src/go/types/object.go b/src/go/types/object.go
index 18015fc967..a8bd62a04e 100644
--- a/src/go/types/object.go
+++ b/src/go/types/object.go
@@ -269,6 +269,8 @@ func (obj *TypeName) IsAlias() bool {
 		return obj.pkg != nil || t.name != obj.name || t == universeByte || t == universeRune
 	case *Named:
 		return obj != t.obj
+	case *TypeParam:
+		return obj != t.obj
 	default:
 		return true
 	}
diff --git a/src/go/types/object_test.go b/src/go/types/object_test.go
index 0ff8fdd6fa..c12af64df7 100644
--- a/src/go/types/object_test.go
+++ b/src/go/types/object_test.go
@@ -30,6 +30,8 @@ func TestIsAlias(t *testing.T) {
 	pkg := NewPackage("p", "p")
 	t1 := NewTypeName(0, pkg, "t1", nil)
 	n1 := NewNamed(t1, new(Struct), nil)
+	t5 := NewTypeName(0, pkg, "t5", nil)
+	NewTypeParam(t5, nil)
 	for _, test := range []struct {
 		name  *TypeName
 		alias bool
@@ -43,6 +45,7 @@ func TestIsAlias(t *testing.T) {
 		{NewTypeName(0, nil, "int32", Typ[Int32]), false},  // type name refers to basic type with same name
 		{NewTypeName(0, pkg, "int32", Typ[Int32]), true},   // type name is declared in user-defined package (outside Universe)
 		{NewTypeName(0, nil, "rune", Typ[Rune]), true},     // type name refers to basic type rune which is an alias already
+		{t5, false}, // type name refers to type parameter and vice versa
 	} {
 		check(test.name, test.alias)
 	}
diff --git a/src/go/types/testdata/fixedbugs/issue45985.go2 b/src/go/types/testdata/fixedbugs/issue45985.go2
index 6e42dbb633..07395911cd 100644
--- a/src/go/types/testdata/fixedbugs/issue45985.go2
+++ b/src/go/types/testdata/fixedbugs/issue45985.go2
@@ -5,7 +5,7 @@
 package issue45985
 
 // TODO(rFindley): this error should be on app[int] below.
-func app[S /* ERROR "type S = S does not match" */ interface{ ~[]T }, T any](s S, e T) S {
+func app[S /* ERROR "type S S does not match" */ interface{ ~[]T }, T any](s S, e T) S {
     return append(s, e)
 }