From 456759b24682a41e282f73855377ac4f341da191 Mon Sep 17 00:00:00 2001 From: Rob Findley Date: Wed, 11 Aug 2021 12:43:27 -0400 Subject: [PATCH] cmd/compile/internal/types2: use the orig object for Named.Obj Exposing a synthetic type name for instantiated types is problematic: there is no way to ensure that type instances are first created in the same type checking pass, and therefore no guarantee that their instantiation positions are the same. Even type checking a given package with different file ordering could result in different positions being associated with type instances. This is therefore an implementation detail that we should not expose. Keep the synthetic type name for accurate error reporting, but hide it in the API. Change-Id: I61f0e3ed322e97b157eb1ca316480f5719dcc174 Reviewed-on: https://go-review.googlesource.com/c/go/+/341858 Trust: Robert Findley Run-TryBot: Robert Findley TryBot-Result: Go Bot Reviewed-by: Robert Griesemer --- src/cmd/compile/internal/types2/named.go | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go index 5967172675..ad29886f7d 100644 --- a/src/cmd/compile/internal/types2/named.go +++ b/src/cmd/compile/internal/types2/named.go @@ -15,7 +15,7 @@ import ( type Named struct { check *Checker info typeInfo // for cycle detection - obj *TypeName // corresponding declared object + obj *TypeName // corresponding declared object for declared types; placeholder for instantiated types orig *Named // original, uninstantiated type fromRHS Type // type (on RHS of declaration) this *Named type is derived from (for cycle reporting) underlying Type // possibly a *Named during setup; never a *Named once set up completely @@ -108,8 +108,11 @@ func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, tpar return typ } -// Obj returns the type name for the named type t. -func (t *Named) Obj() *TypeName { return t.obj } +// Obj returns the type name for the declaration defining the named type t. For +// instantiated types, this is the type name of the base type. +func (t *Named) Obj() *TypeName { + return t.orig.obj // for non-instances this is the same as t.obj +} // Orig returns the original generic type an instantiated type is derived from. // If t is not an instantiated type, the result is t.