From f0fd1d23424f9980ff4da7b2b294f0ac6f6b6c6b Mon Sep 17 00:00:00 2001
From: Richard Smith <richard@metafoo.co.uk>
Date: Wed, 7 Aug 2024 09:21:40 -0700
Subject: [PATCH] Clean up: use across-decl comparison comparing interface.
 (#4195)

This doesn't seem to be observable because we don't support
parameterized impls. But it's consistent with how we compare the type
portion of the impl.
---
 toolchain/check/member_access.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/toolchain/check/member_access.cpp b/toolchain/check/member_access.cpp
index abcc2c27cfd0..aebe729b2627 100644
--- a/toolchain/check/member_access.cpp
+++ b/toolchain/check/member_access.cpp
@@ -138,7 +138,8 @@ static auto LookupInterfaceWitness(Context& context,
             context.types().GetConstantId(impl.self_id), type_const_id)) {
       continue;
     }
-    if (impl.constraint_id != interface_type_id) {
+    if (!context.types().AreEqualAcrossDeclarations(impl.constraint_id,
+                                                    interface_type_id)) {
       // TODO: An impl of a constraint type should be treated as implementing
       // the constraint's interfaces.
       continue;