From 8ddeba50f47ec645eddf03d3fd9824acbf410c0a Mon Sep 17 00:00:00 2001
From: Philip Herron <herron.philip@googlemail.com>
Date: Sat, 21 Jun 2025 14:58:49 +0100
Subject: [PATCH] gccrs: Fix bug with bad type bindings not looking at super
 traits

When resolving type bounds, we need to examine super traits to properly
determine if type bindings are valid in the current context.

gcc/rust/ChangeLog:

	* typecheck/rust-tyty-bounds.cc: Check super traits for type bindings.
	* typecheck/rust-tyty.h: Add helper methods for bound checking.
---
 gcc/rust/typecheck/rust-tyty-bounds.cc | 32 ++++++++++++++++++++------
 gcc/rust/typecheck/rust-tyty.h         |  3 +++
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/gcc/rust/typecheck/rust-tyty-bounds.cc b/gcc/rust/typecheck/rust-tyty-bounds.cc
index a36f7712dac..f5b18004c18 100644
--- a/gcc/rust/typecheck/rust-tyty-bounds.cc
+++ b/gcc/rust/typecheck/rust-tyty-bounds.cc
@@ -754,16 +754,34 @@ size_t
 TypeBoundPredicate::get_num_associated_bindings () const
 {
   size_t count = 0;
+
+  get_trait_hierachy ([&count] (const Resolver::TraitReference &ref) {
+    for (const auto &trait_item : ref.get_trait_items ())
+      {
+	bool is_associated_type
+	  = trait_item.get_trait_item_type ()
+	    == Resolver::TraitItemReference::TraitItemType::TYPE;
+	if (is_associated_type)
+	  count++;
+      }
+  });
+
+  return count;
+}
+
+void
+TypeBoundPredicate::get_trait_hierachy (
+  std::function<void (const Resolver::TraitReference &)> callback) const
+{
   auto trait_ref = get ();
-  for (const auto &trait_item : trait_ref->get_trait_items ())
+  callback (*trait_ref);
+
+  for (auto &super : super_traits)
     {
-      bool is_associated_type
-	= trait_item.get_trait_item_type ()
-	  == Resolver::TraitItemReference::TraitItemType::TYPE;
-      if (is_associated_type)
-	count++;
+      const auto &super_trait_ref = *super.get ();
+      callback (super_trait_ref);
+      super.get_trait_hierachy (callback);
     }
-  return count;
 }
 
 TypeBoundPredicateItem
diff --git a/gcc/rust/typecheck/rust-tyty.h b/gcc/rust/typecheck/rust-tyty.h
index c759521090d..e8ddd3e1d91 100644
--- a/gcc/rust/typecheck/rust-tyty.h
+++ b/gcc/rust/typecheck/rust-tyty.h
@@ -593,6 +593,9 @@ private:
 
   TypeBoundPredicate (mark_is_error);
 
+  void get_trait_hierachy (
+    std::function<void (const Resolver::TraitReference &)> callback) const;
+
   DefId reference;
   location_t locus;
   bool error_flag;
-- 
2.47.2