[gcc r16-2888] gccrs: Fix bug with bad type bindings not looking at super traits

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:8ddeba50f47ec645eddf03d3fd9824acbf410c0a

commit r16-2888-g8ddeba50f47ec645eddf03d3fd9824acbf410c0a
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Sat Jun 21 14:58:49 2025 +0100

    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.

Diff:
---
 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 a36f7712dac4..f5b18004c187 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 c759521090da..e8ddd3e1d91d 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;