[gcc r15-8729] gccrs: derive(Clone): Add Clone bound on generated impl blocks

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:d7794f91e61365bd921faff18ccd07642236aee5

commit r15-8729-gd7794f91e61365bd921faff18ccd07642236aee5
Author: Arthur Cohen <arthur.co...@embecosm.com>
Date:   Wed Jan 15 13:00:45 2025 +0000

    gccrs: derive(Clone): Add Clone bound on generated impl blocks
    
    gcc/rust/ChangeLog:
    
            * expand/rust-derive-clone.cc: Add extra bound when deriving 
generic Clone

Diff:
---
 gcc/rust/expand/rust-derive-clone.cc | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/gcc/rust/expand/rust-derive-clone.cc 
b/gcc/rust/expand/rust-derive-clone.cc
index 7620abe4e13a..0081eb4cdaaa 100644
--- a/gcc/rust/expand/rust-derive-clone.cc
+++ b/gcc/rust/expand/rust-derive-clone.cc
@@ -97,15 +97,15 @@ DeriveClone::clone_impl (
   auto trait_items = std::vector<std::unique_ptr<AssociatedItem>> ();
   trait_items.emplace_back (std::move (clone_fn));
 
-  // we need to build up the generics for this impl block which will be just a
-  // clone of the types specified ones
+  // We need to build up the generics for this impl block which will be just a
+  // clone of the generics specified, with added `Clone` bounds
   //
-  // for example:
+  // For example with:
   //
   // #[derive(Clone)]
-  // struct Be<T: Clone> { ... }
+  // struct Be<T> { ... }
   //
-  // we need to generate the impl block:
+  // We need to generate the following impl block:
   //
   // impl<T: Clone> Clone for Be<T>
 
@@ -138,7 +138,12 @@ DeriveClone::clone_impl (
              = GenericArg::create_type (std::move (associated_type));
            generic_args.push_back (std::move (type_arg));
 
-           auto impl_type_param = builder.new_type_param (type_param);
+           std::vector<std::unique_ptr<TypeParamBound>> extra_bounds;
+           extra_bounds.emplace_back (std::unique_ptr<TypeParamBound> (
+             new TraitBound (builder.type_path (LangItem::Kind::CLONE), loc)));
+
+           auto impl_type_param
+             = builder.new_type_param (type_param, std::move (extra_bounds));
            impl_generics.push_back (std::move (impl_type_param));
          }
          break;