Update args on supertraits of supertraits when cloning trait impls

When cloning implementations of traits from in-crate structs, we
forgot to update the arguments for supertraits of supertraits,
causing methods on that trait to be called against the previous
struct, not the cloned one.

This was ultimately identified downstream in the Java bindings,
fixes lightningdevkit/ldk-garbagecollected#138

Author: TheBlueMatt

c-bindings-gen/src/main.rs

@@ -1254,15 +1254,22 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, w_uses: &mut HashSet<String, NonRa
 							writeln!(w, "extern \"C\" fn {}_{}_cloned(new_obj: &mut crate::{}) {{", trait_obj.ident, ident, full_trait_path).unwrap();
 							writeln!(w, "\tnew_obj.this_arg = {}_clone_void(new_obj.this_arg);", ident).unwrap();
 							writeln!(w, "\tnew_obj.free = Some({}_free_void);", ident).unwrap();
-							walk_supertraits!(trait_obj, Some(&types), (
-								(s, t, _) => {
-									if types.crate_types.traits.get(s).is_some() {
-										assert!(!types.is_clonable(s)); // We don't currently support cloning with a clonable supertrait
-										writeln!(w, "\tnew_obj.{}.this_arg = new_obj.this_arg;", t).unwrap();
-										writeln!(w, "\tnew_obj.{}.free = None;", t).unwrap();
+
+							fn seek_supertraits<W: std::io::Write>(w: &mut W, pfx: &str, tr: &syn::ItemTrait, types: &TypeResolver) {
+								walk_supertraits!(tr, Some(types), (
+									(s, t, _) => {
+										if types.crate_types.traits.get(s).is_some() {
+											assert!(!types.is_clonable(s)); // We don't currently support cloning with a clonable supertrait
+											writeln!(w, "\tnew_obj.{}{}.this_arg = new_obj.this_arg;", pfx, t).unwrap();
+											writeln!(w, "\tnew_obj.{}{}.free = None;", pfx, t).unwrap();
+											let tr = types.crate_types.traits.get(s).unwrap();
+											let resolver = get_module_type_resolver!(s, types.crate_types);
+											seek_supertraits(w, &format!("{}.", t), tr, &resolver);
+										}
 									}
-								}
-							) );
+								) );
+							}
+							seek_supertraits(w, "", trait_obj, types);
 							writeln!(w, "}}").unwrap();
 						}
 						write!(w, "\n").unwrap();