Support supertraits-of-supertraits

If we have a supertrait that requires an in-crate supertrait, we
handle that here by writing the required impls. We don't support
a supertrait-of-a-supertrait-of-a-supertrait.

diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index f5a7656c0af60aecba2729388b9d503087d89ae8..ee800dbcf49c0049a70cf9d7451ec9795a43165d 100644 (file)
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -600,18 +600,31 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                (s, i, generic_args) => {
                        if let Some(supertrait) = types.crate_types.traits.get(s) {
                                let resolver = get_module_type_resolver!(s, types.crate_libs, types.crate_types);
-
-                               // Blindly assume that the same imports where `supertrait` is defined are also
-                               // imported here. This will almost certainly break at some point, but it should be
-                               // a compilation failure when it does so.
-                               write!(w, "impl").unwrap();
-                               maybe_write_lifetime_generics(w, &supertrait.generics, types);
-                               write!(w, " {}", s).unwrap();
-                               maybe_write_generics(w, &supertrait.generics, generic_args, types, false);
-                               writeln!(w, " for {} {{", trait_name).unwrap();
-
-                               impl_trait_for_c!(supertrait, format!(".{}", i), &resolver, generic_args);
-                               writeln!(w, "}}").unwrap();
+                               macro_rules! impl_supertrait {
+                                       ($s: expr, $supertrait: expr, $i: expr, $generic_args: expr) => {
+                                               let resolver = get_module_type_resolver!($s, types.crate_libs, types.crate_types);
+
+                                               // Blindly assume that the same imports where `supertrait` is defined are also
+                                               // imported here. This will almost certainly break at some point, but it should be
+                                               // a compilation failure when it does so.
+                                               write!(w, "impl").unwrap();
+                                               maybe_write_lifetime_generics(w, &$supertrait.generics, types);
+                                               write!(w, " {}", $s).unwrap();
+                                               maybe_write_generics(w, &$supertrait.generics, $generic_args, types, false);
+                                               writeln!(w, " for {} {{", trait_name).unwrap();
+
+                                               impl_trait_for_c!($supertrait, format!(".{}", $i), &resolver, $generic_args);
+                                               writeln!(w, "}}").unwrap();
+                                       }
+                               }
+                               impl_supertrait!(s, supertrait, i, generic_args);
+                               walk_supertraits!(supertrait, Some(&resolver), (
+                                       (s, supertrait_i, generic_args) => {
+                                               if let Some(supertrait) = types.crate_types.traits.get(s) {
+                                                       impl_supertrait!(s, supertrait, format!("{}.{}", i, supertrait_i), generic_args);
+                                               }
+                                       }
+                               ) );
                        } else {
                                do_write_impl_trait(w, s, i, &trait_name);
                        }
@@ -1061,17 +1074,38 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, w_uses: &mut HashSet<String, NonRa
                                                        ("core::fmt::Debug", _, _) => {},
                                                        (s, t, _) => {
                                                                if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
-                                                                       writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
-                                                                       writeln!(w, "\t\t\tthis_arg: unsafe {{ ObjOps::untweak_ptr((*this_arg).inner) as *mut c_void }},").unwrap();
-                                                                       writeln!(w, "\t\t\tfree: None,").unwrap();
-                                                                       for item in supertrait_obj.items.iter() {
-                                                                               match item {
-                                                                                       syn::TraitItem::Method(m) => {
-                                                                                               write_meth!(m, supertrait_obj, "\t");
+                                                                       macro_rules! write_impl_fields {
+                                                                               ($s: expr, $supertrait_obj: expr, $t: expr, $pfx: expr, $resolver: expr) => {
+                                                                                       writeln!(w, "{}\t{}: crate::{} {{", $pfx, $t, $s).unwrap();
+                                                                                       writeln!(w, "{}\t\tthis_arg: unsafe {{ ObjOps::untweak_ptr((*this_arg).inner) as *mut c_void }},", $pfx).unwrap();
+                                                                                       writeln!(w, "{}\t\tfree: None,", $pfx).unwrap();
+                                                                                       for item in $supertrait_obj.items.iter() {
+                                                                                               match item {
+                                                                                                       syn::TraitItem::Method(m) => {
+                                                                                                               write_meth!(m, $supertrait_obj, $pfx);
+                                                                                                       },
+                                                                                                       _ => {},
+                                                                                               }
+                                                                                       }
+                                                                               walk_supertraits!($supertrait_obj, Some(&$resolver), (
+                                                                                       ("Clone", _, _) => {
+                                                                                               writeln!(w, "{}\tcloned: Some({}_{}_cloned),", $pfx, $supertrait_obj.ident, ident).unwrap();
                                                                                        },
-                                                                                       _ => {},
+                                                                                       (_, _, _) => {}
+                                                                               ) );
                                                                                }
                                                                        }
+                                                                       write_impl_fields!(s, supertrait_obj, t, "\t", types);
+
+                                                                       let resolver = get_module_type_resolver!(s, types.crate_libs, types.crate_types);
+                                                                       walk_supertraits!(supertrait_obj, Some(&resolver), (
+                                                                               (s, t, _) => {
+                                                                                       if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
+                                                                                               write_impl_fields!(s, supertrait_obj, t, "\t\t", resolver);
+                                                                                               write!(w, "\t\t\t}},\n").unwrap();
+                                                                                       }
+                                                                               }
+                                                                       ) );
                                                                        write!(w, "\t\t}},\n").unwrap();
                                                                } else {
                                                                        write_trait_impl_field_assign(w, s, ident);