Use trait, not impl, definition for X_as_Trait functions
[ldk-c-bindings] / c-bindings-gen / src / main.rs
index 1d5b8bf1b098a6dc40d01979989cafa58023244a..2aeadaffac2e3024d3c92172bc24d82b5b06ca47 100644 (file)
@@ -102,7 +102,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                        },
                        "lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs"|"lightning::util::ser::MaybeReadable" => {
                                // Create the Result<Object, DecodeError> syn::Type
-                               let mut res_ty: syn::Type = parse_quote!(Result<#for_ty, ::ln::msgs::DecodeError>);
+                               let mut res_ty: syn::Type = parse_quote!(Result<#for_ty, lightning::ln::msgs::DecodeError>);
 
                                writeln!(w, "#[no_mangle]").unwrap();
                                writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
@@ -151,7 +151,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                                                } else { unreachable!(); }
                                        } else { unreachable!(); }
                                } else if t == "lightning::util::ser::MaybeReadable" {
-                                       res_ty = parse_quote!(Result<Option<#for_ty>, ::ln::msgs::DecodeError>);
+                                       res_ty = parse_quote!(Result<Option<#for_ty>, lightning::ln::msgs::DecodeError>);
                                }
                                write!(w, ") -> ").unwrap();
                                types.write_c_type(w, &res_ty, Some(generics), false);
@@ -163,7 +163,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
 
                                write!(w, "\tlet res: ").unwrap();
                                // At least in one case we need type annotations here, so provide them.
-                               types.write_rust_type(w, Some(generics), &res_ty);
+                               types.write_rust_type(w, Some(generics), &res_ty, false);
 
                                if t == "lightning::util::ser::ReadableArgs" {
                                        writeln!(w, " = crate::c_types::deserialize_obj_arg(ser, arg_conv);").unwrap();
@@ -484,7 +484,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                                                                                }
                                                                                _ => panic!("5"),
                                                                        }
-                                                                       $type_resolver.write_rust_type(w, Some(&gen_types), &*arg.ty);
+                                                                       $type_resolver.write_rust_type(w, Some(&gen_types), &*arg.ty, false);
                                                                }
                                                        }
                                                }
@@ -492,7 +492,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                                                match &m.sig.output {
                                                        syn::ReturnType::Type(_, rtype) => {
                                                                write!(w, " -> ").unwrap();
-                                                               $type_resolver.write_rust_type(w, Some(&gen_types), &*rtype)
+                                                               $type_resolver.write_rust_type(w, Some(&gen_types), &*rtype, false)
                                                        },
                                                        _ => {},
                                                }
@@ -735,6 +735,25 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
                                                write!(w, "inner_val").unwrap();
                                                types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
                                                writeln!(w, "\n}}").unwrap();
+                                       } else {
+                                               // If the type isn't reference-able, but is clonable, export a getter that just clones
+                                               if types.understood_c_type(&$field.ty, Some(&gen_types)) {
+                                                       let mut v = Vec::new();
+                                                       types.write_c_type(&mut v, &$field.ty, Some(&gen_types), true);
+                                                       let s = String::from_utf8(v).unwrap();
+                                                       if types.is_clonable(&s) {
+                                                               writeln_arg_docs(w, &$field.attrs, "", types, Some(&gen_types), vec![].drain(..), Some(&$field.ty));
+                                                               writeln!(w, "///\n/// Returns a copy of the field.").unwrap();
+                                                               write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> {}", struct_name, $new_name, struct_name, s).unwrap();
+                                                               write!(w, " {{\n\tlet mut inner_val = this_ptr.get_native_mut_ref().{}.clone();\n\t", $real_name).unwrap();
+                                                               let local_var = types.write_to_c_conversion_new_var(w, &format_ident!("inner_val"), &$field.ty, Some(&gen_types), true);
+                                                               if local_var { write!(w, "\n\t").unwrap(); }
+                                                               types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), true);
+                                                               write!(w, "inner_val").unwrap();
+                                                               types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), true);
+                                                               writeln!(w, "\n}}").unwrap();
+                                                       }
+                                               }
                                        }
                                }
 
@@ -928,7 +947,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                // mappings from a trai defined in a different file, we may mis-resolve or
                                                // fail to resolve the mapped types. Thus, we have to construct a new
                                                // resolver for the module that the trait was defined in here first.
-                                               let trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
+                                               let mut trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
                                                gen_types.learn_associated_types(trait_obj, &trait_resolver);
                                                let mut impl_associated_types = HashMap::new();
                                                for item in i.items.iter() {
@@ -1088,17 +1107,12 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                                _ => {}
                                                                        }
                                                                }
-                                                               if uncallable_function {
-                                                                       let mut trait_resolver = get_module_type_resolver!(full_trait_path, $types.crate_libs, $types.crate_types);
-                                                                       write_method_params(w, &$trait_meth.sig, "c_void", &mut trait_resolver, Some(&meth_gen_types), true, true);
-                                                               } else {
-                                                                       write_method_params(w, &$m.sig, "c_void", $types, Some(&meth_gen_types), true, true);
-                                                               }
+                                                               write_method_params(w, &$trait_meth.sig, "c_void", &mut trait_resolver, Some(&meth_gen_types), true, true);
                                                                write!(w, " {{\n\t").unwrap();
                                                                if uncallable_function {
                                                                        write!(w, "unreachable!();").unwrap();
                                                                } else {
-                                                                       write_method_var_decl_body(w, &$m.sig, "", $types, Some(&meth_gen_types), false);
+                                                                       write_method_var_decl_body(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), false);
                                                                        let mut takes_self = false;
                                                                        for inp in $m.sig.inputs.iter() {
                                                                                if let syn::FnArg::Receiver(_) = inp {
@@ -1128,7 +1142,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                                },
                                                                                _ => {},
                                                                        }
-                                                                       write_method_call_params(w, &$m.sig, "", $types, Some(&meth_gen_types), &real_type, false);
+                                                                       write_method_call_params(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), &real_type, false);
                                                                }
                                                                write!(w, "\n}}\n").unwrap();
                                                                if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
@@ -1166,7 +1180,6 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                        assert!(meth.default.is_some());
                                                                        let old_gen_types = gen_types;
                                                                        gen_types = GenericTypes::new(Some(resolved_path.clone()));
-                                                                       let mut trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
                                                                        impl_meth!(meth, meth, full_trait_path, trait_obj, "", &mut trait_resolver);
                                                                        gen_types = old_gen_types;
                                                                },
@@ -1383,167 +1396,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                        }
                                }
                        } else if let Some(resolved_path) = types.maybe_resolve_ident(&ident) {
-                               if let Some(aliases) = types.crate_types.reverse_alias_map.get(&resolved_path).cloned() {
-                                       let mut gen_types = Some(GenericTypes::new(Some(resolved_path.clone())));
-                                       if !gen_types.as_mut().unwrap().learn_generics(&i.generics, types) {
-                                               gen_types = None;
-                                       }
-                                       let alias_module = rsplit_once(&resolved_path, "::").unwrap().0;
-
-                                       'alias_impls: for (alias_resolved, arguments) in aliases {
-                                               let mut new_ty_generics = Vec::new();
-                                               let mut new_ty_bounds = Vec::new();
-                                               let mut need_generics = false;
-
-                                               let alias_resolver_override;
-                                               let alias_resolver = if alias_module != types.module_path {
-                                                       alias_resolver_override = ImportResolver::new(types.types.crate_name, &types.crate_types.lib_ast.dependencies,
-                                                               alias_module, &types.crate_types.lib_ast.modules.get(alias_module).unwrap().items);
-                                                       &alias_resolver_override
-                                               } else { &types.types };/*.maybe_resolve_path(&alias, None).unwrap();*/
-                                               let mut where_clause = Some(syn::WhereClause {
-                                                       where_token: syn::Token![where](Span::call_site()),
-                                                       predicates: syn::punctuated::Punctuated::new()
-                                               });
-                                               for (idx, gen) in i.generics.params.iter().enumerate() {
-                                                       match gen {
-                                                               syn::GenericParam::Type(type_param) => {
-                                                                       'bounds_check: for bound in type_param.bounds.iter() {
-                                                                               if let syn::TypeParamBound::Trait(trait_bound) = bound {
-                                                                                       if let syn::PathArguments::AngleBracketed(ref t) = &arguments {
-                                                                                               assert!(idx < t.args.len());
-                                                                                               if let syn::GenericArgument::Type(syn::Type::Path(p)) = &t.args[idx] {
-                                                                                                       let generic_bound = types.maybe_resolve_path(&trait_bound.path, None)
-                                                                                                               .unwrap_or_else(|| format!("{}::{}", types.module_path, single_ident_generic_path_to_ident(&trait_bound.path).unwrap()));
-
-                                                                                                       if let Some(generic_arg) = alias_resolver.maybe_resolve_path(&p.path, None) {
-                                                                                                               new_ty_generics.push((type_param.ident.clone(), syn::Type::Path(p.clone())));
-                                                                                                               if let Some(traits_impld) = types.crate_types.trait_impls.get(&generic_arg) {
-                                                                                                                       for trait_impld in traits_impld {
-                                                                                                                               if *trait_impld == generic_bound { continue 'bounds_check; }
-                                                                                                                       }
-                                                                                                                       eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
-                                                                                                                       continue 'alias_impls;
-                                                                                                               } else {
-                                                                                                                       eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
-                                                                                                                       continue 'alias_impls;
-                                                                                                               }
-                                                                                                       } else if gen_types.is_some() {
-                                                                                                               let resp =  types.maybe_resolve_path(&p.path, gen_types.as_ref());
-                                                                                                               if generic_bound == "core::ops::Deref" && resp.is_some() {
-                                                                                                                       new_ty_bounds.push((type_param.ident.clone(),
-                                                                                                                               string_path_to_syn_path("core::ops::Deref")));
-                                                                                                                       let mut bounds = syn::punctuated::Punctuated::new();
-                                                                                                                       bounds.push(syn::TypeParamBound::Trait(syn::TraitBound {
-                                                                                                                               paren_token: None,
-                                                                                                                               modifier: syn::TraitBoundModifier::None,
-                                                                                                                               lifetimes: None,
-                                                                                                                               path: string_path_to_syn_path(&types.resolve_path(&p.path, gen_types.as_ref())),
-                                                                                                                       }));
-                                                                                                                       let mut path = string_path_to_syn_path(&format!("{}::Target", type_param.ident));
-                                                                                                                       path.leading_colon = None;
-                                                                                                                       where_clause.as_mut().unwrap().predicates.push(syn::WherePredicate::Type(syn::PredicateType {
-                                                                                                                               lifetimes: None,
-                                                                                                                               bounded_ty: syn::Type::Path(syn::TypePath { qself: None, path }),
-                                                                                                                               colon_token: syn::Token![:](Span::call_site()),
-                                                                                                                               bounds,
-                                                                                                                       }));
-                                                                                                               } else {
-                                                                                                                       new_ty_generics.push((type_param.ident.clone(),
-                                                                                                                               gen_types.as_ref().resolve_type(&syn::Type::Path(p.clone())).clone()));
-                                                                                                               }
-                                                                                                               need_generics = true;
-                                                                                                       } else {
-                                                                                                               unimplemented!();
-                                                                                                       }
-                                                                                               } else { unimplemented!(); }
-                                                                                       } else { unimplemented!(); }
-                                                                               } else { unimplemented!(); }
-                                                                       }
-                                                               },
-                                                               syn::GenericParam::Lifetime(_) => {},
-                                                               syn::GenericParam::Const(_) => unimplemented!(),
-                                                       }
-                                               }
-                                               let mut params = syn::punctuated::Punctuated::new();
-                                               let alias = string_path_to_syn_path(&alias_resolved);
-                                               let real_aliased =
-                                                       if need_generics {
-                                                               let alias_generics = types.crate_types.opaques.get(&alias_resolved).unwrap().1;
-
-                                                               // If we need generics on the alias, create impl generic bounds...
-                                                               assert_eq!(new_ty_generics.len() + new_ty_bounds.len(), i.generics.params.len());
-                                                               let mut args = syn::punctuated::Punctuated::new();
-                                                               for (ident, param) in new_ty_generics.drain(..) {
-                                                                       // TODO: We blindly assume that generics in the type alias and
-                                                                       // the aliased type have the same names, which we really shouldn't.
-                                                                       if alias_generics.params.iter().any(|generic|
-                                                                               if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
-                                                                       {
-                                                                               args.push(parse_quote!(#ident));
-                                                                       }
-                                                                       params.push(syn::GenericParam::Type(syn::TypeParam {
-                                                                               attrs: Vec::new(),
-                                                                               ident,
-                                                                               colon_token: None,
-                                                                               bounds: syn::punctuated::Punctuated::new(),
-                                                                               eq_token: Some(syn::token::Eq(Span::call_site())),
-                                                                               default: Some(param),
-                                                                       }));
-                                                               }
-                                                               for (ident, param) in new_ty_bounds.drain(..) {
-                                                                       // TODO: We blindly assume that generics in the type alias and
-                                                                       // the aliased type have the same names, which we really shouldn't.
-                                                                       if alias_generics.params.iter().any(|generic|
-                                                                               if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
-                                                                       {
-                                                                               args.push(parse_quote!(#ident));
-                                                                       }
-                                                                       params.push(syn::GenericParam::Type(syn::TypeParam {
-                                                                               attrs: Vec::new(),
-                                                                               ident,
-                                                                               colon_token: Some(syn::token::Colon(Span::call_site())),
-                                                                               bounds: syn::punctuated::Punctuated::from_iter(
-                                                                                       Some(syn::TypeParamBound::Trait(syn::TraitBound {
-                                                                                               path: param, paren_token: None, lifetimes: None,
-                                                                                               modifier: syn::TraitBoundModifier::None,
-                                                                                       }))
-                                                                               ),
-                                                                               eq_token: None,
-                                                                               default: None,
-                                                                       }));
-                                                               }
-                                                               // ... and swap the last segment of the impl self_ty to use the generic bounds.
-                                                               let mut res = alias.clone();
-                                                               res.segments.last_mut().unwrap().arguments = syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
-                                                                       colon2_token: None,
-                                                                       lt_token: syn::token::Lt(Span::call_site()),
-                                                                       args,
-                                                                       gt_token: syn::token::Gt(Span::call_site()),
-                                                               });
-                                                               res
-                                                       } else { alias.clone() };
-                                               let aliased_impl = syn::ItemImpl {
-                                                       attrs: i.attrs.clone(),
-                                                       brace_token: syn::token::Brace(Span::call_site()),
-                                                       defaultness: None,
-                                                       generics: syn::Generics {
-                                                               lt_token: None,
-                                                               params,
-                                                               gt_token: None,
-                                                               where_clause,
-                                                       },
-                                                       impl_token: syn::Token![impl](Span::call_site()),
-                                                       items: i.items.clone(),
-                                                       self_ty: Box::new(syn::Type::Path(syn::TypePath { qself: None, path: real_aliased })),
-                                                       trait_: i.trait_.clone(),
-                                                       unsafety: None,
-                                               };
-                                               writeln_impl(w, &aliased_impl, types);
-                                       }
-                               } else {
-                                       eprintln!("Not implementing anything for {} due to it being marked not exported", ident);
-                               }
+                               create_alias_for_impl(resolved_path, i, types, move |aliased_impl, types| writeln_impl(w, &aliased_impl, types));
                        } else {
                                eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub)", ident);
                        }
@@ -1551,6 +1404,168 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
        }
 }
 
+fn create_alias_for_impl<F: FnMut(syn::ItemImpl, &mut TypeResolver)>(resolved_path: String, i: &syn::ItemImpl, types: &mut TypeResolver, mut callback: F) {
+       if let Some(aliases) = types.crate_types.reverse_alias_map.get(&resolved_path).cloned() {
+               let mut gen_types = Some(GenericTypes::new(Some(resolved_path.clone())));
+               if !gen_types.as_mut().unwrap().learn_generics(&i.generics, types) {
+                       gen_types = None;
+               }
+               let alias_module = rsplit_once(&resolved_path, "::").unwrap().0;
+
+               'alias_impls: for (alias_resolved, arguments) in aliases {
+                       let mut new_ty_generics = Vec::new();
+                       let mut new_ty_bounds = Vec::new();
+                       let mut need_generics = false;
+
+                       let alias_resolver_override;
+                       let alias_resolver = if alias_module != types.module_path {
+                               alias_resolver_override = ImportResolver::new(types.types.crate_name, &types.crate_types.lib_ast.dependencies,
+                                       alias_module, &types.crate_types.lib_ast.modules.get(alias_module).unwrap().items);
+                               &alias_resolver_override
+                       } else { &types.types };
+                       let mut where_clause = syn::WhereClause { where_token: syn::Token![where](Span::call_site()),
+                               predicates: syn::punctuated::Punctuated::new()
+                       };
+                       for (idx, gen) in i.generics.params.iter().enumerate() {
+                               match gen {
+                                       syn::GenericParam::Type(type_param) => {
+                                               'bounds_check: for bound in type_param.bounds.iter() {
+                                                       if let syn::TypeParamBound::Trait(trait_bound) = bound {
+                                                               if let syn::PathArguments::AngleBracketed(ref t) = &arguments {
+                                                                       assert!(idx < t.args.len());
+                                                                       if let syn::GenericArgument::Type(syn::Type::Path(p)) = &t.args[idx] {
+                                                                               let generic_bound = types.maybe_resolve_path(&trait_bound.path, None)
+                                                                                       .unwrap_or_else(|| format!("{}::{}", types.module_path, single_ident_generic_path_to_ident(&trait_bound.path).unwrap()));
+
+                                                                               if let Some(generic_arg) = alias_resolver.maybe_resolve_path(&p.path, None) {
+                                                                                       new_ty_generics.push((type_param.ident.clone(), syn::Type::Path(p.clone())));
+                                                                                       if let Some(traits_impld) = types.crate_types.trait_impls.get(&generic_arg) {
+                                                                                               for trait_impld in traits_impld {
+                                                                                                       if *trait_impld == generic_bound { continue 'bounds_check; }
+                                                                                               }
+                                                                                               eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
+                                                                                               continue 'alias_impls;
+                                                                                       } else {
+                                                                                               eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
+                                                                                               continue 'alias_impls;
+                                                                                       }
+                                                                               } else if gen_types.is_some() {
+                                                                                       let resp =  types.maybe_resolve_path(&p.path, gen_types.as_ref());
+                                                                                       if generic_bound == "core::ops::Deref" && resp.is_some() {
+                                                                                               new_ty_bounds.push((type_param.ident.clone(),
+                                                                                                       string_path_to_syn_path("core::ops::Deref")));
+                                                                                               let mut bounds = syn::punctuated::Punctuated::new();
+                                                                                               bounds.push(syn::TypeParamBound::Trait(syn::TraitBound {
+                                                                                                       paren_token: None,
+                                                                                                       modifier: syn::TraitBoundModifier::None,
+                                                                                                       lifetimes: None,
+                                                                                                       path: string_path_to_syn_path(&types.resolve_path(&p.path, gen_types.as_ref())),
+                                                                                               }));
+                                                                                               let mut path = string_path_to_syn_path(&format!("{}::Target", type_param.ident));
+                                                                                               path.leading_colon = None;
+                                                                                               where_clause.predicates.push(syn::WherePredicate::Type(syn::PredicateType {
+                                                                                                       lifetimes: None,
+                                                                                                       bounded_ty: syn::Type::Path(syn::TypePath { qself: None, path }),
+                                                                                                       colon_token: syn::Token![:](Span::call_site()),
+                                                                                                       bounds,
+                                                                                               }));
+                                                                                       } else {
+                                                                                               new_ty_generics.push((type_param.ident.clone(),
+                                                                                                       gen_types.as_ref().resolve_type(&syn::Type::Path(p.clone())).clone()));
+                                                                                       }
+                                                                                       need_generics = true;
+                                                                               } else {
+                                                                                       unimplemented!();
+                                                                               }
+                                                                       } else { unimplemented!(); }
+                                                               } else { unimplemented!(); }
+                                                       } else { unimplemented!(); }
+                                               }
+                                       },
+                                       syn::GenericParam::Lifetime(_) => {},
+                                       syn::GenericParam::Const(_) => unimplemented!(),
+                               }
+                       }
+                       let mut params = syn::punctuated::Punctuated::new();
+                       let alias = string_path_to_syn_path(&alias_resolved);
+                       let real_aliased =
+                               if need_generics {
+                                       let alias_generics = types.crate_types.opaques.get(&alias_resolved).unwrap().1;
+
+                                       // If we need generics on the alias, create impl generic bounds...
+                                       assert_eq!(new_ty_generics.len() + new_ty_bounds.len(), i.generics.params.len());
+                                       let mut args = syn::punctuated::Punctuated::new();
+                                       for (ident, param) in new_ty_generics.drain(..) {
+                                               // TODO: We blindly assume that generics in the type alias and
+                                               // the aliased type have the same names, which we really shouldn't.
+                                               if alias_generics.params.iter().any(|generic|
+                                                       if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
+                                               {
+                                                       args.push(parse_quote!(#ident));
+                                               }
+                                               params.push(syn::GenericParam::Type(syn::TypeParam {
+                                                       attrs: Vec::new(),
+                                                       ident,
+                                                       colon_token: None,
+                                                       bounds: syn::punctuated::Punctuated::new(),
+                                                       eq_token: Some(syn::token::Eq(Span::call_site())),
+                                                       default: Some(param),
+                                               }));
+                                       }
+                                       for (ident, param) in new_ty_bounds.drain(..) {
+                                               // TODO: We blindly assume that generics in the type alias and
+                                               // the aliased type have the same names, which we really shouldn't.
+                                               if alias_generics.params.iter().any(|generic|
+                                                       if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
+                                               {
+                                                       args.push(parse_quote!(#ident));
+                                               }
+                                               params.push(syn::GenericParam::Type(syn::TypeParam {
+                                                       attrs: Vec::new(),
+                                                       ident,
+                                                       colon_token: Some(syn::token::Colon(Span::call_site())),
+                                                       bounds: syn::punctuated::Punctuated::from_iter(
+                                                               Some(syn::TypeParamBound::Trait(syn::TraitBound {
+                                                                       path: param, paren_token: None, lifetimes: None,
+                                                                       modifier: syn::TraitBoundModifier::None,
+                                                               }))
+                                                       ),
+                                                       eq_token: None,
+                                                       default: None,
+                                               }));
+                                       }
+                                       // ... and swap the last segment of the impl self_ty to use the generic bounds.
+                                       let mut res = alias.clone();
+                                       res.segments.last_mut().unwrap().arguments = syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
+                                               colon2_token: None,
+                                               lt_token: syn::token::Lt(Span::call_site()),
+                                               args,
+                                               gt_token: syn::token::Gt(Span::call_site()),
+                                       });
+                                       res
+                               } else { alias.clone() };
+                       callback(syn::ItemImpl {
+                               attrs: i.attrs.clone(),
+                               brace_token: syn::token::Brace(Span::call_site()),
+                               defaultness: None,
+                               generics: syn::Generics {
+                                       lt_token: None,
+                                       params,
+                                       gt_token: None,
+                                       where_clause: Some(where_clause),
+                               },
+                               impl_token: syn::Token![impl](Span::call_site()),
+                               items: i.items.clone(),
+                               self_ty: Box::new(syn::Type::Path(syn::TypePath { qself: None, path: real_aliased })),
+                               trait_: i.trait_.clone(),
+                               unsafety: None,
+                       }, types);
+               }
+       } else {
+               eprintln!("Not implementing anything for {} due to it being marked not exported", resolved_path);
+       }
+}
+
 /// Replaces upper case charachters with underscore followed by lower case except the first
 /// charachter and repeated upper case characthers (which are only made lower case).
 fn camel_to_snake_case(camel: &str) -> String {
@@ -1592,8 +1607,37 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
 
        let mut needs_free = false;
        let mut constr = Vec::new();
+       let mut is_clonable = true;
+
+       for var in e.variants.iter() {
+               if let syn::Fields::Named(fields) = &var.fields {
+                       needs_free = true;
+                       for field in fields.named.iter() {
+                               if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
+
+                               let mut ty_checks = Vec::new();
+                               types.write_c_type(&mut ty_checks, &field.ty, Some(&gen_types), false);
+                               if !types.is_clonable(&String::from_utf8(ty_checks).unwrap()) {
+                                       is_clonable = false;
+                               }
+                       }
+               } else if let syn::Fields::Unnamed(fields) = &var.fields {
+                       for field in fields.unnamed.iter() {
+                               let mut ty_checks = Vec::new();
+                               types.write_c_type(&mut ty_checks, &field.ty, Some(&gen_types), false);
+                               let ty = String::from_utf8(ty_checks).unwrap();
+                               if ty != "" && !types.is_clonable(&ty) {
+                                       is_clonable = false;
+                               }
+                       }
+               }
+       }
 
-       writeln!(w, "#[must_use]\n#[derive(Clone)]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
+       if is_clonable {
+               writeln!(w, "#[derive(Clone)]").unwrap();
+               types.crate_types.set_clonable(format!("{}::{}", types.module_path, e.ident));
+       }
+       writeln!(w, "#[must_use]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
        for var in e.variants.iter() {
                assert_eq!(export_status(&var.attrs), ExportStatus::Export); // We can't partially-export a mirrored enum
                writeln_docs(w, &var.attrs, "\t");
@@ -1625,14 +1669,17 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                        }
                        if !empty_tuple_variant {
                                needs_free = true;
-                               write!(w, "(").unwrap();
+                               writeln!(w, "(").unwrap();
                                for (idx, field) in fields.unnamed.iter().enumerate() {
                                        if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
-                                       write!(&mut constr, "{}: ", ('a' as u8 + idx as u8) as char).unwrap();
+                                       writeln_field_docs(w, &field.attrs, "\t\t", types, Some(&gen_types), &field.ty);
+                                       write!(w, "\t\t").unwrap();
                                        types.write_c_type(w, &field.ty, Some(&gen_types), true);
+
+                                       write!(&mut constr, "{}: ", ('a' as u8 + idx as u8) as char).unwrap();
                                        types.write_c_type(&mut constr, &field.ty, Some(&gen_types), false);
                                        if idx != fields.unnamed.len() - 1 {
-                                               write!(w, ",").unwrap();
+                                               writeln!(w, ",").unwrap();
                                                write!(&mut constr, ",").unwrap();
                                        }
                                }
@@ -1715,7 +1762,7 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                                let mut sink = ::std::io::sink();
                                                let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
                                                let new_var = if $to_c {
-                                                       types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types), false)
+                                                       types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types), true)
                                                } else {
                                                        types.write_from_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types))
                                                };
@@ -1725,7 +1772,7 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                                                if new_var {
                                                                        let nonref_ident = format_ident!("{}_nonref", $field_ident);
                                                                        if $to_c {
-                                                                               types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types), false);
+                                                                               types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types), true);
                                                                        } else {
                                                                                types.write_from_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types));
                                                                        }
@@ -1757,14 +1804,14 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                        ($field: expr, $field_ident: expr) => { {
                                                if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
                                                if $to_c {
-                                                       types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), false);
+                                                       types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), true);
                                                } else {
                                                        types.write_from_c_conversion_prefix(w, &$field.ty, Some(&gen_types));
                                                }
                                                write!(w, "{}{}", $field_ident,
                                                        if $ref { "_nonref" } else { "" }).unwrap();
                                                if $to_c {
-                                                       types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), false);
+                                                       types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), true);
                                                } else {
                                                        types.write_from_c_conversion_suffix(w, &$field.ty, Some(&gen_types));
                                                }
@@ -1798,9 +1845,13 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                }
        }
 
-       write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
+       if is_clonable {
+               write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
+       }
        write_conv!(format!("into_native(self) -> native{}", e.ident), false, false);
-       write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
+       if is_clonable {
+               write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
+       }
        write_conv!(format!("native_into(native: native{}) -> Self", e.ident), true, false);
        writeln!(w, "}}").unwrap();
 
@@ -1808,11 +1859,13 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                writeln!(w, "/// Frees any resources used by the {}", e.ident).unwrap();
                writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
        }
-       writeln!(w, "/// Creates a copy of the {}", e.ident).unwrap();
-       writeln!(w, "#[no_mangle]").unwrap();
-       writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
-       writeln!(w, "\torig.clone()").unwrap();
-       writeln!(w, "}}").unwrap();
+       if is_clonable {
+               writeln!(w, "/// Creates a copy of the {}", e.ident).unwrap();
+               writeln!(w, "#[no_mangle]").unwrap();
+               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
+               writeln!(w, "\torig.clone()").unwrap();
+               writeln!(w, "}}").unwrap();
+       }
        w.write_all(&constr).unwrap();
        write_cpp_wrapper(cpp_headers, &format!("{}", e.ident), needs_free, None);
 }
@@ -2041,6 +2094,49 @@ fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>
        }
 }
 
+
+/// Walk the FullLibraryAST, determining if impl aliases need to be marked cloneable.
+fn walk_ast_second_pass<'a>(ast_storage: &'a FullLibraryAST, crate_types: &CrateTypes<'a>) {
+       for (module, astmod) in ast_storage.modules.iter() {
+               let orig_crate = module.splitn(2, "::").next().unwrap();
+               let ASTModule { ref attrs, ref items, .. } = astmod;
+               assert_eq!(export_status(&attrs), ExportStatus::Export);
+
+               let import_resolver = ImportResolver::new(orig_crate, &ast_storage.dependencies, module, items);
+               let mut types = TypeResolver::new(module, import_resolver, crate_types);
+
+               for item in items.iter() {
+                       match item {
+                               syn::Item::Impl(i) => {
+                                       match export_status(&i.attrs) {
+                                               ExportStatus::Export => {},
+                                               ExportStatus::NoExport|ExportStatus::TestOnly => continue,
+                                               ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
+                                       }
+                                       if let Some(trait_path) = i.trait_.as_ref() {
+                                               if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) ||
+                                                  path_matches_nongeneric(&trait_path.1, &["Clone"])
+                                               {
+                                                       if let &syn::Type::Path(ref p) = &*i.self_ty {
+                                                               if let Some(resolved_path) = types.maybe_resolve_path(&p.path, None) {
+                                                                       create_alias_for_impl(resolved_path, i, &mut types, |aliased_impl, types| {
+                                                                               if let &syn::Type::Path(ref p) = &*aliased_impl.self_ty {
+                                                                                       if let Some(resolved_aliased_path) = types.maybe_resolve_path(&p.path, None) {
+                                                                                               crate_types.set_clonable("crate::".to_owned() + &resolved_aliased_path);
+                                                                                       }
+                                                                               }
+                                                                       });
+                                                               }
+                                                       }
+                                               }
+                                       }
+                               }
+                               _ => {}
+                       }
+               }
+       }
+}
+
 fn walk_private_mod<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, module: String, items: &'a syn::ItemMod, crate_types: &mut CrateTypes<'a>) {
        let import_resolver = ImportResolver::new(orig_crate, &ast_storage.dependencies, &module, &items.content.as_ref().unwrap().1);
        for item in items.content.as_ref().unwrap().1.iter() {
@@ -2066,7 +2162,7 @@ fn walk_private_mod<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, modul
 }
 
 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
-fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
+fn walk_ast_first_pass<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
        for (module, astmod) in ast_storage.modules.iter() {
                let ASTModule { ref attrs, ref items, submods: _ } = astmod;
                assert_eq!(export_status(&attrs), ExportStatus::Export);
@@ -2221,7 +2317,11 @@ fn main() {
        // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
        // when parsing other file ASTs...
        let mut libtypes = CrateTypes::new(&mut derived_templates, &libast);
-       walk_ast(&libast, &mut libtypes);
+       walk_ast_first_pass(&libast, &mut libtypes);
+
+       // ... using the generated data, determine a few additional fields, specifically which type
+       // aliases are to be clone-able...
+       walk_ast_second_pass(&libast, &libtypes);
 
        // ... finally, do the actual file conversion/mapping, writing out types as we go.
        convert_file(&libast, &libtypes, &args[1], &mut header_file, &mut cpp_header_file);