From: Matt Corallo <git@bluematt.me>
Date: Fri, 24 Jun 2022 01:15:31 +0000 (+0000)
Subject: Correctly generate `impl` blocks for traits with generics
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=ldk-c-bindings;a=commitdiff_plain;h=59dfbf9845fec045d76da8d5a28483c470a2c4a1

Correctly generate `impl` blocks for traits with generics
---

diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index 49bc774..266bf58 100644
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -597,7 +597,16 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
 		(s, i) => {
 			if let Some(supertrait) = types.crate_types.traits.get(s) {
 				let resolver = get_module_type_resolver!(s, types.crate_libs, types.crate_types);
-				writeln!(w, "impl {} for {} {{", s, trait_name).unwrap();
+
+				// 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, types, false);
+				writeln!(w, " for {} {{", trait_name).unwrap();
+
 				impl_trait_for_c!(supertrait, format!(".{}", i), &resolver);
 				writeln!(w, "}}").unwrap();
 			} else {