nandi/rustnim · 9a32146

⑂ 9a32146

Recognise a `&mut` receiver as a generic parameter

`input.checkpoint()` where `input: &mut Input` and `Input: Stream` is the
shape most of winnow's combinators are written in, and the trait-bound
dispatch never fired on it: the receiver's type is `var Input`, whose rendered
name is not the parameter's. Unwrapped before the name is taken.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

nandithebull committed 2026-09-19T19:40:32-07:00 Browse files

9a32146 parent: 0822ec3

modified src/lower.rs +3 -1 Viewed

@@ -7220,9 +7220,11 @@ impl Lowerer {
7220	7220	// Nim at instantiation, so the call just needs the right proc
7221	7221	// name. Every impl of a trait method shares one, so any
7222	7222	// candidate with this method name gives it.
	7223	+ // `.unvar()` first: a `&mut Input` receiver is `var Input`,
	7224	+ // whose rendered name is not the parameter's.
7223	7225	let recv_param = rt
7224	7226	.as_ref()
7225		- .map(type_name)
	7227	+ .map(\|t\| type_name(&t.clone().unvar()))
7226	7228	.filter(\|n\| self.fn_generics.iter().any(\|g\| g == n));
7227	7229
7228	7230	// The receiver's type is a generic parameter and one of its

                  // Nim at instantiation, so the call just needs the right proc
                  // name. Every impl of a trait method shares one, so any
                  // candidate with this method name gives it.
++                // `.unvar()` first: a `&mut Input` receiver is `var Input`,
++                // whose rendered name is not the parameter's.
                  let recv_param = rt
                      .as_ref()
--                    .map(type_name)
++                    .map(|t| type_name(&t.clone().unvar()))
                      .filter(|n| self.fn_generics.iter().any(|g| g == n));
                  // The receiver's type is a generic parameter and one of its