15e2e5185a
Attempt to normalize `FnDef` signature in `InferCtxt::cmp` Stashes a normalization callback in `InferCtxt` so that the signature we get from `tcx.fn_sig(..).subst(..)` in `InferCtxt::cmp` can be properly normalized, since we cannot expect for it to have normalized types since it comes straight from astconv. This is kind of a hack, but I will say that `@jyn514` found the fact that we present unnormalized types to be very confusing in real life code, and I agree with that feeling. Though altogether I am still a bit unsure about whether this PR is worth the effort, so I'm open to alternatives and/or just closing it outright. On the other hand, this isn't a ridiculously heavy implementation anyways -- it's less than a hundred lines of changes, and half of that is just miscellaneous cleanup. This is stacked onto #100471 which is basically unrelated, and it can be rebased off of that when that lands or if needed. --- The code: ```rust trait Foo { type Bar; } impl<T> Foo for T { type Bar = i32; } fn foo<T>(_: <T as Foo>::Bar) {} fn needs_i32_ref_fn(f: fn(&'static i32)) {} fn main() { needs_i32_ref_fn(foo::<()>); } ``` Before: ``` = note: expected fn pointer `fn(&'static i32)` found fn item `fn(<() as Foo>::Bar) {foo::<()>}` ``` After: ``` = note: expected fn pointer `fn(&'static i32)` found fn item `fn(i32) {foo::<()>}` ``` |
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| Cargo.toml | ||
| README.md | ||
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.