Function pointer types never display higher-ranked region when they are used as argument types #44887

tirr-c · 2017-09-27T15:24:50Z

fn f<F>(_: F) where F: for<'a> Fn(&'a u8, for<'b> fn(&'b u8)) {}

fn main() {
    f(|_: (), _: ()| {});
}

error[E0631]: type mismatch in closure arguments
 --> src/main.rs:4:5
  |
4 |     f(|_: (), _: ()| {});
  |     ^ ----------------- found signature of `fn((), ()) -> _`
  |     |
  |     expected signature of `for<'a> fn(&'a u8, fn(&'b u8)) -> _`
  |
  = note: required by `f`

Here, only for<'b> is omitted.

Meta

$ rustc --version --verbose
rustc 1.22.0-nightly (930d3b17d 2017-09-26)
binary: rustc
commit-hash: 930d3b17dd91b6564cf535ac717c688db757be5d
commit-date: 2017-09-26
host: x86_64-unknown-linux-gnu
release: 1.22.0-nightly
LLVM version: 4.0

The text was updated successfully, but these errors were encountered:

@nikomatsakis

Refactor fmt::Display and fmt::Debug impls in ppaux Also fixes #44887. There was a problem that unnamed late-bound regions are *always* named `'r` while they are displayed using `std::fmt::Display`. --- ```rust fn main() { f(|_: (), _: ()| {}); } fn f<F>(_: F) where F: Fn(&(), for<'r> fn(&'r ())) {} ``` Before (incorrectly shadows lifetime, `for<'r>` omitted for the second argument): ``` error[E0631]: type mismatch in closure arguments --> test.rs:2:5 | 2 | f(|_: (), _: ()| {}); | ^ ----------------- found signature of `fn((), ()) -> _` | | | expected signature of `for<'r> fn(&'r (), fn(&'r ())) -> _` | = note: required by `f` ``` After: ``` error[E0631]: type mismatch in closure arguments --> test.rs:2:5 | 2 | f(|_: (), _: ()| {}); | ^ ----------------- found signature of `fn((), ()) -> _` | | | expected signature of `for<'s> fn(&'s (), for<'r> fn(&'r ())) -> _` | = note: required by `f` ``` r? @nikomatsakis

tirr-c changed the title ~~function pointer types never display higher-ranked region when it is used as argument types~~ Function pointer types never display higher-ranked region when it is used as argument types Sep 27, 2017

tirr-c changed the title ~~Function pointer types never display higher-ranked region when it is used as argument types~~ Function pointer types never display higher-ranked region when they are used as argument types Sep 27, 2017

tirr-c mentioned this issue Sep 27, 2017

Refactor fmt::Display and fmt::Debug impls in ppaux #44888

Merged

aidanhs added the C-enhancement Category: An issue proposing an enhancement or a PR with one. label Sep 28, 2017

bors closed this as completed in #44888 Oct 11, 2017

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Function pointer types never display higher-ranked region when they are used as argument types #44887

Function pointer types never display higher-ranked region when they are used as argument types #44887

tirr-c commented Sep 27, 2017

Function pointer types never display higher-ranked region when they are used as argument types #44887

Function pointer types never display higher-ranked region when they are used as argument types #44887

Comments

tirr-c commented Sep 27, 2017

Meta