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ices/67830.rs: fixed with errors#1191

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github-actions[bot] wants to merge 1 commit intomasterfrom
autofix/ices/67830.rs
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ices/67830.rs: fixed with errors#1191
github-actions[bot] wants to merge 1 commit intomasterfrom
autofix/ices/67830.rs

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@github-actions github-actions bot commented Mar 31, 2022

Issue: rust-lang/rust#67830

trait MyFn<Arg> {
    type Output;
    fn call(&self, arg: Arg) -> Self::Output;
}

struct Wrap<F>(F);

impl<A, B, F> MyFn<A> for Wrap<F>
where
    F: Fn(A) -> B
{
    type Output = B;

    fn call(&self, arg: A) -> Self::Output {
        (self.0)(arg)
    }
}


struct A;
fn test() -> impl for<'a> MyFn<&'a A, Output=impl Iterator + 'a> {
    Wrap(|a| Some(a).into_iter())
}

fn main() {}
=== stdout ===
=== stderr ===
error: implementation of `FnOnce` is not general enough
  --> /home/runner/work/glacier/glacier/ices/67830.rs:21:66
   |
21 |   fn test() -> impl for<'a> MyFn<&'a A, Output=impl Iterator + 'a> {
   |  __________________________________________________________________^
22 | |     Wrap(|a| Some(a).into_iter())
23 | | }
   | |_^ implementation of `FnOnce` is not general enough
   |
   = note: closure with signature `fn(&'2 A) -> std::option::IntoIter<&A>` must implement `FnOnce<(&'1 A,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `FnOnce<(&'2 A,)>`, for some specific lifetime `'2`

error: aborting due to previous error

==============

@rustbot
ices/67830.rs: fixed with errors
4c9cb32 
=== stdout ===
=== stderr ===
error: implementation of `FnOnce` is not general enough
  --> /home/runner/work/glacier/glacier/ices/67830.rs:21:66
   |
21 |   fn test() -> impl for<'a> MyFn<&'a A, Output=impl Iterator + 'a> {
   |  __________________________________________________________________^
22 | |     Wrap(|a| Some(a).into_iter())
23 | | }
   | |_^ implementation of `FnOnce` is not general enough
   |
   = note: closure with signature `fn(&'2 A) -> std::option::IntoIter<&A>` must implement `FnOnce<(&'1 A,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `FnOnce<(&'2 A,)>`, for some specific lifetime `'2`

error: aborting due to previous error

==============
@Alexendoo Alexendoo closed this in 1714f42 Mar 31, 2022
@Alexendoo Alexendoo deleted the autofix/ices/67830.rs branch March 31, 2022 21:53
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