Code snippet is machine dependent

[gaurikholkar-zz]

fn invoke<'a, F>(x: &'a i32, f: F) -> &'a i32
where F: FnOnce(&'a i32, &i32) -> &'a i32
{
    let y = 22;
    f(x, &y)
}

fn foo<'a>(x: &'a i32) {
    invoke(&x, |a, b| if a > b { a } else { b }); //~ ERROR E0495
}

This UI test was moved to compile-fail as the finer details of the error seemed to vary on different machines.

Following are the Logs

[01:35:31] failures:
[01:35:31] 
[01:35:31] ---- [ui] ui/lifetime-errors/ex1-return-one-existing-name-if-else-using-closure.rs stdout ----
[01:35:31] 	ui: /checkout/src/test/ui/lifetime-errors/ex1-return-one-existing-name-if-else-using-closure.rs
[01:35:31] normalized stderr:
[01:35:31] error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |     ^^^^^^
[01:35:31]    |
[01:35:31] note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the body at 19:16...
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:16
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[01:35:31] note: ...so that reference does not outlive borrowed content
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:45
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |                                             ^
[01:35:31] note: but, the lifetime must be valid for the call at 19:5...
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[01:35:31] note: ...so that argument is valid for the call
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:12
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |            ^^
[01:35:31] 
[01:35:31] error: aborting due to previous error(s)
[01:35:31] 
[01:35:31] 
[01:35:31] 
[01:35:31] expected stderr:
[01:35:31] error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |     ^^^^^^
[01:35:31]    |
[01:35:31] note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the body at 19:16...
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:16
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[01:35:31] note: ...so that reference does not outlive borrowed content
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:45
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |                                             ^
[01:35:31] note: but, the lifetime must be valid for the expression at 19:5...
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |     ^^^^^^
[01:35:31] note: ...so that a type/lifetime parameter is in scope here
[01:35:31]   --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]    |
[01:35:31] 19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]    |     ^^^^^^
[01:35:31] 
[01:35:31] error: aborting due to previous error(s)
[01:35:31] 
[01:35:31] 
[01:35:31] 
[01:35:31] diff of stderr:
[01:35:31] 
[01:35:31]  error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
[01:35:31]    --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]     |
[01:35:31]  19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]     |     ^^^^^^
[01:35:31]     |
[01:35:31]  note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the body at 19:16...
[01:35:31]    --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:16
[01:35:31]     |
[01:35:31]  19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]     |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[01:35:31]  note: ...so that reference does not outlive borrowed content
[01:35:31]    --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:45
[01:35:31]     |
[01:35:31]  19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31]     |                                             ^
[01:35:31] -note: but, the lifetime must be valid for the expression at 19:5...
[01:35:31] +note: but, the lifetime must be valid for the call at 19:5...
[01:35:31]    --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31]     |
[01:35:31]  19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31] -   |     ^^^^^^
[01:35:31] -note: ...so that a type/lifetime parameter is in scope here
[01:35:31] -  --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:5
[01:35:31] +   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[01:35:31] +note: ...so that argument is valid for the call
[01:35:31] +  --> $DIR/ex1-return-one-existing-name-if-else-using-closure.rs:19:12
[01:35:31]     |
[01:35:31]  19 |     invoke(&x, |a, b| if a > b { a } else { b });
[01:35:31] -   |     ^^^^^^
[01:35:31] +   |            ^^
[01:35:31]  
[01:35:31]  error: aborting due to previous error(s)

Check here for more details

cc @nikomatsakis

[Mark-Simulacrum]

This is a UI test today afaict so closing (https://github.com/rust-lang/rust/blob/master/src/test/ui/error-codes/E0621-does-not-trigger-for-closures.rs and a few others were checked manually).