rust/tests/ui/higher-ranked/trait-bounds/hrtb-identity-fn-borrows.rs
2023-05-30 13:04:25 +02:00

27 lines
562 B
Rust

// Test that the `'a` in the where clause correctly links the region
// of the output to the region of the input.
trait FnLike<A,R> {
fn call(&self, arg: A) -> R;
}
fn call_repeatedly<F>(f: F)
where F : for<'a> FnLike<&'a isize, &'a isize>
{
// Result is stored: cannot re-assign `x`
let mut x = 3;
let y = f.call(&x);
x = 5; //~ ERROR cannot assign to `x` because it is borrowed
// Result is not stored: can re-assign `x`
let mut x = 3;
f.call(&x);
f.call(&x);
f.call(&x);
x = 5;
drop(y);
}
fn main() {
}