rust/tests/ui/nll/closure-requirements/escape-argument-callee.rs

43 lines
1.1 KiB
Rust

// Test closure that:
//
// - takes an argument `y` with lifetime `'a` (in the code, it's anonymous)
// - stores `y` into another, longer-lived spot with lifetime `'b`
//
// Because `'a` and `'b` are two different, unrelated higher-ranked
// regions with no relationship to one another, this is an error. This
// error is reported by the closure itself and is not propagated to
// its creator: this is because `'a` and `'b` are higher-ranked
// (late-bound) regions and the closure is not allowed to propagate
// additional where clauses between higher-ranked regions, only those
// that appear free in its type (hence, we see it before the closure's
// "external requirements" report).
//@ compile-flags:-Zverbose-internals
#![feature(rustc_attrs)]
#[rustc_regions]
fn test() {
let x = 44;
let mut p = &x;
{
let y = 22;
let mut closure = expect_sig(|p, y| *p = y);
//~^ ERROR
closure(&mut p, &y);
}
deref(p);
}
fn expect_sig<F>(f: F) -> F
where F: FnMut(&mut &i32, &i32)
{
f
}
fn deref(_p: &i32) { }
fn main() { }