rust/tests/ui/nll/relate_tys/hr-fn-aau-eq-abu.rs

// Test an interesting corner case that ought to be legal (though the
// current code actually gets it wrong, see below): a fn that takes
// two arguments that are references with the same lifetime is in fact
// equivalent to a fn that takes two references with distinct
// lifetimes. This is true because the two functions can call one
// another -- effectively, the single lifetime `'a` is just inferred
// to be the intersection of the two distinct lifetimes.
//
// check-pass
// compile-flags:-Zno-leak-check

use std::cell::Cell;

fn make_cell_aa() -> Cell<for<'a> fn(&'a u32, &'a u32)> {
    panic!()
}

fn aa_eq_ab() {
    let a: Cell<for<'a, 'b> fn(&'a u32, &'b u32)> = make_cell_aa();
    drop(a);
}

fn main() { }