85 lines
1.9 KiB
Rust
85 lines
1.9 KiB
Rust
// Test cases where we constrain `<T as Anything<'b>>::AssocType` to
|
|
// outlive `'a` and there is a unique bound in the trait definition of
|
|
// `Anything` -- i.e., we know that `AssocType` outlives `'b`. In this
|
|
// case, the best way to satisfy the trait bound is to show that `'b:
|
|
// 'a`, which can be done in various ways.
|
|
|
|
// compile-flags:-Zverbose
|
|
|
|
#![allow(warnings)]
|
|
#![feature(rustc_attrs)]
|
|
|
|
use std::cell::Cell;
|
|
|
|
trait Anything<'a> {
|
|
type AssocType: 'a;
|
|
}
|
|
|
|
fn with_signature<'a, T, F>(cell: Cell<&'a ()>, t: T, op: F)
|
|
where
|
|
F: FnOnce(Cell<&'a ()>, T),
|
|
{
|
|
op(cell, t)
|
|
}
|
|
|
|
fn require<'a, 'b, T>(_cell: Cell<&'a ()>, _t: T)
|
|
where
|
|
T: Anything<'b>,
|
|
T::AssocType: 'a,
|
|
{
|
|
}
|
|
|
|
#[rustc_regions]
|
|
fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
|
|
where
|
|
T: Anything<'b>,
|
|
{
|
|
with_signature(cell, t, |cell, t| require(cell, t));
|
|
//~^ ERROR
|
|
}
|
|
|
|
#[rustc_regions]
|
|
fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
|
|
where
|
|
T: Anything<'b>,
|
|
'a: 'a,
|
|
{
|
|
with_signature(cell, t, |cell, t| require(cell, t));
|
|
//~^ ERROR
|
|
}
|
|
|
|
#[rustc_regions]
|
|
fn projection_outlives<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
|
|
where
|
|
T: Anything<'b>,
|
|
T::AssocType: 'a,
|
|
{
|
|
// We are projecting `<T as Anything<'b>>::AssocType`, and we know
|
|
// that this outlives `'a` because of the where-clause.
|
|
|
|
with_signature(cell, t, |cell, t| require(cell, t));
|
|
}
|
|
|
|
#[rustc_regions]
|
|
fn elements_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
|
|
where
|
|
T: Anything<'b>,
|
|
'b: 'a,
|
|
{
|
|
with_signature(cell, t, |cell, t| require(cell, t));
|
|
}
|
|
|
|
#[rustc_regions]
|
|
fn one_region<'a, T>(cell: Cell<&'a ()>, t: T)
|
|
where
|
|
T: Anything<'a>,
|
|
{
|
|
// Note that in this case the closure still propagates an external
|
|
// requirement between two variables in its signature, but the
|
|
// creator maps both those two region variables to `'a` on its
|
|
// side.
|
|
with_signature(cell, t, |cell, t| require(cell, t));
|
|
}
|
|
|
|
fn main() {}
|