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// Test where we fail to approximate due to demanding a postdom
// relationship between our upper bounds.
// compile-flags:-Zverbose
#![feature(rustc_attrs)]
use std::cell::Cell;
// Callee knows that:
//
// 'x: 'a
// 'x: 'b
// 'c: 'y
//
// we have to prove that `'x: 'y`. We currently can only approximate
// via a postdominator -- hence we fail to choose between `'a` and
// `'b` here and report the error in the closure.
fn establish_relationships<'a, 'b, 'c, F>(
_cell_a: Cell<&'a u32>,
_cell_b: Cell<&'b u32>,
_cell_c: Cell<&'c u32>,
_closure: F,
) where
F: for<'x, 'y> FnMut(
Cell<&'a &'x u32>, // shows that 'x: 'a
Cell<&'b &'x u32>, // shows that 'x: 'b
Cell<&'y &'c u32>, // shows that 'c: 'y
Cell<&'x u32>,
Cell<&'y u32>,
),
{
}
fn demand_y<'x, 'y>(_cell_x: Cell<&'x u32>, _cell_y: Cell<&'y u32>, _y: &'y u32) {}
#[rustc_regions]
fn supply<'a, 'b, 'c>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>, cell_c: Cell<&'c u32>) {
establish_relationships(
cell_a,
cell_b,
cell_c,
|_outlives1, _outlives2, _outlives3, x, y| {
// Only works if 'x: 'y:
let p = x.get();
demand_y(x, y, p) //~ ERROR
},
);
}
fn main() {}
|
