| // Test a case where we are trying to prove `'x: 'y` and are forced to |
| // approximate the shorter end-point (`'y`) to with `'static`. This is |
| // because `'y` is higher-ranked but we know of no relations to other |
| // regions. Note that `'static` shows up in the stderr output as `'0`. |
| |
| // compile-flags:-Zverbose-internals |
| |
| #![feature(rustc_attrs)] |
| |
| use std::cell::Cell; |
| |
| // Callee knows that: |
| // |
| // 'x: 'a |
| // |
| // so the only way we can ensure that `'x: 'y` is to show that |
| // `'a: 'static`. |
| fn establish_relationships<'a, 'b, F>(_cell_a: &Cell<&'a u32>, _cell_b: &Cell<&'b u32>, _closure: F) |
| where |
| F: for<'x, 'y> FnMut( |
| &Cell<&'a &'x u32>, // shows that 'x: 'a |
| &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>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) { |
| establish_relationships(&cell_a, &cell_b, |_outlives, x, y| { |
| //~^ ERROR borrowed data escapes outside of function |
| |
| // Only works if 'x: 'y: |
| demand_y(x, y, x.get()) |
| }); |
| } |
| |
| fn main() {} |