| // Checks that Polonius can compute cases of universal regions errors: |
| // "illegal subset relation errors", cases where analysis finds that |
| // two free regions outlive each other, without any evidence that this |
| // relation holds. |
| |
| // ignore-compare-mode-nll |
| // compile-flags: -Z borrowck=mir -Zpolonius |
| |
| // returning `y` requires that `'b: 'a`, but it's not known to be true |
| fn missing_subset<'a, 'b>(x: &'a u32, y: &'b u32) -> &'a u32 { |
| y //~ ERROR |
| } |
| |
| // `'b: 'a` is explicitly declared |
| fn valid_subset<'a, 'b: 'a>(x: &'a u32, y: &'b u32) -> &'a u32 { |
| y |
| } |
| |
| // because of `x`, it is implied that `'b: 'a` holds |
| fn implied_bounds_subset<'a, 'b>(x: &'a &'b mut u32) -> &'a u32 { |
| x |
| } |
| |
| // `'b: 'a` is declared, and `'a: 'c` is known via implied bounds: |
| // `'b: 'c` is therefore known to hold transitively |
| fn transitively_valid_subset<'a, 'b: 'a, 'c>(x: &'c &'a u32, y: &'b u32) -> &'c u32 { |
| y |
| } |
| |
| fn main() {} |
