| // Test cases where we constrain `<T as Anything<'a, 'b>>::AssocType` |
| // to outlive `'a` and there are two bounds in the trait definition of |
| // `Anything` -- i.e., we know that `AssocType` outlives `'a` and |
| // `'b`. In this case, it's not clear what is the best way to satisfy |
| // the trait bound, and hence we propagate it to the caller as a type |
| // test. |
| |
| //@ compile-flags:-Zverbose-internals |
| |
| #![allow(warnings)] |
| #![feature(rustc_attrs)] |
| |
| use std::cell::Cell; |
| |
| trait Anything<'a, 'b> { |
| type AssocType: 'a + 'b; |
| } |
| |
| 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, 'c, T>(_cell: Cell<&'a ()>, _t: T) |
| where |
| T: Anything<'b, 'c>, |
| T::AssocType: 'a, |
| { |
| } |
| |
| #[rustc_regions] |
| fn no_relationships_late<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'c>, |
| { |
| with_signature(cell, t, |cell, t| require(cell, t)); |
| //~^ ERROR may not live long enough |
| } |
| |
| #[rustc_regions] |
| fn no_relationships_early<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'c>, |
| 'a: 'a, |
| { |
| with_signature(cell, t, |cell, t| require(cell, t)); |
| //~^ ERROR may not live long enough |
| } |
| |
| #[rustc_regions] |
| fn projection_outlives<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'c>, |
| 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_outlive1<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'c>, |
| 'b: 'a, |
| { |
| with_signature(cell, t, |cell, t| require(cell, t)); |
| } |
| |
| #[rustc_regions] |
| fn elements_outlive2<'a, 'b, 'c, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'c>, |
| 'c: 'a, |
| { |
| with_signature(cell, t, |cell, t| require(cell, t)); |
| } |
| |
| #[rustc_regions] |
| fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, 'b>, |
| { |
| with_signature(cell, t, |cell, t| require(cell, t)); |
| //~^ ERROR lifetime may not live long enough |
| } |
| |
| #[rustc_regions] |
| fn two_regions_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T) |
| where |
| T: Anything<'b, '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, '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() {} |