src/test/ui/variance/variance-contravariant-self-trait-match.rs

   1 #![allow(dead_code)]
   2
   3 // Test that even when `Self` is only used in contravariant position, it
   4 // is treated as invariant.
   5
   6 trait Get {
   7     fn get(&self);
   8 }
   9
  10 fn get_min_from_max<'min, 'max, G>()
  11     where 'max : 'min, G : 'max, &'max G : Get
  12 {
  13     impls_get::<&'min G>();
  14     //~^ ERROR lifetime may not live long enough
  15 }
  16
  17 fn get_max_from_min<'min, 'max, G>()
  18     where 'max : 'min, G : 'max, &'min G : Get
  19 {
  20     // Previously OK, but now error because traits are invariant with
  21     // respect to all inputs.
  22
  23     impls_get::<&'max G>();
  24     //~^ ERROR lifetime may not live long enough
  25 }
  26
  27 fn impls_get<G>() where G : Get { }
  28
  29 fn main() { }