src/test/ui/nll/ty-outlives/projection-implied-bounds.rs

   1 // Test that we can deduce when projections like `T::Item` outlive the
   2 // function body. Test that this does not imply that `T: 'a` holds.
   3
   4 // compile-flags:-Zverbose
   5
   6 use std::cell::Cell;
   7
   8 fn twice<F, T>(mut value: T, mut f: F)
   9 where
  10     F: FnMut(&T, Cell<&Option<T::Item>>),
  11     T: Iterator,
  12 {
  13     let mut n = value.next();
  14     f(&value, Cell::new(&n));
  15     f(&value, Cell::new(&n));
  16 }
  17
  18 fn generic1<T: Iterator>(value: T) {
  19     // No error here:
  20     twice(value, |value_ref, item| invoke1(item));
  21 }
  22
  23 fn invoke1<'a, T>(x: Cell<&'a Option<T>>)
  24 where
  25     T: 'a,
  26 {
  27 }
  28
  29 fn generic2<T: Iterator>(value: T) {
  30     twice(value, |value_ref, item| invoke2(value_ref, item));
  31     //~^ ERROR the parameter type `T` may not live long enough
  32 }
  33
  34 fn invoke2<'a, T, U>(a: &T, b: Cell<&'a Option<U>>)
  35 where
  36     T: 'a,
  37 {
  38 }
  39
  40 fn main() {}