tests/ui/traits/issue-91949-hangs-on-recursion.rs

   1 // build-fail
   2 // compile-flags: -Zinline-mir=no
   3 // error-pattern: overflow evaluating the requirement `(): Sized`
   4 // error-pattern: function cannot return without recursing
   5 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
   6
   7 // Regression test for #91949.
   8 // This hanged *forever* on 1.56, fixed by #90423.
   9
  10 #![recursion_limit = "256"]
  11
  12 struct Wrapped<T>(T);
  13
  14 struct IteratorOfWrapped<T, I: Iterator<Item = T>>(I);
  15
  16 impl<T, I: Iterator<Item = T>> Iterator for IteratorOfWrapped<T, I> {
  17     type Item = Wrapped<T>;
  18     fn next(&mut self) -> Option<Wrapped<T>> {
  19         self.0.next().map(Wrapped)
  20     }
  21 }
  22
  23 fn recurse<T>(elements: T) -> Vec<char>
  24 where
  25     T: Iterator<Item = ()>,
  26 {
  27     recurse(IteratorOfWrapped(elements).map(|t| t.0))
  28 }
  29
  30 fn main() {
  31     recurse(std::iter::empty());
  32 }