tests/ui/traits/new-solver/provisional-result-done.rs

   1 // known-bug: unknown
   2 // compile-flags: -Ztrait-solver=next
   3 // failure-status: 101
   4 // normalize-stderr-test "note: .*\n\n" -> ""
   5 // normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
   6 // rustc-env:RUST_BACKTRACE=0
   7
   8 // This tests checks that we update results in the provisional cache when
   9 // we pop a goal from the stack.
  10 #![feature(auto_traits)]
  11 auto trait Coinductive {}
  12 struct Foo<T>(T);
  13 struct Bar<T>(T);
  14
  15 impl<T> Coinductive for Foo<T>
  16 where
  17     Bar<T>: Coinductive
  18 {}
  19
  20 impl<T> Coinductive for Bar<T>
  21 where
  22     Foo<T>: Coinductive,
  23     Bar<T>: ConstrainInfer,
  24 {}
  25
  26 trait ConstrainInfer {}
  27 impl ConstrainInfer for Bar<u8> {}
  28 impl ConstrainInfer for Foo<u16> {}
  29
  30 fn impls<T: Coinductive>() -> T { todo!() }
  31
  32 fn constrain<T: ConstrainInfer>(_: T) {}
  33
  34 fn main() {
  35     // This should constrain `_` to `u8`.
  36     impls::<Foo<_>>();
  37 }