src/test/ui/specialization/specialization-default-types.stderr

   1 warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
   2   --> $DIR/specialization-default-types.rs:5:12
   3    |
   4 LL | #![feature(specialization)]
   5    |            ^^^^^^^^^^^^^^
   6    |
   7    = note: `#[warn(incomplete_features)]` on by default
   8    = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
   9
  10 error[E0308]: mismatched types
  11   --> $DIR/specialization-default-types.rs:15:9
  12    |
  13 LL |     default type Output = Box<T>;
  14    |     ----------------------------- expected this associated type
  15 LL |     default fn generate(self) -> Self::Output {
  16    |                                  ------------ expected `<T as Example>::Output` because of return type
  17 LL |         Box::new(self)
  18    |         ^^^^^^^^^^^^^^ expected associated type, found struct `std::boxed::Box`
  19    |
  20    = note: expected associated type `<T as Example>::Output`
  21                        found struct `std::boxed::Box<T>`
  22
  23 error[E0308]: mismatched types
  24   --> $DIR/specialization-default-types.rs:25:5
  25    |
  26 LL | fn trouble<T>(t: T) -> Box<T> {
  27    |                        ------ expected `std::boxed::Box<T>` because of return type
  28 LL |     Example::generate(t)
  29    |     ^^^^^^^^^^^^^^^^^^^^ expected struct `std::boxed::Box`, found associated type
  30    |
  31    = note:       expected struct `std::boxed::Box<T>`
  32            found associated type `<T as Example>::Output`
  33    = help: consider constraining the associated type `<T as Example>::Output` to `std::boxed::Box<T>`
  34    = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
  35
  36 error: aborting due to 2 previous errors; 1 warning emitted
  37
  38 For more information about this error, try `rustc --explain E0308`.