warning: the feature `type_alias_impl_trait` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/negative-reasoning.rs:5:32
   |
LL | #![cfg_attr(full_tait, feature(type_alias_impl_trait))]
   |                                ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(incomplete_features)]` on by default
   = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information

error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<impl OpaqueTrait>`
  --> $DIR/negative-reasoning.rs:22:1
   |
LL | impl<T: std::fmt::Debug> AnotherTrait for T {}
   | ------------------------------------------- first implementation here
...
LL | impl AnotherTrait for D<OpaqueType> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<impl OpaqueTrait>`
   |
   = note: upstream crates may add a new impl of trait `std::fmt::Debug` for type `impl OpaqueTrait` in future versions

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0119`.