error[E0748]: found both positive and negative implementation of trait `MyTrait` for type `u32`:
  --> $DIR/positive-specializes-negative.rs:7:1
   |
LL | impl<T> !MyTrait for T {}
   | ---------------------- negative implementation here
LL | impl MyTrait for u32 {}
   | ^^^^^^^^^^^^^^^^^^^^ positive implementation here

error: aborting due to previous error

For more information about this error, try `rustc --explain E0748`.