error[E0308]: mismatched types
  --> $DIR/issue-52893.rs:53:22
   |
LL | impl<F, Name, P> AddClass<Name, F> for Class<P>
   |      - this type parameter
...
LL |         builder.push(output);
   |                      ^^^^^^ expected type parameter `F`, found struct `Class`
   |
   = note: expected type parameter `F`
                      found struct `Class<P>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.