error[E0121]: the placeholder `_` is not allowed within types on item signatures for functions
  --> $DIR/method-argument-mismatch-variance-ice-119867.rs:8:23
   |
LL |     fn deserialize(s: _) {}
   |                       ^ not allowed in type signatures
   |
help: try replacing `_` with the type in the corresponding trait method signature
   |
LL |     fn deserialize(s: &ArchivedVec<T>) {}
   |                       ~~~~~~~~~~~~~~~

error[E0186]: method `deserialize` has a `&self` declaration in the trait, but not in the impl
  --> $DIR/method-argument-mismatch-variance-ice-119867.rs:8:5
   |
LL |     fn deserialize(&self);
   |     ---------------------- `&self` used in trait
...
LL |     fn deserialize(s: _) {}
   |     ^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0121, E0186.
For more information about an error, try `rustc --explain E0121`.