error[E0121]: the type placeholder `_` is not allowed within types on item signatures
  --> $DIR/self-infer.rs:4:16
   |
LL |     fn f(self: _) {}
   |                ^ not allowed in type signatures

error[E0121]: the type placeholder `_` is not allowed within types on item signatures
  --> $DIR/self-infer.rs:5:17
   |
LL |     fn g(self: &_) {}
   |                 ^ not allowed in type signatures

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0121`.