error[E0308]: mismatched types
  --> $DIR/issue-4517.rs:15:9
   |
LL |     bar(foo);
   |         ^^^ expected usize, found array of 4 elements
   |
   = note: expected type `usize`
              found type `[u8; 4]`

error: aborting due to previous error

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