error: expected `;` or `]`, found `3`
  --> $DIR/better-expected.rs:2:19
   |
LL |     let x: [isize 3];
   |                   ^ expected `;` or `]`
   |
   = note: you might have meant to write a slice or array type
help: you might have meant to use `;` as the separator
   |
LL |     let x: [isize ;3];
   |                   +

error: aborting due to 1 previous error