error: malformed `repr` attribute input
  --> $DIR/repr.rs:1:1
   |
LL | #[repr]
   | ^^^^^^^ help: must be of the form: `#[repr(C, packed, ...)]`

error: malformed `repr` attribute input
  --> $DIR/repr.rs:4:1
   |
LL | #[repr = "B"]
   | ^^^^^^^^^^^^^ help: must be of the form: `#[repr(C, packed, ...)]`

error: malformed `repr` attribute input
  --> $DIR/repr.rs:7:1
   |
LL | #[repr = "C"]
   | ^^^^^^^^^^^^^ help: must be of the form: `#[repr(C, packed, ...)]`

error: aborting due to 3 previous errors