error[E0423]: expected value, found type parameter `O`
  --> $DIR/issue-69654.rs:5:25
   |
LL | impl<O> Bar<O> for [u8; O] {}
   |                         ^ help: a tuple variant with a similar name exists: `Ok`
   | 
  ::: $SRC_DIR/libcore/result.rs:LL:COL
   |
LL |     Ok(#[stable(feature = "rust1", since = "1.0.0")] T),
   |     --------------------------------------------------- similarly named tuple variant `Ok` defined here

error: aborting due to previous error

For more information about this error, try `rustc --explain E0423`.