error[E0119]: conflicting implementations of trait `Copy` for type `S<_>`
  --> $DIR/bad-const-wf-doesnt-specialize.rs:9:1
   |
LL | impl<const N: i32> Copy for S<N> {}
   | -------------------------------- first implementation here
LL | impl<const M: usize> Copy for S<M> {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `S<_>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0119`.