error: generic parameters may not be used in const operations
  --> $DIR/issue-67945-4.rs:10:27
   |
LL |         let x: Option<Box<S>> = None;
   |                           ^ cannot perform const operation using `S`
   |
   = note: type parameters may not be used in const expressions
   = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions

error[E0392]: type parameter `S` is never used
  --> $DIR/issue-67945-4.rs:8:12
   |
LL | struct Bug<S> {
   |            ^ unused type parameter
   |
   = help: consider removing `S`, referring to it in a field, or using a marker such as `PhantomData`
   = help: if you intended `S` to be a const parameter, use `const S: /* Type */` instead

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0392`.