error: generic parameters may not be used in const operations
  --> $DIR/bad-multiply.rs:7:16
   |
LL |     SmallVec<{ D * 2 }>:,
   |                ^ cannot perform const operation using `D`
   |
   = help: const parameters may only be used as standalone arguments, i.e. `D`
   = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions

error[E0747]: constant provided when a type was expected
  --> $DIR/bad-multiply.rs:7:14
   |
LL |     SmallVec<{ D * 2 }>:,
   |              ^^^^^^^^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0747`.