src/test/ui/const-generics/const-argument-if-length.rs

   1 // revisions: full min
   2
   3 #![cfg_attr(full, feature(generic_const_exprs))]
   4 #![cfg_attr(full, allow(incomplete_features))]
   5
   6 pub const fn is_zst<T: ?Sized>() -> usize {
   7     if std::mem::size_of::<T>() == 0 {
   8         1
   9     } else {
  10         0
  11     }
  12 }
  13
  14 pub struct AtLeastByte<T: ?Sized> {
  15     value: T,
  16     //~^ ERROR the size for values of type `T` cannot be known at compilation time
  17     pad: [u8; is_zst::<T>()],
  18     //[min]~^ ERROR generic parameters may not be used in const operations
  19     //[full]~^^ ERROR unconstrained generic constant
  20 }
  21
  22 fn main() {}