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// build-fail
#![warn(const_err)]
trait ZeroSized: Sized {
const I_AM_ZERO_SIZED: ();
fn requires_zero_size(self);
}
impl<T: Sized> ZeroSized for T {
const I_AM_ZERO_SIZED: () = [()][std::mem::size_of::<Self>()]; //~ WARN any use of this value
//~| WARN this was previously accepted by the compiler but is being phased out
fn requires_zero_size(self) {
let () = Self::I_AM_ZERO_SIZED; //~ ERROR erroneous constant encountered
println!("requires_zero_size called");
}
}
fn main() {
().requires_zero_size();
42_u32.requires_zero_size();
}
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