error[E0080]: evaluation of constant value failed --> $DIR/const-evalutation-ice.rs:10:22 | LL | pub const N: usize = 0 - (mem::size_of::() != 400) as usize; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to compute `0_usize - 1_usize`, which would overflow error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0080`.