// check-pass #![feature(generic_const_exprs)] #![allow(incomplete_features)] use std::mem::size_of; struct Foo(T); impl Foo() }> { fn test() { let _: [u8; std::mem::size_of::()]; } } trait Bar { fn test_me(); } impl Bar<{ size_of::() }> for Foo { fn test_me() { let _: [u8; std::mem::size_of::()]; } } fn main() {}