Error code E0741
A non-structural-match type was used as the type of a const generic parameter.
Erroneous code example:
#![allow(unused)] #![feature(adt_const_params)] fn main() { struct A; struct B<const X: A>; // error! }
Only structural-match types, which are types that derive PartialEq and Eq
and implement ConstParamTy, may be used as the types of const generic
parameters.
To fix the previous code example, we derive PartialEq, Eq, and
ConstParamTy:
#![allow(unused)] #![feature(adt_const_params)] fn main() { use std::marker::ConstParamTy; #[derive(PartialEq, Eq, ConstParamTy)] // We derive both traits here. struct A; struct B<const X: A>; // ok! }