Error code E0203
Having multiple relaxed default bounds is unsupported.
Erroneous code example:
#![allow(unused)] fn main() { struct Bad<T: ?Sized + ?Send>{ inner: T } }
Here the type T cannot have a relaxed bound for multiple default traits
(Sized and Send). This can be fixed by only using one relaxed bound.
#![allow(unused)] fn main() { struct Good<T: ?Sized>{ inner: T } }