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# Error code E0203

Having duplicate relaxed default bounds is unsupported.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    struct Bad<T: ?Sized + ?Sized>{
        inner: T,
    }
    }

Here the type parameter `T` cannot have duplicate relaxed bounds for default trait `Sized`. This can be fixed by only using one relaxed bound:

    #![allow(unused)]
    fn main() {
    struct Good<T: ?Sized>{
        inner: T
    }
    }