# Error code E0367

An attempt was made to implement `Drop` on a specialization of a generic type.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    trait Foo {}

    struct MyStruct<T> {
        t: T
    }

    impl<T: Foo> Drop for MyStruct<T> {
        fn drop(&mut self) {}
    }
    }

This code is not legal: it is not possible to specialize `Drop` to a subset of implementations of a generic type. In order for this code to work, `MyStruct` must also require that `T` implements `Foo`. Alternatively, another option is to wrap the generic type in another that specializes appropriately:

    #![allow(unused)]
    fn main() {
    trait Foo{}

    struct MyStruct<T> {
        t: T
    }

    struct MyStructWrapper<T: Foo> {
        t: MyStruct<T>
    }

    impl <T: Foo> Drop for MyStructWrapper<T> {
        fn drop(&mut self) {}
    }
    }