TraitConcat

Source

pub trait Concat<Item>where    Item: ?Sized,
{    typeOutput;    // Required method    fnconcat(slice: &Self) -> Self::Output;}

🔬This is a nightly-only experimental API. (slice_concat_trait #27747)

Expand description

Helper trait for[T]::concat.

Note: theItem type parameter is not used in this trait,but it allows impls to be more generic.Without it, we get this error:

error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica   --> library/alloc/src/slice.rs:608:6    |608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {    |      ^ unconstrained type parameter

This is because there could existV types with multipleBorrow<[_]> impls,such that multipleT types would apply:

pub structFoo(Vec<u32>, Vec<String>);implstd::borrow::Borrow<[u32]>forFoo {fnborrow(&self) ->&[u32] {&self.0}}implstd::borrow::Borrow<[String]>forFoo {fnborrow(&self) ->&[String] {&self.1}}