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generic associated type

An associated type that takes its own type or lifetime parameters.

A GAT (type Item<'a> where Self: 'a) lets a trait's associated type depend on a lifetime or type chosen per use, as in lending iterators.

Examples

  • type Item<'a> where Self: 'a; lets a trait's item borrow from &'a mut self, which Iterator's plain type Item can't express.

See also

associated type lending iterator lifetime parameter
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