Swift：使用where子句扩展类以符合协议

Question

I am trying to extend a specific type of Array, so as to conform to an existing protocol.

extension Array where Element == Int : ProtocolX { }

But the compiler complains that

Closure expression is unused

How do i go about implementing a protocol for a type with certain criteria?

Answer 1

声明条件一致性时，协议一致性需要放在where子句之前。

extension Array: ProtocolX where Element == Int { }