Implementing `ExpressibleByStringLiteral`: can use either type `StringLiteralType`,`StaticString` or `String` to implement the require init

[xwu (Xiaodi Wu)]

@young

Why StringLiteralType can be used? It's associatedtype StringLiteralType . So how does the compiler infer what is StringLiteralType ?

@young

So I was wondering how did the compiler infer what StringLiteralType is?

You're not looking at the right StringLiteralType. There's a default literal typealias:

StringLiteralType | Apple Developer Documentation

By conforming to ExpressibleByStringLiteral with an initializer that takes an argument of type StringLiteralType, what you're doing is allowing Foo.StringLiteralType to be inferred as StringLiteralType (aka String, unless you shadow the typealias with another value).