Pattern matching for types. See https://twitter.com/Gernot/status/918490645118976000 for context.

type-pattern-matching.swift

func ~= <T, U> (pattern: T.Type, value: U.Type) -> Bool {
    return pattern == value
}

func f<T>(_ type: T.Type) {
    switch T.self {
    case Int.self:
        print("Int")
    default:
        print("Something else")
    }
}

f(Int.self)
f(String.self)