Override Swift function by extension

overwrite_function.swift

// hm... override function implementation. This may be unexpected.

public extension String {
	// wait wait wait... why no error here?
	// String already have `public func hasPrefix(_ prefix: String) -> Bool` in stdlib
	// https://github.com/apple/swift/blob/caa173b27a34a26f82a15ccc76cf4d8f95587637/stdlib/public/core/StringLegacy.swift#L143
	public func hasPrefix(_ prefix: String) -> Bool {
		return true // fake it till you make it
	}
}

let s = "abcd"
if s.hasPrefix("oooo") {
	print("hasPrefix true")
}