==(_:_:)

Declaration

static func == (lhs: AnyHashable, rhs: AnyHashable) -> Bool

Parameters

• lhs:

  A type-erased hashable value.

• rhs:

  Another type-erased hashable value.

Discussion

AnyHashable considers bridged counterparts (such as a String and an NSString) of the same value to be equivalent when type-erased. If those compatible types use different definitions for equality, values that were originally distinct might compare as equal when they are converted to AnyHashable:

let string1 = "café"
let string2 = "cafe\u{301}" // U+301 COMBINING ACUTE ACCENT
let nsString1 = string1 as NSString
let nsString2 = string2 as NSString
let typeErased1 = nsString1 as AnyHashable
let typeErased2 = nsString2 as AnyHashable
print(string1 == string2)         // prints "true"
print(nsString1 == nsString2)     // prints "false"
print(typeErased1 == typeErased2) // prints "true"