Any

The any type is a built-in type and is represented by the any keyword. It can hold any data type and might be nil. Because its type is ambiguous at comptime, it can accept assignments from different types and, once assigned, can be reassigned with a different type.

It only supports equals (==) and not equals (!=) operators. Panics if the type is incomparable.

x == nil: true if any is nil, not checks whether data is nil
x == y: true if x and y is nil
x == y: true if x and y has same data type and returns true of equals operator of data type for two value

Supports casting to any type. You can get type-safe value of any with casting. For example:

let myAny: any = 10
let x = (int)(myAny)

any type protects itself against mutability if necessary. For example, you have a slice value held by any-typed variable. And your variable is immutable. So, if you cast your value to slice for assignment to a mutable variable, you will get an error. Because a slice is a mutable type, it's breaking immutability.