Open Radar

 
Summary:
Many functional languages treat constructors the same as any other function: they take a set of parameters of certain types, and return a single value of the expected type. This allows passing constructors anywhere where the parameter and return types match.

Switch treats types and constructors of those types as special non-functional entities. While their calling syntax looks like a function call, they can’t be referenced as functions themselves.

This means, for instance, that to convert an `Int?` to a `UInt?`, I must wrap the UInt constructor in a block: `maybeInt.map({ UInt($0)})`. It would be much nicer to more succinctly type `maybeInt.map(UInt)`, or at least, `maybeInt.map(UInt.init)`.

Steps to Reproduce:
let i: Int? = 200
let g = i.map(UInt.init)

Expected Results:
The code compiles

Actual Results:
“Initializer cannot be referenced without arguments”

Regression:
Many of the functional languages (or even not-particularly-functional, like Python) Swift has heritage from allow references initializers as functions.