Open Radar

 
Summary:
Playing with the predefined comparison operators for optionals, I noticed the following strange behavior in Swift 2.1:

let a = 42
let b: Int? = nil

42 < nil    ==> false
nil > 42    ==> false
42 + 0 < nil    ==> error: value of type 'Int' can never be nil, comparison isn't allowed
nil > 42 + 0    ==> false
42 < b    ==> false
b > 42    ==> false
a < b    ==> false
b > a    ==> false
a < nil    ==> error: value of type 'Int' can never be nil, comparison isn't allowed
nil > a    ==> error: type of expression is ambiguous without more context
-a < nil    ==> false
nil > -a    ==> false
a + 0 < nil    ==> error: ambiguous use of operator '+'
nil > a + 0    ==> false
Double.infinity < nil    ==> error: value of type ’Double’ can never be nil, comparison isn't allowed
-Double.infinity < nil    ==> false

I’m now very confused.

Steps to Reproduce:

Evaluate the above expressions using “xcrun swift” or in an Xcode playground.

Expected Results:
All expressions compile cleanly (or, even better, none of them do).

Actual Results:
Some of the expressions result in compiler errors. This is highly unintuitive.

Regression:
Unknown

Notes:

$ swift
Welcome to Apple Swift version 2.1 (700.1.101.6 700.1.76). Type :help for assistance.