relates to:

• SR-11992 Unused variables in lazy properties should generate a warning

Issue Description:

In the code below, var x = 42 appropriately gives us an 'x' was never mutated warning. However, the var z = 42 does not.

class Foo {
    lazy var y: Int = {
        var z = 42
        return z
    }()

    func run() {
        var x = 42 // Variable 'x' was never mutated; consider changing to 'let' constant
        print("\(x)")
    }
}

Variables never mutated in lazy properties should produce the never mutated variable warning.