Issue Description:

We've been running in to very high memory usage and I think I've tracked it down. The following code will cause memory usage to continuously grow:

func checkIfNil(_ value: Any) -> Bool {
    switch value {
    case Optional<Any>.none: return true
    default: return false
    }
}

let wrapped = ("bar", Int?.some(2))
while true {
    checkIfNil(wrapped)
}

There are a few different type of tuples that trigger this:

• (String, Int?)

• (String?, Int?)

• (String?, Int?, Int)

• (String, Int, Int?)

• (String, Int?, Int?)

• (String, Int?, Int)

• (String?, Int, Int)

• (String, Int, Int)

The types within the tuple don't seem to matter, only the optionality seems to matter. The issue also occurs whether the tuple itself is optional or not.

There are also a few types that don't trigger this:

• (String?, Int)

• (String, Int)

Xcode's memory graph debugger shows the issue as coming from:

case Optional<Any>.none: return true

When the `value` is `nil` (e.g. `Wrapper<(String, Int?)>(value: nil)`) it does not cause a memory leak.

A workaround for this is to use `if case`:

if case Optional<Any>.none = value as Any {
    return true
} else {
    return false
}