Debugger (LLDB)

The debugger doesn't use description to print values -- which kind of makes sense, since not every value is guaranteed to have that property.

Whatever internal LLVM function it does use, though, is notoriously unreliable. (For a few years, it printed file URLs as "ile".) Be very careful trusting anything it prints that isn't a string or number. For example, an Optional that prints as nil might not be Optional<T>.none:

> import Foundation
> URL(string: "\n")
$R0: URL? = nil
> URL(string: "http://")
$R1: URL? = nil
> $R0 == nil
$R2: Bool = true
> $R1 == nil
$R3: Bool = false