Commits
Andrew Trick committed a8a49afd9ea
Add Builtin.isOptional. There was previously no way to detect a type that is nominally Optional at runtime. The standard library, namely OutputStream, needs to handle Optionals specially in order to cirumvent conversion to the Optional's wrapped type. This should be done with conditional conformance, but until that feature is available, Builtin.isOptional will serve as a useful crutch.