All the methods in Foundation classes
NSMutableDictionary have been precisely mapped to Swift thus improving conversion results when converting code which calls these methods.
Improved code conversion while converting methods which take in
NSMutable type objects parameters. Try it!
Improved converter speed when dealing with code having very high nested method calls. This results in these conversions not timing out and failing. Try it!
Improved scope awareness, the local variable type is effective for only the current scope. Try it!
These changes improve the quality of converted code and reduce conversion failure rates.