is duplicated by:

• SR-309 Unable to coerce String -> NSString
• SR-5160 NSMutableCharacterSet cannot be coerced to CharacterSet under Linux
• SR-5404 Linux: Cannot cast NSData to Data

Issue Description:

Foundation in this build does include NSString but there's lots a caveats associated with it. It's not bridged to String as it is on OS X yet and I suspect (but haven't verified yet,) that most other Foundation objects that are bridged on OS X are not yet bridged on Linux. So casting as in the example below will fail:

3> let foo: NSString = "foo"
 foo: Foundation.NSString = \{
 Foundation.NSObject = \{}
 _cfinfo =

\{ info = 1920 pad = 0 }

_storage = "foo"
 }
 4> let bar = foo as String
 repl.swift:4:11: error: cannot convert value of type 'NSString' to type 'String' in coercion
 let bar = foo as String
 ^~~

While on OS X, it will do as expected:

3> let foo:NSString = "foo"
 foo: NSString = "foo"
 4> let bar = foo as String
 bar: String = "foo"

In order for the Linux version of Swift-repl to recognize Foundation, it needs to be invoked as follows:

%: swift -lFoundation <rest of the parameters>

This tells Swift that you're using Foundation and to link (-l) with the Foundation shared library. However, this is not needed on OS X.

Feel free to contact me if you have any questions,