Open Radar

 
Summary:
Attempts to use dispatch_semaphore_create() in a Swift playground lead to an unrecoverable error.

Steps to Reproduce:
Paste this code into a new Swift playground:


import Foundation

let sem = dispatch_semaphore_create(0)


Expected Results:
Playground should display some sort of value for the sem variable, and allow additional code to use that value.

Actual Results:
Console Output contains the following text:

fatal error: Can't unwrap Optional.None
Playground execution failed: error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been left at the point where it was interrupted, use "thread return -x" to return to the state before expression evaluation.
* thread #1: tid = 0x1bd9b3, 0x000000010dfd802d libswift_stdlib_core.dylib`Swift._StringCore._growBuffer (@inout Swift._StringCore)(Swift.Int, minElementWidth : Swift.Int) -> Swift.COpaquePointer + 813, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x000000010dfd802d libswift_stdlib_core.dylib`Swift._StringCore._growBuffer (@inout Swift._StringCore)(Swift.Int, minElementWidth : Swift.Int) -> Swift.COpaquePointer + 813
    frame #1: 0x000000010dfd343f libswift_stdlib_core.dylib`Swift._StringCore.append (@inout Swift._StringCore)(Swift._StringCore) -> () + 607
    frame #2: 0x000000010dfd3fa5 libswift_stdlib_core.dylib`Swift.+ @infix (Swift.String, Swift.String) -> Swift.String + 117
    frame #3: 0x000000010e195a97 PlaygroundLogger`Swift.String._workaround17041741 (Swift.String)() -> Swift.String + 87
    frame #4: 0x000000010e1948e2 PlaygroundLogger`Swift.String.byteLength (Swift.String)() -> Swift.Int + 82
    frame #5: 0x000000010e18617f PlaygroundLogger`PlaygroundLogger.BytesStream.write (PlaygroundLogger.BytesStream)(Swift.String) -> PlaygroundLogger.BytesStream + 127
    frame #6: 0x000000010e18ddbf PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_structured_impl (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64, Swift.Array<Swift.Range<Swift.UInt64>>...) -> () + 2143
    frame #7: 0x000000010e188e0c PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_structured (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64, PlaygroundLogger.LoggerCappingPolicy) -> () + 1996
    frame #8: 0x000000010e189e7d PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_structured (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64) -> () + 989
    frame #9: 0x000000010e18f856 PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64) -> () + 2486
    frame #10: 0x000000010e18a899 PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_children (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64, Swift.Range<Swift.UInt64>) -> () + 2233
    frame #11: 0x000000010e18e96a PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_structured_impl (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64, Swift.Array<Swift.Range<Swift.UInt64>>...) -> () + 5130
    frame #12: 0x000000010e188e0c PlaygroundLogger`PlaygroundLogger.PlaygroundObjectWriter.encode_structured (PlaygroundLogger.PlaygroundObjectWriter)(Swift.Mirror, Swift.UInt64, PlaygroundLo

Version:
Xcode Version 6.0 (6A215l)