Open Radar

 
Summary:
When using a closed range in a switch case, and then end of the range is the maximum value for the variable type (e.g.: 0xFF for UInt8, 0xFFFF for UIn16, etc...), the application will crash at runtime when reaching the switch

Steps to Reproduce:
Sample code

let a: UInt8 = 0 // Any number here, doesn't matter
switch a {
case 0xF0...0xFF: // Any start value, doesn't matter
    println("a")
default:
    break
}

Expected Results:
Switch is executed correctly

Actual Results:
Console output:

fatal error: Range end index has no valid successor

Exception stack:

* thread #1: tid = 0x29ac1, 0x000000010589e0de libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> () + 158, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x000000010589e0de libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> () + 158
    frame #1: 0x0000000105dfc4d3 $__lldb_expr332`main + 1235 at playground332.swift:9
    frame #2: 0x0000000105673230 MyPlayground`_mh_execute_header + 25136
    frame #3: 0x00000001056757f1 MyPlayground`reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 17
    frame #4: 0x0000000105674a51 MyPlayground`partial apply forwarder for reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 81
    frame #5: 0x0000000105675870 MyPlayground`reabstraction thunk helper from @callee_owned (@in ()) -> (@out ()) to @callee_owned () -> (@unowned ()) + 32
    frame #6: 0x00000001056758a7 MyPlayground`reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @objc_block () -> (@unowned ()) + 39
    frame #7: 0x00007fff8d5992ac CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #8: 0x00007fff8d58b3b5 CoreFoundation`__CFRunLoopDoBlocks + 341
    frame #9: 0x00007fff8d58ab6e CoreFoundation`__CFRunLoopRun + 910
    frame #10: 0x00007fff8d58a598 CoreFoundation`CFRunLoopRunSpecific + 296
    frame #11: 0x00007fff90b2cc4f HIToolbox`RunCurrentEventLoopInMode + 235
    frame #12: 0x00007fff90b2c8ce HIToolbox`ReceiveNextEventCommon + 179
    frame #13: 0x00007fff90b2c80b HIToolbox`_BlockUntilNextEventMatchingListInModeWithFilter + 71
    frame #14: 0x00007fff8c776a91 AppKit`_DPSNextEvent + 964
    frame #15: 0x00007fff8c776090 AppKit`-[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 194
    frame #16: 0x00007fff8c76bd93 AppKit`-[NSApplication run] + 594
    frame #17: 0x00000001056735a5 MyPlayground`main + 885
    frame #18: 0x00007fff8e5da5c9 libdyld.dylib`start + 1