Why my Swift code explodes when comparing upper to lower case? - swift

Question

I'm actually learning swift and I'm testing the switch control flow. I try this code on IBM Swift Sandbox:
let const = "Z"
switch const {
case "a" ,
"A": print("La primera letra del abecedario")
case "z": print("La ultima letra del abecedario")
default: print("NPI de que letra se trate")
}
It all works fine, tested with const = {"a","A","f","z"}. But when const is "Z" i get this error:
terminate called after throwing an instance of 'std::system_error'
what(): Resource temporarily unavailable
0 swift-build-tool 0x000000000050bade llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 46
1 swift-build-tool 0x000000000050ca49
2 swift-build-tool 0x000000000050cd53
3 libpthread.so.0 0x00007f960ca22330
4 libc.so.6 0x00007f960bc5fc37 gsignal + 55
5 libc.so.6 0x00007f960bc63028 abort + 328
6 libstdc++.so.6 0x00007f960c56a535 __gnu_cxx::__verbose_terminate_handler() + 341
7 libstdc++.so.6 0x00007f960c5686d6
8 libstdc++.so.6 0x00007f960c568703
9 libstdc++.so.6 0x00007f960c568922
10 libstdc++.so.6 0x00007f960c5ba800 std::__throw_system_error(int) + 128
11 libstdc++.so.6 0x00007f960c5bbd68 std::thread::_M_start_thread(std::shared_ptr<std::thread::_Impl_base>) + 584
12 swift-build-tool 0x0000000000494d6d
13 swift-build-tool 0x0000000000494b0d
14 swift-build-tool 0x0000000000494a01 llbuild::buildsystem::createLaneBasedExecutionQueue(llbuild::buildsystem::BuildExecutionQueueDelegate&, int) + 49
15 swift-build-tool 0x0000000000490ba8 llbuild::buildsystem::BuildSystemFrontendDelegate::createExecutionQueue() + 264
16 swift-build-tool 0x00000000004b98e9
17 swift-build-tool 0x00000000004b9823 llbuild::buildsystem::BuildSystem::build(llvm::StringRef) + 67
18 swift-build-tool 0x000000000049150d llbuild::buildsystem::BuildSystemFrontend::build(llvm::StringRef) + 1405
19 swift-build-tool 0x000000000048e086
20 swift-build-tool 0x000000000048dc7a main + 170
21 libc.so.6 0x00007f960bc4af45 __libc_start_main + 245
22 swift-build-tool 0x000000000048db04
swift-build: error: Child process exited with signal

Answer 1

Trying your code in the Sandbox now, it looks like it works just fine with const = "Z". This was an error on the Sandbox end, it looks like. We were having issues with a handful of our servers over the holidays, and we're working on getting them fixed. Your code seems to be correct.