func ~=<T>(pattern: KeyPath<T, Bool>, value: T) -> Bool {
    return value[keyPath: pattern]
}

let char: Character = "A"
switch char {
case \.isASCII:
    print("ASCII")
default:
    print("no match")
}

Fatal error: load from misaligned raw pointer
2019-03-26 22:07:57.578793+0100 repl_swift[64810:6294573] Fatal error: load from misaligned raw pointer
Process 64810 stopped
* thread #​1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #&#8203;0: 0x0000000101229073 libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage(_: Swift.StaticString, _: Swift.StaticString, file: Swift.StaticString, line: Swift.UInt, flags: Swift.UInt32) -> Swift.Never + 307
libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage(_: Swift.StaticString, _: Swift.StaticString, file: Swift.StaticString, line: Swift.UInt, flags: Swift.UInt32) -> Swift.Never:
->  0x101229073 <+307>: ud2
    0x101229075 <+309>: movq   %r12, %rdi
    0x101229078 <+312>: addq   $0x10, %rdi
    0x10122907c <+316>: cmpl   $0x80, %r14d
Target 0: (repl_swift) stopped.
char: Character = {
  _str = {
    _guts = {
      _object = {
        _countAndFlagsBits = <extracting data from value failed>

        _object = <extracting data from value failed>

      }
    }
  }
}
Execution interrupted. Enter code to recover and continue.
Enter LLDB commands to investigate (type :help for assistance.)

extension Character {
    var isASCII: Bool {
        return true
    }
}