kishikawakatsumi

extension String.StringInterpolation { mutating func appendInterpolation<T>(_ val: T?, default defaultValue: String) { if let val = val { appendInterpolation(val) } else { defaultValue.write(to: &self) } } } let value: Int? = nil print("The value is: \(value, default: "<nil>")")

Version:

swift-DEVELOPMENT-SNAPSHOT-2018-12-15-a

Output:

Error:

Stack dump: 0. Program arguments: /usr/bin/swift -frontend -interpret /usercode/main.swift -disable-objc-interop -module-name main /usr/bin/swift[0x4608a04] /usr/bin/swift[0x46067d0] /usr/bin/swift[0x4608bb2] /lib/x86_64-linux-gnu/libpthread.so.0(+0x11390)[0x7f5500154390] [0x7f55005834e8] [0x7f5500583343] [0x7f550058313a] /usr/bin/swift[0xcec7de] /usr/bin/swift[0xcf09f2] /usr/bin/swift[0x515eff] /usr/bin/swift[0x4eae3e] /usr/bin/swift[0x4e6712] /usr/bin/swift[0x48db1e] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f54fe87e830] /usr/bin/swift[0x48b959] Segmentation fault (core dumped)