exit status: 4 with stderr:
main/<stdin>:4: Fatal error: preconditionFailure! Current stack trace: 0 libswiftCore.so 0x00007f1c29b157b0 swift_reportError + 50 1 libswiftCore.so 0x00007f1c29b89d30 _swift_stdlib_reportFatalErrorInFile + 112 2 libswiftCore.so 0x00007f1c29873320 _assertionFailure(_:_:file:line:flags:) + 1329 5 swift-frontend 0x00000000005a07e5 <unavailable> + 1705957 6 swift-frontend 0x000000000056a1de <unavailable> + 1483230 7 swift-frontend 0x000000000053a902 <unavailable> + 1288450 8 swift-frontend 0x0000000000539f6c <unavailable> + 1285996 9 swift-frontend 0x000000000052e445 <unavailable> + 1238085 10 swift-frontend 0x00000000004b8d98 <unavailable> + 757144 11 libc.so.6 0x00007f1c2bbc4740 __libc_start_main + 240 12 swift-frontend 0x00000000004b8869 <unavailable> + 755817 Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the project and the crash backtrace. Stack dump: 0. Program arguments: /usr/bin/swift-frontend -frontend -interpret - -disable-objc-interop -I /Libraries/.build/x86_64-unknown-linux-gnu/debug -module-cache-path /Libraries/.build/x86_64-unknown-linux-gnu/debug/ModuleCache -D DEBUG -Xcc -fmodule-map-file=/Libraries/.build/checkouts/SwiftBacktrace/Sources/CSwiftBacktrace/include/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/SwiftBacktrace/Sources/CSwiftBacktrace/include -Xcc -fmodule-map-file=/Libraries/.build/checkouts/SwiftBacktrace/Sources/Clibunwind/include/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/SwiftBacktrace/Sources/Clibunwind/include -Xcc -fmodule-map-file=/Libraries/.build/x86_64-unknown-linux-gnu/debug/CNIOSHA1.build/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/swift-nio/Sources/CNIOSHA1/includ