exit status: 134 with stderr:
swift-frontend: /home/buildnode/jenkins/workspace/oss-swift-package-linux-ubuntu-16_04/swift/lib/Sema/CSApply.cpp:4968: swift::Expr *(anonymous namespace)::ExprRewriter::visitKeyPathExpr(swift::KeyPathExpr *): Assertion `leafTy->getOptionalObjectType()->isEqual( componentTy->getWithoutSpecifierType())' failed. 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 -new-driver-path /usr/bin/swift-driver -resource-dir /usr/lib/swift -Xllvm -enable-swifttailcc-musttail-check -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/include -Xcc -fmodule-map-file=/Libraries/.build/x86_64-unknown-linux-gnu/debug/CNIOHTTPParser.build/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/swift-nio/Sources/CNIOHTTPParser/include -Xcc -fmodule-map-file=/Libraries/.build/x86_64-unknown-linux-gnu/debug/CNIOAtomics.build/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/swift-nio/Sources/CNIOAtomics/include -Xcc -fmodule-map-file=/Libraries/.build/checkouts/swift-nio/Sources/CNIOWindows/include/module.modulemap -Xcc -I -Xcc /Libraries/.build/checkouts/swift-nio/Sources/CNIOWindows/include -Xcc -fmodule-map-file=/Libraries/