Our nightly master branch build on s390x failed with the following error: 09:09:39 /home/swiftbuild/workspace/Swift/CONFIG/FIVE/GIT_BRANCH/master/label/csz25097/swift/lib/Parse/Lexer.cpp:2460:17: error: overflow converting case value to switch condition type (-2 to 254) [-Werror,-Wswitch] 09:09:39 case -1: case -2: 09:09:39 ^ 09:09:39 /home/swiftbuild/workspace/Swift/CONFIG/FIVE/GIT_BRANCH/master/label/csz25097/swift/lib/Parse/Lexer.cpp:2460:8: error: overflow converting case ...