diff --git a/Dockerfile b/Dockerfile
index c59a58e556..15991d1b05 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,7 +15,7 @@ COPY Tests Tests/
 COPY Package.* ./
 
 RUN swift package update
-ARG SWIFT_FLAGS="-c release -Xswiftc -static-stdlib -Xlinker -l_CFURLSessionInterface -Xlinker -l_CFXMLInterface -Xlinker -lcurl -Xlinker -lxml2 -Xswiftc -I. -Xlinker -fuse-ld=lld -Xlinker -L/usr/lib/swift/linux"
+ARG SWIFT_FLAGS="-c debug -Xswiftc -static-stdlib -Xlinker -l_CFURLSessionInterface -Xlinker -l_CFXMLInterface -Xlinker -lcurl -Xlinker -lxml2 -Xswiftc -I. -Xlinker -fuse-ld=lld -Xlinker -L/usr/lib/swift/linux"
 RUN swift build $SWIFT_FLAGS --product swiftlint
 RUN mv `swift build $SWIFT_FLAGS --show-bin-path`/swiftlint /usr/bin