Try to group several random words and at some point you will get this error in the backend:

CallStack (from HasCallStack): error, called at src/Data/Patch/Class.hs:798:42 in patches-class-0.1.0.1-9wH919WBVFCJ9FksVhtLTV:Data.Patch.Class transformWith/MaybePatch CallStack (from HasCallStack): error, called at src/Data/Patch/Class.hs:798:42 in patches-class-0.1.0.1-9wH919WBVFCJ9FksVhtLTV:Data.Patch.Class