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yesod: src\System\Win32\Notify.hs:(136,1)-(146,45): Non-exhaustive patterns in function actsToEvent
The issue is triggered when there are multiple events occurs at once. There is no patterns to handle this case.
I found a blog post desribing the ReadDirectoryChangesW API :
Due to difficulties described there, I believe that the events handling code should be changed to just past all recieved events to a handler as is.
Rename events (FileRenamedOld and FileRenamedNew) are coming in separate batches at my box, so rename detection logic looks broken too. As for me, this logic can be dropped for now, as the primary use of the lib is to detect any changes.