[Haskell-cafe] unexpected behavior from filterM doesFileExist =<< getDirectoryContents

[Thomas Hartman]

Can somebody explain this?

> getDirectoryContents inD

["..","#sanity.txt#",".","sanity.txt","etc.txt","patchTagDir.txt","jail.txt","notjail.txt","alldata.txt","allobjs.txt","namesNSizes.txt"]

> filterM doesFileExist =<< getDirectoryContents inD

> ["sanity.txt"]