diff --git a/shake-ext.cabal b/shake-ext.cabal
--- a/shake-ext.cabal
+++ b/shake-ext.cabal
@@ -1,5 +1,5 @@
 name:                shake-ext
-version:             2.0.0.5
+version:             2.1.0.0
 synopsis:            Helper functions for linting with shake 
 description:         This package provides several linters out of the box, for use with [shake](http://shakebuild.com/).
 homepage:            https://hub.darcs.net/vmchale/shake-ext
diff --git a/src/Development/Shake/Cabal.hs b/src/Development/Shake/Cabal.hs
--- a/src/Development/Shake/Cabal.hs
+++ b/src/Development/Shake/Cabal.hs
@@ -1,4 +1,5 @@
 module Development.Shake.Cabal ( getCabalDeps
+                               , getCabalDepsV
                                ) where
 
 import           Control.Arrow
@@ -13,7 +14,7 @@
 import           Distribution.Verbosity
 
 libraryToFiles :: Library -> [FilePath]
-libraryToFiles lib = cs <> is <> (toFilePath <$> explicitLibModules lib)
+libraryToFiles lib = cs <> is <> ((<> ".hs" . toFilePath <$> explicitLibModules lib)
     where (cs, is) = (cSources &&& includes) $ libBuildInfo lib
 
 extract :: CondTree a b Library -> [Library]
@@ -21,8 +22,8 @@
 extract (CondNode d _ bs) = d : (g =<< bs)
     where g (CondBranch _ tb fb) = join $ catMaybes [Just $ extract tb, extract <$> fb]
 
--- | Get library dependencies from a @.cabal@ file. Note that these will be
--- extension-less,
+-- | Get library dependencies from a @.cabal@ file. This will only work for
+-- @.hs@ files; module signatures are not supported.
 getCabalDeps :: FilePath -> IO [FilePath]
 getCabalDeps = getCabalDepsV normal