diff --git a/purescript.cabal b/purescript.cabal
--- a/purescript.cabal
+++ b/purescript.cabal
@@ -1,5 +1,5 @@
 name: purescript
-version: 0.4.12
+version: 0.4.12.1
 cabal-version: >=1.8
 build-type: Custom
 license: MIT
diff --git a/src/Language/PureScript/TypeChecker.hs b/src/Language/PureScript/TypeChecker.hs
--- a/src/Language/PureScript/TypeChecker.hs
+++ b/src/Language/PureScript/TypeChecker.hs
@@ -180,9 +180,10 @@
 typeCheckAll mainModuleName currentModule (d@(ImportDeclaration moduleName _ _) : rest) = do
   env <- getEnv
   let instances = filter (\tcd -> let Qualified (Just mn) _ = tcdName tcd in moduleName == mn) (typeClassDictionaries env)
-  forM_ instances $ \tcd -> do
-    let (Qualified _ ident) = tcdName tcd
-    addTypeClassDictionaries [tcd { tcdName = Qualified (Just currentModule) ident, tcdType = TCDAlias (canonicalizeDictionary tcd) }]
+  addTypeClassDictionaries [ tcd { tcdName = Qualified (Just currentModule) ident, tcdType = TCDAlias (canonicalizeDictionary tcd) }
+                           | tcd <- instances
+                           , let (Qualified _ ident) = tcdName tcd
+                           ]
   ds <- typeCheckAll mainModuleName currentModule rest
   return $ d : ds
 typeCheckAll mainModuleName moduleName (d@(TypeClassDeclaration pn args tys) : rest) = do