diff --git a/purescript.cabal b/purescript.cabal
--- a/purescript.cabal
+++ b/purescript.cabal
@@ -1,5 +1,5 @@
 name: purescript
-version: 0.4.11
+version: 0.4.11.1
 cabal-version: >=1.8
 build-type: Custom
 license: MIT
diff --git a/src/Language/PureScript/Optimizer/Common.hs b/src/Language/PureScript/Optimizer/Common.hs
--- a/src/Language/PureScript/Optimizer/Common.hs
+++ b/src/Language/PureScript/Optimizer/Common.hs
@@ -47,7 +47,7 @@
   check _ = False
 
 isRebound :: (Data d) => JS -> d -> Bool
-isRebound js d = any (`isReassigned` d) (everything (++) (mkQ [] variablesOf) js)
+isRebound js d = any (\v -> isReassigned v d || isUpdated v d) (everything (++) (mkQ [] variablesOf) js)
   where
   variablesOf (JSVar var) = [var]
   variablesOf _ = []
diff --git a/src/Language/PureScript/Pretty/Values.hs b/src/Language/PureScript/Pretty/Values.hs
--- a/src/Language/PureScript/Pretty/Values.hs
+++ b/src/Language/PureScript/Pretty/Values.hs
@@ -72,7 +72,7 @@
     , withIndent $ prettyPrintMany prettyPrintDoNotationElement els
     , currentIndent
     ]
-  match (TypeClassDictionary _ _) = error "Type class dictionary was not replaced"
+  match (TypeClassDictionary _ _) = return "<<dict>>"
   match (TypedValue _ val _) = prettyPrintValue' val
   match (PositionedValue _ val) = prettyPrintValue' val
   match _ = mzero