diff --git a/common/Pass.hs b/common/Pass.hs
index 188ee5b..bc758dd 100644
--- a/common/Pass.hs
+++ b/common/Pass.hs
@@ -42,7 +42,7 @@ instance Die PassM where
 type Pass = A.Process -> PassM A.Process
 
 -- | Compose a list of passes into a single pass.
-runPasses :: [(String, Pass)] -> A.Process -> PassM A.Process
+runPasses :: [(String, Pass)] -> Pass
 runPasses [] ast = return ast
 runPasses ((s, p):ps) ast
     =  do debug $ "{{{ " ++ s
@@ -83,7 +83,7 @@ veryDebug :: (CSM m, MonadIO m) => String -> m ()
 veryDebug = verboseMessage 3
 
 -- | Dump the AST and parse state.
-debugAST :: (CSM m, MonadIO m) => A.Process -> m ()
+debugAST :: (CSM m, MonadIO m, Data t) => t -> m ()
 debugAST p
     =  do veryDebug $ "{{{ AST"
           veryDebug $ pshow p
diff --git a/transformations/SimplifyComms.hs b/transformations/SimplifyComms.hs
index 29a2c43..17ef40b 100644
--- a/transformations/SimplifyComms.hs
+++ b/transformations/SimplifyComms.hs
@@ -29,7 +29,7 @@ import Metadata
 import Types
 import Pass
 
-simplifyComms :: A.Process -> PassM A.Process
+simplifyComms :: Pass
 simplifyComms = runPasses passes
   where
     passes =
diff --git a/transformations/SimplifyExprs.hs b/transformations/SimplifyExprs.hs
index 922c709..0177f34 100644
--- a/transformations/SimplifyExprs.hs
+++ b/transformations/SimplifyExprs.hs
@@ -30,7 +30,7 @@ import Metadata
 import Pass
 import Types
 
-simplifyExprs :: A.Process -> PassM A.Process
+simplifyExprs :: Pass
 simplifyExprs = runPasses passes
   where
     passes =
diff --git a/transformations/SimplifyProcs.hs b/transformations/SimplifyProcs.hs
index b5d22b5..4b0a3c2 100644
--- a/transformations/SimplifyProcs.hs
+++ b/transformations/SimplifyProcs.hs
@@ -28,7 +28,7 @@ import Metadata
 import Types
 import Pass
 
-simplifyProcs :: A.Process -> PassM A.Process
+simplifyProcs :: Pass
 simplifyProcs = runPasses passes
   where
     passes =
diff --git a/transformations/SimplifyTypes.hs b/transformations/SimplifyTypes.hs
index a0f3184..548f2fe 100644
--- a/transformations/SimplifyTypes.hs
+++ b/transformations/SimplifyTypes.hs
@@ -26,7 +26,7 @@ import qualified AST as A
 import Pass
 import Types
 
-simplifyTypes :: A.Process -> PassM A.Process
+simplifyTypes :: Pass
 simplifyTypes = runPasses passes
   where
     passes =
@@ -46,10 +46,6 @@ resolveNamedTypes = doGeneric `extM` doType
     doType t = doGeneric t
 
 -- | Resolve named types in CompState.
-rntState :: A.Process -> PassM A.Process
-rntState p
-    =  do st <- get
-          st' <- resolveNamedTypes st
-          put st'
-          return p
+rntState :: Data t => t -> PassM t
+rntState p = (get >>= resolveNamedTypes >>= put) >> return p
 
diff --git a/transformations/Unnest.hs b/transformations/Unnest.hs
index 02321fa..f0ba51f 100644
--- a/transformations/Unnest.hs
+++ b/transformations/Unnest.hs
@@ -32,7 +32,7 @@ import Metadata
 import Pass
 import Types
 
-unnest :: A.Process -> PassM A.Process
+unnest :: Pass
 unnest = runPasses passes
   where
     passes =