diff --git a/Test/Control.hs b/Test/Control.hs
--- a/Test/Control.hs
+++ b/Test/Control.hs
@@ -74,10 +74,10 @@
       input9 = Control {unControl = [Paragraph [Field ("Field1", " field1 content\n"), Field ("Field2", " an actual second field")]]} :: Control' String
       -- parsed9buggy = Control {unControl = [Paragraph [Field ("Field1"," field1 content")],Paragraph [Field ("Field2"," an actual second field")]]} :: Control' String
       expected9 =    Control {unControl = [Paragraph [Field ("Field1"," field1 content"),Field ("Field2"," an actual second field")]]}
-      (Right parsed6) = parseControl "string" (prettyShow input6) :: Either ParseError (Control' String)
-      (Right parsed7) = parseControl "string" (prettyShow input7) :: Either ParseError (Control' String)
-      (Right parsed8) = parseControl "string" (prettyShow input8) :: Either ParseError (Control' String)
-      (Right parsed9) = parseControl "string" (prettyShow input9) :: Either ParseError (Control' String)
+      parsed6 = either (error . show) id $ (parseControl "string" (prettyShow input6) :: Either ParseError (Control' String))
+      parsed7 = either (error . show) id $ (parseControl "string" (prettyShow input7) :: Either ParseError (Control' String))
+      parsed8 = either (error . show) id $ (parseControl "string" (prettyShow input8) :: Either ParseError (Control' String))
+      parsed9 = either (error . show) id $ (parseControl "string" (prettyShow input9) :: Either ParseError (Control' String))
 
 -- | These paragraphs have no terminating newlines.  They are added
 -- where appropriate to the expected test results.
diff --git a/debian.cabal b/debian.cabal
--- a/debian.cabal
+++ b/debian.cabal
@@ -1,6 +1,6 @@
 cabal-version:  3.0
 Name:           debian
-Version:        4.1
+Version:        4.1.1
 License:        BSD-3-Clause
 License-File:   debian/copyright
 Author:         David Fox <dsf@seereason.com>, Jeremy Shaw <jeremy@seereason.com>, Clifford Beshers <beshers@seereason.com>
@@ -30,7 +30,6 @@
    Cabal >= 2.2.0.1,
    containers,
    directory >= 1.2.3.0,
-   either,
    exceptions,
    filepath,
    hostname,
@@ -38,18 +37,14 @@
    lens,
    ListLike >= 4.3.5,
    mtl,
-   old-locale,
    ordered-containers >= 0.2,
    parsec >= 2 && <4,
    pretty >= 1.1.2,
    process,
-   process-extras >= 0.2.0,
    pureMD5,
-   QuickCheck,
    regex-compat,
    regex-tdfa,
    SHA,
-   syb,
    template-haskell,
    temporary,
    text,
@@ -57,7 +52,6 @@
    th-orphans,
    time,
    unix,
-   utf8-string,
    zlib
  if flag(network-uri)
    Build-Depends: network-uri >= 2.6
diff --git a/src/Debian/Apt/Dependencies.hs b/src/Debian/Apt/Dependencies.hs
--- a/src/Debian/Apt/Dependencies.hs
+++ b/src/Debian/Apt/Dependencies.hs
@@ -131,7 +131,7 @@
 
 -- |JAS: deal with 'Provides' (can a package provide more than one package?)
 conflict' :: (BinPkgName, DebianVersion) -> Relation -> Bool
-conflict' (pName, pVersion) (Rel pkgName mVersionReq _) =
+conflict' (pName, pVersion) (RRel pkgName mVersionReq _ _) =
     (pName == pkgName) && (checkVersionReq mVersionReq (Just pVersion))
 
 
@@ -274,7 +274,6 @@
     | (not (lastvar `elem` c)) && null m = cs
     | null c && null m = ([],[]) -- is this case ever used?
     | otherwise = combine csp ns ((c, m):acc)
-    where lastvar =
-              let (_,(p:_)) = s in (packageVersion csp) p
-
-
+    where lastvar = case s of
+                        (_, p:_) -> packageVersion csp p
+                        _        -> error "combine: empty stack"
diff --git a/src/Debian/Control/ByteString.hs b/src/Debian/Control/ByteString.hs
--- a/src/Debian/Control/ByteString.hs
+++ b/src/Debian/Control/ByteString.hs
@@ -116,8 +116,11 @@
              Nothing -> Left (newErrorMessage (Message ("Failed to parse " ++ sourceName)) (newPos sourceName 0 0))
              Just (cntl,_) -> Right cntl
     lookupP fieldName (Paragraph fields) =
-        let pFieldName = C.pack (map toLower fieldName) in
-        find (\ (Field (fieldName',_)) -> C.map toLower fieldName' == pFieldName) fields
+        let pFieldName = C.pack (map toLower fieldName)
+            matches (Field (fieldName', _)) = C.map toLower fieldName' == pFieldName
+            matches (Comment _) = False
+        in find matches fields
+
     -- NOTE: probably inefficient
     stripWS = C.reverse . strip . C.reverse . strip
         where strip = C.dropWhile (flip elem [' ', '\t'])
diff --git a/src/Debian/GenBuildDeps.hs b/src/Debian/GenBuildDeps.hs
--- a/src/Debian/GenBuildDeps.hs
+++ b/src/Debian/GenBuildDeps.hs
@@ -149,8 +149,8 @@
                         , allBlocked = List.map ofVertex blocked }
     where
       makeReady :: [Vertex] -> [Vertex] -> Vertex -> ReadyTarget a
-      makeReady blocked ready thisReady =
-          let otherReady = filter (/= thisReady) ready
+      makeReady blocked ready' thisReady =
+          let otherReady = filter (/= thisReady) ready'
               (directlyBlocked, otherBlocked) = partition (\ x -> elem x (reachable isDep thisReady)) blocked in
           ReadyTarget { ready = ofVertex thisReady
                       , waiting = List.map ofVertex directlyBlocked
@@ -215,6 +215,7 @@
       sccCycles t = mapMaybe addBackEdge (treePaths t)
 
       addBackEdge :: [Vertex] -> Maybe [Edge]
+      addBackEdge [] = Nothing
       addBackEdge path@(root : _) =
           let back = (last path, root) in
           if elem back (edges g) then Just (pathEdges (path ++ [root])) else Nothing
diff --git a/src/Debian/Relation.hs b/src/Debian/Relation.hs
--- a/src/Debian/Relation.hs
+++ b/src/Debian/Relation.hs
@@ -13,6 +13,7 @@
     , ArchOS(..)
     , ArchCPU(..)
     , VersionReq(..)
+    , RestrictionList
     -- * Helper Functions
     , checkVersionReq
     -- * Relation Parser
@@ -21,5 +22,5 @@
     ) where
 
 import Debian.Arch (Arch(..), ArchOS(..), ArchCPU(..))
-import Debian.Relation.Common (SrcPkgName(..), BinPkgName(..), PkgName(pkgNameFromString))
+import Debian.Relation.Common (SrcPkgName(..), BinPkgName(..), PkgName(pkgNameFromString), RestrictionList)
 import Debian.Relation.String