diff --git a/src/THInstanceReification.hs b/src/THInstanceReification.hs
--- a/src/THInstanceReification.hs
+++ b/src/THInstanceReification.hs
@@ -35,23 +35,29 @@
 -- It simply considers them to be true.
 typesSatisfyDecConstraints :: [Type] -> InstanceDec -> Q Bool
 typesSatisfyDecConstraints tl = \case
-  InstanceD c it _ -> let
-    ([ConT n], htl) = splitAt 1 $ reverse $ unapplyType it
-    in analyze c n htl
+  InstanceD c it _ -> do
+    let ([ConT n], htl) = splitAt 1 $ reverse $ unapplyType it
+    etl <- mapM expandSyns tl
+    ehtl <- mapM expandSyns htl
+    maybe 
+      (fail $ "Unmatching amounts of types: " <> show etl <> ", " <> show ehtl)
+      (analyze c n)
+      (pair etl ehtl)
   d -> fail $ "Not an instance dec: " <> show d
   where
-    analyze c n htl = and <$> mapM analyzeConstraint c
+    analyze c n pl = and <$> mapM analyzeConstraint c
       where
         actualTypeByVarName = \n ->
           Map.lookup n m ?: 
-          ($bug $ "Unexpected key: " <> show n <> ", in a map: " <> show m)
+          ($bug $ "Unexpected key: " <> show n <> ", in a map: " <> show m <> 
+                  ", from a list: " <> show tl)
           where
-            m = Map.fromList $ concat $ map accRecords $ zip tl htl
+            m = Map.fromList $ concat $ map accRecords $ pl
               where
                 accRecords = \case
                   (AppT al ar, AppT hl hr) -> accRecords (al, hl) ++ accRecords (ar, hr)
                   (a, VarT n) -> [(n, a)]
-                  (a, h) | a /= h -> fail $ "Unmatching types: " <> show a <> ", " <> show h
+                  (a, h) | a /= h -> $bug $ "Unmatching types: " <> show a <> ", " <> show h
                   _ -> []
         analyzeConstraint = \case
           EqualP _ _ -> return True
diff --git a/src/THInstanceReification/Prelude/Basic.hs b/src/THInstanceReification/Prelude/Basic.hs
--- a/src/THInstanceReification/Prelude/Basic.hs
+++ b/src/THInstanceReification/Prelude/Basic.hs
@@ -55,6 +55,9 @@
 -- placeholders
 import Development.Placeholders as Exports
 
+-- list-extras
+import Data.List.Extras as Exports
+
 
 import qualified Debug.Trace.LocationTH
 
diff --git a/src/THInstanceReification/Prelude/TH.hs b/src/THInstanceReification/Prelude/TH.hs
--- a/src/THInstanceReification/Prelude/TH.hs
+++ b/src/THInstanceReification/Prelude/TH.hs
@@ -9,6 +9,7 @@
 
 import THInstanceReification.Prelude.Basic
 import Language.Haskell.TH as Exports
+import Language.Haskell.TH.ExpandSyns as Exports
 
 
 purify :: Q a -> a
diff --git a/th-instance-reification.cabal b/th-instance-reification.cabal
--- a/th-instance-reification.cabal
+++ b/th-instance-reification.cabal
@@ -1,7 +1,7 @@
 name:
   th-instance-reification
 version:
-  0.1.0
+  0.1.1
 synopsis:
   Fixed versions of instances reification functions
 description:
@@ -51,8 +51,11 @@
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
-    -- general:
+    -- template-haskell:
+    th-expand-syns == 0.3.*,
     template-haskell,
+    -- general:
+    list-extras == 0.4.*,
     base >= 4.5 && < 5
   default-extensions:
     Arrows
@@ -112,8 +115,11 @@
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
-    -- general:
+    -- template-haskell:
+    th-expand-syns == 0.3.*,
     template-haskell,
+    -- general:
+    list-extras == 0.4.*,
     base >= 4.5 && < 5
   default-extensions:
     Arrows