diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,15 @@
 # ChangeLog
 
+## 0.2.2.0
+
+* Fixes derive and instantiator mechanisms to work with ghc 7.10 and
+  earlier.  Previously, invocation was broken when type variables were
+  used.
+
+* Fixes `freeVarsT` - it now looks through more constructors of `Type`.
+
+* Adds `dequalifyTyVars` to dequalify every type variable.
+
 ## 0.2.0.1
 
 * Fixes build on 7.8
diff --git a/src/TH/Derive.hs b/src/TH/Derive.hs
--- a/src/TH/Derive.hs
+++ b/src/TH/Derive.hs
@@ -84,18 +84,25 @@
     toStmt (varName, dec) = case fromPlainInstanceD dec of
         Just (preds, AppT (ConT ((== ''Deriving) -> True)) cls, []) ->
             bindS (varP varName)
-                  [e| runDeriver $(proxyE (return cls))
+                  [e| runDeriver $(proxyE (return (unitTyVars cls)))
                                  preds
                                  cls |]
         Just (preds, ty, decs) ->
             bindS (varP varName)
-                  [e| runInstantiator $(proxyE (return ty))
+                  [e| runInstantiator $(proxyE (return (unitTyVars ty)))
                                       preds
                                       ty
                                       decs |]
         _ -> fail $
             "Expected deriver or instantiator, instead got:\n" ++
             show dec
+
+-- | Turn type variables into unit types.
+unitTyVars :: Data a => a -> a
+unitTyVars = everywhere (id `extT` modifyType)
+  where
+    modifyType (VarT _) = TupleT 0
+    modifyType ty = ty
 
 -- | Useful function for defining 'Instantiator' instances. It uses
 -- 'Data' to generically replace references to the methods with plain
diff --git a/src/TH/Utilities.hs b/src/TH/Utilities.hs
--- a/src/TH/Utilities.hs
+++ b/src/TH/Utilities.hs
@@ -94,17 +94,18 @@
 dequalify :: Name -> Name
 dequalify = mkName . nameBase
 
+-- | Apply 'dequalify' to every type variable.
+dequalifyTyVars :: Data a => a -> a
+dequalifyTyVars = everywhere (id `extT` modifyType)
+  where
+    modifyType (VarT n) = VarT (dequalify n)
+    modifyType ty = ty
+
 -- | Get the free type variables of a 'Type'.
 freeVarsT :: Type -> [Name]
 freeVarsT (ForallT tvs _ ty) = filter (`notElem` (map tyVarBndrName tvs)) (freeVarsT ty)
-freeVarsT (AppT l r) = freeVarsT l ++ freeVarsT r
-freeVarsT (SigT ty k) = freeVarsT ty ++ freeVarsT k
 freeVarsT (VarT n) = [n]
-#if MIN_VERSION_template_haskell(2,11,0)
-freeVarsT (InfixT x n r) = freeVarsT x ++ freeVarsT r
-freeVarsT (UInfixT x n r) = freeVarsT x ++ freeVarsT r
-#endif
-freeVarsT _ = []
+freeVarsT ty = concat $ gmapQ (const [] `extQ` freeVarsT) ty
 
 -- | Utility to conveniently handle change to 'InstanceD' API in
 -- template-haskell-2.11.0
diff --git a/th-utilities.cabal b/th-utilities.cabal
--- a/th-utilities.cabal
+++ b/th-utilities.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: f65b38d225125ec3f0a4ec974c8bcae0ae5358894abd8c118aa1a6b3c9b457e7
+-- hash: fffcc9b9550bfe2e35141d3aadeb19bc6d5536025381f9c21188fc104a24b062
 
 name:           th-utilities
-version:        0.2.1.0
+version:        0.2.2.0
 synopsis:       Collection of useful functions for use with Template Haskell
 category:       Template Haskell
 homepage:       https://github.com/fpco/th-utilities#readme