diff --git a/macros.h b/macros.h
new file mode 100644
--- /dev/null
+++ b/macros.h
@@ -0,0 +1,65 @@
+#ifndef TYPE_EQ_MACROS_H
+#define TYPE_EQ_MACROS_H
+
+-- NT: TypeableN
+-- NC: unsafeCoercionN
+-- EQ: :~:, ::~::, ...
+-- T1, T2: a, b; f, g; ...
+-- ARGS: () ()...
+#define DYNAMIC_EQ(NT, NC, EQ, T1, T2, ARGS)                                                         \
+    ; {- | Runtime type equality evidence from @Typeable/**/NT@ -};                                  \
+    dynamicEq/**/NT :: (Typeable/**/NT T1, Typeable/**/NT T2) => Maybe (T1 EQ T2);                   \
+    dynamicEq/**/NT = r where {                                                                      \
+        r       = if typeOf/**/NT T1 == typeOf/**/NT T2 then Just unsafeCoercion/**/NC else Nothing; \
+        T1      = x/**/T1 r;                                                                         \
+        T2      = x/**/T2 r;                                                                         \
+        x/**/T1 :: Maybe (T1 EQ T2) -> T1 ARGS;                                                      \
+        x/**/T1 = const undefined;                                                                   \
+        x/**/T2 :: Maybe (T1 EQ T2) -> T2 ARGS;                                                      \
+        x/**/T2 = const undefined;                                                                   \
+    }
+
+#define INSTANCE_TYPEABLE(NT, EQ, T1, T2, MOD, CON, ARGS)                                            \
+    instance (Typeable/**/NT T1, Typeable/**/NT T2) => Typeable (T1 EQ T2) where                     \
+        typeOf a = tyCon `mkTyConApp` (map unapply [typeOf/**/NT (type1 a), typeOf/**/NT (type2 a)]) \
+            where {                                                                                  \
+                tyCon = MK_TY_CON(MOD, CON);                                                         \
+                unapply t = mkTyConApp (typeRepTyCon t) [];                                          \
+                type1 :: T1 EQ T2 -> T1 ARGS;                                                        \
+                type1 = const undefined;                                                             \
+                type2 :: T1 EQ T2 -> T2 ARGS;                                                        \
+                type2 = const undefined;                                                             \
+            }
+
+#if MIN_VERSION_base(4,4,0)
+#   define MK_TY_CON(MOD, CON) mkTyCon3 "type-eq" MOD CON
+#else
+#   define MK_TY_CON(MOD, CON) mkTyCon ("type-eq::" ++ MOD ++ "." ++ CON)
+#endif
+
+-- http://hackage.haskell.org/trac/ghc/ticket/5591
+#if (__GLASGOW_HASKELL__ >= 702) && (__GLASGOW_HASKELL__ <= 704)
+#   define BUG_5591(X) (unsafeCoerce X)
+#else
+#   define BUG_5591(X) X
+#endif
+
+#if (__GLASGOW_HASKELL__ >= 702)
+#   define LANGUAGE_TRUSTWORTHY {-# LANGUAGE Trustworthy #-}
+#else
+#   define LANGUAGE_TRUSTWORTHY
+#endif
+
+#if (__GLASGOW_HASKELL__ >= 704)
+#   define LANGUAGE_UNSAFE    {-# LANGUAGE Unsafe #-}
+#else
+#   define LANGUAGE_UNSAFE
+#endif
+
+#if (__GLASGOW_HASKELL__ >= 706)
+#   define LANGUAGE_POLYKINDS {-# LANGUAGE PolyKinds #-}
+#else
+#   define LANGUAGE_POLYKINDS
+#endif
+
+#endif
diff --git a/type-eq.cabal b/type-eq.cabal
--- a/type-eq.cabal
+++ b/type-eq.cabal
@@ -1,6 +1,6 @@
 name:          type-eq
 category:      Type System
-version:       0.1.1
+version:       0.1.2
 author:        Gábor Lehel
 maintainer:    Gábor Lehel <illissius@gmail.com>
 homepage:      http://github.com/glehel/type-eq
@@ -41,6 +41,8 @@
         - <http://hackage.haskell.org/package/dependent-sum>
     .
         - <http://hackage.haskell.org/package/categories> (@Data.Category.Discrete@)
+
+extra-source-files: macros.h
 
 source-repository head
     type:      git