1 files changed, 15 insertions, 0 deletions
diff --git a/src/Lemmas.hs b/src/Lemmas.hs
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index 0000000..7dbf680
--- /dev/null
+++ b/src/Lemmas.hs
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+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE PolyKinds #-}
+
+{-# LANGUAGE AllowAmbiguousTypes #-}
+module Lemmas (module Lemmas, (:~:)(Refl)) where
+
+import Data.Type.Equality
+import Unsafe.Coerce (unsafeCoerce)
+
+import AST.Weaken
+
+
+lemAppendAssoc :: Append a (Append b c) :~: Append (Append a b) c
+lemAppendAssoc = unsafeCoerce Refl