diff --git a/ghc-pandoc-types.spec b/ghc-pandoc-types.spec
index e2505dd..31ba21e 100644
--- a/ghc-pandoc-types.spec
+++ b/ghc-pandoc-types.spec
@@ -18,6 +18,7 @@ BuildRequires:  ghc-aeson-devel
 BuildRequires:  ghc-bytestring-devel
 BuildRequires:  ghc-containers-devel
 BuildRequires:  ghc-syb-devel
+# aeson needs TemplateHaskell
 ExclusiveArch:  %{ghc_arches_with_ghci}
 # End cabal-rpm deps