diff --git a/test/doctests.hs b/test/doctests.hs
index 8bf21ed..b860d45 100644
--- a/test/doctests.hs
+++ b/test/doctests.hs
@@ -6,6 +6,7 @@ main :: IO ()
 main = doctest [
     "-package"
   , "ghc"
+  , "-XConstraintKinds", "-XFlexibleContexts"
   , "-idist/build/autogen/"
   , "-optP-include"
   , "-optPdist/build/autogen/cabal_macros.h"