diff --git a/src/Cryptol/Eval/FFI.hs b/src/Cryptol/Eval/FFI.hs
index c47d6d363..4accda339 100644
--- a/src/Cryptol/Eval/FFI.hs
+++ b/src/Cryptol/Eval/FFI.hs
@@ -29,8 +29,9 @@ evalForeignDecls :: ModulePath -> Module -> EvalEnv ->
   Eval (Either [FFILoadError] EvalEnv)
 evalForeignDecls path m env = do
   foreignSrc <- liftIO $ newIORef Nothing
-  let evalForeignDeclGroup e (Recursive ds)   = foldlM evalForeignDecl e ds
-      evalForeignDeclGroup e (NonRecursive d) = evalForeignDecl e d
+  let evalForeignDeclGroup e (NonRecursive d) = evalForeignDecl e d
+      evalForeignDeclGroup _ (Recursive _) = panic "evalForeignDecls"
+        ["Recursive foreign declaration group"]
       evalForeignDecl e d = case dDefinition d of
         DForeign -> do
           fsrc <- liftIO (readIORef foreignSrc) >>= \case