diff --git a/src/ShellCheck/CFG.hs b/src/ShellCheck/CFG.hs
index 2fe11e7..0cd6326 100644
--- a/src/ShellCheck/CFG.hs
+++ b/src/ShellCheck/CFG.hs
@@ -887,7 +887,9 @@ build t = do
         T_Less _ -> none
         T_ParamSubSpecialChar _ _ -> none
 
-        x -> error ("Unimplemented: " ++ show x)
+        x -> do
+            error ("Unimplemented: " ++ show x) -- STRIP
+            none
 
 --  Still in `where` clause
     forInHelper id name words body = do