1 files changed, 2 insertions, 0 deletions
diff --git a/lib/url.c b/lib/url.c
index 689668e04..837e62a09 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -1213,6 +1213,8 @@ ConnectionExists(struct Curl_easy *data,
         }
       }
 
+      DEBUGASSERT(!check->data || GOOD_EASY_HANDLE(check->data));
+
       if(!canmultiplex && check->data)
         /* this request can't be multiplexed but the checked connection is
            already in use so we skip it */