diff --git a/debug.hpp b/debug.hpp
index 87ac774f..7caf9e22 100644
--- a/debug.hpp
+++ b/debug.hpp
@@ -341,7 +341,7 @@
                                                             \
         try                                                 \
             { C; }                                          \
-        catch (E)                                           \
+        catch (E const&)                                    \
             { caught = true; }                              \
                                                             \
         if (!caught)                                        \