diff --git a/src/core/tree/ocarina-me_aadl-aadl_instances-debug.adb b/src/core/tree/ocarina-me_aadl-aadl_instances-debug.adb
index a075fc986ed48cde16a1dd98b11cd032edf2c388..4025f9efa54026a07c09d1f6e4b275885cb7a177 100644
--- a/src/core/tree/ocarina-me_aadl-aadl_instances-debug.adb
+++ b/src/core/tree/ocarina-me_aadl-aadl_instances-debug.adb
@@ -262,7 +262,7 @@ package body Ocarina.ME_AADL.AADL_Instances.Debug is
    ---------
 
    procedure wni (N : Node_Id) is
-      I : constant Natural := N_Indents;
+      I : constant Integer := N_Indents;
    begin
       N_Indents := 1;
       W_Node_Id (N);