diff --git a/compiler/mono/src/decision_tree.rs b/compiler/mono/src/decision_tree.rs
index a329408439..a24620ad23 100644
--- a/compiler/mono/src/decision_tree.rs
+++ b/compiler/mono/src/decision_tree.rs
@@ -145,7 +145,7 @@ impl<'a> Hash for GuardedTest<'a> {
                 state.write_u8(1);
             }
             GuardedTest::TestNotGuarded { test } => {
-                state.write_u8(2);
+                state.write_u8(0);
                 test.hash(state);
             }
         }