diff --git a/lib/modules/Function.pmod b/lib/modules/Function.pmod
index c475b2ff5eabaab54502dd80833cc6a4bae15cf7..87022697a2c3cc7b381c24ab92599fc954f022f0 100644
--- a/lib/modules/Function.pmod
+++ b/lib/modules/Function.pmod
@@ -1,4 +1,5 @@
 #pike __REAL_VERSION__
+#pragma strict_type
 
 constant defined = __builtin.function_defined;