Index: libcfa/prelude/builtins.c
===================================================================
--- libcfa/prelude/builtins.c	(revision 3acc863213f08d015401fe973cfa1d4eb8a0f4d3)
+++ libcfa/prelude/builtins.c	(revision 8a972486173f920eea1f1868fff138e1568a8a59)
@@ -10,6 +10,6 @@
 // Created On       : Fri Jul 21 16:21:03 2017
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Sat Aug 14 08:45:54 2021
-// Update Count     : 133
+// Last Modified On : Thu Feb  2 11:33:56 2023
+// Update Count     : 135
 //
 
@@ -64,5 +64,6 @@
 static inline void ^?{}(generator$ &) {}
 
-trait is_generator(T &) {
+forall( T & )
+trait is_generator {
       void main(T & this);
       generator$ * get_generator(T & this);
Index: libcfa/prelude/prelude-gen.cc
===================================================================
--- libcfa/prelude/prelude-gen.cc	(revision 3acc863213f08d015401fe973cfa1d4eb8a0f4d3)
+++ libcfa/prelude/prelude-gen.cc	(revision 8a972486173f920eea1f1868fff138e1568a8a59)
@@ -10,6 +10,6 @@
 // Created On       : Sat Feb 16 08:44:58 2019
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Tue Apr  2 17:18:24 2019
-// Update Count     : 37
+// Last Modified On : Thu Feb  2 11:40:01 2023
+// Update Count     : 38
 //
 
@@ -159,5 +159,5 @@
 int main() {
 	cout << "# 2 \"prelude.cfa\"  // needed for error messages from this file" << endl;
-	cout << "trait sized(T &) {};" << endl;
+	cout << "forall( T & ) trait sized {};" << endl;
 
 	cout << "//////////////////////////" << endl;