Index: src/prelude/prelude.cf
===================================================================
--- src/prelude/prelude.cf	(revision 5ccb10d750e81ef921035bdd254327997acd80ae)
+++ src/prelude/prelude.cf	(revision be9036d588c561590b98fa24451d88cd00ce0af1)
@@ -15,4 +15,14 @@
 
 // Section numbers from: http://plg.uwaterloo.ca/~cforall/refrat.pdf
+
+// ------------------------------------------------------------
+//
+// Section 6.7.11 Trait Declarations
+// Note: the sized trait is used in declarations later in this
+// file, so it must be out of order.
+//
+// ------------------------------------------------------------
+
+trait sized(dtype T) {};
 
 // ------------------------------------------------------------