Index: doc/proposals/vtable.md
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--- doc/proposals/vtable.md	(revision 9e1867701101eae06a928bbf5d5a246ef29a9872)
+++ doc/proposals/vtable.md	(revision daefe93df0da625f84188e00b080a708ff2281f2)
@@ -512,4 +512,28 @@
 possibly like the one used to create the assertion.
 
+### Extension: Associated Types Use
+If the `associated_types.md` proposal is accepted the following trait could
+be added:
+
+    trait is_virtual(dtype T) {
+        dtype table;
+        // An example assertion:
+        const table & get_virtual_table(T &);
+    }
+
+There may be more assertions but there has to be at least one way to find
+the (possibly default) virtual table. It is required to construct instances
+of the type.
+
+Without the assotiated type it would look like this:
+
+    trait is_virtual(dtype T, dtype table) {
+        const table & get_virtual_table(T &);
+    }
+
+Which is just a little bit longer to use but becomes more problematic if the
+user has to explicately provide the table's name as it doesn't really have its
+own type name. If it does it is probably mangled.
+
 ### Virtual Tables as Types
 Here we consider encoding plus the implementation of functions on it to be a