Fix set literals not being visited in symtable creation.

Python/Python-ast.c

@@ -3043,7 +3043,7 @@ init_ast(void)
         if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;
         if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)
                 return;
-        if (PyModule_AddStringConstant(m, "__version__", "51600") < 0)
+        if (PyModule_AddStringConstant(m, "__version__", "51631") < 0)
                 return;
         if (PyDict_SetItemString(d, "mod", (PyObject*)mod_type) < 0) return;
         if (PyDict_SetItemString(d, "Module", (PyObject*)Module_type) < 0)

Python/symtable.c

@@ -1147,6 +1147,9 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
 		VISIT_SEQ(st, expr, e->v.Dict.keys);
 		VISIT_SEQ(st, expr, e->v.Dict.values);
 		break;
+	case Set_kind:
+		VISIT_SEQ(st, expr, e->v.Set.elts);
+		break;
         case ListComp_kind:
 		if (!symtable_new_tmpname(st))
 			return 0;