Trace the reads a render makes, gather a render's draws in renderDraws and columnDraws, and drop the done item

holdset.go

@@ -35,6 +35,10 @@ func renderOnce(s *session, n node) string {
 //go:noinline
 func expandAnew(s *session, t *template) string {
 	var set holdSet
+	if s.trace != nil {
+		s.trace.depth++
+		defer func() { s.trace.depth-- }()
+	}
 	return expand(s, t, renderScope{set: &set})
 }