// Already found a path to target.
			return
		}

		// Record the path.
		funcs[target] = nowritebarrierrecCall{target: src, lineno: pos}
		q.PushRight(target.Nname)
	}
	for !q.Empty() {
		fn := q.PopLeft().Func

		// Check fn.
		if fn.WBPos.IsKnown() {
			var err strings.Builder
			call := funcs[fn]
			for call.target != nil {