---
title: MARKLESS_OVERLAY_VALUE_UNSUPPORTED
description: "overlay accepts only a literal: a Markless compiler error."
sidebar: { hidden: true }
search: { keywords: ["OVERLAY_VALUE_UNSUPPORTED","overlay value unsupported","markless error"] }
pagination: false
---

**Error** from the compiler, while it builds your `.tsrx` files.

## What happened

Markless prints the message, the reason, and a suggestion:

```text
MARKLESS_OVERLAY_VALUE_UNSUPPORTED: <bound>. overlay must be written on the element itself as bare `overlay`, `overlay={true}`, or `overlay={false}`.
Elevation is structural, not reactive. The overlay record carries no inputs, so it has no dependencies and can never re-run; a value that varies at runtime would have nothing to re-elevate the element.
Let `@if` decide whether the element exists and keep `overlay` a literal on the element inside the branch.
https://markless.dev/errors/MARKLESS_OVERLAY_VALUE_UNSUPPORTED
```

Words in angle brackets change from case to case.

## How to fix it

Start with the suggestion in the message above.

This page has no guide yet. [Help write it](/contributing/improve-these-docs).

## Where it comes from

`@markless/compiler` raises this code. Source:

- [packages/compiler/src/passes/semantic-graph/diagnostics.ts](https://github.com/compiled-run/markless/blob/main/packages/compiler/src/passes/semantic-graph/diagnostics.ts)

Read [how to read a Markless error](/tooling/diagnostics), or go back to [all error codes](/errors).