---
title: MARKLESS_REPEAT_COLLECTION_UNREADABLE
description: "This @for collection reaches no cell on its shared instance: a Markless compiler error."
sidebar: { hidden: true }
search: { keywords: ["REPEAT_COLLECTION_UNREADABLE","repeat collection unreadable","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_REPEAT_COLLECTION_UNREADABLE: @for (const <itemName> of <collectionSource>) reads through `<rootName>`, a shared instance local of this component, but `<collectionSource>` resolves to no graph cell. `<rootName>` exists only inside the component function, so the rows would be taken from an expression that names nothing where the repeat renders.
Rows come from a reactive graph read; a shared-instance path that resolves to no cell leaves the repeat with an authored expression whose receiver is undeclared in the emitted scope, which throws on the first server render.
Return the cell as a property of a spread object from the shared factory, so `<collectionSource>` names a graph cell. Before: `shared(() => { const box = state({ items: [] }); return box; })`; after: `shared(() => { const box = state({ items: [] }); return { ...box }; })`.
https://markless.dev/errors/MARKLESS_REPEAT_COLLECTION_UNREADABLE
```

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