# Valen developer describes compiler checks that allow multiple writable references

_Published Sunday, October 11, 2026 at 11:06 AM EDT · Products · Latest · Tier 2 — Notable_

Valen's developer describes an experimental compiler approach that catches use of references after their underlying data has been invalidated while allowing multiple references to modify the same object. The post presents examples of both a rejected unsafe program and an accepted program with two writable references.

The approach, called group borrowing, tracks where references point using information specified by programmers. It relaxes restrictions imposed by conventional borrow checking, which checks reference use before a program runs. The current compiler still requires manual dereferencing, direct array indexing and explicit parameter types in places.

## Sources

- [verdagon.dev](https://verdagon.dev/blog/valen-group-borrowing)

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Canonical: https://techandbusiness.org/newswire/qEb9O_VVRxJZmb_umBu9EO
Published: 2026-10-11T15:06:47.158Z
Story chronology: 2026-10-11T12:06:22.000Z
Retrieved: 2026-10-11T17:58:09.340Z
Publisher: Tech & Business (techandbusiness.org)