Verifying the Rust Standard Library

2026-06-15

AI Summary

This work addresses the pervasive reliance on unsafe code in the Rust standard library, whose memory safety has traditionally lacked static guarantees and instead depended primarily on testing. For the first time, the authors systematically introduce machine-checked proofs into the Rust standard library by integrating Miri-based dynamic analysis with multiple complementary formal verification tools through an open-source, community-driven approach. They establish a dedicated verification repository embedded within the continuous integration pipeline, enabling what is to date the largest-scale formal verification effort for any software library. This initiative effectively detects and verifies critical undefined behaviors—including out-of-bounds accesses, null or dangling pointer dereferences, and uses of uninitialized memory—thereby providing strong memory safety assurances for the Rust ecosystem and presenting the formal methods community with novel, scalable verification challenges.

Abstract

Rust's type system prevents many classes of memory errors, yet its standard library relies heavily on unsafe code whose correctness is validated through testing, including dynamic checks under Miri, but lacks static verification. We present what is, to the best of our knowledge, the largest verification campaign reported for a software library: an open, crowdsourced effort that integrates complementary verification tools into the continuous integration of a verification repository forked from the Rust standard library. We analyze the campaign's effectiveness, discuss the practical value of machine-checked proofs for a subset of undefined behaviors (e.g., out-of-bounds access, null and dangling pointer dereferences, and use of uninitialized memory), and frame the remaining obstacles as open challenges for the formal-methods community.

Problem

• Rust standard library
• unsafe code
• static verification
• undefined behavior
• formal verification

Innovation

• formal verification
• Rust standard library
• unsafe code
• continuous integration
• undefined behavior