Reducing the Costs of Proof Synthesis on Rust Systems by Scaling Up a Seed Training Set

Fuente: arXiv
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Main Authors: Di, Nongyu, Chen, Tianyu, Lu, Shan, Lu, Shuai, Gong, Yeyun, Cheng, Peng, Lorch, Jacob R., Yao, Yuan, Ma, Xiaoxing
Format: Preprint
Published: 2026
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_version_ 1866911666011111424
author Di, Nongyu
Chen, Tianyu
Lu, Shan
Lu, Shuai
Gong, Yeyun
Cheng, Peng
Lorch, Jacob R.
Yao, Yuan
Ma, Xiaoxing
author_facet Di, Nongyu
Chen, Tianyu
Lu, Shan
Lu, Shuai
Gong, Yeyun
Cheng, Peng
Lorch, Jacob R.
Yao, Yuan
Ma, Xiaoxing
contents Large Language Models (LLMs) are widely used for code generation. However, the correctness of code generated by LLMs remains a concern. A potential remedy to this concern is to have LLMs generate formal correctness proofs along with such code. However, compared with code generation, code-proof generation requires much higher reasoning capability and has much less existing data to learn from. In this paper, we present VeruSyn, a data synthesis pipeline for Verus, a state-of-the-art verification tool for system software written in Rust. Through self-synthesis and tutorial-based synthesis, VeruSyn achieves much larger scale and Verus-feature coverage than previous data-synthesis techniques designed for Verus; VeruSyn also supplements its dataset with long-chain-of-thought (CoT) data through agent trajectory synthesis. With VeruSyn, we synthesize the largest set of Verus verified programs: 6.9 million Rust programs, each with a formal specification and a proof that it meets that specification. This dataset lets us create a fine-tuned Qwen2.5-Coder-32B-Instruct model with appealing cost-proof tradeoff compared with state-of-the-art commercial models like Claude Sonnet 4.5. It also significantly outperforms models like o4-mini and previously proposed research models.
format Preprint
id arxiv_https___arxiv_org_abs_2602_04910
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Reducing the Costs of Proof Synthesis on Rust Systems by Scaling Up a Seed Training Set
Di, Nongyu
Chen, Tianyu
Lu, Shan
Lu, Shuai
Gong, Yeyun
Cheng, Peng
Lorch, Jacob R.
Yao, Yuan
Ma, Xiaoxing
Software Engineering
Large Language Models (LLMs) are widely used for code generation. However, the correctness of code generated by LLMs remains a concern. A potential remedy to this concern is to have LLMs generate formal correctness proofs along with such code. However, compared with code generation, code-proof generation requires much higher reasoning capability and has much less existing data to learn from. In this paper, we present VeruSyn, a data synthesis pipeline for Verus, a state-of-the-art verification tool for system software written in Rust. Through self-synthesis and tutorial-based synthesis, VeruSyn achieves much larger scale and Verus-feature coverage than previous data-synthesis techniques designed for Verus; VeruSyn also supplements its dataset with long-chain-of-thought (CoT) data through agent trajectory synthesis. With VeruSyn, we synthesize the largest set of Verus verified programs: 6.9 million Rust programs, each with a formal specification and a proof that it meets that specification. This dataset lets us create a fine-tuned Qwen2.5-Coder-32B-Instruct model with appealing cost-proof tradeoff compared with state-of-the-art commercial models like Claude Sonnet 4.5. It also significantly outperforms models like o4-mini and previously proposed research models.
title Reducing the Costs of Proof Synthesis on Rust Systems by Scaling Up a Seed Training Set
topic Software Engineering
url https://arxiv.org/abs/2602.04910