arXiv AI

Verified but Vacuous: Three Failure Surfaces of LLM-Driven Verified Code Generation

The paper argues that the term "verified" in LLM‑generated code is ambiguous, identifying three distinct failure surfaces: verifier acceptance (Surface A), syntactic specification binding (Surface B), and semantic specification fidelity (Surface C). Empirical tests on Python and Rust benchmarks show that high verifier acceptance does not guarantee binding to a specification, and even fully‑verified Rust outputs can fail hidden tests, revealing gaps between formal proofs and real‑world correctness.

arXiv AI
Sep 21

SWE-Proof: Can Language Models Resolve Real-World Issues with Machine-Checked Proofs?

arXiv:2609.21190v1 Announce Type: cross Abstract: Ensuring the correctness of LLM-generated code is a core challenge for modern software engineering. Benchmarks for agentic code generation check corr...

By George Ma, Benjamin Mikek, Haoyu Li, Ferhat Erata, Yuhao Zhang, Zeren Shui, Behrooz Omidvar Tehrani, Jun Huan, Murali Krishna Ramanathan, Somayeh Sojoudi, Hao Zhou, Anoop Deoras
arXiv AI
Oct 28

SemLoc: Structured Grounding of Free-Form LLM Reasoning for Fault Localization

SemLoc transforms free‑form reasoning from large language models into executable semantic constraints that are attached to specific code anchors such as variable definitions, branches, loops, or returns. These constraints are inserted as runtime checks, and the resulting semantic violation spectrum is used to guide counterfactual verification and patch generation. On the QuixBugs and new SemBugs datasets, SemLoc’s constraints achieve high ranking of faulty lines and a high proportion of verifiable, correct patches, matching the accuracy of the underlying LLMs while outperforming traditional spectrum‑based methods.

By Zhaorui Yang, Haichao Zhu, Qian Zhang, Rajiv Gupta, Ashish Kundu
arXiv AI
Oct 28

How Stable Are LLM-Generated Proofs Under Program Refactoring? A Stress Test for Verifiable Code Generation

The paper introduces RefactorProof, a benchmark that tests whether proofs generated for code remain valid after program refactoring that preserves behavior. Using 458 Lean-certified variants derived from 185 VERINA tasks, the study finds that structural refactorings expose brittleness in proofs, with task-normalized structural PSR ranging from 4.3% for supplied references to 13.3–26.8% for specialized provers. Despite higher failure rates, specialized prover proofs (DeepSeek-Prover-V2-7B, Goedel-Prover-V2-32B, Goedel-Prover-V2-8B) show significantly higher unchanged-proof survival compared to reference artifacts, and many failures can be repaired with minimal edits.

By Aravind Mandiga, Guoming Li
arXiv AI
Sep 12

SemVerBench: Benchmarking LLM Comprehension of Version-Constraint Resolution Semantics

SemVerBench is a benchmark that evaluates how well large language models (LLMs) understand and apply version-constraint resolution semantics, such as determining whether a version satisfies constraints like ^1.2.3 or >=2.0. The study finds that many models struggle with certain corner cases, with GPT‑5.1 performing poorly while Claude and Opus perform much better. The authors suggest that the failures stem from an activation/application gap rather than a lack of knowledge, and recommend that coding agents delegate version resolution to a dedicated resolver tool.

By Qibai Chen, Zeming Liu
arXiv AI
Oct 9

Beyond Type-checking: Towards Holistic Evaluation of Formal Specification Generation

The paper presents a unified dataset of 350 Lean tasks to evaluate specification generation (SpecGen) for verifiable code, combining metrics of formal validity, reference similarity, equivalence, and behavioural adequacy. It highlights that restricting similarity measures to a subset of tasks can shift rankings, and shows that a perfect postcondition score can still miss critical input coverage, underscoring the need for separate feedback on input and output constraints.

By Srijith Nair, Aditya Vempaty, Jia Liu, Ashish Jagmohan
arXiv Computation and Language
Oct 16

Jev-as-a-Judge for RAG Claim Verification: Confidence-Gated Cascading Between a Non-Generative Verifier and a Frontier LLM

The paper compares a non‑generative verifier (Jev) with a frontier LLM (Astra) on 495 human‑labelled claims from LLM‑AggreFact. Both models achieve statistically indistinguishable accuracy, yet Jev is 187‑fold cheaper and admits more unsupported claims. A confidence‑gated cascade that escalates uncertain claims improves cost‑efficiency, though the benefit comes mainly from the escalation share rather than the probability estimates.

By Alden Do Rosario, Kirollos Atef