LintEval: Benchmarking LLMs on Linter-Guided File Refactoring

Tongwei Deng, Jinyu Zhu, Yue Cao, Chenxu Wang, Yanzhen Zou, Bing Xie


Abstract
Linters are widely used in code maintenance and real-time IDE editing to surface lint alerts related to performance, style, error-prone, and other patterns in source files. However, existing code benchmarks do not explicitly evaluate linter-guided file refactoring, where models must reduce lint alerts in source files with correct initial functionality while satisfying functionality preservation. We introduce LintEval, a multilingual benchmark for linter-guided file refactoring across C++, Python, and Java, comprising 13,061 programs with correct initial functionality and 171,662 lint alerts extracted using language-specific linters. LintEval jointly evaluates functionality preservation, lint alert reduction, new alert avoidance, and edit minimality. Experiments reveal a persistent trade-off: closed-source commercial models reach up to 90.4% Reduction@P but achieve only 67.1%–68.3% Pass@1, while several open-source small models show low or negative Reduction@P. A controlled fine-tuning study further shows that supervision format matters: refactoring-oriented SFT raises Qwen2.5-Coder-7B Reduction@P from 24.7% to 76.0%. LintEval enables controlled evaluation of models that improve source files under functionality preservation.
Anthology ID:
2026.findings-emnlp.157
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
3288–3308
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.157/
DOI:
Bibkey:
Cite (ACL):
Tongwei Deng, Jinyu Zhu, Yue Cao, Chenxu Wang, Yanzhen Zou, and Bing Xie. 2026. LintEval: Benchmarking LLMs on Linter-Guided File Refactoring. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3288–3308, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LintEval: Benchmarking LLMs on Linter-Guided File Refactoring (Deng et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.157.pdf