[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-85194-en":3,"doc-seo-85194-105":30,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":21,"is_downloadable":21,"audit_status":21,"page_count":22,"language":23,"language_code":24,"site_id":25,"html_lang":24,"table_of_contents":26,"faqs":27,"seo_title":13,"seo_description":14,"update_tm":28,"read_time":29},85194,962075114101,"Seraphina","https://ap-avatar.wpscdn.com/avatar/e000253a75eb197efd?x-image-process=image/resize,m_fixed,w_180,h_180&k=1780044092746381165",8,"Research & Report","Partial Contracts Suffice Sound, LLM-Inferred Regression Verification","Software continuously evolves, and ensuring a patch preserves intended behavior without re-verifying the entire codebase is difficult. Regression verification exists, but prior methods are either expensive whole-program analyses or depend on manual specifications that are often unavailable. The work introduces a contract-based regression verification tool using automatically inferred contracts. It verifies program flow via assume-guarantee under caller-sufficiency, then assesses contract tightness and soundness on benchmark suites while avoiding false equivalence proofs.","Partial Contracts Suffice: Sound, LLM-Inferred  \nRegression Verification  \nYiannis Charalambous  \nThe University of Manchester 0009-0000-5755-5099  \nRafael Menezes  \nThe University of Manchester 0000-0002-6102-4343  \nYoucheng Sun  \nThe University of Manchester 0000-0002-1893-6259  \nLucas C. Cordeiro  \nThe University of Manchester 0000-0002-6235-4272  \narXiv :2607 . 1029 1v 1 [ cs . SE] 11 Jul 2026  \nAbstract—Software evolves continuously, yet ensuring that a patch preserves intended behavior without re-verifying an entire codebase remains difficult. Regression verification addresses this problem, but existing techniques either require expensive wholeprogram reasoning or rely on manually written specifications that are rarely available in practice. In this work, we present the first contract-based regression verification tool. In our approach, the contract soundness is ensured by proving that all function versions match the behavior. Additionally, to ensure the behavior, the contract is used to verify the program flow (i.e., assumeguarantee). We ask whether a partial, caller-sufficient contract, rather than a full behavioral specification, is enough. On FramaC-Problems we strengthen each inferred contract past what the caller needs and measure how much tighter it becomes. It barely moves: for most targets in every model the callersufficient contract is already the tightest the loop reaches, and our tightness comparator rates the partial and strengthened contracts equivalent for the large majority of targets it can compare (18 of 20, 13 of 15, and 14 of 18 across the three models). Partialspec contracts thus capture nearly all the attainable tightness, so stopping at caller-sufficiency costs almost nothing. The regression check underneath is sound: on the third-party EqBench-C suite it never fabricates an equivalence, returning zero false proofs on the pairs it decides and reporting an unprovable difference rather than a false proof. Used as a soundness oracle this way, it also surfaced nine pairs that EqBench mislabels as equivalent, more thana concurrent tool reports. The contracts themselves are inferred automatically from the checker’s own counterexamples, with no separate specification step; on Frama-C-Problems and the ANSSIX509 parser this reaches a verification rate comparable to the weakest-precondition (WP) tools AutoSpec and Preguss, while a passing result certifies at least as strong a property, which we call safety-preserving conditional equivalence: enforcement plus callersufficiency, with runtime-error freedom covered by the safety encoding.  \nIndex Terms—formal verification, software testing, artificial intelligence, software safety, large language models  \nI. INTRODUCTION  \nSoftware changes constantly, and most changes are meant to be conservative: a refactor, a bug fix, or a small feature should preserve the behavior callers already rely on. They don’t always manage it. A fix that corrects one execution path can quietly perturb an output some other caller reads, and if no test exercises that caller the regression ships unnoticed; across major operating systems, between 14.8% and 24.4% of post-release fixes were themselves found to be incorrect [1] . Catching it means deciding whether the new and old versions still agree, and there’s no general procedure for that: deciding full input/output equivalence is undecidable [2], and even a  \nbounded check stays expensive, since it has to reason about each function together with all its side-effects [3] .  \nIn a bug-fixing or refactoring context, full equivalence asks too much: the developer means to change some paths and leave the rest, so requiring agreement everywhere, old bugs and all, rejects the very edit being made. The useful notions form a spectrum, ordered by how much of each execution they compare, and the weaker the relation the cheaper the proof. Full equivalence is the strongest: the two versions must terminate on the same inputs and return the same outputs","cbCaiiDDcI7mzRBP","https://ap.wps.com/l/cbCaiiDDcI7mzRBP","pdf",381717,4,1,12,"English","en",105,"# Introduction\n## Regression equivalence notions\n## Modular sound proofs via function contracts\n## Assume-guarantee and caller-sufficiency\n## Contract inference and soundness evaluation","[{\"question\":\"What problem does the paper address in regression verification?\",\"answer\":\"Ensuring a patch preserves the behavior callers rely on without having to re-verify the entire codebase. Existing approaches are either computationally expensive or require manual specifications that are rarely available.\"},{\"question\":\"How does the method use function contracts?\",\"answer\":\"It enforces contracts as preconditions and postconditions to over-approximate callees, enabling modular proofs. The regression check uses assume-guarantee so behavior is verified only where the caller-specified property holds.\"},{\"question\":\"What evidence is given for soundness and tightness?\",\"answer\":\"The regression check is reported to produce zero false equivalence proofs on the EqBench-C suite and to flag unprovable differences instead. Contract tightness is evaluated on FramaC-Problems, where caller-sufficient contracts are found to capture nearly all attainable tightness.\"}]",1784201669,30,{"code":4,"msg":31,"data":32},"ok",{"site_id":25,"language":24,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":28},"partial-contracts-suffice-sound-llm-inferred-regression-verification","",{"@graph":36,"@context":85},[37,53,68],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,48,51],{"item":41,"name":42,"@type":43,"position":21},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":47},"https://docshare.wps.com/document/","Document",2,{"item":49,"name":12,"@type":43,"position":50},"https://docshare.wps.com/document/research-report/",3,{"item":52,"name":13,"@type":43,"position":20},"https://docshare.wps.com/document/partial-contracts-suffice-sound-llm-inferred-regression-verification/85194/",{"url":52,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":24,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":41,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-24","2026-07-16",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"What problem does the paper address in regression verification?","Question",{"text":75,"@type":76},"Ensuring a patch preserves the behavior callers rely on without having to re-verify the entire codebase. Existing approaches are either computationally expensive or require manual specifications that are rarely available.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"How does the method use function contracts?",{"text":80,"@type":76},"It enforces contracts as preconditions and postconditions to over-approximate callees, enabling modular proofs. The regression check uses assume-guarantee so behavior is verified only where the caller-specified property holds.",{"name":82,"@type":73,"acceptedAnswer":83},"What evidence is given for soundness and tightness?",{"text":84,"@type":76},"The regression check is reported to produce zero false equivalence proofs on the EqBench-C suite and to flag unprovable differences instead. Contract tightness is evaluated on FramaC-Problems, where caller-sufficient contracts are found to capture nearly all attainable tightness.","https://schema.org",{"og:url":52,"og:type":87,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":89,"canonical":52},"index,follow",{"doc_id":7,"site_id":25},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,120,122,127,130,134],{"id":21,"doc_module":4,"doc_module_name":46,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":47,"doc_module":4,"doc_module_name":46,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":20,"doc_module":4,"doc_module_name":46,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":46,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":46,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":116,"doc_module":4,"doc_module_name":46,"category_name":117,"show_sort_weight":118,"slug":119},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":46,"category_name":12,"show_sort_weight":29,"slug":121},"research-report",{"id":123,"doc_module":4,"doc_module_name":46,"category_name":124,"show_sort_weight":125,"slug":126},9,"Religion & Spirituality",20,"religion-spirituality",{"id":125,"doc_module":4,"doc_module_name":46,"category_name":128,"show_sort_weight":125,"slug":129},"World Cup","world-cup",{"id":131,"doc_module":4,"doc_module_name":46,"category_name":132,"show_sort_weight":131,"slug":133},10,"Lifestyle","lifestyle",{"id":135,"doc_module":4,"doc_module_name":46,"category_name":136,"show_sort_weight":106,"slug":137},19,"General","general"]