CINXE.COM

<!doctype html> <html lang="en" dir="ltr" class="docs-wrapper plugin-docs plugin-id-default docs-version-1.23.8 docs-doc-page docs-doc-id-rules/potential-bugs" data-has-hydrated="false"> <head> <meta charset="UTF-8"> <meta name="generator" content="Docusaurus v3.7.0"> <title data-rh="true">Potential-bugs Rule Set | detekt</title><meta data-rh="true" name="viewport" content="width=device-width,initial-scale=1"><meta data-rh="true" name="twitter:card" content="summary_large_image"><meta data-rh="true" property="og:url" content="https://detekt.dev/docs/rules/potential-bugs"><meta data-rh="true" property="og:locale" content="en"><meta data-rh="true" name="docusaurus_locale" content="en"><meta data-rh="true" name="docsearch:language" content="en"><meta data-rh="true" name="docusaurus_version" content="1.23.8"><meta data-rh="true" name="docusaurus_tag" content="docs-default-1.23.8"><meta data-rh="true" name="docsearch:version" content="1.23.8"><meta data-rh="true" name="docsearch:docusaurus_tag" content="docs-default-1.23.8"><meta data-rh="true" property="og:title" content="Potential-bugs Rule Set | detekt"><meta data-rh="true" name="description" content="The potential-bugs rule set provides rules that detect potential bugs."><meta data-rh="true" property="og:description" content="The potential-bugs rule set provides rules that detect potential bugs."><meta data-rh="true" name="keywords" content="rules,potential-bugs"><link data-rh="true" rel="icon" href="/img/favicon.svg"><link data-rh="true" rel="canonical" href="https://detekt.dev/docs/rules/potential-bugs"><link data-rh="true" rel="alternate" href="https://detekt.dev/docs/rules/potential-bugs" hreflang="en"><link data-rh="true" rel="alternate" href="https://detekt.dev/docs/rules/potential-bugs" hreflang="x-default"><link data-rh="true" rel="preconnect" href="https://5PZNXB7M3G-dsn.algolia.net" crossorigin="anonymous"><link rel="alternate" type="application/rss+xml" href="/blog/rss.xml" title="detekt RSS Feed"> <link rel="alternate" type="application/atom+xml" href="/blog/atom.xml" title="detekt Atom Feed"> <link rel="search" type="application/opensearchdescription+xml" title="detekt" href="/opensearch.xml"><link rel="stylesheet" href="/assets/css/styles.80918a2e.css"> <script src="/assets/js/runtime~main.49574ca9.js" defer="defer"></script> <script src="/assets/js/main.8ff3ed71.js" defer="defer"></script> </head> <body class="navigation-with-keyboard"> <script>!function(){function t(t){document.documentElement.setAttribute("data-theme",t)}var e=function(){try{return new URLSearchParams(window.location.search).get("docusaurus-theme")}catch(t){}}()||function(){try{return window.localStorage.getItem("theme")}catch(t){}}();t(null!==e?e:"light")}(),function(){try{const n=new URLSearchParams(window.location.search).entries();for(var[t,e]of n)if(t.startsWith("docusaurus-data-")){var a=t.replace("docusaurus-data-","data-");document.documentElement.setAttribute(a,e)}}catch(t){}}()</script><div id="__docusaurus"><link rel="preload" as="image" href="/img/favicon.svg"><div role="region" aria-label="Skip to main content"><a class="skipToContent_fXgn" href="#__docusaurus_skipToContent_fallback">Skip to main content</a></div><nav aria-label="Main" class="navbar navbar--fixed-top"><div class="navbar__inner"><div class="navbar__items"><button aria-label="Toggle navigation bar" aria-expanded="false" class="navbar__toggle clean-btn" type="button"><svg width="30" height="30" viewBox="0 0 30 30" aria-hidden="true"><path stroke="currentColor" stroke-linecap="round" stroke-miterlimit="10" stroke-width="2" d="M4 7h22M4 15h22M4 23h22"></path></svg></button><a class="navbar__brand" href="/"><div class="navbar__logo"><img src="/img/favicon.svg" alt="detekt logo" class="themedComponent_mlkZ themedComponent--light_NVdE"><img src="/img/favicon.svg" alt="detekt logo" class="themedComponent_mlkZ themedComponent--dark_xIcU"></div>detekt</a><a aria-current="page" class="navbar__item navbar__link navbar__link--active" href="/docs/intro">Docs</a><a class="navbar__item navbar__link" href="/blog">Blog</a><a href="https://detekt.dev/kdoc/" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link">APIs</a><a class="navbar__item navbar__link" href="/marketplace">Marketplace</a></div><div class="navbar__items navbar__items--right"><div class="navbar__item dropdown dropdown--hoverable dropdown--right"><a class="navbar__link" aria-haspopup="true" aria-expanded="false" role="button" href="/docs/rules/potential-bugs">1.23.8</a><ul class="dropdown__menu"><li><a class="dropdown__link" href="/docs/next/rules/potential-bugs">Next</a></li><li><a aria-current="page" class="dropdown__link dropdown__link--active" href="/docs/rules/potential-bugs">1.23.8</a></li><li><a class="dropdown__link" href="/docs/1.23.7/rules/potential-bugs">1.23.7</a></li><li><a class="dropdown__link" href="/docs/1.23.6/rules/potential-bugs">1.23.6</a></li><li><a class="dropdown__link" href="/docs/1.23.5/rules/potential-bugs">1.23.5</a></li><li><a class="dropdown__link" href="/docs/1.23.4/rules/potential-bugs">1.23.4</a></li><li><a class="dropdown__link" href="/docs/1.23.3/rules/potential-bugs">1.23.3</a></li><li><a class="dropdown__link" href="/docs/1.23.1/rules/potential-bugs">1.23.1</a></li><li><a class="dropdown__link" href="/docs/1.23.0/rules/potential-bugs">1.23.0</a></li><li><a class="dropdown__link" href="/docs/1.22.0/rules/potential-bugs">1.22.0</a></li><li><a class="dropdown__link" href="/docs/1.21.0/rules/potential-bugs">1.21.0</a></li><li><a class="dropdown__link" href="/changelog">All changelogs</a></li></ul></div><a href="https://github.com/detekt/detekt" target="_blank" rel="noopener noreferrer" class="navbar__item navbar__link header-github-link" aria-label="GitHub repository">GitHub<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a><div class="toggle_vylO colorModeToggle_DEke"><button class="clean-btn toggleButton_gllP toggleButtonDisabled_aARS" type="button" disabled="" title="Switch between dark and light mode (currently light mode)" aria-label="Switch between dark and light mode (currently light mode)" aria-live="polite" aria-pressed="false"><svg viewBox="0 0 24 24" width="24" height="24" class="lightToggleIcon_pyhR"><path fill="currentColor" d="M12,9c1.65,0,3,1.35,3,3s-1.35,3-3,3s-3-1.35-3-3S10.35,9,12,9 M12,7c-2.76,0-5,2.24-5,5s2.24,5,5,5s5-2.24,5-5 S14.76,7,12,7L12,7z M2,13l2,0c0.55,0,1-0.45,1-1s-0.45-1-1-1l-2,0c-0.55,0-1,0.45-1,1S1.45,13,2,13z M20,13l2,0c0.55,0,1-0.45,1-1 s-0.45-1-1-1l-2,0c-0.55,0-1,0.45-1,1S19.45,13,20,13z M11,2v2c0,0.55,0.45,1,1,1s1-0.45,1-1V2c0-0.55-0.45-1-1-1S11,1.45,11,2z M11,20v2c0,0.55,0.45,1,1,1s1-0.45,1-1v-2c0-0.55-0.45-1-1-1C11.45,19,11,19.45,11,20z M5.99,4.58c-0.39-0.39-1.03-0.39-1.41,0 c-0.39,0.39-0.39,1.03,0,1.41l1.06,1.06c0.39,0.39,1.03,0.39,1.41,0s0.39-1.03,0-1.41L5.99,4.58z M18.36,16.95 c-0.39-0.39-1.03-0.39-1.41,0c-0.39,0.39-0.39,1.03,0,1.41l1.06,1.06c0.39,0.39,1.03,0.39,1.41,0c0.39-0.39,0.39-1.03,0-1.41 L18.36,16.95z M19.42,5.99c0.39-0.39,0.39-1.03,0-1.41c-0.39-0.39-1.03-0.39-1.41,0l-1.06,1.06c-0.39,0.39-0.39,1.03,0,1.41 s1.03,0.39,1.41,0L19.42,5.99z M7.05,18.36c0.39-0.39,0.39-1.03,0-1.41c-0.39-0.39-1.03-0.39-1.41,0l-1.06,1.06 c-0.39,0.39-0.39,1.03,0,1.41s1.03,0.39,1.41,0L7.05,18.36z"></path></svg><svg viewBox="0 0 24 24" width="24" height="24" class="darkToggleIcon_wfgR"><path fill="currentColor" d="M9.37,5.51C9.19,6.15,9.1,6.82,9.1,7.5c0,4.08,3.32,7.4,7.4,7.4c0.68,0,1.35-0.09,1.99-0.27C17.45,17.19,14.93,19,12,19 c-3.86,0-7-3.14-7-7C5,9.07,6.81,6.55,9.37,5.51z M12,3c-4.97,0-9,4.03-9,9s4.03,9,9,9s9-4.03,9-9c0-0.46-0.04-0.92-0.1-1.36 c-0.98,1.37-2.58,2.26-4.4,2.26c-2.98,0-5.4-2.42-5.4-5.4c0-1.81,0.89-3.42,2.26-4.4C12.92,3.04,12.46,3,12,3L12,3z"></path></svg></button></div><div class="navbarSearchContainer_Bca1"><button type="button" class="DocSearch DocSearch-Button" aria-label="Search (Command+K)"><svg width="20" height="20" class="DocSearch-Search-Icon" viewBox="0 0 20 20" aria-hidden="true"><path d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" stroke="currentColor" fill="none" fill-rule="evenodd" stroke-linecap="round" stroke-linejoin="round"></path></svg>Search</button></div></div></div><div role="presentation" class="navbar-sidebar__backdrop"></div></nav><div id="__docusaurus_skipToContent_fallback" class="main-wrapper mainWrapper_z2l0"><div class="docsWrapper_hBAB"><button aria-label="Scroll back to top" class="clean-btn theme-back-to-top-button backToTopButton_sjWU" type="button"></button><div class="docRoot_UBD9"><aside class="theme-doc-sidebar-container docSidebarContainer_YfHR"><div class="sidebarViewport_aRkj"><div class="sidebar_njMd"><nav aria-label="Docs sidebar" class="menu thin-scrollbar menu_SIkG"><ul class="theme-doc-sidebar-menu menu__list"><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="/docs/intro">Welcome</a></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" role="button" aria-expanded="false" href="/docs/introduction/configurations">Introduction</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" role="button" aria-expanded="false" href="/docs/gettingstarted/cli">Getting Started</a></div></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret menu__link--active" role="button" aria-expanded="true" href="/docs/rules/comments">Rules Documentation</a></div><ul style="display:block;overflow:visible;height:auto" class="menu__list"><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/comments">Comments Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/complexity">Complexity Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/coroutines">Coroutines Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/empty-blocks">Empty-blocks Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/exceptions">Exceptions Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/formatting">Formatting Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/libraries">Libraries Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/naming">Naming Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/performance">Performance Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link menu__link--active" aria-current="page" tabindex="0" href="/docs/rules/potential-bugs">Potential-bugs Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/ruleauthors">Ruleauthors Rule Set</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-2 menu__list-item"><a class="menu__link" tabindex="0" href="/docs/rules/style">Style Rule Set</a></li></ul></li><li class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" role="button" aria-expanded="false" href="/changelog">Changelogs</a></div></li></ul></nav></div></div></aside><main class="docMainContainer_TBSr"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_VOVn"><div class="docItemContainer_Djhp"><article><nav class="theme-doc-breadcrumbs breadcrumbsContainer_Z_bl" aria-label="Breadcrumbs"><ul class="breadcrumbs" itemscope="" itemtype="https://schema.org/BreadcrumbList"><li class="breadcrumbs__item"><a aria-label="Home page" class="breadcrumbs__link" href="/"><svg viewBox="0 0 24 24" class="breadcrumbHomeIcon_YNFT"><path d="M10 19v-5h4v5c0 .55.45 1 1 1h3c.55 0 1-.45 1-1v-7h1.7c.46 0 .68-.57.33-.87L12.67 3.6c-.38-.34-.96-.34-1.34 0l-8.36 7.53c-.34.3-.13.87.33.87H5v7c0 .55.45 1 1 1h3c.55 0 1-.45 1-1z" fill="currentColor"></path></svg></a></li><li class="breadcrumbs__item">Rules Documentation<meta itemprop="position" content="1"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item breadcrumbs__item--active">Potential-bugs Rule Set<meta itemprop="position" content="2"></li></ul></nav>Version: 1.23.8<div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type="button" class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Potential-bugs Rule Set</h1></header>The potential-bugs rule set provides rules that detect potential bugs. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="avoidreferentialequality">AvoidReferentialEquality<a href="#avoidreferentialequality" class="hash-link" aria-label="Direct link to AvoidReferentialEquality" title="Direct link to AvoidReferentialEquality"></a></h3> Kotlin supports two types of equality: structural equality and referential equality. While there are use cases for both, checking for referential equality for some types (such as <code>String</code> or <code>List</code>) is likely not intentional and may cause unexpected results. Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options">Configuration options:<a href="#configuration-options" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <code>forbiddenTypePatterns</code> (default: <code>['kotlin.String']</code>) Specifies those types for which referential equality checks are considered a rule violation. The types are defined by a list of simple glob patterns (supporting <code>*</code> and <code>?</code> wildcards) that match the fully qualified type name. </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code">Noncompliant Code:<a href="#noncompliant-code" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv"> val areEqual = "aString" === otherString val areNotEqual = "aString" !== otherString </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code">Compliant Code:<a href="#compliant-code" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv"> val areEqual = "aString" == otherString val areNotEqual = "aString" != otherString </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="castnullabletononnullabletype">CastNullableToNonNullableType<a href="#castnullabletononnullabletype" class="hash-link" aria-label="Direct link to CastNullableToNonNullableType" title="Direct link to CastNullableToNonNullableType"></a></h3> Reports cast of nullable variable to non-null type. Cast like this can hide <code>null</code> problems in your code. The compliant code would be that which will correctly check for two things (nullability and type) and not just one (cast). Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-1">Noncompliant Code:<a href="#noncompliant-code-1" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(bar: Any?) { val x = bar as String } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-1">Compliant Code:<a href="#compliant-code-1" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(bar: Any?) { val x = checkNotNull(bar) as String } // Alternative fun foo(bar: Any?) { val x = (bar ?: error("null assertion message")) as String } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="casttonullabletype">CastToNullableType<a href="#casttonullabletype" class="hash-link" aria-label="Direct link to CastToNullableType" title="Direct link to CastToNullableType"></a></h3> Reports unsafe cast to nullable types. <code>as String?</code> is unsafed and may be misused as safe cast (<code>as? String</code>). Active by default: No Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-2">Noncompliant Code:<a href="#noncompliant-code-2" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(a: Any?) { val x: String? = a as String? // If 'a' is not String, ClassCastException will be thrown. } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-2">Compliant Code:<a href="#compliant-code-2" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(a: Any?) { val x: String? = a as? String } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="deprecation">Deprecation<a href="#deprecation" class="hash-link" aria-label="Direct link to Deprecation" title="Direct link to Deprecation"></a></h3> Deprecated elements are expected to be removed in the future. Alternatives should be found if possible. Active by default: No Requires Type Resolution Debt: 20min Aliases: DEPRECATION <h3 class="anchor anchorWithStickyNavbar_LWe7" id="dontdowncastcollectiontypes">DontDowncastCollectionTypes<a href="#dontdowncastcollectiontypes" class="hash-link" aria-label="Direct link to DontDowncastCollectionTypes" title="Direct link to DontDowncastCollectionTypes"></a></h3> Down-casting immutable types from kotlin.collections should be discouraged. The result of the downcast is platform specific and can lead to unexpected crashes. Prefer to use instead the <code>toMutable<Type>()</code> functions. Active by default: No Requires Type Resolution Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-3">Noncompliant Code:<a href="#noncompliant-code-3" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val list : List<Int> = getAList() if (list is MutableList) { list.add(42) } (list as MutableList).add(42) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-3">Compliant Code:<a href="#compliant-code-3" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val list : List<Int> = getAList() list.toMutableList().add(42) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="doublemutabilityforcollection">DoubleMutabilityForCollection<a href="#doublemutabilityforcollection" class="hash-link" aria-label="Direct link to DoubleMutabilityForCollection" title="Direct link to DoubleMutabilityForCollection"></a></h3> Using <code>var</code> when declaring a mutable collection or value holder leads to double mutability. Consider instead declaring your variable with <code>val</code> or switching your declaration to use an immutable type. By default, the rule triggers on standard mutable collections, however it can be configured to trigger on other types of mutable value types, such as <code>MutableState</code> from Jetpack Compose. Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 5min Aliases: DoubleMutability <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-1">Configuration options:<a href="#configuration-options-1" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <code>mutableTypes</code> (default: <code>['kotlin.collections.MutableList', 'kotlin.collections.MutableMap', 'kotlin.collections.MutableSet', 'java.util.ArrayList', 'java.util.LinkedHashSet', 'java.util.HashSet', 'java.util.LinkedHashMap', 'java.util.HashMap']</code>) Define a list of mutable types to trigger on when defined with <code>var</code>. </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-4">Noncompliant Code:<a href="#noncompliant-code-4" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">var myList = mutableListOf(1,2,3) var mySet = mutableSetOf(1,2,3) var myMap = mutableMapOf("answer" to 42) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-4">Compliant Code:<a href="#compliant-code-4" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">// Use val val myList = mutableListOf(1,2,3) val mySet = mutableSetOf(1,2,3) val myMap = mutableMapOf("answer" to 42) // Use immutable types var myList = listOf(1,2,3) var mySet = setOf(1,2,3) var myMap = mapOf("answer" to 42) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="duplicatecaseinwhenexpression"><del>DuplicateCaseInWhenExpression</del><a href="#duplicatecaseinwhenexpression" class="hash-link" aria-label="Direct link to duplicatecaseinwhenexpression" title="Direct link to duplicatecaseinwhenexpression"></a></h3> Rule deprecated as compiler performs this check by default Flags duplicate <code>case</code> statements in <code>when</code> expressions. If a <code>when</code> expression contains the same <code>case</code> statement multiple times they should be merged. Otherwise, it might be easy to miss one of the cases when reading the code, leading to unwanted side effects. Active by default: Yes - Since v1.0.0 Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-5">Noncompliant Code:<a href="#noncompliant-code-5" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">when (i) { 1 -> println("one") 1 -> println("one") else -> println("else") } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-5">Compliant Code:<a href="#compliant-code-5" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">when (i) { 1 -> println("one") else -> println("else") } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="elsecaseinsteadofexhaustivewhen">ElseCaseInsteadOfExhaustiveWhen<a href="#elsecaseinsteadofexhaustivewhen" class="hash-link" aria-label="Direct link to ElseCaseInsteadOfExhaustiveWhen" title="Direct link to ElseCaseInsteadOfExhaustiveWhen"></a></h3> This rule reports <code>when</code> expressions that contain an <code>else</code> case even though they have an exhaustive set of cases. This occurs when the subject of the <code>when</code> expression is either an enum class, sealed class or of type boolean. Using <code>else</code> cases for these expressions can lead to unintended behavior when adding new enum types, sealed subtypes or changing the nullability of a boolean, since this will be implicitly handled by the <code>else</code> case. Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-2">Configuration options:<a href="#configuration-options-2" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <code>ignoredSubjectTypes</code> (default: <code>[]</code>) List of fully qualified types which should be ignored for when expressions with a subject. Example <code>kotlinx.serialization.json.JsonObject</code> </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-6">Noncompliant Code:<a href="#noncompliant-code-6" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } when(c) { Color.RED -> {} Color.GREEN -> {} else -> {} } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-6">Compliant Code:<a href="#compliant-code-6" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } when(c) { Color.RED -> {} Color.GREEN -> {} Color.BLUE -> {} } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="equalsalwaysreturnstrueorfalse">EqualsAlwaysReturnsTrueOrFalse<a href="#equalsalwaysreturnstrueorfalse" class="hash-link" aria-label="Direct link to EqualsAlwaysReturnsTrueOrFalse" title="Direct link to EqualsAlwaysReturnsTrueOrFalse"></a></h3> Reports <code>equals()</code> methods which will always return true or false. Equals methods should always report if some other object is equal to the current object. See the Kotlin documentation for Any.equals(other: Any?): <a href="https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/equals.html" target="_blank" rel="noopener noreferrer">https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/equals.html</a> Active by default: Yes - Since v1.2.0 Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-7">Noncompliant Code:<a href="#noncompliant-code-7" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">override fun equals(other: Any?): Boolean { return true } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-7">Compliant Code:<a href="#compliant-code-7" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">override fun equals(other: Any?): Boolean { return this === other } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="equalswithhashcodeexist">EqualsWithHashCodeExist<a href="#equalswithhashcodeexist" class="hash-link" aria-label="Direct link to EqualsWithHashCodeExist" title="Direct link to EqualsWithHashCodeExist"></a></h3> When a class overrides the equals() method it should also override the hashCode() method. All hash-based collections depend on objects meeting the equals-contract. Two equal objects must produce the same hashcode. When inheriting equals or hashcode, override the inherited and call the super method for clarification. Active by default: Yes - Since v1.0.0 Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-8">Noncompliant Code:<a href="#noncompliant-code-8" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Foo { override fun equals(other: Any?): Boolean { return super.equals(other) } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-8">Compliant Code:<a href="#compliant-code-8" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Foo { override fun equals(other: Any?): Boolean { return super.equals(other) } override fun hashCode(): Int { return super.hashCode() } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="exitoutsidemain">ExitOutsideMain<a href="#exitoutsidemain" class="hash-link" aria-label="Direct link to ExitOutsideMain" title="Direct link to ExitOutsideMain"></a></h3> Reports the usage of <code>System.exit()</code>, <code>Runtime.exit()</code>, <code>Runtime.halt()</code> and Kotlin's <code>exitProcess()</code> when used outside the <code>main</code> function. This makes code more difficult to test, causes unexpected behaviour on Android, and is a poor way to signal a failure in the program. In almost all cases it is more appropriate to throw an exception. Active by default: No Requires Type Resolution Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-9">Noncompliant Code:<a href="#noncompliant-code-9" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun randomFunction() { val result = doWork() if (result == FAILURE) { exitProcess(2) } else { exitProcess(0) } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-9">Compliant Code:<a href="#compliant-code-9" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun main() { val result = doWork() if (result == FAILURE) { exitProcess(2) } else { exitProcess(0) } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="explicitgarbagecollectioncall">ExplicitGarbageCollectionCall<a href="#explicitgarbagecollectioncall" class="hash-link" aria-label="Direct link to ExplicitGarbageCollectionCall" title="Direct link to ExplicitGarbageCollectionCall"></a></h3> Reports all calls to explicitly trigger the Garbage Collector. Code should work independently of the garbage collector and should not require the GC to be triggered in certain points in time. Active by default: Yes - Since v1.0.0 Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-10">Noncompliant Code:<a href="#noncompliant-code-10" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">System.gc() Runtime.getRuntime().gc() System.runFinalization() </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="hasplatformtype">HasPlatformType<a href="#hasplatformtype" class="hash-link" aria-label="Direct link to HasPlatformType" title="Direct link to HasPlatformType"></a></h3> Platform types must be declared explicitly in public APIs to prevent unexpected errors. Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-11">Noncompliant Code:<a href="#noncompliant-code-11" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Person { fun apiCall() = System.getProperty("propertyName") } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-10">Compliant Code:<a href="#compliant-code-10" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Person { fun apiCall(): String = System.getProperty("propertyName") } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="ignoredreturnvalue">IgnoredReturnValue<a href="#ignoredreturnvalue" class="hash-link" aria-label="Direct link to IgnoredReturnValue" title="Direct link to IgnoredReturnValue"></a></h3> This rule warns on instances where a function, annotated with either <code>@CheckReturnValue</code> or <code>@CheckResult</code>, returns a value but that value is not used in any way. The Kotlin compiler gives no warning for this scenario normally so that's the rationale behind this rule. fun returnsValue() = 42 fun returnsNoValue() Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-3">Configuration options:<a href="#configuration-options-3" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <del><code>restrictToAnnotatedMethods</code></del> (default: <code>true</code>) Deprecated: Use <code>restrictToConfig</code> instead if the rule should check only annotated methods </li> <li> <code>restrictToConfig</code> (default: <code>true</code>) If the rule should check only methods matching to configuration, or all methods </li> <li> <code>returnValueAnnotations</code> (default: <code>['CheckResult', '*.CheckResult', 'CheckReturnValue', '*.CheckReturnValue']</code>) List of glob patterns to be used as inspection annotation </li> <li> <code>ignoreReturnValueAnnotations</code> (default: <code>['CanIgnoreReturnValue', '*.CanIgnoreReturnValue']</code>) Annotations to skip this inspection </li> <li> <code>returnValueTypes</code> (default: <code>['kotlin.sequences.Sequence', 'kotlinx.coroutines.flow.*Flow', 'java.util.stream.*Stream']</code>) List of return types that should not be ignored </li> <li> <code>ignoreFunctionCall</code> (default: <code>[]</code>) List of function signatures which should be ignored by this rule. Specifying fully-qualified function signature with name only (i.e. <code>java.time.LocalDate.now</code>) will ignore all function calls matching the name. Specifying fully-qualified function signature with parameters (i.e. <code>java.time.LocalDate.now(java.time.Clock)</code>) will ignore only function calls matching the name and parameters exactly. </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-12">Noncompliant Code:<a href="#noncompliant-code-12" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">returnsValue() </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-11">Compliant Code:<a href="#compliant-code-11" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">if (42 == returnsValue()) {} val x = returnsValue() </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="implicitdefaultlocale">ImplicitDefaultLocale<a href="#implicitdefaultlocale" class="hash-link" aria-label="Direct link to ImplicitDefaultLocale" title="Direct link to ImplicitDefaultLocale"></a></h3> Prefer passing [java.util.Locale] explicitly than using implicit default value when formatting strings or performing a case conversion. The default locale is almost always inappropriate for machine-readable text like HTTP headers. For example, if locale with tag <code>ar-SA-u-nu-arab</code> is a current default then <code>%d</code> placeholders will be evaluated to a number consisting of Eastern-Arabic (non-ASCII) digits. [java.util.Locale.US] is recommended for machine-readable output. Active by default: Yes - Since v1.16.0 Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-13">Noncompliant Code:<a href="#noncompliant-code-13" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">String.format("Timestamp: %d", System.currentTimeMillis()) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-12">Compliant Code:<a href="#compliant-code-12" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">String.format(Locale.US, "Timestamp: %d", System.currentTimeMillis()) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="implicitunitreturntype">ImplicitUnitReturnType<a href="#implicitunitreturntype" class="hash-link" aria-label="Direct link to ImplicitUnitReturnType" title="Direct link to ImplicitUnitReturnType"></a></h3> Functions using expression statements have an implicit return type. Changing the type of the expression accidentally, changes the functions return type. This may lead to backward incompatibility. Use a block statement to make clear this function will never return a value. Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-4">Configuration options:<a href="#configuration-options-4" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <code>allowExplicitReturnType</code> (default: <code>true</code>) if functions with explicit <code>Unit</code> return type should be allowed </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-14">Noncompliant Code:<a href="#noncompliant-code-14" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun errorProneUnit() = println("Hello Unit") fun errorProneUnitWithParam(param: String) = param.run { println(this) } fun String.errorProneUnitWithReceiver() = run { println(this) } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-13">Compliant Code:<a href="#compliant-code-13" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun blockStatementUnit() { // code } // explicit Unit is compliant by default; can be configured to enforce block statement fun safeUnitReturn(): Unit = println("Hello Unit") </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="invalidrange">InvalidRange<a href="#invalidrange" class="hash-link" aria-label="Direct link to InvalidRange" title="Direct link to InvalidRange"></a></h3> Reports ranges which are empty. This might be a bug if it is used for instance as a loop condition. This loop will never be triggered then. This might be due to invalid ranges like (10..9) which will cause the loop to never be entered. Active by default: Yes - Since v1.2.0 Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-15">Noncompliant Code:<a href="#noncompliant-code-15" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">for (i in 2..1) {} for (i in 1 downTo 2) {} val range1 = 2 until 1 val range2 = 2 until 2 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-14">Compliant Code:<a href="#compliant-code-14" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">for (i in 2..2) {} for (i in 2 downTo 2) {} val range = 2 until 3 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="iteratorhasnextcallsnextmethod">IteratorHasNextCallsNextMethod<a href="#iteratorhasnextcallsnextmethod" class="hash-link" aria-label="Direct link to IteratorHasNextCallsNextMethod" title="Direct link to IteratorHasNextCallsNextMethod"></a></h3> Verifies implementations of the Iterator interface. The hasNext() method of an Iterator implementation should not have any side effects. This rule reports implementations that call the next() method of the Iterator inside the hasNext() method. Active by default: Yes - Since v1.2.0 Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-16">Noncompliant Code:<a href="#noncompliant-code-16" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class MyIterator : Iterator<String> { override fun hasNext(): Boolean { return next() != null } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="iteratornotthrowingnosuchelementexception">IteratorNotThrowingNoSuchElementException<a href="#iteratornotthrowingnosuchelementexception" class="hash-link" aria-label="Direct link to IteratorNotThrowingNoSuchElementException" title="Direct link to IteratorNotThrowingNoSuchElementException"></a></h3> Reports implementations of the <code>Iterator</code> interface which do not throw a NoSuchElementException in the implementation of the next() method. When there are no more elements to return an Iterator should throw a NoSuchElementException. See: <a href="https://docs.oracle.com/javase/7/docs/api/java/util/Iterator.html#next()" target="_blank" rel="noopener noreferrer">https://docs.oracle.com/javase/7/docs/api/java/util/Iterator.html#next()</a> Active by default: Yes - Since v1.2.0 Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-17">Noncompliant Code:<a href="#noncompliant-code-17" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class MyIterator : Iterator<String> { override fun next(): String { return "" } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-15">Compliant Code:<a href="#compliant-code-15" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class MyIterator : Iterator<String> { override fun next(): String { if (!this.hasNext()) { throw NoSuchElementException() } // ... } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="lateinitusage">LateinitUsage<a href="#lateinitusage" class="hash-link" aria-label="Direct link to LateinitUsage" title="Direct link to LateinitUsage"></a></h3> Reports usages of the lateinit modifier. Using lateinit for property initialization can be error-prone and the actual initialization is not guaranteed. Try using constructor injection or delegation to initialize properties. Active by default: No Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-5">Configuration options:<a href="#configuration-options-5" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <del><code>excludeAnnotatedProperties</code></del> (default: <code>[]</code>) Deprecated: Use <code>ignoreAnnotated</code> instead Allows you to provide a list of annotations that disable this check. </li> <li> <code>ignoreOnClassesPattern</code> (default: <code>''</code>) Allows you to disable the rule for a list of classes </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-18">Noncompliant Code:<a href="#noncompliant-code-18" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Foo { private lateinit var i1: Int lateinit var i2: Int } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="mapgetwithnotnullassertionoperator">MapGetWithNotNullAssertionOperator<a href="#mapgetwithnotnullassertionoperator" class="hash-link" aria-label="Direct link to MapGetWithNotNullAssertionOperator" title="Direct link to MapGetWithNotNullAssertionOperator"></a></h3> Reports calls of the map access methods <code>map[]</code> or <code>map.get()</code> with a not-null assertion operator <code>!!</code>. This may result in a NullPointerException. Preferred access methods are <code>map[]</code> without <code>!!</code>, <code>map.getValue()</code>, <code>map.getOrDefault()</code> or <code>map.getOrElse()</code>. Based on an IntelliJ IDEA inspection MapGetWithNotNullAssertionOperatorInspection. Active by default: Yes - Since v1.21.0 Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-19">Noncompliant Code:<a href="#noncompliant-code-19" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val map = emptyMap<String, String>() map["key"]!! val map = emptyMap<String, String>() map.get("key")!! </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-16">Compliant Code:<a href="#compliant-code-16" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val map = emptyMap<String, String>() map["key"] val map = emptyMap<String, String>() map.getValue("key") val map = emptyMap<String, String>() map.getOrDefault("key", "") val map = emptyMap<String, String>() map.getOrElse("key", { "" }) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="missingpackagedeclaration">MissingPackageDeclaration<a href="#missingpackagedeclaration" class="hash-link" aria-label="Direct link to MissingPackageDeclaration" title="Direct link to MissingPackageDeclaration"></a></h3> Reports when the package declaration is missing. Active by default: No Debt: 5min <h3 class="anchor anchorWithStickyNavbar_LWe7" id="missingwhencase"><del>MissingWhenCase</del><a href="#missingwhencase" class="hash-link" aria-label="Direct link to missingwhencase" title="Direct link to missingwhencase"></a></h3> Rule deprecated as compiler performs this check by default Turn on this rule to flag <code>when</code> expressions that do not check that all cases are covered when the subject is an enum or sealed class and the <code>when</code> expression is used as a statement. When this happens it's unclear what was intended when an unhandled case is reached. It is better to be explicit and either handle all cases or use a default <code>else</code> statement to cover the unhandled cases. Active by default: Yes - Since v1.2.0 Requires Type Resolution Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="configuration-options-6">Configuration options:<a href="#configuration-options-6" class="hash-link" aria-label="Direct link to Configuration options:" title="Direct link to Configuration options:"></a></h4> <ul> <li> <code>allowElseExpression</code> (default: <code>true</code>) whether <code>else</code> can be treated as a valid case for enums and sealed classes </li> </ul> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-20">Noncompliant Code:<a href="#noncompliant-code-20" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } fun whenOnEnumFail(c: Color) { when(c) { Color.BLUE -> {} Color.GREEN -> {} } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-17">Compliant Code:<a href="#compliant-code-17" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } fun whenOnEnumCompliant(c: Color) { when(c) { Color.BLUE -> {} Color.GREEN -> {} Color.RED -> {} } } fun whenOnEnumCompliant2(c: Color) { when(c) { Color.BLUE -> {} else -> {} } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="nullcheckonmutableproperty">NullCheckOnMutableProperty<a href="#nullcheckonmutableproperty" class="hash-link" aria-label="Direct link to NullCheckOnMutableProperty" title="Direct link to NullCheckOnMutableProperty"></a></h3> Reports null-checks on mutable properties, as these properties' value can be changed - and thus make the null-check invalid - after the execution of the if-statement. Active by default: No Requires Type Resolution Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-21">Noncompliant Code:<a href="#noncompliant-code-21" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class A(private var a: Int?) { fun foo() { if (a != null) { println(2 + a!!) } } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-18">Compliant Code:<a href="#compliant-code-18" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class A(private val a: Int?) { fun foo() { if (a != null) { println(2 + a) } } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="nullabletostringcall">NullableToStringCall<a href="#nullabletostringcall" class="hash-link" aria-label="Direct link to NullableToStringCall" title="Direct link to NullableToStringCall"></a></h3> Reports <code>toString()</code> calls with a nullable receiver that may return the string "null". Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-22">Noncompliant Code:<a href="#noncompliant-code-22" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(a: Any?): String { return a.toString() } fun bar(a: Any?): String { return "$a" } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-19">Compliant Code:<a href="#compliant-code-19" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(a: Any?): String { return a?.toString() ?: "-" } fun bar(a: Any?): String { return "${a ?: "-"}" } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="propertyusedbeforedeclaration">PropertyUsedBeforeDeclaration<a href="#propertyusedbeforedeclaration" class="hash-link" aria-label="Direct link to PropertyUsedBeforeDeclaration" title="Direct link to PropertyUsedBeforeDeclaration"></a></h3> Reports properties that are used before declaration. Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-23">Noncompliant Code:<a href="#noncompliant-code-23" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class C { private val number get() = if (isValid) 1 else 0 val list = listOf(number) private val isValid = true } fun main() { println(C().list) // [0] } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-20">Compliant Code:<a href="#compliant-code-20" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class C { private val isValid = true private val number get() = if (isValid) 1 else 0 val list = listOf(number) } fun main() { println(C().list) // [1] } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="redundantelseinwhen"><del>RedundantElseInWhen</del><a href="#redundantelseinwhen" class="hash-link" aria-label="Direct link to redundantelseinwhen" title="Direct link to redundantelseinwhen"></a></h3> Rule deprecated as compiler performs this check by default Reports <code>when</code> expressions that contain a redundant <code>else</code> case. This occurs when it can be verified that all cases are already covered when checking cases on an enum or sealed class. Active by default: Yes - Since v1.2.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-24">Noncompliant Code:<a href="#noncompliant-code-24" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } fun whenOnEnumFail(c: Color) { when(c) { Color.BLUE -> {} Color.GREEN -> {} Color.RED -> {} else -> {} } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-21">Compliant Code:<a href="#compliant-code-21" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">enum class Color { RED, GREEN, BLUE } fun whenOnEnumCompliant(c: Color) { when(c) { Color.BLUE -> {} Color.GREEN -> {} else -> {} } } fun whenOnEnumCompliant2(c: Color) { when(c) { Color.BLUE -> {} Color.GREEN -> {} Color.RED -> {} } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unconditionaljumpstatementinloop">UnconditionalJumpStatementInLoop<a href="#unconditionaljumpstatementinloop" class="hash-link" aria-label="Direct link to UnconditionalJumpStatementInLoop" title="Direct link to UnconditionalJumpStatementInLoop"></a></h3> Reports loops which contain jump statements that jump regardless of any conditions. This implies that the loop is only executed once and thus could be rewritten without a loop altogether. Active by default: No Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-25">Noncompliant Code:<a href="#noncompliant-code-25" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">for (i in 1..2) break </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-22">Compliant Code:<a href="#compliant-code-22" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">for (i in 1..2) { if (i == 1) break } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unnecessarynotnullcheck">UnnecessaryNotNullCheck<a href="#unnecessarynotnullcheck" class="hash-link" aria-label="Direct link to UnnecessaryNotNullCheck" title="Direct link to UnnecessaryNotNullCheck"></a></h3> Reports unnecessary not-null checks with <code>requireNotNull</code> or <code>checkNotNull</code> that can be removed by the user. Active by default: No Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-26">Noncompliant Code:<a href="#noncompliant-code-26" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">var string = "foo" println(requireNotNull(string)) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-23">Compliant Code:<a href="#compliant-code-23" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">var string : String? = "foo" println(requireNotNull(string)) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unnecessarynotnulloperator">UnnecessaryNotNullOperator<a href="#unnecessarynotnulloperator" class="hash-link" aria-label="Direct link to UnnecessaryNotNullOperator" title="Direct link to UnnecessaryNotNullOperator"></a></h3> Reports unnecessary not-null operator usage (!!) that can be removed by the user. Active by default: Yes - Since v1.16.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-27">Noncompliant Code:<a href="#noncompliant-code-27" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val a = 1 val b = a!! </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-24">Compliant Code:<a href="#compliant-code-24" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val a = 1 val b = a </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unnecessarysafecall">UnnecessarySafeCall<a href="#unnecessarysafecall" class="hash-link" aria-label="Direct link to UnnecessarySafeCall" title="Direct link to UnnecessarySafeCall"></a></h3> Reports unnecessary safe call operators (<code>?.</code>) that can be removed by the user. Active by default: Yes - Since v1.16.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-28">Noncompliant Code:<a href="#noncompliant-code-28" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val a: String = "" val b = a?.length </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-25">Compliant Code:<a href="#compliant-code-25" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val a: String? = null val b = a?.length </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unreachablecatchblock">UnreachableCatchBlock<a href="#unreachablecatchblock" class="hash-link" aria-label="Direct link to UnreachableCatchBlock" title="Direct link to UnreachableCatchBlock"></a></h3> Reports unreachable catch blocks. Catch blocks can be unreachable if the exception has already been caught in the block above. Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-29">Noncompliant Code:<a href="#noncompliant-code-29" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun test() { try { foo() } catch (t: Throwable) { bar() } catch (e: Exception) { // Unreachable baz() } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-26">Compliant Code:<a href="#compliant-code-26" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun test() { try { foo() } catch (e: Exception) { baz() } catch (t: Throwable) { bar() } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unreachablecode">UnreachableCode<a href="#unreachablecode" class="hash-link" aria-label="Direct link to UnreachableCode" title="Direct link to UnreachableCode"></a></h3> Reports unreachable code. Code can be unreachable because it is behind return, throw, continue or break expressions. This unreachable code should be removed as it serves no purpose. Active by default: Yes - Since v1.0.0 Requires Type Resolution Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-30">Noncompliant Code:<a href="#noncompliant-code-30" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">for (i in 1..2) { break println() // unreachable } throw IllegalArgumentException() println() // unreachable fun f() { return println() // unreachable } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unsafecallonnullabletype">UnsafeCallOnNullableType<a href="#unsafecallonnullabletype" class="hash-link" aria-label="Direct link to UnsafeCallOnNullableType" title="Direct link to UnsafeCallOnNullableType"></a></h3> Reports unsafe calls on nullable types. These calls will throw a NullPointerException in case the nullable value is null. Kotlin provides many ways to work with nullable types to increase null safety. Guard the code appropriately to prevent NullPointerExceptions. Active by default: Yes - Since v1.2.0 Requires Type Resolution Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-31">Noncompliant Code:<a href="#noncompliant-code-31" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(str: String?) { println(str!!.length) } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-27">Compliant Code:<a href="#compliant-code-27" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(str: String?) { println(str?.length) } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unsafecast">UnsafeCast<a href="#unsafecast" class="hash-link" aria-label="Direct link to UnsafeCast" title="Direct link to UnsafeCast"></a></h3> Reports casts that will never succeed. Active by default: Yes - Since v1.16.0 Requires Type Resolution Debt: 20min Aliases: UNCHECKED_CAST <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-32">Noncompliant Code:<a href="#noncompliant-code-32" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(s: String) { println(s as Int) } fun bar(s: String) { println(s as? Int) } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-28">Compliant Code:<a href="#compliant-code-28" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">fun foo(s: Any) { println(s as Int) } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="unusedunaryoperator">UnusedUnaryOperator<a href="#unusedunaryoperator" class="hash-link" aria-label="Direct link to UnusedUnaryOperator" title="Direct link to UnusedUnaryOperator"></a></h3> Detects unused unary operators. Active by default: Yes - Since v1.21.0 Requires Type Resolution Debt: 5min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-33">Noncompliant Code:<a href="#noncompliant-code-33" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val x = 1 + 2 + 3 + 4 println(x) // 3 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-29">Compliant Code:<a href="#compliant-code-29" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">val x = 1 + 2 + 3 + 4 println(x) // 10 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="uselesspostfixexpression">UselessPostfixExpression<a href="#uselesspostfixexpression" class="hash-link" aria-label="Direct link to UselessPostfixExpression" title="Direct link to UselessPostfixExpression"></a></h3> Reports postfix expressions (++, --) which are unused and thus unnecessary. This leads to confusion as a reader of the code might think the value will be incremented/decremented. However, the value is replaced with the original value which might lead to bugs. Active by default: Yes - Since v1.21.0 Debt: 20min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-34">Noncompliant Code:<a href="#noncompliant-code-34" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">var i = 0 i = i-- i = 1 + i++ i = i++ + 1 fun foo(): Int { var i = 0 // ... return i++ } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-30">Compliant Code:<a href="#compliant-code-30" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">var i = 0 i-- i = i + 2 i = i + 2 fun foo(): Int { var i = 0 // ... i++ return i } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="wrongequalstypeparameter">WrongEqualsTypeParameter<a href="#wrongequalstypeparameter" class="hash-link" aria-label="Direct link to WrongEqualsTypeParameter" title="Direct link to WrongEqualsTypeParameter"></a></h3> Reports equals() methods which take in a wrongly typed parameter. Correct implementations of the equals() method should only take in a parameter of type Any? See: <a href="https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/equals.html" target="_blank" rel="noopener noreferrer">https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/equals.html</a> Active by default: Yes - Since v1.2.0 Debt: 10min <h4 class="anchor anchorWithStickyNavbar_LWe7" id="noncompliant-code-35">Noncompliant Code:<a href="#noncompliant-code-35" class="hash-link" aria-label="Direct link to Noncompliant Code:" title="Direct link to Noncompliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Foo { fun equals(other: String): Boolean { return super.equals(other) } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="compliant-code-31">Compliant Code:<a href="#compliant-code-31" class="hash-link" aria-label="Direct link to Compliant Code:" title="Direct link to Compliant Code:"></a></h4> <div class="language-kotlin codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-kotlin codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Foo { fun equals(other: Any?): Boolean { return super.equals(other) } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="row margin-top--sm theme-doc-footer-edit-meta-row"><div class="col"><a href="https://github.com/detekt/detekt/edit/main/website/versioned_docs/version-1.23.8/rules/potential-bugs.md" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_JAkA"></div></div></footer></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"><a class="pagination-nav__link pagination-nav__link--prev" href="/docs/rules/performance"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">Performance Rule Set</div></a><a class="pagination-nav__link pagination-nav__link--next" href="/docs/rules/ruleauthors"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">Ruleauthors Rule Set</div></a></nav></div></div><div class="col col--3"><div class="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#avoidreferentialequality" class="table-of-contents__link toc-highlight">AvoidReferentialEquality</a></li><li><a href="#castnullabletononnullabletype" class="table-of-contents__link toc-highlight">CastNullableToNonNullableType</a></li><li><a href="#casttonullabletype" class="table-of-contents__link toc-highlight">CastToNullableType</a></li><li><a href="#deprecation" class="table-of-contents__link toc-highlight">Deprecation</a></li><li><a href="#dontdowncastcollectiontypes" class="table-of-contents__link toc-highlight">DontDowncastCollectionTypes</a></li><li><a href="#doublemutabilityforcollection" class="table-of-contents__link toc-highlight">DoubleMutabilityForCollection</a></li><li><a href="#duplicatecaseinwhenexpression" class="table-of-contents__link toc-highlight"><del>DuplicateCaseInWhenExpression</del></a></li><li><a href="#elsecaseinsteadofexhaustivewhen" class="table-of-contents__link toc-highlight">ElseCaseInsteadOfExhaustiveWhen</a></li><li><a href="#equalsalwaysreturnstrueorfalse" class="table-of-contents__link toc-highlight">EqualsAlwaysReturnsTrueOrFalse</a></li><li><a href="#equalswithhashcodeexist" class="table-of-contents__link toc-highlight">EqualsWithHashCodeExist</a></li><li><a href="#exitoutsidemain" class="table-of-contents__link toc-highlight">ExitOutsideMain</a></li><li><a href="#explicitgarbagecollectioncall" class="table-of-contents__link toc-highlight">ExplicitGarbageCollectionCall</a></li><li><a href="#hasplatformtype" class="table-of-contents__link toc-highlight">HasPlatformType</a></li><li><a href="#ignoredreturnvalue" class="table-of-contents__link toc-highlight">IgnoredReturnValue</a></li><li><a href="#implicitdefaultlocale" class="table-of-contents__link toc-highlight">ImplicitDefaultLocale</a></li><li><a href="#implicitunitreturntype" class="table-of-contents__link toc-highlight">ImplicitUnitReturnType</a></li><li><a href="#invalidrange" class="table-of-contents__link toc-highlight">InvalidRange</a></li><li><a href="#iteratorhasnextcallsnextmethod" class="table-of-contents__link toc-highlight">IteratorHasNextCallsNextMethod</a></li><li><a href="#iteratornotthrowingnosuchelementexception" class="table-of-contents__link toc-highlight">IteratorNotThrowingNoSuchElementException</a></li><li><a href="#lateinitusage" class="table-of-contents__link toc-highlight">LateinitUsage</a></li><li><a href="#mapgetwithnotnullassertionoperator" class="table-of-contents__link toc-highlight">MapGetWithNotNullAssertionOperator</a></li><li><a href="#missingpackagedeclaration" class="table-of-contents__link toc-highlight">MissingPackageDeclaration</a></li><li><a href="#missingwhencase" class="table-of-contents__link toc-highlight"><del>MissingWhenCase</del></a></li><li><a href="#nullcheckonmutableproperty" class="table-of-contents__link toc-highlight">NullCheckOnMutableProperty</a></li><li><a href="#nullabletostringcall" class="table-of-contents__link toc-highlight">NullableToStringCall</a></li><li><a href="#propertyusedbeforedeclaration" class="table-of-contents__link toc-highlight">PropertyUsedBeforeDeclaration</a></li><li><a href="#redundantelseinwhen" class="table-of-contents__link toc-highlight"><del>RedundantElseInWhen</del></a></li><li><a href="#unconditionaljumpstatementinloop" class="table-of-contents__link toc-highlight">UnconditionalJumpStatementInLoop</a></li><li><a href="#unnecessarynotnullcheck" class="table-of-contents__link toc-highlight">UnnecessaryNotNullCheck</a></li><li><a href="#unnecessarynotnulloperator" class="table-of-contents__link toc-highlight">UnnecessaryNotNullOperator</a></li><li><a href="#unnecessarysafecall" class="table-of-contents__link toc-highlight">UnnecessarySafeCall</a></li><li><a href="#unreachablecatchblock" class="table-of-contents__link toc-highlight">UnreachableCatchBlock</a></li><li><a href="#unreachablecode" class="table-of-contents__link toc-highlight">UnreachableCode</a></li><li><a href="#unsafecallonnullabletype" class="table-of-contents__link toc-highlight">UnsafeCallOnNullableType</a></li><li><a href="#unsafecast" class="table-of-contents__link toc-highlight">UnsafeCast</a></li><li><a href="#unusedunaryoperator" class="table-of-contents__link toc-highlight">UnusedUnaryOperator</a></li><li><a href="#uselesspostfixexpression" class="table-of-contents__link toc-highlight">UselessPostfixExpression</a></li><li><a href="#wrongequalstypeparameter" class="table-of-contents__link toc-highlight">WrongEqualsTypeParameter</a></li></ul></div></div></div></div></main></div></div></div><footer class="footer footer--dark"><div class="container container-fluid"><div class="row footer__links"><div class="col footer__col"><div class="footer__title">Docs</div><ul class="footer__items clean-list"><li class="footer__item"><a class="footer__link-item" href="/docs/gettingstarted/gradle">Getting Started with Gradle</a></li><li class="footer__item"><a class="footer__link-item" href="/docs/gettingstarted/cli">Getting Started with the CLI</a></li><li class="footer__item"><a class="footer__link-item" href="/docs/rules/comments">Rules Documentation</a></li></ul></div><div class="col footer__col"><div class="footer__title">Community</div><ul class="footer__items clean-list"><li class="footer__item"><a href="https://kotlinlang.slack.com/archives/C88E12QH4" target="_blank" rel="noopener noreferrer" class="footer__link-item">Slack<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><li class="footer__item"><a href="https://stackoverflow.com/questions/tagged/detekt" target="_blank" rel="noopener noreferrer" class="footer__link-item">Stack Overflow<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li></ul></div><div class="col footer__col"><div class="footer__title">More</div><ul class="footer__items clean-list"><li class="footer__item"><a class="footer__link-item" href="/blog">Blog</a></li><li class="footer__item"><a href="https://github.com/detekt/detekt" target="_blank" rel="noopener noreferrer" class="footer__link-item">GitHub<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><li class="footer__item"><a href="https://detekt.dev/kdoc" target="_blank" rel="noopener noreferrer" class="footer__link-item">KDoc<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_nPIU"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li></ul></div></div><div class="footer__bottom text--center"><div class="footer__copyright">Copyright © 2025 detekt team - Built with Docusaurus.</div></div></div></footer></div> </body> </html>