New rule: Shared else-value for if/case #784

Open
Open
New rule: Shared else-value for if/case#784
Labels
new lintIssues suggesting new lints or pull requests implementing new lints

Description

@soegaard
soegaard
opened on Mar 21, 2026

Rule summary

From:

 (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

To:

 (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

The observation is that the value return by the else-arm of the if-expression,
is the same as the expression returned in the else-expression of the case.

Test case

#lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------

No-change test case

Additional context
Spotted here:
https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
Activity
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Metadata
Metadata
Assignees
No one assigned
    Labels
    new lintIssues suggesting new lints or pull requests implementing new lints
    Projects
    No projects
      Milestone
      No milestone
      Relationships
      None yet
      Development
      No branches or pull requests
      Issue actions
      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Add copy buttons to all 
       blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      New rule: Shared else-value for if/case #784
      Open
      Open
      New rule: Shared else-value for if/case#784
      Labels
      new lintIssues suggesting new lints or pull requests implementing new lints
      Description
      @soegaard
      soegaard
      opened on Mar 21, 2026
      Rule summary
      From:
       (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

      To:
       (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

      The observation is that the value return by the else-arm of the if-expression,
      
is the same as the expression returned in the else-expression of the case.
      Test case
      #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
      No-change test case
      Additional context
      Spotted here:
      https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
      Activity
      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
      Metadata
      Metadata
      Assignees
      No one assigned
        Labels
        new lintIssues suggesting new lints or pull requests implementing new lints
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          New rule: Shared else-value for if/case #784
          Open
          Open
          New rule: Shared else-value for if/case#784
          Labels
          new lintIssues suggesting new lints or pull requests implementing new lints
          Description
          @soegaard
          soegaard
          opened on Mar 21, 2026
          Rule summary
          From:
           (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

          To:
           (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

          The observation is that the value return by the else-arm of the if-expression,
          
is the same as the expression returned in the else-expression of the case.
          Test case
          #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
          No-change test case
          Additional context
          Spotted here:
          https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
          Activity
          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            new lintIssues suggesting new lints or pull requests implementing new lints
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              New rule: Shared else-value for if/case #784
              Open
              Open
              New rule: Shared else-value for if/case#784
              Labels
              new lintIssues suggesting new lints or pull requests implementing new lints
              Description
              @soegaard
              soegaard
              opened on Mar 21, 2026
              Rule summary
              From:
               (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

              To:
               (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

              The observation is that the value return by the else-arm of the if-expression,
              
is the same as the expression returned in the else-expression of the case.
              Test case
              #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
              No-change test case
              Additional context
              Spotted here:
              https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
              Activity
              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                new lintIssues suggesting new lints or pull requests implementing new lints
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  New rule: Shared else-value for if/case #784
                  Open
                  Open
                  New rule: Shared else-value for if/case#784
                  Labels
                  new lintIssues suggesting new lints or pull requests implementing new lints
                  Description
                  @soegaard
                  soegaard
                  opened on Mar 21, 2026
                  Rule summary
                  From:
                   (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

                  To:
                   (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

                  The observation is that the value return by the else-arm of the if-expression,
                  
is the same as the expression returned in the else-expression of the case.
                  Test case
                  #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
                  No-change test case
                  Additional context
                  Spotted here:
                  https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
                  Activity
                  Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    new lintIssues suggesting new lints or pull requests implementing new lints
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      New rule: Shared else-value for if/case #784
                      Open
                      Open
                      New rule: Shared else-value for if/case#784
                      Labels
                      new lintIssues suggesting new lints or pull requests implementing new lints
                      Description
                      @soegaard
                      soegaard
                      opened on Mar 21, 2026
                      Rule summary
                      From:
                       (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

                      To:
                       (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

                      The observation is that the value return by the else-arm of the if-expression,
                      
is the same as the expression returned in the else-expression of the case.
                      Test case
                      #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
                      No-change test case
                      Additional context
                      Spotted here:
                      https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
                      Activity
                      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        new lintIssues suggesting new lints or pull requests implementing new lints
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          New rule: Shared else-value for if/case #784
                          Open
                          Open
                          New rule: Shared else-value for if/case#784
                          Labels
                          new lintIssues suggesting new lints or pull requests implementing new lints
                          Description
                          @soegaard
                          soegaard
                          opened on Mar 21, 2026
                          Rule summary
                          From:
                           (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

                          To:
                           (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

                          The observation is that the value return by the else-arm of the if-expression,
                          
is the same as the expression returned in the else-expression of the case.
                          Test case
                          #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
                          No-change test case
                          Additional context
                          Spotted here:
                          https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
                          Activity
                          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            new lintIssues suggesting new lints or pull requests implementing new lints
                            Projects
                            No projects
                              Milestone
                              No milestone
                              Relationships
                              None yet
                              Development
                              No branches or pull requests
                              Issue actions
                              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                              Skip to content
                              New rule: Shared else-value for if/case #784
                              Open
                              Open
                              New rule: Shared else-value for if/case#784
                              Labels
                              new lintIssues suggesting new lints or pull requests implementing new lints
                              Description
                              @soegaard
                              soegaard
                              opened on Mar 21, 2026
                              Rule summary
                              From:
                               (if (symbol? level)
(case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])
'info)

                              To:
                               (case level
[(warning) 'warning]
[(danger) 'danger]
[(info success warning danger
primary secondary light dark) level]
[else 'info])

                              The observation is that the value return by the else-arm of the if-expression,
                              
is the same as the expression returned in the else-expression of the case.
                              Test case
                              #lang resyntax/test
test: "original code should be refactorable to new code"
--------------------
#lang racket
(definelevel 'foo)
(if (symbol? level)
(case level
[(warning) 'warning]
[else'info])
'info)
====================
#lang racket
(definelevel 'foo)
(case level
[(warning) 'warning]
[else'info])
--------------------
                              No-change test case
                              Additional context
                              Spotted here:
                              https://github.com/soegaard/webracket/blob/main/lib/web-easy/renderer.rkt#L892
                              Activity
                              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                new lintIssues suggesting new lints or pull requests implementing new lints
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions