yCodeTech · yCodeTech · Mar 26, 2026 · Mar 26, 2026
diff --git a/README.md b/README.md
@@ -579,6 +579,56 @@ $bar = (integer) $count;
 </tr>
 </table>
 
+### yCodeTech.Types.DisallowVoidType
+
+Explicit `void` return type declarations are disallowed on functions, methods, and closures. The absence of a return type already implies void.
+
+<table>
+  <tr>
+    <th>Rules</th>
+    <th>Fixable?</th>
+  </tr>
+  <tr>
+    <td>Explicit <code>: void</code> return type declarations must be removed.</td>
+    <td>✔️</td>
+  </tr>
+</table>
+
+#### Violation Codes:
+
+`yCodeTech.Types.DisallowVoidType.Found`
+
+#### Examples:
+
+<table>
+<tr>
+  <th>✔️ Valid: No return type (implicitly void)</th>
+  <th>❌ Invalid: Explicit void return type</th>
+</tr>
+<tr>
+<td>
+
+```php
+function doSomething()
+{
+    echo "Hello";
+}
+```
+
+</td>
+<td>
+
+```php
+function doSomething(): void
+{
+    echo "Hello";
+}
+```
+
+</td>
+</tr>
+</table>
+
 ## Testing
 
 To test the standard against the provided comprehensive test file, please see [the specific instructions](./test_utils/README.md).

diff --git a/test_utils/TestFile.php b/test_utils/TestFile.php
@@ -270,11 +270,14 @@ public function testMissingGeneratorReturn()
      ***********************/
 
     /**
-     * Function that returns void with an explicit `void` typing
-     * (should NOT be flagged for missing `@return` tag).
+    * Function that returns void with an explicit `void` typing
+     * (should be flagged for explicit void type, but NOT for missing `@return` tag).
+     *
+     * The following should be fixed:
+     * - The explicit `: void` return type should be removed.
      *
      * The following should NOT be fixed:
-     * - A `@return` tag should not be added for an explicit `void` return.
+     * - A `@return` tag should not be added.
      *
      * @param string $message Message to display
      */
@@ -360,6 +363,7 @@ function testVoidFunctionWithAnonymousFunction()
      *
      * The following should be fixed:
      * - The `@return` tag should be removed.
+     * - The explicit `: void` return type should be removed.
      *
      * @return void
      */

diff --git a/test_utils/TestFile_WithErrors_DoNotFix.php b/test_utils/TestFile_WithErrors_DoNotFix.php
@@ -270,11 +270,14 @@ public function testMissingGeneratorReturn()
      ***********************/
 
     /**
-     * Function that returns void with an explicit `void` typing
-     * (should NOT be flagged for missing `@return` tag).
+    * Function that returns void with an explicit `void` typing
+     * (should be flagged for explicit void type, but NOT for missing `@return` tag).
+     *
+     * The following should be fixed:
+     * - The explicit `: void` return type should be removed.
      *
      * The following should NOT be fixed:
-     * - A `@return` tag should not be added for an explicit `void` return.
+     * - A `@return` tag should not be added.
      *
      * @param string $message Message to display
      */
@@ -360,6 +363,7 @@ function testVoidFunctionWithAnonymousFunction()
      *
      * The following should be fixed:
      * - The `@return` tag should be removed.
+     * - The explicit `: void` return type should be removed.
      *
      * @return void
      */

diff --git a/yCodeTech/Docs/Types/DisallowVoidTypeStandard.xml b/yCodeTech/Docs/Types/DisallowVoidTypeStandard.xml
@@ -0,0 +1,28 @@
+<documentation title="Disallow Void Type">
+    <standard>
+        <![CDATA[
+        Explicit void return type declarations are disallowed. The absence of a return type already implies void.
+
+        ---
+
+        ]]>
+    </standard>
+    <code_comparison>
+        <code title="✔️ Valid: No return type (implicitly void)">
+            <![CDATA[
+function doSomething()
+{
+    echo "Hello";
+}
+            ]]>
+        </code>
+        <code title="❌ Invalid: Explicit void return type">
+            <![CDATA[
+function doSomething()<em>: void</em>
+{
+    echo "Hello";
+}
+            ]]>
+        </code>
+    </code_comparison>
+</documentation>
diff --git a/yCodeTech/Sniffs/Types/DisallowVoidTypeSniff.php b/yCodeTech/Sniffs/Types/DisallowVoidTypeSniff.php
@@ -0,0 +1,144 @@
+<?php
+
+/**
+ * DisallowVoidType sniff for yCodeTech PHPCS Standard.
+ *
+ * Disallows explicit void return type declarations on functions and methods.
+ *
+ * @category PHP
+ * @package PHP_CodeSniffer
+ * @author yCodeTech
+ * @license https://github.com/squizlabs/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
+ */
+
+namespace yCodeTech\Sniffs\Types;
+
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Files\File;
+
+/**
+ * DisallowVoidType sniff.
+ *
+ * Disallows explicit `: void` return type declarations on functions, methods,
+ * and closures. The absence of a return type already implies void.
+ */
+class DisallowVoidTypeSniff implements Sniff
+{
+    /**
+     * Returns an array of tokens this test wants to listen for.
+     *
+     * @return array<int>
+     */
+    public function register()
+    {
+        return [T_FUNCTION, T_CLOSURE];
+    }
+
+    /**
+     * Processes this test, when one of its tokens is encountered.
+     *
+     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
+     * @param int $stackPtr The position of the current token in the
+     *                                                   stack passed in $tokens.
+     */
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        $voidPtr = $this->getExplicitVoidTypePtr($phpcsFile, $stackPtr);
+        if ($voidPtr === false) {
+            return;
+        }
+
+        $error = 'Explicit void return type is not allowed and should be removed';
+        $fix = $phpcsFile->addFixableError($error, $voidPtr, 'Found');
+        if ($fix === true) {
+            $this->removeExplicitVoidType($phpcsFile, $stackPtr);
+        }
+    }
+
+    /**
+     * Get the position of the explicit `void` return type token, if present.
+     *
+     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
+     * @param int $stackPtr The position of the function token.
+     *
+     * @return int|false The position of the void token, or false if not found.
+     */
+    private function getExplicitVoidTypePtr(File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $openParen = $phpcsFile->findNext(T_OPEN_PARENTHESIS, $stackPtr);
+        if ($openParen === false) {
+            return false;
+        }
+
+        $closeParen = $tokens[$openParen]['parenthesis_closer'] ?? null;
+        if ($closeParen === null) {
+            return false;
+        }
+
+        $scopeOpener = $tokens[$stackPtr]['scope_opener'] ?? null;
+        $semicolonPtr = $phpcsFile->findNext(T_SEMICOLON, $closeParen + 1);
+        $searchEnd = $scopeOpener ?? ($semicolonPtr !== false ? $semicolonPtr + 1 : null);
+
+        $colonPtr = $phpcsFile->findNext(T_COLON, $closeParen + 1, $searchEnd);
+        if ($colonPtr === false) {
+            return false;
+        }
+
+        $returnTypePtr = $phpcsFile->findNext(T_WHITESPACE, $colonPtr + 1, null, true);
+        if ($returnTypePtr === false) {
+            return false;
+        }
+
+        if ($tokens[$returnTypePtr]['code'] === T_STRING && $tokens[$returnTypePtr]['content'] === 'void') {
+            return $returnTypePtr;
+        }
+
+        return false;
+    }
+
+    /**
+     * Remove explicit `: void` return type from a function signature.
+     *
+     * Removes the colon, any whitespace between colon and void, and the `void`
+     * token itself, leaving the rest of the signature intact.
+     *
+     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
+     * @param int $stackPtr The position of the function token.
+     */
+    private function removeExplicitVoidType(File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $openParen = $phpcsFile->findNext(T_OPEN_PARENTHESIS, $stackPtr);
+        if ($openParen === false) {
+            return;
+        }
+
+        $closeParen = $tokens[$openParen]['parenthesis_closer'] ?? null;
+        if ($closeParen === null) {
+            return;
+        }
+
+        $scopeOpener = $tokens[$stackPtr]['scope_opener'] ?? null;
+        $semicolonPtr = $phpcsFile->findNext(T_SEMICOLON, $closeParen + 1);
+        $searchEnd = $scopeOpener ?? ($semicolonPtr !== false ? $semicolonPtr + 1 : null);
+
+        $colonPtr = $phpcsFile->findNext(T_COLON, $closeParen + 1, $searchEnd);
+        if ($colonPtr === false) {
+            return;
+        }
+
+        $voidPtr = $phpcsFile->findNext(T_WHITESPACE, $colonPtr + 1, null, true);
+        if ($voidPtr === false || $tokens[$voidPtr]['content'] !== 'void') {
+            return;
+        }
+
+        $phpcsFile->fixer->beginChangeset();
+        for ($i = $colonPtr; $i <= $voidPtr; $i++) {
+            $phpcsFile->fixer->replaceToken($i, '');
+        }
+        $phpcsFile->fixer->endChangeset();
+    }
+}
diff --git a/yCodeTech/Tests/Types/DisallowVoidTypeUnitTest.inc b/yCodeTech/Tests/Types/DisallowVoidTypeUnitTest.inc
@@ -0,0 +1,40 @@
+<?php
+
+// @phpcs:disable yCodeTech.Commenting.FunctionComment
+// We're not concerned with docblocks here.
+
+/**
+ * Test file for DisallowVoidTypeSniff.
+ *
+ * Tests detection of explicit void return type declarations.
+ */
+
+class TestClass
+{
+    public function explicitVoidMethod(): void
+    {
+        echo "Hello";
+    }
+
+    public function explicitVoidWithParam(string $message): void
+    {
+        echo $message;
+    }
+
+    // Should not flag - no void type
+    public function regularMethod(): string
+    {
+        return "Hello";
+    }
+
+    // Should not flag - no return type
+    public function noReturnType()
+    {
+        echo "Hello";
+    }
+}
+
+function explicitVoidFunction(): void
+{
+    echo "Hello";
+}
diff --git a/yCodeTech/Tests/Types/DisallowVoidTypeUnitTest.inc.fixed b/yCodeTech/Tests/Types/DisallowVoidTypeUnitTest.inc.fixed
@@ -0,0 +1,40 @@
+<?php
+
+// @phpcs:disable yCodeTech.Commenting.FunctionComment
+// We're not concerned with docblocks here.
+
+/**
+ * Test file for DisallowVoidTypeSniff.
+ *
+ * Tests detection of explicit void return type declarations.
+ */
+
+class TestClass
+{
+    public function explicitVoidMethod()
+    {
+        echo "Hello";
+    }
+
+    public function explicitVoidWithParam(string $message)
+    {
+        echo $message;
+    }
+
+    // Should not flag - no void type
+    public function regularMethod(): string
+    {
+        return "Hello";
+    }
+
+    // Should not flag - no return type
+    public function noReturnType()
+    {
+        echo "Hello";
+    }
+}
+
+function explicitVoidFunction()
+{
+    echo "Hello";
+}