Fixed bug #3284 : Unused parameter false positive when using array index in arrow function

Author: gsherwood

package.xml

@@ -150,6 +150,7 @@ http://pear.php.net/dtd/package-2.0.xsd">
     -- Thanks to Juliette Reinders Folmer for the patch
   - Fixed bug #3273 : Squiz.Functions.FunctionDeclarationArgumentSpacing reports line break as 0 spaces between parenthesis
   - Fixed bug #3277 : Nullable static return typehint causes whitespace error
+  - Fixed bug #3284 : Unused parameter false positive when using array index in arrow function
  </notes>
  <contents>
   <dir name="/">

src/Standards/Generic/Sniffs/CodeAnalysis/UnusedFunctionParameterSniff.php

@@ -91,7 +91,7 @@ public function process(File $phpcsFile, $stackPtr)
 
         foreach ($methodParams as $param) {
             if (isset($param['property_visibility']) === true) {
-                // Ignore. Constructor property promotion.
+                // Ignore constructor property promotion.
                 continue;
             }
 
@@ -101,6 +101,13 @@ public function process(File $phpcsFile, $stackPtr)
         $next = ++$token['scope_opener'];
         $end  = --$token['scope_closer'];
 
+        // Check the end token for arrow functions as
+        // they can end at a content token due to not having
+        // a clearly defined closing token.
+        if ($token['code'] === T_FN) {
+            ++$end;
+        }
+
         $foundContent = false;
         $validTokens  = [
             T_HEREDOC              => T_HEREDOC,

src/Standards/Generic/Tests/CodeAnalysis/UnusedFunctionParameterUnitTest.inc

@@ -150,3 +150,5 @@ class ConstructorPropertyPromotionWithContentInMethod {
         }
     }
 }
+
+$found = in_array_cb($needle, $haystack, fn($array, $needle) => $array[2] === $needle);

src/Tokenizers/PHP.php

@@ -2343,7 +2343,12 @@ protected function processAdditional()
                                     && $this->tokens[$scopeCloser]['code'] === T_CLOSE_PARENTHESIS
                                     && $this->tokens[$scopeCloser]['parenthesis_opener'] < $arrow
                                 ) {
-                                    $scopeCloser = $lastEndToken;
+                                    for ($lastNonEmpty = ($scopeCloser - 1); $lastNonEmpty > $arrow; $lastNonEmpty--) {
+                                        if (isset(Util\Tokens::$emptyTokens[$this->tokens[$lastNonEmpty]['code']]) === false) {
+                                            $scopeCloser = $lastNonEmpty;
+                                            break;
+                                        }
+                                    }
                                 }
 
                                 break;

tests/Core/Tokenizer/BackfillFnTokenTest.inc

@@ -40,6 +40,9 @@ $extended = fn($c) => $callable(function() {
     echo 'done';
 }, $c);
 
+/* testArrayIndex */
+$found = in_array_cb($needle, $haystack, fn($array, $needle) => $array[2] === $needle);
+
 $result = array_map(
     /* testReturnType */
     static fn(int $number) : int => $number + 1,

tests/Core/Tokenizer/BackfillFnTokenTest.php

@@ -192,6 +192,22 @@ public function testClosure()
     }//end testClosure()
 
 
+    /**
+     * Test arrow functions using an array index.
+     *
+     * @covers PHP_CodeSniffer\Tokenizers\PHP::processAdditional
+     *
+     * @return void
+     */
+    public function testArrayIndex()
+    {
+        $token = $this->getTargetToken('/* testArrayIndex */', T_FN);
+        $this->backfillHelper($token);
+        $this->scopePositionTestHelper($token, 8, 17, 'comma');
+
+    }//end testArrayIndex()
+
+
     /**
      * Test arrow functions with a return type.
      *