Use custom logic for finding arrow function scope (#296)

* Add test for arrow function as argument

* Do not rely on phpcs to find scope for arrow functions

Author: sirbrillig

Tests/VariableAnalysisSniff/fixtures/ArrowFunctionFixture.php

@@ -87,3 +87,8 @@ function staticArrowFunctionAsVariableWithUnusedInside($subject) {
     $arrowFunc = static fn($foo) => $subject; // unused variable $foo
     echo $arrowFunc('hello');
 }
+
+function arrowFunctionAsExpressionInArgumentWithArray() {
+    $type = do_something(fn($array, $needle) => $array[2] === $needle);
+    echo $type;
+}

VariableAnalysis/Lib/Helpers.php

@@ -628,12 +628,6 @@ public static function isArrowFunction(File $phpcsFile, $stackPtr)
 	public static function getArrowFunctionOpenClose(File $phpcsFile, $stackPtr)
 	{
 		$tokens = $phpcsFile->getTokens();
-		if (defined('T_FN') && $tokens[$stackPtr]['code'] === T_FN) {
-			return [
-				'scope_opener' => $tokens[$stackPtr]['scope_opener'],
-				'scope_closer' => $tokens[$stackPtr]['scope_closer'],
-			];
-		}
 		if ($tokens[$stackPtr]['content'] !== 'fn') {
 			return null;
 		}