UnusedVariableSniff: Fixed false positive

Author: kukulich

SlevomatCodingStandard/Sniffs/Variables/UnusedVariableSniff.php

@@ -41,6 +41,7 @@
 use const T_MUL_EQUAL;
 use const T_OBJECT_OPERATOR;
 use const T_OPEN_SHORT_ARRAY;
+use const T_OPEN_SQUARE_BRACKET;
 use const T_OPEN_TAG;
 use const T_OR_EQUAL;
 use const T_PLUS_EQUAL;
@@ -400,6 +401,11 @@ private function isUsedAsKeyOrValueInArray(File $phpcsFile, int $variablePointer
 	{
 		$tokens = $phpcsFile->getTokens();
 
+		$previousPointer = TokenHelper::findPreviousEffective($phpcsFile, $variablePointer - 1);
+		if ($tokens[$previousPointer]['code'] === T_OPEN_SQUARE_BRACKET) {
+			return true;
+		}
+
 		$arrayOpenerPointer = TokenHelper::findPrevious($phpcsFile, T_OPEN_SHORT_ARRAY, $variablePointer - 1);
 		if ($arrayOpenerPointer === null) {
 			return false;

tests/Sniffs/Variables/data/unusedVariableNoErrors.php

@@ -265,3 +265,14 @@ function () {
 		echo ".";
 	}
 };
+
+function () {
+	$a = [];
+	$i = 0;
+
+	foreach ([1, 2, 3] as $x) {
+	    $a[$i++] = $x;
+	}
+
+	return $a;
+};