diff --git a/VariableAnalysis/Lib/Helpers.php b/VariableAnalysis/Lib/Helpers.php
index 9b03bcd..b05917e 100644
--- a/VariableAnalysis/Lib/Helpers.php
+++ b/VariableAnalysis/Lib/Helpers.php
@@ -69,6 +69,9 @@ public static function findContainingOpeningBracket(File $phpcsFile, $stackPtr)
 	{
 		$tokens = $phpcsFile->getTokens();
 		if (isset($tokens[$stackPtr]['nested_parenthesis'])) {
+			/**
+			 * @var array<int|string|null>
+			 */
 			$openPtrs = array_keys($tokens[$stackPtr]['nested_parenthesis']);
 			return (int)end($openPtrs);
 		}
@@ -1081,6 +1084,9 @@ public static function getFunctionIndexForFunctionCallArgument(File $phpcsFile,
 		if (empty($token['nested_parenthesis'])) {
 			return null;
 		}
+		/**
+		 * @var array<int|string|null>
+		 */
 		$startingParenthesis = array_keys($token['nested_parenthesis']);
 		$startOfArguments = end($startingParenthesis);
 		if (! is_int($startOfArguments)) {