protected function isValidAssignment(File $phpcsFile, $stackPtr, $end)
    {
        $tokens = $phpcsFile->getTokens();
        $next   = $phpcsFile->findNext(Tokens::$emptyTokens, ($stackPtr + 1), $end, true);
        if ($next === false || $tokens[$next]['code'] !== \T_EQUAL) {
            // No value assigned.
            return true;
        }

        return $this->isStaticValue($phpcsFile, $tokens, ($next + 1), ($end - 1));
    }