src/Fixer/FunctionNotation/VoidReturnFixer.php
private function hasVoidReturn(Tokens $tokens, $startIndex, $endIndex)
    {
        $tokensAnalyzer = new TokensAnalyzer($tokens);

        for ($i = $startIndex; $i < $endIndex; ++$i) {
            if (
                // skip anonymous classes
                ($tokens[$i]->isGivenKind(T_CLASS) && $tokensAnalyzer->isAnonymousClass($i)) ||
                 // skip lambda functions
                ($tokens[$i]->isGivenKind(T_FUNCTION) && $tokensAnalyzer->isLambda($i))
            ) {
                $i = $tokens->getNextTokenOfKind($i, ['{']);
                $i = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_CURLY_BRACE, $i);

                continue;
            }

            if ($tokens[$i]->isGivenKind([T_YIELD, T_YIELD_FROM])) {
                return false; // Generators cannot return void.
            }

            if (!$tokens[$i]->isGivenKind(T_RETURN)) {
                continue;
            }

            $i = $tokens->getNextMeaningfulToken($i);
            if (!$tokens[$i]->equals(';')) {
                return false;
            }
        }

        return true;
    }
private function hasVoidReturn(Tokens $tokens, $startIndex, $endIndex)
    {
        $tokensAnalyzer = new TokensAnalyzer($tokens);

        for ($i = $startIndex; $i < $endIndex; ++$i) {
            if (
                // skip anonymous classes
                ($tokens[$i]->isGivenKind(T_CLASS) && $tokensAnalyzer->isAnonymousClass($i)) ||
                 // skip lambda functions
                ($tokens[$i]->isGivenKind(T_FUNCTION) && $tokensAnalyzer->isLambda($i))
            ) {
                $i = $tokens->getNextTokenOfKind($i, ['{']);
                $i = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_CURLY_BRACE, $i);

                continue;
            }

            if ($tokens[$i]->isGivenKind([T_YIELD, T_YIELD_FROM])) {
                return false; // Generators cannot return void.
            }

            if (!$tokens[$i]->isGivenKind(T_RETURN)) {
                continue;
            }

            $i = $tokens->getNextMeaningfulToken($i);
            if (!$tokens[$i]->equals(';')) {
                return false;
            }
        }

        return true;
    }
Determine whether the function has a void return.

@param Tokens $tokens
@param int    $startIndex Start of function body
@param int    $endIndex   End of function body

@return bool