src/Fixer/ControlStructure/YodaStyleFixer.php
private function fixTokensCompare(
        Tokens $tokens,
        $startLeft,
        $endLeft,
        $compareOperatorIndex,
        $startRight,
        $endRight
    ) {
        $type = $tokens[$compareOperatorIndex]->getId();
        $content = $tokens[$compareOperatorIndex]->getContent();
        if (\array_key_exists($type, $this->candidatesMap)) {
            $tokens[$compareOperatorIndex] = clone $this->candidatesMap[$type];
        } elseif (\array_key_exists($content, $this->candidatesMap)) {
            $tokens[$compareOperatorIndex] = clone $this->candidatesMap[$content];
        }

        $right = $this->fixTokensComparePart($tokens, $startRight, $endRight);
        $left = $this->fixTokensComparePart($tokens, $startLeft, $endLeft);

        for ($i = $startRight; $i <= $endRight; ++$i) {
            $tokens->clearAt($i);
        }

        for ($i = $startLeft; $i <= $endLeft; ++$i) {
            $tokens->clearAt($i);
        }

        $tokens->insertAt($startRight, $left);
        $tokens->insertAt($startLeft, $right);

        return $startLeft;
    }
private function fixTokensCompare(
        Tokens $tokens,
        $startLeft,
        $endLeft,
        $compareOperatorIndex,
        $startRight,
        $endRight
    ) {
        $type = $tokens[$compareOperatorIndex]->getId();
        $content = $tokens[$compareOperatorIndex]->getContent();
        if (\array_key_exists($type, $this->candidatesMap)) {
            $tokens[$compareOperatorIndex] = clone $this->candidatesMap[$type];
        } elseif (\array_key_exists($content, $this->candidatesMap)) {
            $tokens[$compareOperatorIndex] = clone $this->candidatesMap[$content];
        }

        $right = $this->fixTokensComparePart($tokens, $startRight, $endRight);
        $left = $this->fixTokensComparePart($tokens, $startLeft, $endLeft);

        for ($i = $startRight; $i <= $endRight; ++$i) {
            $tokens->clearAt($i);
        }

        for ($i = $startLeft; $i <= $endLeft; ++$i) {
            $tokens->clearAt($i);
        }

        $tokens->insertAt($startRight, $left);
        $tokens->insertAt($startLeft, $right);

        return $startLeft;
    }
Fixes the comparison at the given index.

A comparison is considered fixed when
- both sides are a variable (e.g. $a === $b)
- neither side is a variable (e.g. self::CONST === 3)
- only the right-hand side is a variable (e.g. 3 === self::$var)

If the left-hand side and right-hand side of the given comparison are
swapped, this function runs recursively on the previous left-hand-side.

@param Tokens $tokens
@param int    $startLeft
@param int    $endLeft
@param int    $compareOperatorIndex
@param int    $startRight
@param int    $endRight

@return int a upper bound for all non-fixed comparisons