src/Composer/DependencyResolver/Solver.php
private function enableDisableLearnedRules()
    {
        foreach ($this->rules->getIteratorFor(RuleSet::TYPE_LEARNED) as $rule) {
            $why = $this->learnedWhy[spl_object_hash($rule)];
            $problemRules = $this->learnedPool[$why];

            $foundDisabled = false;
            foreach ($problemRules as $problemRule) {
                if ($problemRule->isDisabled()) {
                    $foundDisabled = true;
                    break;
                }
            }

            if ($foundDisabled && $rule->isEnabled()) {
                $rule->disable();
            } elseif (!$foundDisabled && $rule->isDisabled()) {
                $rule->enable();
            }
        }
    }
private function enableDisableLearnedRules()
    {
        foreach ($this->rules->getIteratorFor(RuleSet::TYPE_LEARNED) as $rule) {
            $why = $this->learnedWhy[spl_object_hash($rule)];
            $problemRules = $this->learnedPool[$why];

            $foundDisabled = false;
            foreach ($problemRules as $problemRule) {
                if ($problemRule->isDisabled()) {
                    $foundDisabled = true;
                    break;
                }
            }

            if ($foundDisabled && $rule->isEnabled()) {
                $rule->disable();
            } elseif (!$foundDisabled && $rule->isDisabled()) {
                $rule->enable();
            }
        }
    }
enable/disable learnt rules

we have enabled or disabled some of our rules. We now re-enable all
of our learnt rules except the ones that were learnt from rules that
are now disabled.