Optimize memoization

Author: joshdifabio

demo/auto/AutoValue_Address.php

@@ -108,10 +108,7 @@ public function foo()
 
     public function linesString(): string
     {
-        if (!isset($this->__memoized['linesString'])) {
-            $this->__memoized['linesString'] = parent::linesString();
-        }
-        return $this->__memoized['linesString'];
+        return $this->__memoized['linesString'] ?? ($this->__memoized['linesString'] = parent::linesString());
     }
 
     /**

src/Memoize/MemoizeMethodProcessor.php

@@ -42,10 +42,7 @@ function (MethodDefinitionCollection $methodDefinitions, ReflectionMethod $metho
 THEPHP;
                 } else {
                     $methodBody = <<<THEPHP
-        if (!isset(\$this->__memoized['$methodName'])) {
-            \$this->__memoized['$methodName'] = parent::$methodName();
-        }
-        return \$this->__memoized['$methodName'];
+        return \$this->__memoized['$methodName'] ?? (\$this->__memoized['$methodName'] = parent::$methodName());
 THEPHP;
                 }
                 return $methodDefinitions->withAdditionalMethodDefinition(MethodDefinition::of($method, $methodBody));