Fixes #6589: updated code style guide to mention else after return, adjusted…

docs/internals/core-code-style.md

@@ -262,6 +262,29 @@ if (!$model && null === $event)
     throw new Exception('test');
 ```
 
+Prefer avoiding `else` after `return` where it makes sense.
+Use [guard conditions](http://refactoring.com/catalog/replaceNestedConditionalWithGuardClauses.html).
+
+```php
+$result = $this->getResult();
+if (empty($result)) {
+  return true;
+} else {
+  // process result
+}
+```
+
+is better as
+
+```php
+$result = $this->getResult();
+if (empty($result)) {
+  return true;
+}
+
+// process result
+```
+
 #### switch
 
 Use the following formatting for switch:

framework/validators/Validator.php

@@ -267,7 +267,8 @@ class Validator extends Component
         $result = $this->validateValue($value);
         if (empty($result)) {
             return true;
-        } else {
+        }
+
         list($message, $params) = $result;
         $params['attribute'] = Yii::t('yii', 'the input value');
         $params['value'] = is_array($value) ? 'array()' : $value;
@@ -275,7 +276,6 @@ class Validator extends Component
 
         return false;
     }
-    }
 
     /**
      * Validates a value.