fix(php): 解决类方法参数中使用$this的问题并优化静态属性访问

- 添加对类方法中使用$this作为参数名的错误检查
- 修复静态属性被当作动态属性访问时返回null的逻辑
- 在关键词列表中添加this_作为phpx保留关键字

src/Php/CompilerBase.php

@@ -1046,14 +1046,17 @@ class CompilerBase extends \PhpAot\Core\Translator
                     $this->fatalError($param, 'Variadic parameters cannot be passed by reference');
                 }
             }
-            $name          = $this->parseIdentifier($param->var);
+            $name = $this->parseIdentifier($param->var);
-            $type          = $this->parseParameterType($param, $name);
+            if ($this->method and $name == 'this_') {
+                $this->fatalError($param, 'Cannot use `$this` as parameter of class method');
+            }
+            $type = $this->parseParameterType($param, $name);
             if ($param->variadic) {
-                $list[]        = self::TYPE_ARRAY . ' ' . $name;
+                $list[] = self::TYPE_ARRAY . ' ' . $name;
             } else {
-                $list[]        = $type . ' ' . $name;
+                $list[] = $type . ' ' . $name;
             }
-            $argInfo       = new ArgInfo();
+            $argInfo = new ArgInfo();
             $argInfo->name = $name;
             $argInfo->type = $type;
             $argInfo->byRef = $param->byRef;
@@ -4005,6 +4008,10 @@ class CompilerBase extends \PhpAot\Core\Translator
                 $classDef = $this->getClass($findClass);
                 if ($classDef->hasProperty($property)) {
                     $propertyDef = $classDef->getProperty($property);
+                    // 属性是静态的，但作为动态属性访问，只能动态获取
+                    if ($propertyDef->isStatic()) {
+                        return null;
+                    }
                     if ($propertyDef->isPublic()) {
                         return $this->getPropertyOffset($classDef->getNamespacedName(false), $property);
                     }

src/Php/Constants.php

@@ -54,6 +54,7 @@ class Constants
         'template',
         'namespace',
         'errno', // Linux error code
+        'this_', // phpx keywords
     ];
 
     public const UNSUPPORTED_FUNCTIONS = [