diff --git a/lib/vast/ExprParser.py b/lib/vast/ExprParser.py
index b78282c..7131d15 100644
--- a/lib/vast/ExprParser.py
+++ b/lib/vast/ExprParser.py
@@ -77,7 +77,18 @@ class TokenStream:
         return self.Tokens[max(0, self.Idx - 1)]
 
     def _At(self, tok_type: str, value: str | None = None) -> bool:
-        tok: Token = self._Peek()
+        # 内联 _Peek(0) 缓存逻辑（行为与 _Peek(offset=0) 完全一致）：
+        # 命中缓存直接取 _PeekCacheTok，miss 时读 Tokens[i] 并更新缓存；
+        # i >= len(Tokens) 时取末尾哨兵 token（不更新缓存）。
+        i: int = self.Idx
+        if i >= len(self.Tokens):
+            tok: Token = self.Tokens[-1]
+        elif self._PeekCacheIdx == i:
+            tok = self._PeekCacheTok
+        else:
+            self._PeekCacheIdx = i
+            self._PeekCacheTok = self.Tokens[i]
+            tok = self._PeekCacheTok
         if tok.Type != tok_type:
             return False
         if value is not None and tok.Value != value:
diff --git a/lib/vast/Nodes.py b/lib/vast/Nodes.py
index a8aa790..8d8c498 100644
--- a/lib/vast/Nodes.py
+++ b/lib/vast/Nodes.py
@@ -310,9 +310,9 @@ def _MakeNodeClass(name: str, fields: tuple[str, ...], attrs: tuple[str, ...]) -
                 f'{name} constructor takes at most {len(fields)} positional arguments'
             )
         for fname, val in zip(fields, args):
-            setattr(self, fname, val)
+            self.__dict__[fname] = val
         for k, v in kwargs.items():
-            setattr(self, k, v)
+            self.__dict__[k] = v
 
     base_name: str | None = _BASE_CLASS.get(name)
     base_cls: type = globals()[base_name] if base_name else AST