diff --git a/.gitignore b/.gitignore
index aee02fc..6a56064 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,5 @@
 build
 dist
 luaparser.egg-info
-venv
\ No newline at end of file
+venv
+.venv
diff --git a/luaparser/astnodes.py b/luaparser/astnodes.py
index ea2fa69..6f1f3f6 100644
--- a/luaparser/astnodes.py
+++ b/luaparser/astnodes.py
@@ -7,7 +7,7 @@
 from enum import Enum
 from typing import List, Optional
 
-from antlr4 import Token
+from antlr4.Token import CommonToken
 
 Comments = Optional[List["Comment"]]
 
@@ -30,8 +30,8 @@ def __init__(
         self,
         name: str,
         comments: Comments = None,
-        first_token: Optional[Token] = None,
-        last_token: Optional[Token] = None,
+        first_token: Optional[CommonToken] = None,
+        last_token: Optional[CommonToken] = None,
     ):
         """
 
@@ -45,8 +45,19 @@ def __init__(
             comments = []
         self._name: str = name
         self.comments: Comments = comments
-        self._first_token: Optional[Token] = first_token
-        self._last_token: Optional[Token] = last_token
+        self._first_token: Optional[CommonToken] = first_token
+        self._last_token: Optional[CommonToken] = last_token
+
+        # We want to have nodes be serializable with pickle.
+        # To allow that we must not have mutable fields such as streams.
+        # Tokens have streams, create a stream-less copy of tokens.
+        if self._first_token is not None:
+            self._first_token = self._first_token.clone()
+            self._first_token.source = CommonToken.EMPTY_SOURCE
+
+        if self._last_token is not None:
+            self._last_token = self._last_token.clone()
+            self._last_token.source = CommonToken.EMPTY_SOURCE
 
     @property
     def display_name(self) -> str:
@@ -60,20 +71,34 @@ def __eq__(self, other) -> bool:
         return False
 
     @property
-    def first_token(self) -> Optional[Token]:
+    def first_token(self) -> Optional[CommonToken]:
+        """
+        First token of a node.
+
+        Note: Token is disconnected from underline source streams.
+        """
         return self._first_token
 
     @first_token.setter
-    def first_token(self, val):
-        self._first_token = val
+    def first_token(self, val: Optional[CommonToken]):
+        if val is not None:
+            self._first_token = val.clone()
+            self._first_token.source = CommonToken.EMPTY_SOURCE
 
     @property
-    def last_token(self) -> Optional[Token]:
+    def last_token(self) -> Optional[CommonToken]:
+        """
+        Last token of a node.
+
+        Note: Token is disconnected from underline source streams.
+        """
         return self._last_token
 
     @last_token.setter
-    def last_token(self, val):
-        self._last_token = val
+    def last_token(self, val: Optional[CommonToken]):
+        if val is not None:
+            self._last_token = val.clone()
+            self._last_token.source = CommonToken.EMPTY_SOURCE
 
     @property
     def start_char(self) -> Optional[int]:
diff --git a/luaparser/builder.py b/luaparser/builder.py
index ed53505..490b369 100644
--- a/luaparser/builder.py
+++ b/luaparser/builder.py
@@ -220,7 +220,7 @@ def __init__(self, source):
         self._hidden_handled_stack: List[bool] = []
 
     @property
-    def _LT(self) -> Token:
+    def _LT(self) -> CommonToken:
         """Last token that was consumed in next_i*_* method."""
         return self._stream.LT(-1)
 
@@ -665,9 +665,7 @@ def parse_tail(self) -> Node or bool:
                 last_token=self._LT,
             )
             if self.next_is_rc(Tokens.STRING, False):
-                string = self.parse_lua_str(self.text)
-                string.first_token = self._LT.start
-                string.last_token = self._LT
+                string = self.parse_lua_str(self.text, self._LT)
                 self.success()
                 # noinspection PyTypeChecker
                 return Invoke(None, name, [string])
@@ -705,9 +703,7 @@ def parse_tail(self) -> Node or bool:
 
         self.failure_save()
         if self.next_is_rc(Tokens.STRING, False):
-            string = self.parse_lua_str(self.text)
-            string.first_token = self._LT
-            string.last_token = self._LT
+            string = self.parse_lua_str(self.text, self._LT)
             self.success()
             return string
 
@@ -1410,9 +1406,7 @@ def parse_atom(self) -> Expression or bool:
             )
 
         if self.next_is(Tokens.STRING) and self.next_is_rc(Tokens.STRING):
-            string = self.parse_lua_str(self.text)
-            string.first_token = self._LT
-            string.last_token = self._LT
+            string = self.parse_lua_str(self.text, self._LT)
             return string
 
         if self.next_is(Tokens.NIL) and self.next_is_rc(Tokens.NIL):
@@ -1426,7 +1420,7 @@ def parse_atom(self) -> Expression or bool:
         return None
 
     @staticmethod
-    def parse_lua_str(lua_str) -> String:
+    def parse_lua_str(lua_str, token: Optional[CommonToken] = None) -> String:
         delimiter: StringDelimiter = StringDelimiter.SINGLE_QUOTE
         p = re.compile(r"^\[=+\[(.*)]=+]")  # nested quote pattern
         # try remove double quote:
@@ -1444,7 +1438,7 @@ def parse_lua_str(lua_str) -> String:
         # nested quote
         elif p.match(lua_str):
             lua_str = p.search(lua_str).group(1)
-        return String(lua_str, delimiter)
+        return String(lua_str, delimiter, first_token=token, last_token=token)
 
     def parse_function_literal(self) -> AnonymousFunction or bool:
         self.save()