fix #699 check nil

Author: sumneko

changelog.md

@@ -2,7 +2,8 @@
 
 ## 2.4.1
 * `FIX` broken with single file
-* `CHG` [#698](https://github.com/sumneko/lua-language-server/issues/698)
+* `FIX` [#698](https://github.com/sumneko/lua-language-server/issues/698)
+* `FIX` [#699](https://github.com/sumneko/lua-language-server/issues/699)
 
 ## 2.4.0
 `2021-10-1`

script/parser/newparser.lua

@@ -3645,7 +3645,9 @@ return function (lua, mode, version, options)
     elseif mode == 'Action' then
         State.ast = parseAction()
     end
-    State.ast.state = State
+    if State.ast then
+        State.ast.state = State
+    end
 
     return State
 end