fix #1275 check nil

Author: sumneko

changelog.md

@@ -5,6 +5,7 @@
   * `type.weakNilCheck`
 * `FIX` [#1256](https://github.com/sumneko/lua-language-server/issues/1256)
 * `FIX` [#1257](https://github.com/sumneko/lua-language-server/issues/1257)
+* `FIX` [#1275](https://github.com/sumneko/lua-language-server/issues/1275)
 
 ## 3.4.0
 `2022-6-29`

script/vm/compiler.lua

@@ -1012,7 +1012,7 @@ local function compileLocal(source)
     -- for x in ... do
     if source.parent.type == 'in' then
         compileForVars(source.parent)
-        local keyNode = source.parent._iterVars[source]
+        local keyNode = source.parent._iterVars and source.parent._iterVars[source]
         if keyNode then
             vm.setNode(source, keyNode)
         end