fix #1320

Author: sumneko

Diff for: changelog.md

@@ -25,6 +25,7 @@
 * `FIX` [#1292](https://github.com/sumneko/lua-language-server/issues/1292)
 * `FIX` [#1294](https://github.com/sumneko/lua-language-server/issues/1294)
 * `FIX` [#1317](https://github.com/sumneko/lua-language-server/issues/1317)
+* `FIX` [#1320](https://github.com/sumneko/lua-language-server/issues/1320)
 
 ## 3.4.2
 `2022-7-6`

Diff for: script/vm/runner.lua

@@ -136,6 +136,7 @@ function mt:_lookIntoChild(action, topNode, outNode)
         if action.op.type == 'not' then
             outNode = outNode or topNode:copy()
             outNode, topNode = self:_lookIntoChild(action[1], topNode, outNode)
+            outNode = outNode:copy()
         end
     elseif action.type == 'binary' then
         if not action[1] or not action[2] then
@@ -242,8 +243,13 @@ function mt:_lookIntoChild(action, topNode, outNode)
             mainNode  = topNode:copy()
         end
         blockNode = self:_lookIntoBlock(action, blockNode:copy())
-        if mainNode then
-            topNode = mainNode:merge(blockNode)
+        topNode = mainNode:merge(blockNode)
+        if action.filter then
+            -- look into filter again
+            guide.eachSource(action.filter, function (src)
+                self._mark[src] = nil
+            end)
+            blockNode, topNode = self:_lookIntoChild(action.filter, topNode:copy(), topNode:copy())
         end
     elseif action.type == 'if' then
         local hasElse

Diff for: script/vm/value.lua

@@ -23,7 +23,8 @@ function vm.testCondition(source)
                 hasFalse = true
             end
         elseif n.type == 'global' and n.cate == 'type' then
-            if n.name == 'boolean' then
+            if n.name == 'boolean'
+            or n.name == 'unknown' then
                 return nil
             end
             if n.name == 'false'

Diff for: test/type_inference/init.lua

@@ -3680,3 +3680,26 @@ local t
 
 local <?x?> = t and t[i]
 ]]
+
+TEST 'number' [[
+---@type number
+local x
+
+if not <?x?>.y then
+    x = nil
+end
+]]
+
+TEST 'number' [[
+---@type number|nil
+local x
+while x == nil do
+    if x == nil then
+        return
+    end
+
+    x = nil
+end
+
+print(<?x?>)
+]]