resolve #1154 resolve #1165

infer type by `t and t.x`

Author: sumneko

changelog.md

@@ -10,7 +10,7 @@
   ```
 * `CHG` infer type by `error`
   ```lua
-  ---@type integer?
+  ---@type integer|nil
   local n
 
   if not n then
@@ -19,6 +19,13 @@
 
   print(n) -- `n` is `integer` here
   ```
+* `CHG` infer type by `t and t.x`
+  ```lua
+  ---@type table|nil
+  local t
+
+  local s = t and t.x or 1 -- `t` in `t.x` is `table`
+  ```
 * `FIX` with clients that support LSP 3.17 (VSCode), workspace diagnostics are triggered every time when opening a file.
 * `FIX` [#1204](https://github.com/sumneko/lua-language-server/issues/1204)
 * `FIX` [#1208](https://github.com/sumneko/lua-language-server/issues/1208)

script/vm/runner.lua

@@ -8,6 +8,7 @@ local guide     = require 'parser.guide'
 ---@field _loc      parser.object
 ---@field _objs     parser.object[]
 ---@field _callback vm.runner.callback
+---@field _mark     table
 local mt = {}
 mt.__index = mt
 mt._index = 1
@@ -117,6 +118,17 @@ function mt:_lookInto(action, topNode, outNode)
     if not action then
         return topNode, outNode
     end
+    if self._mark[action] then
+        return
+    end
+    self._mark[action] = true
+    local top = self._objs[self._index]
+    if not top then
+        return topNode, outNode
+    end
+    if not guide.isInRange(action, top.finish) then
+        return topNode, outNode
+    end
     local set
     local value = vm.getObjectValue(action)
     if value then
@@ -232,10 +244,10 @@ function mt:_lookInto(action, topNode, outNode)
                 self:_lookInto(arg, topNode)
             end
         end
-    elseif action.type == 'return' then
-        for _, rtn in ipairs(action) do
-            self:_lookInto(rtn, topNode)
-        end
+    else
+        guide.eachSourceContain(action, top.finish, function(source)
+             self:_lookInto(source, topNode)
+        end)
     end
     ::RETURN::
     topNode = self:_fastWard(action.finish, topNode)
@@ -275,6 +287,7 @@ function vm.launchRunner(loc, callback)
     local self = setmetatable({
         _loc      = loc,
         _objs     = {},
+        _mark     = {},
         _callback = callback,
     }, mt)
 

test/type_inference/init.lua

@@ -2559,3 +2559,24 @@ end
 
 print(<?n?>)
 ]]
+
+TEST 'table' [[
+---@type table?
+local n
+
+print((n and <?n?>.x))
+]]
+
+TEST 'table' [[
+---@type table?
+local n
+
+n = n and <?n?>.x or 1
+]]
+
+TEST 'table' [[
+---@type table?
+local n
+
+n = ff[n and <?n?>.x]
+]]