fix #1902

Author: sumneko

changelog.md

@@ -6,11 +6,13 @@
 * `FIX` [#1887]
 * `FIX` [#1889]
 * `FIX` [#1895]
+* `FIX` [#1902]
 
 [#1886]: https://github.com/LuaLS/lua-language-server/issues/1886
 [#1887]: https://github.com/LuaLS/lua-language-server/issues/1887
 [#1889]: https://github.com/LuaLS/lua-language-server/issues/1889
 [#1895]: https://github.com/LuaLS/lua-language-server/issues/1895
+[#1902]: https://github.com/LuaLS/lua-language-server/issues/1902
 
 ## 3.6.10
 `2023-2-7`

script/vm/tracer.lua

@@ -641,7 +641,8 @@ local lookIntoChild = util.switch()
             and    handler.args[1]
             and    tracer.getMap[handler.args[1]] then
                 -- if type(x) == 'string' then
-                tracer:lookIntoChild(handler, topNode:copy())
+                tracer:lookIntoChild(handler, topNode)
+                topNode = topNode:copy()
                 if action.op.type == '==' then
                     topNode:narrow(tracer.uri, checker[1])
                     if outNode then

test/diagnostics/type-check.lua

@@ -1201,6 +1201,16 @@ local function some_fn(some_param) return end
 some_fn { { "test" } } -- <- diagnostic: "Cannot assign `table` to `string`."
 ]]
 
+TEST [[
+---@param p integer|string
+local function get_val(p)
+    local is_number = type(p) == 'number'
+    return is_number and p or p
+end
+
+get_val('hi')
+]]
+
 config.remove(nil, 'Lua.diagnostics.disable', 'unused-local')
 config.remove(nil, 'Lua.diagnostics.disable', 'unused-function')
 config.remove(nil, 'Lua.diagnostics.disable', 'undefined-global')