Globals set with `rawset` are always parsed as a table

[LJSonik]

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Windows

What is the issue affecting?

Annotations, Type Checking

Expected Behaviour

I expect x to be parsed as an integer:

rawset(_G, "x", 42)
print(x) -- x should be parsed as integer here

Actual Behaviour

x is parsed as integer|table instead.

Reproduction steps

rawset(_G, "x", 42)
print(x) -- x is parsed as integer|table here

Additional Notes

No response

Log File

No response

[tomlau10]

Root cause analysis

After some debugging, I found that the table infer type seems to be inserted by this code block 🤔:

lua-language-server/script/vm/compiler.lua

Lines 1869 to 1879 in 1831e60

	: case 'call'
	: call(function (source)
	local node = getReturn(source.node, 1, source.args)
	if not node then
	return
	end
	if not node:isTyped() then
	node = vm.runOperator('call', source.node) or node
	end
	vm.setNode(source, node)
	end)

• When compiling a rawset() call statement, this code block will be executed.
• I believe this logic is to use the return value of the call statement to set the left hand side variable if any (?),
  and the return value of rawset() is annotated as table type by built-in meta file:

  lua-language-server/meta/template/basic.lua

  Lines 198 to 202 in 1831e60

  	---@param table table
  	---@param index any
  	---@param value any
  	---@return table
  	function rawset(table, index, value) end

• so in the following code snippet

  local a = rawset() -- a: table

• But as rawset(_G, ...) is handled specially, the created global is treated as the (assignment) value of this call (?):

  lua-language-server/script/vm/global.lua

  Lines 296 to 299 in 1831e60

  	local global = vm.declareGlobal('variable', name, uri)
  	if source.node.special == 'rawset' then
  	global:addSet(uri, source)
  	source.value = source.args[3]

• This explains why the injected type is always table (the return type of rawset())

Proposed solution

I just tried to skip the logic if it is a rawset statement, and it worked perfectly 🎉

    : case 'call'
    : call(function (source)
        -- ignore rawset
        if source.node.special == 'rawset' then
            return
        end

• I originally afraid that this will break the local a = rawset() case, but seems not 😄
  a can still be inferred as table
• All existing tests passed, so no obvious side effects for this proposed change.

---

I believe this is the solution to this issue. I will try to open a PR for this, along with the proposed changes in #2862 (comment) to resolve these 2 issues together later 😄