Optional TaggedUnions not refining to correct type when if validation is present

[23sinek345 (Dr_Sinek)]

From what I discovered the type solver just freaks out and evaluates to one of the types in the union when if validation is present.

Working Example (Union is not optional)

Source:

--!strict
type Type1 = {
	Type: "Type1",
	CommonKey: string,
	Type1Key: string,
}
type Type2 = {
	Type: "Type2",
	CommonKey: string,
	Type2Key: string,
}
type UnionType = Type1 | Type2

local foo: UnionType = nil
if foo.Type == "Type2" then
	foo.
end

---

Not Working Example (Union is optional)

Source:

--!strict
type Type1 = {
	Type: "Type1",
	CommonKey: string,
	Type1Key: string,
}
type Type2 = {
	Type: "Type2",
	CommonKey: string,
	Type2Key: string,
}
type UnionType = Type1 | Type2

local foo: UnionType? = nil
if foo then
	if foo.Type == "Type2" then
		foo.
	end
end

MORE INFO:

• Tried both the new and the old solver. They both fail
• Uninstalled all plugins before testing.
• No significant beta feature related to type solver other than New Typesolver
• Using latest build of roblox studio as of posting this

Expected behavior

Expected behaviour should be type still getting correctly refined.

[MercuryBromine0]

Hello! Thank you for the report and for beta testing the new type solver. This looks like a pretty strange issue, but I am able to reproduce the issue from your second example so we’ll take a look. We’ll try to keep you in the loop on any updates here.

[MercuryBromine0]

Just closing the loop here: the fix for this should have gone out some time ago! Please reach out if you encounter any further issues.