Allow Instance.new("Model") :: (Model & {kid: BasePart})

[0x13479]

--!strict
local a = Instance.new("Model") :: (Model & {kid: BasePart})
--Type Error: (68,11) Cannot cast 'Model' into 'Model & { kid: BasePart }'
--because the types are unrelated

It would be sensible to allow such casts. they are allowed in the old solver but not in the new one

[0x13479]

From the looks of it, instances are not considered tables... here is a very similar warning:

type Widget =
	ButtonWidget |
	InputWidget

type ButtonWidget = {
	type: {
		Value: "Button",
	},
}

type InputWidget = {
	type: {
		Value: "Input",
	}
}

-- "Button" | "Input"
type WidgetClass = index<index<Widget, "type">, "Value">

A warning appears when i add roblox types:

type Widget =
	ButtonWidget |
	InputWidget

type ButtonWidget = {
	type: StringValue & {
		Value: "Button",
	},
}

type InputWidget = {
	type: StringValue & {
		Value: "Input",
	}
}

--Type Error: (57,20) Property '"Value"' does not exist on type
--'(StringValue & { Value: "Button" }) | (StringValue & { Value: "Input" })'
type WidgetClass = index<index<Widget, "type">, "Value">

AND it does not appear if:

type ButtonWidget = {
	type: StringValue & {
		Value: "Button",
	},
}

type InputWidget = {
	-- 'StringValue &' is missing
	type: {
		Value: "Input",
	}
}