# Typed Lua inference notes

All code samples assume `--!strict`.

Typed Lua uses HM-typing according to an engineer at Roblox.

Typed Lua does not attempt to infer multiple return types. It infers that the return type is the first return used.

function foo(x)
	if x == 1 then
		return "foo"
	else
		return 2 -- Type mismatch: string and number
	end
end

Typed Lua, unlike Rust (HM) or TypeScript (not HM), attempts to infer function parameters.

function foo(x)
	return Vector3.new(x, x, x)
end

foo("foo") -- Type mismatch nil | number and string