So you want the compiler to automatically generate alias types for every un-typed variable and parameter? I assume you would also want the compiler to (somehow?) infer types that should be the same type and merge them, since otherwise the first step is kind of silly. I'd argue that that's a pretty difficult task, tantamount to inferring programmer intent.
Yes, I want merging, but I imagine there could also be an indication that the merge was automatic and in an IDE setting, I'd expect to be able to easily split out the types, if I want.