What types are expected from stacked dot notation?

Question

Consider:

#include "share/atspre_staload.hats"

fun plus_int_int(x: int, y: int): int = x + y

symintr .plus
overload .plus with plus_int_int

implement main0() =
        println!("4+4+4 = ", ((4).plus(4)).plus(4))

This works, and it's clear that it can't be 4.plus() as the 4. is taken as a float. What I'd like to know is, why doesn't (4).plus(4).plus(4) work? ATS finds no valid overload for the second .plus, which tells me that it's expecting some other type than (int, int) -> int. What type is it expecting?

Answer 1

The current ATS2 parser interprets

(4).plus(4).plus(4)

as

((4).plus)((4).plus)(4)

I cannot easily fix the parser. I will think about it when implementing ATS3.