Typed Racket cannot handle compose that use multiple values

[OnorioCatenacci]

What version of Racket are you using?
8.15

What program did you run?

#lang typed/racket

(require qi)


(: add-up (-> Number Number Number))
(define (add-up n m) (+ n m))

(: cube (-> Number Number))
(define (cube n) (* n n n))

(: flow-values (-> Number Number Number))
(define (flow-values n m) (~> (n m) (add-up _ _) cube))

What should have happened?
The code should have compiled without a problem. This code compiles correctly:

#lang typed/racket

(require qi)


(: add-up (-> Number Number Number))
(define (add-up n m) (+ n m))

(: cube (-> Number Number))
(define (cube n) (* n n n))

(: flow-values (-> Number Number Number))
(define (flow-values n m) (~> (n m) (add-up _ _)))

If you got an error message, please include it here.

3-unsaved-editor:18:0: Type Checker: Polymorphic function `compose' could not be applied to arguments:
Argument 1:
  Expected: (-> b c)
  Given:    (-> Number Number)
Argument 2:
  Expected: (-> a b)
  Given:    (-> Number Number Number)
 in: (define (flow-values n m) (~> (n m) (add-up _ _) cube))

Please include any other relevant details
On Ubuntu 24.04 and using DrRacket for testing. Also tested with racket -I typed/racket (8.15 [cs]) and got the same error message.

[sorawee]

Here's a more minimal program that demonstrates the issue:

#lang typed/racket

(: f (-> Number (Values Number Number)))
(define (f x)
  (values x x))

(: g (-> Number Number Number))
(define (g x y)
  (+ x y))

((compose g f) 5)

[OnorioCatenacci]

Thank you! I try to keep my examples minimal but I can't always figure out the smallest example that will demonstrate an issue. Thanks for adding that!