Re: continuation not a subtype of procedure

the type `continuation' is to be used w/ https://wiki.call-cc.org/man/6/Module%20(chicken%20continuation)

the type of a continuation captured by call/cc is a `procedure’

the https://wiki.call-cc.org/man/6/Types should reference 

> On Aug 20, 2026, at 9:09 AM, Hernán Ibarra Mejia via Chicken-users <[email protected]> wrote:
> 
> Greetings,
> 
> I am new to using the type system, so this is probably a mistake on my part.
> When passing continuations around I get compiler warnings with the
> `-strict-types` flag. Here is a MWE:
> 
> ```
> ; test.scm
> (import (scheme base))
> 
> (: send-message (continuation -> noreturn))
> (define (send-message k) (k "Hello world!"))
> 
> (display (call/cc (lambda (k) (send-message k))))
> (newline)
> ```
> 
> When compiling:
> 
> ```
> % csc -strict-types test.scm
> 
> Warning: Invalid procedure
>  In file `test.scm:4',
>  In procedure `send-message',
>  In procedure call:
> 
>    (k "Hello world!")
> 
>  Variable `k14' is not a procedure.
> 
>  It has this type:
> 
>    (struct continuation)
> ```
> 
> The program works as expected, i.e., it prints "Hello world!" but the warning
> seems unwarranted. For truly unexpected behaviour, replace the definition of
> `send-message` with:
> 
> ```
> (define (send-message k) (k (procedure? k)))
> ```
> 
> Then the program prints #f or #t depending on whether `-strict-types` is used or
> not, respectively.
> 
> I am using this version of csc (congrats on the CHICKEN 6 release, by the way):
> 
> ```
> % csc -version
> CHICKEN
> (c)2000-2007 Felix L. Winkelmann, (c)2008 The CHICKEN Team
> Version 6.0.0rc3 ((HEAD detached at 6.0.0rc3)) (rev 0e61d660)
> linux-unix-gnu-x86-64 [ 64bit dload ptables ]
> ```
> 
> What am I missing? Shouldn't the continuation type be a subtype of the procedure
> type?
> 
> Cheers,
> Hernán
>