Bug in Typed Racket

[Antonio Menezes Leitao]

Hi,

The following example works fine:

#lang racket

(define v (vector 1 2 3))

(for ([t (in-vector v 0 2)])

  (displayln t))

However, in Typed Racket, it does not:

Welcome to DrRacket, version 6.3.0.3--2015-11-06(58c919c/a) [3m].

Language: typed/racket; memory limit: 4096 MB.

. Type Checker: missing type for identifier;

 consider using `require/typed' to import it

  identifier: normalise-inputs

  from module: for.rkt in: (for ((t (in-vector v 0 2))) (displayln t))

. Type Checker: type mismatch

  expected: VectorTop

  given: Any in: (for ((t (in-vector v 0 2))) (displayln t))

. Type Checker: Summary: 2 errors encountered in:

  (for ((t (in-vector v 0 2))) (displayln t))

  (for ((t (in-vector v 0 2))) (displayln t))

Best,

António.

[Sam Tobin-Hochstadt]

Thanks for the report! I've got a fix here, which I'm still testing: https://github.com/racket/typed-racket/pull/238

Sam

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[Antonio Menezes Leitao]

BTW, the following example typechecks:

(define #:forall (A) (foo [f : (Real -> A)] [b : Boolean]) : (Listof A)

  (list (f 0.1) (f 0.2)))

but the following example generates a lot of complaints:

(define #:forall (A) (foo [f : (Real -> A)] [b : Boolean #t]) : (Listof A)

  (list (f 0.1) (f 0.2)))

Welcome to DrRacket, version 6.3.0.3--2015-11-06(58c919c/a) [3m].

Language: typed/racket; memory limit: 4096 MB.

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: parse error in type;

 type name `A' is unbound in: A

. Type Checker: Summary: 8 errors encountered in:

  A

  A

  A

  A

  A

  A

  A

  A

Best,

António.

[Sam Tobin-Hochstadt]

On Sun, Nov 8, 2015 at 2:31 PM Sam Tobin-Hochstadt <sa...@cs.indiana.edu> wrote:

Thanks for the report! I've got a fix here, which I'm still testing: https://github.com/racket/typed-racket/pull/238

This is now fixed in the git source.

[Sam Tobin-Hochstadt]

Yes, there seems to be a bug with how type variables are scoped with `#:forall`. I recommend using this syntax, which works fine:

(: foo (All (A) (->* ((-> Real A)) (Boolean) (Listof A) )))

(define (foo f [b #t])

  (list (f 0.1) (f 0.2)))

But if you can open an issue on github for your program as well, that would be great.

Sam

On Sun, Nov 8, 2015 at 4:32 PM Antonio Menezes Leitao <antonio.men...@ist.utl.pt> wrote:

BTW, the following example typechecks:

(define #:forall (A) (foo [f : (Real -> A)] [b : Boolean]) : (Listof A)

  (list (f 0.1) (f 0.2)))

but the following example generates a lot of complaints:

(define #:forall (A) (foo [f : (Real -> A)] [b : Boolean #t]) : (Listof A)

  (list (f 0.1) (f 0.2)))

Welcome to DrRacket, version 6.3.0.3--2015-11-06(58c919c/a) [3m].

Language: typed/racket; memory limit: 4096 MB.