typed-racket

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What version of Racket are you using?

v8.12 [cs]

What program did you run?

mve

(for/sum : Float ([i : Float (in-range 0 1 0.1)]) i)

What should have happened?

same output as the following program

(for/sum : Real ([i : Real (in-range 0 1 0.1)]) i)

which returns 5.5.

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

string:1:0: Type Checker: type mismatch
  expected: Flonum
  given: Zero
  in: (for/sum : Float ((i : Float (in-range 0 1 0.1))) i)
 [,bt for context]

the backtrace, if it's useful :)

string:1:0: Type Checker: type mismatch
  expected: Flonum
  given: Zero
  in: (for/sum : Float ((i : Float (in-range 0 1 0.1))) i)
  location...:
   string:1:0
  context...:
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/check-below.rkt:130:5: perform-check!
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/private/type-annotation.rkt:83:0: get-type/infer
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-let-unit.rkt:381:0: tc/let-values
   .../private/parse-interp.rkt:643:50
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-expr-unit.rkt:112:0: tc-expr/check
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/private/type-annotation.rkt:83:0: get-type/infer
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-let-unit.rkt:381:0: tc/let-values
   .../private/parse-interp.rkt:643:50
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-expr-unit.rkt:112:0: tc-expr/check
   [repeats 2 more times]
   .../private/parse-interp.rkt:643:50
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-expr-unit.rkt:112:0: tc-expr/check
   /Applications/Racket v8.12/share/pkgs/typed-racket-lib/typed-racket/typecheck/tc-toplevel.rkt:724:0: tc-toplevel-form
   .../private/parse-interp.rkt:643:50
   /Applications/Racket v8.12/share/pkgs/xrepl-lib/xrepl/xrepl.rkt:1573:0
   /Applications/Racket v8.12/collects/racket/repl.rkt:11:26

from what I can tell, the literal zero in the definition seems to be the issue. The comment a little before seems to acknowledge this as intentional.

https://github.com/racket/typed-racket/blob/26534e7c8c27155cf1aa37e0390599bc5b56040e/typed-racket-lib/typed-racket/base-env/prims.rkt#L523-L528

https://github.com/racket/typed-racket/blob/26534e7c8c27155cf1aa37e0390599bc5b56040e/typed-racket-lib/typed-racket/base-env/prims.rkt#L553

My current workaround is to just use a foldl for now to avoid mangling Real and Float conversions in my actual program. Just making sure I'm not missing an obvious approach.

Unfortunately this is the racket semantics for for/sum, so this is not fixable.

Alrighty, thank you! I'll close this then.