racket / racket/typed-racket

Refinement type error in repl

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Dominant language
Racket
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Forks
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2h 1m
Merged PRs (30d)
2

Description

What version of Racket are you using?

6.12

What program did you run?
(define-type test (Refine [a : (Pairof Integer Integer)]
                          (<= (car a) (cdr a))))
(ann '(1 . 2) test)  ;;in repl
What should have happened?
  • : test
    '(1 . 2)
If you got an error message, please include it here.

Type Checker: type mismatch
expected: test
given: (Pairof One Positive-Byte) in: (quote (1 . 2))

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported program in the Racket 6.12 REPL and inspect how the type checker handles the Refine type, Pairof values, and the quoted pair in ann. Done means the example is accepted and produces the expected test value and type output without the reported mismatch.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
32/100

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