`for/and` expects body to return `Boolean` regardless of annotation
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Description
This is in Racket snapshot 6.2.0.2--2015-03-26(56a701b/a).
The following expression does not type check:
(for/and : Any ([i (list)]) 42)
; /tmp/test/test.rkt:3:0: Type Checker: type mismatch
; expected: Boolean
; given: Positive-Byte
; in: (for/and : Any ((i (list))) 42)
This one gives more errors, if that helps:
(for/and : (U #f Integer) ([i (list)]) 42)
; /tmp/test/test.rkt:3:0: Type Checker: type mismatch
; expected: Boolean
; given: Positive-Byte
; in: (for/and : (U #f Integer) ((i (list))) 42)
; /tmp/test/test.rkt:3:0: Type Checker: type mismatch
; expected: (U Integer False)
; given: Boolean
; in: (for/and : (U #f Integer) ((i (list))) 42)
; /tmp/test/test.rkt:3:0: Type Checker: type mismatch
; expected: (U Integer False)
; given: Boolean
; in: (for/and : (U #f Integer) ((i (list))) 42)
; Type Checker: Summary: 3 errors encountered
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the two for/and expressions from the issue in the referenced Racket snapshot and inspect the Typed Racket type-checking path for for/and. Done means the body is no longer incorrectly required to return Boolean when an annotation permits another result type, without introducing the additional reported errors.
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
- 35/100