Subtyping between case-> and functions with U in the domain fails
Open
Nobody has claimed this yet.
- Dominant language
- Racket
- Stars
- 575
- Forks
- 106
- Avg merge
- 2h 1m
- Merged PRs (30d)
- 2
Description
#lang typed/racket
(: f : (case-> (-> 'foo Integer)
(-> 'bar String)))
(define (f x) (error 'fail))
(: g : String -> (-> (U 'foo 'bar) Any))
(define (g s) f)
Fails to type check.
Contributor guide
No contributing guide indexed for this repository
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 running the Typed Racket example from the issue and confirming the type-checking failure. Trace the case-> and function subtyping paths involved in the example; done means the snippet type-checks with the declared types and existing behavior remains covered by an appropriate regression test.
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
- Needs clarification
- Newbie friendliness
- 25/100