racket / racket/typed-racket

type mismatch?

Open
#593 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
Racket
Stars
575
Forks
106
Avg merge
2h 1m
Merged PRs (30d)
2

Description

What version of Racket are you using?

6.8-1~zesty1~ppa2

What program did you run?
#lang typed/racket
(: id (All (a) (-> a a)))
(define (id x) x)
(ann id (All (b) (-> (Stream b) (Stream b))))
What should have happened?
- : (All (b) (-> (Stream b) (Stream b)))
#<procedure:id>
If you got an error message, please include it here.
Type Checker: type mismatch
  expected: (All (a) (-> (Stream a) (Stream a)))
  given: (All (a) (-> a a)) in: id

Contributor guide

No contributing guide indexed for this repository

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 running the provided #lang typed/racket program with the reported Racket 6.8 version and compare the type-checker result with the expected procedure output. The issue is resolved when annotating id as a polymorphic Stream-to-Stream function is accepted and produces the shown result.

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

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.