racket / racket/typed-racket

Problems with unreachable code warnings

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#402 1 comment 0 reactions 0 assignees View on GitHub

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

Description

#lang typed/racket
(define h2 : (HashTable Any Any)
  (for/hash ([i : Integer (in-list (list 1 2 3))])
    (values i i)))

In the above code, we warn 3 times for the same syntax (the full for/hash loop), and also it isn't really unreachable (something else with that source location is unreachable).

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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 warning behavior with the typed/racket snippet in the issue and inspect how unreachable-code warnings are generated and assigned source locations. Done means the loop no longer produces three duplicate warnings and the warning points to the unreachable source rather than the whole for/hash form.

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

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