racket / racket/htdp

Stepper shows different error than "Run" for use-before-definition

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Dominant language
Racket
Stars
112
Forks
73
Avg merge
9h 41m
Merged PRs (30d)
1

Description

In BSL, running this program:

(define a (list b))
(define b "don't care")

prints the error message, b is used here before its definition.

However, the Stepper shows the #lang racket error message on the right-hand side:

b: undefined;
 cannot reference an identifier before its definition

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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

Reproduce the BSL example from the issue in both Run and the Stepper, then compare where each error is generated. The issue names no files or tests, so trace the Stepper entry point for handling the use-before-definition case and make its displayed message match Run; verify both views with the supplied program.

Written by the indexing model from the issue text.

Assessment

Domain
devtools
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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