Summary

nested guard forms loop

Metadata

• Id: d82b727047007078e351dabbaddb118af2423e9d
• Trac id:
• Type: defect
• Reporter: felix
• Owner:
• Cc:
• Status: new
• Component: core libraries
• Estimated difficulty: hard
• Resolution:
• Priority: major
• Milestone:
• Version: 6.0.1pre1
• Changetime: 2026-09-08 20:32:25 UTC
• Created: 2026-09-06 23:06:50 UTC
• Keywords:

Attachments

• d82b727047007078e351dabbaddb118af2423e9d/attachments/a.scm

Description

Reported by Daniel Colascione:

This runs forever. Should print caught and exit.

 (import (scheme base) (scheme write))

 (write
  (guard (catcher (else 'caught))
    (guard (outer (#f #f))
      (guard (inner (#f #f))
        (raise 'boom)))))
 (newline)

Changes and comments

[2026-09-08 20:31:50 UTC] felix attached a.scm

[2026-09-08 20:32:25 UTC] felix wrote:

Attached a file with a "clean room" implementation, for experimentation.