Stream: bugs

Topic: Changing type definition causes program behaviour to change

Jamie (Dec 18 2025 at 19:04):

Github issue: https://github.com/roc-lang/roc/issues/8676

I've got 2 questions relating to this:

• If I wanted to try and fix this myself, where would I start?
• Are there any advantages of creating a zulip thread for a bug if there is already a github issue?

Brendan Hansknecht (Dec 19 2025 at 07:29):

For question 2:

Main advantage is getting more attention to the issue and having live discussion to help solve the issue.

Anton (Dec 19 2025 at 08:19):

Hi @Jamie,

If I wanted to try and fix this myself, where would I start?

1. Check if the issue still occurs on the latest main branch and using the latest release of roc-platform-template-zig (0.6):

• zig build roc
• ./zig-out/bin/roc temp.roc

I was prepared to write up the other steps but it I just tried that and it works for me now :)

❯ ./zig-out/bin/roc temp.roc
Running main function
Started parsing
parsed: Try.Ok(<tag_union variant=0>)

This was on macOS apple silicon, it is possible that you still experience the problem your machine, please let me know.

Last updated: Dec 21 2025 at 12:15 UTC