Scala3 Regression Issue

Scala3 Regression Issue

Use this skill after the regression is already confirmed and minimized. The goal is to draft a scala/scala3 issue that is concise, reproducible, and formatted like existing regression reports.

Workflow

1. Gather the inputs.

   • Use the smallest confirmed reproducer, ideally a self-contained test.scala or test-macro.scala file set.
   • Capture the exact compiler boundary: last good release, first bad release.
   • Capture the bisect result: commit SHA, PR link if known, and the bisect command if available.
   • Capture provenance: affected community-build projects and build-log links, if relevant.

2. Draft the title.

   • Use the pattern <symptom>` regression in <construct / usage>.
   • Keep the title about the compiler behavior, not the discovery project, unless multiple projects were needed to discover the regression.
   • Backtick concrete flags, APIs, or syntax.

3. Draft the body in this order.

   • Based on the OpenCB failures in: only when OpenCB context is relevant.
   • ## Compiler version
   • ## Minimized code
   • ## Output
   • ## Expectation

4. Fill the sections with the right level of detail.

   • In ## Compiler version, include last good, first bad, bisect commit, PR link if known, and the bisect command if available.
   • In ## Minimized code, prefer the smallest dependency-free repro that still fails.
   • In ## Output, include the decisive compile command and the relevant error excerpt, not unrelated warnings.
   • In ## Expectation, state the expected successful behavior in one sentence.

Style Rules

• Preserve exact version strings, commit hashes, and error text.
• If build logs exist, include them; if they do not, omit the link rather than inventing one.
• If a bisect commit exists but the PR is unknown, link the commit directly.
• Keep the issue body scannable and avoid narrative filler.
• Prefer fenced scala, bash, and text blocks.

Template

Use this structure as the default draft:

Based on the OpenCB failures in:
- org/repo - [build logs](...)

## Compiler version

Last good release: ...
First bad release: ...
Bisect points to ... / PR $<pr_number>

## Minimized code

```scala
...
```

## Output

```scala
...
```

## Expectation
Should compile without ...

Delete the OpenCB section or the bisect command subsection when they are not available.