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: ````markdown 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.