Support -Wunused:patvars on Scala 3#255
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lenguyenthanh merged 2 commits intoMay 16, 2026
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The safe `-Wunused:patvars` was forward-ported from Scala 2 in 3.7.0 (scala/scala3#20894) and backported to the 3.3 LTS in 3.3.7 (scala/scala3-lts#223). Earlier 3.x only offered the unsafe variant `-Wunused:unsafe-warn-patvars`, which is not exposed by this library. Verified empirically with scala-cli: rejected on 3.3.6 and 3.6.4, accepted on 3.3.7 and 3.7.0. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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@lenguyenthanh 🙏 I'll follow up with an sbt-tpolecat PR, unless you want a draft before this is merged |
lenguyenthanh
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May 16, 2026
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thanks! the release note isn't clear about this change at all. I bet a lot of people miss this.
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at least it's automatically available in |
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@lenguyenthanh can you make a release? btw. happy to help with some routine maintenance stuff |
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yeah, I'll make one now
thanks a lot, and hey @armanbilge, we have a volunteer 😄 |
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Summary
-Wunused:patvarson Scala 3 versions where the safe variant is available-Wunused:unsafe-warn-patvars, which this library does not expose-Wunused:patvarswas forward-ported from Scala 2 in 3.7.0 (scala/scala3#20894) and backported to the 3.3 LTS in 3.3.7 (scala/scala3-lts#223)The resulting gating is
[2.13.0, 3.0.0) ∪ [3.3.7, 3.4.0) ∪ [3.7.0, ∞).Note: the LTS PR description claims it was backported "to the 3.3.6", but that PR did not actually ship in 3.3.6 — it landed in 3.3.7 (confirmed in the 3.3.7 release notes which list #20894 under "Highlights").
Test plan
scala-cli:-Wunused:patvarsis rejected on 3.3.6 and 3.6.4, accepted on 3.3.7 and 3.7.0sbt libJVM/testpasses (26/26)🤖 Generated with Claude Code