# Scala 3.9.0-RC5

- Product: Scala (https://whatsnew.fyi/product/scala)
- Vendor: Scala Center
- Date: 2026-08-19
- Version: 3.9.0-RC5
- Original notes: https://github.com/scala/scala3/releases/tag/3.9.0-RC5
- Permalink: https://whatsnew.fyi/product/scala/releases/3.9.0-rc5
- Labels: Pre-release

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **changed** — Bump Scala CLI to v1.16.0
- **fixed** — Fix stale baseTypeCache after synthetic Product.Mirror parents added
- **fixed** — Ignore coverage probes in unused update analysis
- **fixed** — Fix crash when unapply returns a Boolean-deriving opaque type
- **added** — Emit inline info attribute
- **fixed** — Fix false unused-var warning on self-assignment reads
- **fixed** — Stop hiding errors in GenericSignatureVisitor
- **fixed** — Emit a super init call for primitives on the JVM
- **fixed** — Preserve qualifier purity through compiler-generated casts
- **fixed** — Fix regression in dotty-cps-async use typer skolems as inline proxy's type
- **fixed** — Fix a couple issues related to erased value types
- **changed** — Scaladoc remove jquery and hanging javascript assets
- **added** — Scaladoc add fallback lookup from nearest package
- **fixed** — Fix Scaladoc top package order to be alphabetical
- **fixed** — Wrap with-to-& rewrite in parens for typed patterns
- **changed** — Make Option.orNull public in binary

#### Backported changes

- Bump Scala CLI to v1.16.0 [#26703](https://github.com/scala/scala3/pull/26703)
- Fix stale `baseTypeCache` after synthetic Product.Mirror parents added [#26714](https://github.com/scala/scala3/pull/26714)
- Ignore coverage probes in unused update analysis [#26711](https://github.com/scala/scala3/pull/26711)
- Fix crash when `unapply` returns a Boolean-deriving opaque type [#26658](https://github.com/scala/scala3/pull/26658)
- Emit inline info attribute [#26650](https://github.com/scala/scala3/pull/26650)
- Fix false unused-var warning on self-assignment reads (#26620) [#26635](https://github.com/scala/scala3/pull/26635)
- Stop hiding errors in `GenericSignatureVisitor` [#26632](https://github.com/scala/scala3/pull/26632)
- Emit a super init call for primitives on the JVM [#26630](https://github.com/scala/scala3/pull/26630)
- Preserve qualifier purity through compiler-generated casts [#26579](https://github.com/scala/scala3/pull/26579)
- Fix regression #26153 (in dotty-cps-async) use typer skolems as inline proxy's type [#26563](https://github.com/scala/scala3/pull/26563)
- Fix a couple issues related to erased value types [#26213](https://github.com/scala/scala3/pull/26213)
- Scaladoc: Remove jquery and hanging javascript assets. [#22014](https://github.com/scala/scala3/pull/22014)
- Scaladoc: add fallback lookup from nearest package [#26661](https://github.com/scala/scala3/pull/26661)
- Fix Scaladoc top package order to be alphabetical [#26653](https://github.com/scala/scala3/pull/26653)
- Fixes #26013: Wrap `with`->`&` rewrite in parens for typed patterns [#26016](https://github.com/scala/scala3/pull/26016)
- Make Option.orNull public in binary [#26751](https://github.com/scala/scala3/pull/26751)


#### Contributors

Thank you to all the contributors who made this release possible 🎉

According to `git shortlog -sn --no-merges 3.9.0-RC4..3.9.0-RC5` these are:

```
     8	Wojciech Mazur
     4	Rikito Taniguchi
     4	Solal Pirelli
     1	Anatolii Kmetiuk
     1	Jack Koenig
     1	Mathias
     1	Oron Port
     1	Piotr Chabelski
```