[Scala 3] consolidate type+val aliases to export#872
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Replace `type X = Y` + `final val X = Y` pairs with single Scala 3 `export` clauses. Behavior identical for downstream (same imports resolve, same types/terms available); declaration count cut in half. Mirrors halotukozak fork `origin/master` shape for CommonAliases.
Replace `type X[+A] = ... ; final val X = ...` pairs with single `export` clauses. Mirrors halotukozak fork shape.
Replace `type X[+A] = pkg.Y[A]` + `final def X: pkg.Y.type = pkg.Y`
pairs with single Scala 3 `export pkg.Y as X` clauses. Each rename
collapses two declarations to one; variance is preserved by the
re-exported source symbol.
`MColBuilder` kept as plain `type` — its RHS shape
(`scm.Builder[Elem, Col[Elem]]`) is a higher-kinded substitution,
not a symbol rename, so `export` doesn't apply.
`MBuilder` converts cleanly (pure rename of `scm.Builder`).
Drift from halotukozak fork: fork `origin/master` keeps the
`type + final def` pair shape for CollectionAliases. We diverge
per user directive 2026-06-01 to consolidate via `export`.
Also modernized one Scala 2-style import to Scala 3 form
(`scala.{collection => sc}` → `scala.collection as sc`).
Trivial polish: now that `MBuilder` is exported, `MColBuilder`'s RHS references the project-local alias instead of `scm.Builder` directly. Pure cosmetic; same resolved symbol.
Document the `CommonAliases` / `MiscAliases` / `CollectionAliases` shape change in MIGRATION.md §3 source-compat. Source-level callers unaffected; JVM bytecode no longer emits redundant forwarders.
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Slice: 3.6 of Phase 3 (Scala 3 syntax modernization)
Merge order: Independent — can land any time (no overlap with 3.1/3.2/3.3/3.4/3.5)
Depends on: none
Base branch: upstream/scala-3 (not stacked)
Consolidate
type X = Y; final def X: Y.type = Yandtype X = Y; final val X: Y.type = Ypatterns into Scala 3export Y(orexport Y as Xfor rename) clauses. Reduces redundancy: a single declaration re-exports both the type AND the term.Touches:
core/.../CommonAliases.scala—Try/Success/Failure/Future/Promise/ExecutionContext/NonFatal/ClassTag/classTag/Annotation/StaticAnnotationcore/.../misc/MiscAliases.scala—Opt/OptArg/NOpt/OptRefcore/.../collection/CollectionAliases.scala— ~30 rename pairs (BIterable/IIterable/MIterable/…/MArrayBuffer);MColBuilderretained as plaintype(RHS is HK substitution, not a pure rename)MIGRATION.md§3 updated with the source-compat note.sbt compile + Test/compile + scalafmtCheckAllexit 0. No new warnings, no@nowarn/-Wconf.Drift note
halotukozak fork (
origin/master) already usesexportforCommonAliasesandMiscAliases; we mirror it. ForCollectionAliasesthe fork still keeps thetype + final defpair shape — we diverge per user directive 2026-06-01 to consolidate viaexport.