preserve immutable collections in to(Target) conversions #495
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lrytz force-pushed the toConserve branch 2 times, most recently from 0af7d33 to 0b2fc40 Compare 
lrytz commented Oct 29, 2021
| sharedSourceDir / "scala-2.11_2.12" | ||
| } | ||
| }, | ||
| Test / unmanagedSourceDirectories += { |
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copy paste from above, not sure how to factor things out in sbt
| cc @martijnhoekstra, since you originally wrote |
| this might interest @scala/collections |
johnynek reviewed Oct 30, 2021
compat/src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala Outdated Show resolved Hide resolved
compat/src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala Outdated Show resolved Hide resolved
NthPortal reviewed Nov 1, 2021
compat/src/main/scala-2.11_2.12/scala/collection/compat/CompatImpl.scala Show resolved Hide resolved
NthPortal reviewed Nov 1, 2021
| Thank you @NthPortal! |
johnynek approved these changes Nov 1, 2021
retronym approved these changes Nov 4, 2021
| @lrytz can you fill in the PR description? |
SethTisue changed the title to(Target) conversions | 👍 done |
| oh, this is already released, awesome! |
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In Scala 2.13,
collection.to(Target)conversions return thecollectionobject unchanged if it is immutable and is already a subtype of theTargettype.This PR brings the same behavior to Scala 2.12 when using scala-collection-compat.
The 2.12 codebase is unchanged, so a
to[Target]conversion may still create unnecessary copies.Remaining differences between 2.12 and 2.13:
static types: 2.12's
tois defined asdef to[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A]]): Col[A], soto(Map)has static typeIterable[(K, V)], notMap[K, V]lazy maps:
mapValuesreturns a lazy map that's a subtype ofimmutable.Map, so