Investigate warnings produced by Scala 3 compiler when compiling 2.13 standard library

scala / scala-dev

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Investigate warnings produced by Scala 3 compiler when compiling 2.13 standard library #775

Closed SethTisue closed 3 years ago

SethTisue commented 3 years ago

With an eye towards eventually enabling fatal warnings.

For example, at https://github.com/scala/bug/issues/12408 Lukas observed that compiling the collections gives a bunch of "the type test for ... cannot be checked at runtime" warnings.

Some warnings could be things we should simply silence with @unchecked or the like
Some warnings could be false negatives in 2 (opportunities to make Scala 2 emit warnings in more situations where it should)
Some warnings could be Scala 3 emitting false positives
Some warnings could indicate actual quality problems in the standard library

som-snytt commented 3 years ago

The deprecated case class issue is already lodged at https://github.com/lampepfl/dotty/issues/11022

som-snytt commented 3 years ago

The deprecation in scala.io.Position companion is explained at https://github.com/lampepfl/dotty/issues/12706

lrytz commented 3 years ago

https://github.com/scala/bug/issues/12439 covers the remaining unchecked warnings

@nowarn support (https://github.com/lampepfl/dotty/pull/12857) will handle most deprecations that Scala 3 issues.

dwijnand commented 3 years ago

scala/bug#12439 covers the remaining unchecked warnings