Scala 2.13.2 bridge builds with warnings

[soronpo]

reproduction steps

Any fresh build of a project with 2.13.2.

problem

I get

[info] Non-compiled module 'compiler-bridge_2.13' for Scala 2.13.2. Compiling...
9 warnings

It's only occurring at the first bridge build

expectation

No warnings displayed

[smarter]

The bridge is built with -nowarn: https://github.com/sbt/zinc/blob/2f1bad9874d9a4fdca7e17f071ae1943ec45521e/internal/zinc-compile-core/src/main/scala/sbt/internal/inc/AnalyzingCompiler.scala#L376. @lrytz Did scala/scala#8373 change the behavior of -nowarn? Is there another flag that should be used by zinc, or should zinc filter the compiler output manually?

[lrytz]

Not that I'm aware. The regression seems to be in 2.13.1:

$> cat Test.scala
class C {
  def f = 1 → 2
  def g: Unit = 1
}
$> scv 2.13.0 Test.scala
Test.scala:3: warning: a pure expression does nothing in statement position
  def g: Unit = 1
                ^
warning: there was one deprecation warning (since 2.13.0); re-run with -deprecation for details
two warnings found
$> scv 2.13.0 Test.scala -nowarn
$> scv 2.13.1 Test.scala -nowarn
two warnings found
$> scv 2.13.2 Test.scala -nowarn
2 warnings
$>