Deprecations from Java may be not taken into account in mixed projects

[scabug]

There's a problem that deprecations from Java are not taken into account in Scala after parsing Java sources in mixed projects (when they are not yet compiled). I mean that warnings are not generated.

They would be generated only during the incremental compilation (Java files already compiled using javac). It's esp. problematic in case of -Xfatal-warnings as the CI build may pass but users will report problems in Scala IDE or IntelliJ.

The minimal reproduction:

1. Create two files.

J.java

public class J {
    @Deprecated
    public static void foo() {}
}

S.scala

class S {
  J.foo()
}

2. Make project (for the first time) or Rebuild Project. Everything is okay.

3. Now add some blank line in S.scala and start build:

Warning (or obviously Error in case of -Xfatal-warnings):scalac: there was one deprecation warning; re-run with -deprecation for details

4. Then Rebuild Project and, again, there are no warnings.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-9617?orig=1
Reporter: @mpociecha
Assignee: @mpociecha
Affected Versions: 2.10.6, 2.11.7, 2.12.0-M3

[scabug]

@retronym said:
A fix for this bug might fall out of [~soc]'s pending work to parse annotations from Java sources: https://github.com/scala/scala/pull/4848/commits

[scabug]

@mpociecha said:
Yes, I know. I asked Lukas about this before I created the ticket. And also Simon was added to the discussion (just in case).

[scabug]

@mpociecha said:
Btw, when we'll have the support for annotations finished, it will be pretty simple to handle Java @deprecated annotation.

There's even already my very old PR in Simon's repo (only the last commit does matter): soc/scala#3

[scabug]

@soc said:
Don't worry, I'm still on it! I hope I can get it merged before 2.12.0-M5, depending on how many unexpected issues appear out of nowhere. :-)

[scabug]

@SethTisue said:
Simon, is this something you plan to come back to?

[scabug]

@soc said:
Yes, I have just been very busy.

[dwijnand]

Fixed in scala/scala#8781