Imported From: https://issues.scala-lang.org/browse/SI-10042?orig=1
Reporter: @jvican
Affected Versions: 2.11.0, 2.12.0

@lrytz said:
TRANS_FLAG does not (and should not) correspond to JAVA_ACC_TRANSIENT: it is a special flag that can be used within a phase to pass information from one traversal to another. By convention, it should always be reset at the end of the phase.

In fact, there is no Scala flag that corresponds to JAVA_ACC_TRANSIENT. The same is also true for JAVA_ACC_VOLATILE, JAVA_ACC_NATIVE, probably others. The actual Scala equivalent for these is an annotation, so I think the classfile parser should add the corresponding annotation to the symbol. I don't think there's an existing example where this is being done.

@jvican said (edited on Nov 11, 2016 10:22:18 AM UTC):
I'm happy to implement this, since it's a blocker for me. Would you accept these changes for 2.12.1 if I make a PR?

@lrytz said:
For 2.12.1, it depends on the size / risk of the patch and how quickly it would be available for review. Also cc @retronym, @adriaanm, do you think what I outlined above makes sense?

@adriaanm said (edited on Nov 23, 2016 6:27:42 PM UTC):
I agree with Lukas that these Java classfile flags should be turned into Scala annotations. We could consider this for 2.12.2.

@retronym said:
{quote}I don't think there's an existing example where this is being done.{quote}

Probably the most similar is the way we parse the Throws attribute and add the @throws annotation to Java method symbols.

@retronym said (edited on Dec 1, 2016 7:24:30 AM UTC):
For consistency, we'll also have populate this annotation in our Java source file compiler, and in runtime reflection.

Looks like we forgot to create the @throwable annotation for runtime reflection Java method symbols, we should have added:

diff --git a/src/reflect/scala/reflect/runtime/JavaMirrors.scala b/src/reflect/scala/reflect/runtime/JavaMirrors.scala
index 95440ebc00..eabaa6b389 100644
--- a/src/reflect/scala/reflect/runtime/JavaMirrors.scala
+++ b/src/reflect/scala/reflect/runtime/JavaMirrors.scala
@@ -1162,6 +1162,7 @@ private[scala] trait JavaMirrors extends internal.SymbolTable with api.JavaUnive
       copyAnnotations(meth, jmeth)
       if (jmeth.javaFlags.isVarargs) meth modifyInfo arrayToRepeated
       if (jmeth.getDefaultValue != null) meth.addAnnotation(AnnotationDefaultAttr)
+      jmeth.getExceptionTypes.foreach(cls => meth.addThrowsAnnotation(classToScala(cls)))
       markAllCompleted(meth)
       meth
     }