necessary and sufficient conditions for inclusion in InnerClasses JVM attribute

[magarciaEPFL]

Emitting a class file involves populating its InnerClass table as per the JVM spec.

For that, GenBCode follows the same strategy GenASM does (which in turn follows what GenJVM did): intercepting via asmClassType() each usage of a class-name in the class file being emitted.

That gives the right answer about 99.9% of the time. However as https://issues.scala-lang.org/browse/SI-6759 explains, there are cases where that approach includes too much in the InnerClasses table.

GenBCode has a solution for that, refreshInnerClasses(), which should be adopted as the primary mechanism (throwing away the innerClassBufferASM that's part of the BCInnerClassGen trait).

[DarkDimius]

I'm not going to work on this any time soon and this is low priority.

[lrytz]

I recently re-wrote how we compute the InnerClass table in scalac, this should just work for dotty, too. scala/scala#4807.

[dwijnand]

See also the PRs linked in the original issue: scala/bug#6759 (comment), which include a thorough set of test cases.