OPAL Release 5.0.0

• we are now using sbt 1.6.2
• we are now using Scala 2.13
  • Scala 2.13 changes:
    • replace Unicode arrows (⇒,→,←) by ASCII arrows (=>,->,<-)
    • replace Traversable by scala.collection.Iterable
    • replace TraversableOnce by scala.collection.IterableOnce
    • changes to OPAL's custom data structures:
      • replace RefIterator by scala.collection.iterator
      • replace Chain by scala.collection.immutable.List
      • replace RefArray and IntArray by scala.collection.immutable.ArraySeq
      • replace RefArrayStack by scala.collection.immutable.Stack
      • replace RefAppendChain by scala.collection.mutable.ArrayDeque
      • replace RefArrayBuffer by scala.collection.mutable.ArrayBuffer
• full support for Java 17 up to 19
  • support for Java 17 Sealed Classes
  • added isStrict attribute to classes
  • ignore isStrict attribute on classes and methods for Java >= 17
• completed framework for call graph analyses
  • introduced TypeIterator to uniformly access type information
  • using contexts instead of methods to enable context-sensitive analysis (0-1-CFA, 1-1-CFA)
  • support library analysis with CFA
• introduced new immutability analyses
  • replaced FieldMutabilityAnalysis with FieldAssignabilityAnalysis
    • support for thread-safe and unsafe lazy initialization
    • support for clone pattern
  • introduced new FieldImmutabilityAnalysis to integrate field assignability with mutability of values
    • support for transitive and non-transitive immutability
    • support for immutability dependent on generic type parameters
  • updated ClassImmutabilityAnalysis and TypeImmutabilityAnalysis to use new FieldImmutability properties
• added EntrypointsFinder for Android apps
• allow flushing caches for ObjectTypes/ArrayTypes to free memory when creating many projects in a row