Groovy 2.5.15

What's new in this version:

Fixed:
 - @AnnotationCollector does not work with JUnit 5
 - Compilation failure: ClassCastException
 - Different treatment of property expressions in closures from 2.4 to 2.5
 - Static scope error for variable in non-static method of static inner class
- Adding "return" automatically in nested switch statements
- "Expecting to find object/array on stack" VerifyError when passing static member as argument to chained ctor call
- Reference to static member of parent class in enum constructor fails at runtime
- Map-style constructor call, inner class and static compilation
- void tail calls in closures break @CompileStatic type inference
- Issue With Static Compiler And Generics
- StreamingMarkupBuilder adds namespace on elements not expected
- Can not call a java parameterized type method from groovy with java enum. Compile error
- Cannot pass generic list into explicit setter
- Debugger Step Into doesn't work in Groovy-compiled classes
- Groovy 3 BUG! exception in phase 'conversion' in source unit Caused by NullPointerException
- Compiler error for use of variable expression within tap closure
- SC: ClassCastException on delegate object property set
- Groovy 3.0.5: Closure delegate is not working properly
- Method call "main" is replaced with StaticMethodCallExpression in script
- SC: set groovy property written for variable expression assignment that should be direct setter call
- VerifyError if superclass has static and non-static overloads
- NPE in ClassNode.isDerivedFrom while compiling trait with Groovy 3.0.5
- STC: UnionTypeClassNode created for simple instanceof scenarios
- STC: "putAt" shortcut notation to outer class private field from Closure leads to GroovyCastException
- SC: cast exception for variable assigned within conditional blocks
- SC: cross-package protected field access uses dynamic property methods
- STC: regression in private inner class type inference
- arithmetic using an implicit getter fails to compile with "BUG! exception in phase 'class generation'" under static compilation
- GroovyCastException when using a map while iterating over something in a @CompileStatic object
- Switch return statement transformation misses last case without break
- ArrayIndexOutOfBoundsException when compiling method call with many overloaded methods
- IllegalAccessError exception is raised when accessing inherited static field
- Stub generation malforms annotation values
- Build Error: StringIndexOutOfBoundsException when the stars align...
- STC: Access to field/property is forbidden after instanceof.
- Can't assign a field with the result of a method call of the same name from a base class

Dependency upgrade:
- Upgrade Jansi to 2
- Bump openbeans to 1.0.2

Improvement:
- In generated closures, annotate generated call() methods with @Generated
- GroovyClassLoader#fileReallyExists is inefficient

New Feature:
 - Provide a helper factory class to assist with porting

Task:
- Prepare for bintray/jcenter sunset
- Investigate impact of Bintray/JCenter shutdown (grape config aspects)