SI-6178 reflective invocation of magic symbols

In Scala there are some methods that only exist in symbol tables,
but don't have corresponding method entries in Java class files.

To the best of my knowledge, these methods can be subdivided into five groups:
1) stuff weaved onto Any, AnyVal and AnyRef (aka Object),
2) magic methods that Scala exposes to fix Java arrays,
3) magic methods declared on Scala primitive value classes,
4) compile-time methods (such as classOf and all kinds of macros),
5) miscellaneous stuff (currently only String_+).

To support these magic symbols, I've modified the `checkMemberOf` validator
to special case Any/AnyVal/AnyRef methods and adjusted MethodMirror and
ConstructorMirror classes to use special invokers for those instead of
relying on Java reflection.

Support for value classes will arrive in the subsequent commit, because
it requires some unrelated changes to the mirror API (currently mirrors
only support AnyRefs as their targets).

4 files changed, 226 insertions, 0 deletions

diff --git a/test/files/run/reflection-magicsymbols-invoke.check b/test/files/run/reflection-magicsymbols-invoke.check
new file mode 100644
index 0000000000..a180ed806e
--- /dev/null
+++ b/test/files/run/reflection-magicsymbols-invoke.check
@@ -0,0 +1,124 @@
+============
+Any

+it's important to print the list of Any's members

+if some of them change (possibly, adding and/or removing magic symbols), we must update this test

+method !=: (x$1: Any)Boolean

+method ##: ()Int

+method ==: (x$1: Any)Boolean

+method asInstanceOf: [T0]=> T0

+method equals: (x$1: Any)Boolean

+method getClass: ()java.lang.Class[_]

+method hashCode: ()Int

+method isInstanceOf: [T0]=> Boolean

+method toString: ()java.lang.String

+testing Any.!=: false

+testing Any.##: 50

+testing Any.==: true

+testing Any.asInstanceOf: class scala.ScalaReflectionException: Any.asInstanceOf requires a type argument, it cannot be invoked with mirrors

+testing Any.asInstanceOf: class scala.ScalaReflectionException: scala.Any.asInstanceOf[T0]: T0 takes 0 arguments

+testing Any.equals: true

+testing Any.getClass: class java.lang.String

+testing Any.hashCode: 50

+testing Any.isInstanceOf: class scala.ScalaReflectionException: Any.isInstanceOf requires a type argument, it cannot be invoked with mirrors

+testing Any.isInstanceOf: class scala.ScalaReflectionException: scala.Any.isInstanceOf[T0]: Boolean takes 0 arguments

+testing Any.toString: 2

+============
+AnyVal

+it's important to print the list of AnyVal's members

+if some of them change (possibly, adding and/or removing magic symbols), we must update this test

+constructor AnyVal: ()AnyVal

+method getClass: ()Class[_ <: AnyVal]

+testing AnyVal.<init>: class java.lang.InstantiationException: null

+testing AnyVal.getClass: class scala.ScalaReflectionException: expected a member of class Integer, you provided method scala.AnyVal.getClass

+============
+AnyRef

+it's important to print the list of AnyRef's members

+if some of them change (possibly, adding and/or removing magic symbols), we must update this test

+constructor Object: ()java.lang.Object

+method !=: (x$1: Any)Boolean

+method !=: (x$1: AnyRef)Boolean

+method ##: ()Int

+method $asInstanceOf: [T0]()T0

+method $isInstanceOf: [T0]()Boolean

+method ==: (x$1: Any)Boolean

+method ==: (x$1: AnyRef)Boolean

+method asInstanceOf: [T0]=> T0

+method clone: ()java.lang.Object

+method eq: (x$1: AnyRef)Boolean

+method equals: (x$1: Any)Boolean

+method finalize: ()Unit

+method getClass: ()java.lang.Class[_]

+method hashCode: ()Int

+method isInstanceOf: [T0]=> Boolean

+method ne: (x$1: AnyRef)Boolean

+method notify: ()Unit

+method notifyAll: ()Unit

+method synchronized: [T0](x$1: T0)T0

+method toString: ()java.lang.String

+method wait: ()Unit

+method wait: (x$1: Long)Unit

+method wait: (x$1: Long, x$2: Int)Unit

+testing Object.!=: false

+testing Object.##: 50

+testing Object.$asInstanceOf: class scala.ScalaReflectionException: AnyRef.$asInstanceOf is an internal method, it cannot be invoked with mirrors

+testing Object.$asInstanceOf: class scala.ScalaReflectionException: java.lang.Object.$asInstanceOf[T0](): T0 takes 0 arguments

+testing Object.$isInstanceOf: class scala.ScalaReflectionException: AnyRef.$isInstanceOf is an internal method, it cannot be invoked with mirrors

+testing Object.$isInstanceOf: class scala.ScalaReflectionException: java.lang.Object.$isInstanceOf[T0](): Boolean takes 0 arguments

+testing Object.==: true

+testing Object.clone: class java.lang.CloneNotSupportedException: java.lang.String

+testing Object.eq: true

+testing Object.equals: true

+testing Object.finalize: null

+testing Object.getClass: class java.lang.String

+testing Object.hashCode: 50

+testing Object.ne: false

+testing Object.notify: class java.lang.IllegalMonitorStateException: null

+testing Object.notifyAll: class java.lang.IllegalMonitorStateException: null

+testing Object.synchronized: 2

+testing Object.toString: 2

+TODO: also test AnyRef.wait overloads

+============
+Array

+it's important to print the list of Array's members

+if some of them change (possibly, adding and/or removing magic symbols), we must update this test

+constructor Array: (_length: Int)Array[T]

+constructor Object: ()java.lang.Object

+method !=: (x$1: Any)Boolean

+method !=: (x$1: AnyRef)Boolean

+method ##: ()Int

+method $asInstanceOf: [T0]()T0

+method $isInstanceOf: [T0]()Boolean

+method ==: (x$1: Any)Boolean

+method ==: (x$1: AnyRef)Boolean

+method apply: (i: <?>)T

+method asInstanceOf: [T0]=> T0

+method clone: ()Array[T]

+method eq: (x$1: AnyRef)Boolean

+method equals: (x$1: Any)Boolean

+method finalize: ()Unit

+method getClass: ()java.lang.Class[_]

+method hashCode: ()Int

+method isInstanceOf: [T0]=> Boolean

+method length: => Int

+method ne: (x$1: AnyRef)Boolean

+method notify: ()Unit

+method notifyAll: ()Unit

+method synchronized: [T0](x$1: T0)T0

+method toString: ()java.lang.String

+method update: (i: <?>, x: <?>)Unit

+method wait: ()Unit

+method wait: (x$1: Long)Unit

+method wait: (x$1: Long, x$2: Int)Unit

+value _length: Int

+testing Array.length: 2

+testing Array.apply: 1

+testing Array.update: ()

+testing Array.clone: List(1, 2)

+============
+Other

+testing String.+: 23

+============
+CTM

+testing Predef.classOf: class scala.ScalaReflectionException: Predef.classOf is a compile-time function, it cannot be invoked with mirrors

+testing Predef.classOf: class scala.ScalaReflectionException: scala.Predef.classOf[T]: Class[T] takes 0 arguments

+testing Universe.reify: class scala.ScalaReflectionException: scala.reflect.base.Universe.reify is a macro, i.e. a compile-time function, it cannot be invoked with mirrors

diff --git a/test/files/run/reflection-magicsymbols-invoke.scala b/test/files/run/reflection-magicsymbols-invoke.scala
new file mode 100644
index 0000000000..61ecc6458d
--- /dev/null
+++ b/test/files/run/reflection-magicsymbols-invoke.scala
@@ -0,0 +1,94 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.universe.definitions._
+import scala.reflect.runtime.{currentMirror => cm}
+
+object Test extends App {
+  def key(sym: Symbol) = sym + ": " + sym.typeSignature
+  def test(tpe: Type, receiver: Any, method: String, args: Any*) {
+    def wrap[T](op: => T) =
+      try {
+        var result = op.asInstanceOf[AnyRef]
+        if (scala.runtime.ScalaRunTime.isArray(result))
+          result = scala.runtime.ScalaRunTime.toObjectArray(result).toList
+        println(result)
+      } catch {
+        case ex: Throwable =>
+          val realex = scala.reflect.runtime.ReflectionUtils.unwrapThrowable(ex)
+          println(realex.getClass + ": " + realex.getMessage)
+      }
+    print(s"testing ${tpe.typeSymbol.name}.$method: ")
+    wrap({
+      if (method == nme.CONSTRUCTOR.toString) {
+        val ctor = tpe.declaration(nme.CONSTRUCTOR).asMethod
+        cm.reflectClass(ctor.owner.asClass).reflectConstructor(ctor)(args: _*)
+      } else {
+        val meth = tpe.declaration(newTermName(method).encodedName.toTermName).asMethod
+        cm.reflect(receiver).reflectMethod(meth)(args: _*)
+      }
+    })
+  }
+
+  println("============\nAny")
+  println("it's important to print the list of Any's members")
+  println("if some of them change (possibly, adding and/or removing magic symbols), we must update this test")
+  typeOf[Any].members.toList.sortBy(key).foreach(sym => println(key(sym)))
+  test(typeOf[Any], "2", "!=", "2")
+  test(typeOf[Any], "2", "##")
+  test(typeOf[Any], "2", "==", "2")
+  test(typeOf[Any], "2", "asInstanceOf")
+  test(typeOf[Any], "2", "asInstanceOf", typeOf[String])
+  test(typeOf[Any], "2", "equals", "2")
+  test(typeOf[Any], "2", "getClass")
+  test(typeOf[Any], "2", "hashCode")
+  test(typeOf[Any], "2", "isInstanceOf")
+  test(typeOf[Any], "2", "isInstanceOf", typeOf[String])
+  test(typeOf[Any], "2", "toString")
+
+  println("============\nAnyVal")
+  println("it's important to print the list of AnyVal's members")
+  println("if some of them change (possibly, adding and/or removing magic symbols), we must update this test")
+  typeOf[AnyVal].declarations.toList.sortBy(key).foreach(sym => println(key(sym)))
+  test(typeOf[AnyVal], null, "<init>")
+  test(typeOf[AnyVal], 2, "getClass")
+
+  println("============\nAnyRef")
+  println("it's important to print the list of AnyRef's members")
+  println("if some of them change (possibly, adding and/or removing magic symbols), we must update this test")
+  typeOf[AnyRef].members.toList.sortBy(key).foreach(sym => println(key(sym)))
+  test(typeOf[AnyRef], "2", "!=", "2")
+  test(typeOf[AnyRef], "2", "##")
+  test(typeOf[AnyRef], "2", "$asInstanceOf")
+  test(typeOf[AnyRef], "2", "$asInstanceOf", typeOf[String])
+  test(typeOf[AnyRef], "2", "$isInstanceOf")
+  test(typeOf[AnyRef], "2", "$isInstanceOf", typeOf[String])
+  test(typeOf[AnyRef], "2", "==", "2")
+  test(typeOf[AnyRef], "2", "clone")
+  test(typeOf[AnyRef], "2", "eq", "2")
+  test(typeOf[AnyRef], "2", "equals", "2")
+  test(typeOf[AnyRef], "2", "finalize")
+  test(typeOf[AnyRef], "2", "getClass")
+  test(typeOf[AnyRef], "2", "hashCode")
+  test(typeOf[AnyRef], "2", "ne", "2")
+  test(typeOf[AnyRef], "2", "notify")
+  test(typeOf[AnyRef], "2", "notifyAll")
+  test(typeOf[AnyRef], "2", "synchronized", "2")
+  test(typeOf[AnyRef], "2", "toString")
+  println("TODO: also test AnyRef.wait overloads")
+
+  println("============\nArray")
+  println("it's important to print the list of Array's members")
+  println("if some of them change (possibly, adding and/or removing magic symbols), we must update this test")
+  ArrayClass.typeSignature.members.toList.sortBy(key).foreach(sym => println(key(sym)))
+  test(ArrayClass.typeSignature, Array(1, 2), "length")
+  test(ArrayClass.typeSignature, Array(1, 2), "apply", 0)
+  test(ArrayClass.typeSignature, Array(1, 2), "update", 0, 0)
+  test(ArrayClass.typeSignature, Array(1, 2), "clone")
+
+  println("============\nOther")
+  test(typeOf[String], "2", "+", 3)
+
+  println("============\nCTM")
+  test(PredefModule.moduleClass.typeSignature, Predef, "classOf")
+  test(PredefModule.moduleClass.typeSignature, Predef, "classOf", typeOf[String])
+  test(typeOf[scala.reflect.base.Universe], scala.reflect.runtime.universe, "reify", "2")
+}
\ No newline at end of file
diff --git a/test/files/run/t6178.check b/test/files/run/t6178.check
new file mode 100644
index 0000000000..d8263ee986
--- /dev/null
+++ b/test/files/run/t6178.check
@@ -0,0 +1 @@
+2
\ No newline at end of file
diff --git a/test/files/run/t6178.scala b/test/files/run/t6178.scala
new file mode 100644
index 0000000000..0b4cf0bbf5
--- /dev/null
+++ b/test/files/run/t6178.scala
@@ -0,0 +1,7 @@
+import scala.reflect.runtime.universe._
+import scala.reflect.runtime.{currentMirror => cm}
+
+object Test extends App {
+  val plus = typeOf[java.lang.String].member(newTermName("$plus")).asMethod
+  println(cm.reflect("").reflectMethod(plus).apply("2"))
+}
\ No newline at end of file