SI-7779 Account for class name compactification in reflection

We have to assume that the classes we are reflecting on were
compiled with the default value for -Xmax-classfile-name (255).

With this assumption, we can apply the same name compactification
as done in the regular compiler.

The REPL is particularly prone to generating long class names
with the '$iw' prefixes, so this is an important fix for runtime
reflection.

Also adds support for getting the runtime class of `O.type` if
`O` is a module.

1 files changed, 67 insertions, 0 deletions

diff --git a/test/files/run/t7779.scala b/test/files/run/t7779.scala
new file mode 100644
index 0000000000..db32cb751f
--- /dev/null
+++ b/test/files/run/t7779.scala
@@ -0,0 +1,67 @@
+// -Xmax-classfile-length doesn't compress top-level classes.
+// class :::::::::::::::::::::::::::::::::::::::::::::::::
+
+trait Marker
+
+class Short extends Marker
+
+// We just test with member classes
+object O {
+  object ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+}
+class C {
+  class D {
+    class ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+  }
+}
+
+package pack {
+  // abbreviates to: $colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon to $read$$iw$$iw$$colon$colon$colon$colon$colon$colon$colon$colon$$$$c39b3f245029fbed9732fc888d44231b$$$$on$colon$colon$colon$colon$colon$colon$colon$colon$colon$colon
+  // class :::::::::::::::::::::::::::::::::::::::::::::::::
+
+  class Short extends Marker
+
+  // We just test with member classes
+  object O {
+    object ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+  }
+  class C {
+    class D {
+      class ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+    }
+  }
+  package p2 {
+    class Short extends Marker
+
+    object O {
+      object ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+    }
+    class C {
+      class D {
+        class ::::::::::::::::::::::::::::::::::::::::::::::::: extends Marker
+      }
+    }
+  }
+}
+
+
+object Test extends App {
+  import reflect.runtime.universe._
+  def test[T: TypeTag] = {
+    val tt = typeTag[T]
+    val clz = tt.mirror.runtimeClass(tt.tpe)
+    assert(classOf[Marker].isAssignableFrom(clz), clz.toString)
+  }
+
+  test[Short]
+  test[O.:::::::::::::::::::::::::::::::::::::::::::::::::.type]
+  test[C#D#`:::::::::::::::::::::::::::::::::::::::::::::::::`]
+
+  test[pack.Short]
+  test[pack.O.:::::::::::::::::::::::::::::::::::::::::::::::::.type]
+  test[pack.C#D#`:::::::::::::::::::::::::::::::::::::::::::::::::`]
+
+  test[pack.p2.Short]
+  test[pack.p2.O.:::::::::::::::::::::::::::::::::::::::::::::::::.type]
+  test[pack.p2.C#D#`:::::::::::::::::::::::::::::::::::::::::::::::::`]
+}