SI-8954 Make @deprecated{Overriding,Inheritance} aware of @deprecated.

This makes sure that:
 - there is no warning for a @deprecated class inheriting a
   @deprecatedInheritance class
 - there is no warning for a @deprecated method overriding a
   @deprecatedOverriding method
 - there is no "deprecation won't work" warning when overriding a member
   of a @deprecatedInheritance class with a @deprecated member
 - the above works even if the classes/methods are indirectly deprecated
   (i.e. enclosed in something @deprecated)

This should remove quite a few useless deprecation warnings from the
library.

1 files changed, 13 insertions, 0 deletions

diff --git a/test/files/pos/t8954/t1.scala b/test/files/pos/t8954/t1.scala
new file mode 100644
index 0000000000..3986d9f3b5
--- /dev/null
+++ b/test/files/pos/t8954/t1.scala
@@ -0,0 +1,13 @@
+package scala.foo
+
+// 1. a class about to be made final
+@deprecatedInheritance class A {
+  def foo(): Unit = ???
+}
+
+// 1.1:
+// - no inheritance warning because same file
+// - no "override non-deprecated member" because @deprecatedInheritance
+class B2 extends A {
+  @deprecated("","") override def foo(): Unit = ???
+}