SI-8143 Regressions with override checks, private members

These regressed in e609f1f20b, which excluded all private methods from
overriding checks. We should only exclude private[this] members on the
low end of a pair, as was done before that commit, and, we must also
exclude private members on the high side.

Why? Warning: reverse engineered intuition follows.

We need to report an error when if a private method in a subclass
has matches a less-private method in the super class and report an
error, lest the user be fooled into thinking it might be invoked
virtually. On the other hand, adding a private method to a super
class shouldn't invalidate the choice names of public members in
its superclasses.

I've removed the test case added by that commit and will lodge a
reworked version of it that Paul provided as a new issue. That shows
a bug with qualified private + inheritance.

In addition, the expectation of `neg/accesses.check` is reverted
to its 2.10.3 version, which I believe is correct. When it was
changed in e609f1f20b it sprouted a variation, `neg/accesses-2`,
which has now changed behaviour. The intent of that test will
be captured in the aforementioned issue covering qualified private
inheritance.

1 files changed, 5 insertions, 1 deletions

diff --git a/test/files/neg/accesses.check b/test/files/neg/accesses.check
index 5a5e03233e..db58af12ce 100644
--- a/test/files/neg/accesses.check
+++ b/test/files/neg/accesses.check
@@ -1,3 +1,7 @@
+accesses.scala:23: error: overriding method f2 in class A of type ()Unit;
+ method f2 has weaker access privileges; it should not be private
+  private def f2(): Unit = ()
+              ^
 accesses.scala:24: error: overriding method f3 in class A of type ()Unit;
  method f3 has weaker access privileges; it should be at least protected
   private[p2] def f3(): Unit = ()
@@ -10,4 +14,4 @@ accesses.scala:26: error: overriding method f5 in class A of type ()Unit;
  method f5 has weaker access privileges; it should be at least protected[p1]
   protected[p2] def f5(): Unit
                     ^
-three errors found
+four errors found