SI-8129 Make Object#== override Any#==

And the same for !=

If we tried to declare these signatures in non-fictional classes,
we would be chastised about collapsing into the "same signature after
erasure".

This will have an influence of typing, as the typechecking of
arguments is sensitive to overloading: if multiple variants are
feasible, the argument will be typechecked with a wildcard expected
type. So people inspecting the types of the arguments to `==` before
this change might have seen an interesting type for
`if (true) x else y`, but now the `If` will have type `Any`, as we
don't need to calculate the LUB.

I've left a TODO to note that we should really make `Any#{==, !=}`
non-final and include a final override in `AnyVal`. But I don't think
that is particularly urgent.

1 files changed, 1 insertions, 3 deletions

diff --git a/test/files/presentation/implicit-member.check b/test/files/presentation/implicit-member.check
index 5ad52b4dd3..3bd3d8af41 100644
--- a/test/files/presentation/implicit-member.check
+++ b/test/files/presentation/implicit-member.check
@@ -3,7 +3,7 @@ reload: ImplicitMember.scala
 askTypeCompletion at ImplicitMember.scala(7,7)
 ================================================================================
 [response] askTypeCompletion at (7,7)
-retrieved 34 members
+retrieved 32 members
 def +(other: String): String
 def ->[B](y: B): (Implicit.type, B)
 def ensuring(cond: Boolean): Implicit.type
@@ -17,10 +17,8 @@ def toString(): String
 def →[B](y: B): (Implicit.type, B)
 final class AppliedImplicit[A] extends AnyRef
 final def !=(x$1: Any): Boolean
-final def !=(x$1: AnyRef): Boolean
 final def ##(): Int
 final def ==(x$1: Any): Boolean
-final def ==(x$1: AnyRef): Boolean
 final def asInstanceOf[T0]: T0
 final def eq(x$1: AnyRef): Boolean
 final def isInstanceOf[T0]: Boolean