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, 3 insertions, 9 deletions

diff --git a/test/files/presentation/ide-bug-1000475.check b/test/files/presentation/ide-bug-1000475.check
index f5b4253e1a..4fb7f18285 100644
--- a/test/files/presentation/ide-bug-1000475.check
+++ b/test/files/presentation/ide-bug-1000475.check
@@ -3,7 +3,7 @@ reload: Foo.scala
 askTypeCompletion at Foo.scala(3,7)
 ================================================================================
 [response] askTypeCompletion at (3,7)
-retrieved 31 members
+retrieved 29 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -18,10 +18,8 @@ def hashCode(): Int
 def toString(): String
 def →[B](y: B): (Object, B)
 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
@@ -37,7 +35,7 @@ final def wait(x$1: Long,x$2: Int): Unit
 askTypeCompletion at Foo.scala(6,10)
 ================================================================================
 [response] askTypeCompletion at (6,10)
-retrieved 31 members
+retrieved 29 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -52,10 +50,8 @@ def hashCode(): Int
 def toString(): String
 def →[B](y: B): (Object, B)
 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
@@ -71,7 +67,7 @@ final def wait(x$1: Long,x$2: Int): Unit
 askTypeCompletion at Foo.scala(7,7)
 ================================================================================
 [response] askTypeCompletion at (7,7)
-retrieved 31 members
+retrieved 29 members
 [inaccessible] protected[package lang] def clone(): Object
 [inaccessible] protected[package lang] def finalize(): Unit
 def +(other: String): String
@@ -86,10 +82,8 @@ def hashCode(): Int
 def toString(): String
 def →[B](y: B): (Object, B)
 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