From 4a8edc03653cb0f6b6ed1cdea1779a19df20f8f5 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Tue, 4 Feb 2014 15:55:59 +0100 Subject: 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. --- src/library-aux/scala/AnyRef.scala | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/library-aux') diff --git a/src/library-aux/scala/AnyRef.scala b/src/library-aux/scala/AnyRef.scala index 362fbcf0f5..8c1862e729 100644 --- a/src/library-aux/scala/AnyRef.scala +++ b/src/library-aux/scala/AnyRef.scala @@ -76,8 +76,8 @@ trait AnyRef extends Any { * @param arg0 the object to compare against this object for equality. * @return `true` if the receiver object is equivalent to the argument; `false` otherwise. */ - final def ==(that: AnyRef): Boolean = - if (this eq null) that eq null + final def ==(that: Any): Boolean = + if (this eq null) that.asInstanceOf[AnyRef] eq null else this equals that /** Create a copy of the receiver object. -- cgit v1.2.3