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From: "gcc-90 at tbilles dot hu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94061] defaulted member operator <=> defined as deleted if
 a base has protected member operator <=>
Date: Wed, 24 Apr 2024 07:42:03 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94061

Tibor Billes <gcc-90 at tbilles dot hu> changed:

           What    |Removed                     |Added
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                 CC|                            |gcc-90 at tbilles dot hu

--- Comment #5 from Tibor Billes <gcc-90 at tbilles dot hu> ---
I ran into this problem, I found a detailed stackoverflow discussion that
explains that the standard mandate the derived to base conversion mentioned
earlier in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94061#c2

It says that the list of subobjects are "formed by a sequence of
derived-to-base conversions, class member access expressions, and array
subscript expressions applied to x".
(https://timsong-cpp.github.io/cppwp/n4868/class.compare.default#6.sentence=
-3)

I'm not a C++ language lawyer, just wanted to provide additional information
for anyone looking for this problem. And yeah, I also wish this would work..

Here is the stackoverflow discussion with all the good references to the
specific sections of the standard:
https://stackoverflow.com/questions/73055625/deriving-class-with-protected-=
equality-operator-results-in-deleted-default=