Hello,

pls, pay attention to this possible couple of formal ambiguities
in the standard:

around the possible differences that the signature for the assignment
operators may have, compared to the implicitly-declared ones, when
the default implementation is required through '= default',
(F1 being the explicit used signature and F2 the one that compiler
 would have used in case of implicit declaration)

[dcl.fct.def.default]-p(2.4) reads:

if F2 has a non-object parameter of type const C&, the corresponding
non-object parameter of F1 may be of type C&.

However, since the text never makes explicit what 'C' is, it is
theoretically possible to think C as MyClass&, which would make the
aforementioned text ineffective (while remaining correct) because
the const qualifier becomes useless.


The other point is that, since [dcl.fct.def.default]-p(2.2) reads

if F2 has an implicit object parameter of type "reference to C",
F1 may be an explicit object member function whose explicit
object parameter is of (possibly different) type "reference to C",
in which case the type of F1 would differ from the type of F2 in
that the type of F1 has an additional parameter;

then the following sentence in [class.copy.assign]-p12:

The implicitly-defined copy/move assignment operator for
a non-union class X performs memberwise copy/move
assignment of its subobjects.

is not fully formally correct in my opinion, because 'its subobjects'
refers. to me, the data members of the object '*this'.
Some modified wording (or additional note) might be used to cover
the case of explicit object parameter ( as allowed by [dcl.fct.def.default]
-p(2.2 ) ).