QProperty: fix comparison with comparable typeHEADdev

After e115c60b6da0db7013229e678720f36632c2e614, the comparison with
a type which is different from QProperty::value_type, but is comparable
to it, could result in ambiguous operator==() overloads.

Fix it by adding a new overload for operator==(QProperty<T>, U), where
operator==(T, U) exists.

Explicitly delete operator==(QProperty<T>, QProperty<U>) for such
types T and U, because the implicit conversion might be unwanted here.
The user should manually call .value() at least on one property, if
they want the comparison. Note that GCC does not allow to do it,
treating `= delete` as declaration and complaining about a default
template argument in friend template declaration. So, do it only for
Clang and MSVC.

Amends e115c60b6da0db7013229e678720f36632c2e614.

Task-number: QTBUG-134921
Pick-to: 6.10
Change-Id: Id3ed48738cc462b5b0820fa3b25d80d4d4414548
Reviewed-by: Fabian Kosmale <[email protected]>

0 files changed, 0 insertions, 0 deletions