When declaring metatypes, the metatype system tries to detect if the
comparison operators for the given type exist and automatically register
them. In case of QHash, the equality operator was enabled if the value
type provides one. But the implementation needs equality operator of
the key type as well. As a result, when the key type has no equality
operator, the metatype system detects that the equality operator is
available for the QHash itself, but the compilation for metatype
registration fails when trying to instantiate the code that uses
equality operator for the key. This is fixed by enabling equality
operators for the QHash only when both the key and value types provide
one.
The same issue existed also for QMultiHash, with the difference, that
QMultiHash didn't have the constraints even on the value type. So added
checks for both.
Fixes: QTBUG-96256
Pick-to: 6.2
Change-Id: Ib8b6d365223f2b3515cbcb1843524cd6f867a6ac
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>