Only allow implicit conversions when the types involved are compatible.
That means, only allow construction and copy assignment when the type
X* is convertible to type T*. This is done using SFINAE and the
std::is_convertible type trait, which makes the previous
QSHAREDPOINTER_VERIFY_AUTO_CAST obsolete.
This patch fixes compilation when a function is overloaded with
Q{Shared,Weak}Pointer of different, incompatible types. Previously, this
resulted in a compilation error due to an ambiguous overload.
Change-Id: I069d22f3582e69842f14284d4f27827326597ca2
Fixes: QTBUG-75222
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>