Use the fact that we return the conversion function as a lambda
to find out reliably whether a conversion between two types
can be done.
This requires some minor adjustments to our tests:
* Nothing can convert to an unknown type and vice versa
* Adjust results to the fact that we don't convert from char
to QString anymore (where the old method was incorrect)
* QStringList->QString requires some adjustments, as we only
convert if the string list has exactly one element. For now
we return true in canConvert(), but the conversion behavior
in this case is something we should rethink, as it is very
surprising.
Change-Id: I3f5f87ee9cb99d690f5a7d13b13d6a6313d8038e
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>
9d36032370