SystemVerilog defines different levels of type compatibility.
* Matching
* Equivalent
* Assignment compatible
* Cast compatible
At the moment the `nettype_t` has only one type compatibility test. It is
used to check assignment compatibility when assigning to a dynamic array,
queue or class.
The current implementation rejects a few cases that should allowed and
allows a few cases that should be rejected.
Dynamic arrays and queues are assignment compatible if their element types
are compatible. And two packed types are equivalent if they are both
2-state or 4-state, both signed or unsigned and have the same packed with.
In the current implementation the sign is not considered and instead of
checking if the packed width is the same it checks that the dimensions are
identical.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen
Cary R
Stephen Williams
Arun Persaud