General Description: When I implement a design with two or more top level-schematics, the creation of a netlist in Schematic Editor (Options -> Create Netlist) generates the following sourceless/loadless warning for each hanging net that runs across the pages:
This is a known problem with the integrity test feature of Foundation Schematic Editor. This feature does not correctly analyze nets across multiple pages; instead, it sees them as sourceless and generates the warning messages above. These messages can therefore be safely ignored or disabled.
To disable the warnings, open the Schematic Editor and select Options -> Integrity Test Options. Then, deselect "Sourceless nets" and "Loadless nets".
Doing this will cause the integrity test to ignore these options -- this means that you will not be warned of such problems at the netlist level. However, the implementation tools will still perform the standard design rules checks; if problems do actually exist, they will be caught at the appropriate stage during the implementation process. (For example, multiple drivers will be flagged in the "Translate" stage; loadless nets will be flagged in the ""Map" stage.)
Therefore, you may disable these options with confidence that the tools will still detect any design problems.