BraveSirKevin wrote:You need the base building to add the building to the production queue, but as far as I can tell, you don't need it there during the construction.
You do, in fact, need it there during construction. If a building's location conditions are no longer met while it is under construction, it will cease to be allocated PP.
When I first added shipyards to the game, I actually did make each destroy the previous, and also so that the previous shipyards couldn't be built when an upgrade was present. The scripting was incredibly tedious and ugly, due to all the conditions for a building destroying itself, and being able to or not able to be constructed. But one of the most unexpected (at least to me) inelegancies that came out of it was all the extra conditions needed for ship hull location conditions. When Orbital Drydock sticks around, you can just say, "OK, Basic Hull requires Basic Shipyard". When it gets replaced by the next upgrade, then you have to say, "OK, Basic Hull requires Basic Shipyard, OR Orbital Drydock OR Geo-Integration Facility, etc...".
I would consider rather than forcing particular buildings to not be built together, that we continue with the trend of limiting where particular upgrades or streams of upgrades can be built (for example, on an asteroid belt, or in systems with a star of a particular intensity). That way the player would be more likely to have various specialized shipyards in different locations, as opposed to clumping them all in one place.
However, that's still really off-topic from the original point of infrastructure, about which I unfortunately don't have much to say at the moment, except feel free to try something new and see if it works.