These were all cases where the parameter was the new value when setting
a variable. The variables should always be initialized when that code is
reached but it is still better to check the pointers before using them.
These were found by @niffiwan.
This will automatically call the destructor of a type of Lua calls the
garbage collector for an object of that type. This is the last step
towards fully supporting non-trivial objects in the Lua API and all
previous workarounds have been removed.
Goober5000