luaC_checkGC in luaD_call

[Matthew Wild <mwild1@...>]

Hi,

luaC_checkGC() is called throughout Lua in places that cause
allocations, such as OP_NEWTABLE, OP_CONCAT, etc.

While reviewing places the GC may be triggered, I noticed it is also
checked in luaD_call(). Is there a practical or theoretical reason
this is necessary? It seems the mechanism of a function call/return
itself doesn't create any new collectable objects that I can see.

Regards,
Matthew