[Bug c++/96283] "undefined vtable" error should indicate which members are missing

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96283

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Eyal Rozenberg from comment #2)
> Ok, still - the linker knows which virtual methods it needs, and it knows
> which are provided by each compiled translation unit. Isn't that enough?

The linker does not need the virtual functions though. It needs the vtable.

Nothing references the virtual functions, so they don't need to be defined.