[C++ PATCH] [PR2204] Check for parameters of abstract types - Take 3

[Mark Mitchell]

Giovanni Bajo wrote:

> I will have to create a different incomplete_vars list which stores couples of
> IDENTIFIER_NODE and TREE_TYPE instead of declarations, for the purpose of
> delayed evaluation of abstractness.

I'm sure I'm being dense, but can you back up and explain why we need to 
save away information at all?

Are we trying to detect cases like

   struct S;

   void f(S s);

   struct S {
     virtual void g() = 0;
   };

where "f" has a parameter with an abstract type?

Does the standard actually require us to diagnose this case? 
Presumably, we would already diagnose it if someone tried to call or 
define "f"?

Thanks,

-- 
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com