[Bug c++/27177] [4.1/4.2/4.3 Regression] ICE in build_simple_base_path, at cp/class.c:474

["crowl at google dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #17 from crowl at google dot com  2008-01-14 21:29 -------
Subject: Re:  [4.1/4.2/4.3 Regression] ICE in build_simple_base_path, at
cp/class.c:474

The consensus of the C++ standards reflector is that all three
following code snippets are well-formed.

explicit:
   struct B {};
   struct D : public B {
       static const int i = sizeof((B*)(D*)0);
   };

implicit:
   struct Z {};
   struct A : Z {};
   Z* implicitToZ (Z*);
   struct B : A {
       static const int i = sizeof(implicitToZ((B*)0));
   };

non-null:
   struct B {};
   struct D;
   D* p;
   struct D: public B {
       static const int i = sizeof ((B*)p);
   };

The rational is that even though the classes are not complete
within their body, the bases must be known.  The reason is that
other features of the language, like co-variant returns, would fail.
Since the bases are known, the conversions are well-formed.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27177