In article <IMMEL.94Jul25154936@chord.centerline.com> immel@chord.centerline.com (Mark Immel) writes:
>
>Folks --
>
>  Can anyone tell me *where* the standard (May WP, preferably) says that
>  the following code is illegal.  I think it should be illegal; so do some
>  compilers.  Cfront, does not.  The relevant section of the WP seems to
>  be 10.2, but the answer doesn't quite seem to be there.
>
>class A
>{
>public:
>  int i;
>};
>
>class B : virtual public A {
>};
>
>class C1 : public B
>{
>};
>
>class C2 : public B
>{
>};
>
>class D : public C1, public C2
>{
>  D() { B::i; }
>};
>
>  The reference to B::i is (IMO) ambiguous, since D has two B's as base
>  classes.  However, D has only one i anyplace, so Cfront says it's OK.  The
>  only thing I can find in the WP 10.2 is:
>
>  "An explicit or implicit conversion from a pointer to or an lvalue of a
>   derived class to a pointer to a reference to one of its base classes must
>   unambiguously refer to a unique object representing the abse class."
>
>  An example follows which contains lots of address-of operators and so forth.
>  If this is meant to cover my example, it should be explicit.  It also says
>  earlier in 10.2 that the following *IS* legal (as it should be):
>
>    D() {i;}
>
>  As always, you may email me at immel@centerline.com and I'll follow up.
>
>-- Mark Immel
>   immel@centerline.com


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Folks --

  Can anyone tell me *where* the standard (May WP, preferably) says that
  the following code is illegal.  I think it should be illegal; so do some
  compilers.  Cfront, does not.  The relevant section of the WP seems to
  be 10.2, but the answer doesn't quite seem to be there.

class A
{
public:
  int i;
};

class B : virtual public A {
};

class C1 : public B
{
};

class C2 : public B
{
};

class D : public C1, public C2
{
  D() { B::i; }
};

  The reference to B::i is (IMO) ambiguous, since D has two B's as base
  classes.  However, D has only one i anyplace, so Cfront says it's OK.  The
  only thing I can find in the WP 10.2 is:

  "An explicit or implicit conversion from a pointer to or an lvalue of a
   derived class to a pointer to a reference to one of its base classes must
   unambiguously refer to a unique object representing the abse class."

  An example follows which contains lots of address-of operators and so forth.
  If this is meant to cover my example, it should be explicit.  It also says
  earlier in 10.2 that the following *IS* legal (as it should be):

    D() {i;}

  As always, you may email me at immel@centerline.com and I'll follow up.

-- Mark Immel
   immel@centerline.com