PATCH for Re: foo.cc:15: Internal compiler error.

[Mark Mitchell]

>>>>> "Alexandre" == Alexandre Oliva <oliva@dcc.unicamp.br> writes:

    Alexandre> Mark Mitchell <mark@markmitchell.com> writes:

    >> template <class A*> void f();

    >> declares an (anonymous) non-type parameter of type `class A*',
    >> and forward-declares `class A'.  Would you believe it?

    Alexandre> IMO, it shouldn't forward-declare `class A'; this code
    Alexandre> should only be accepted if `class A' is declared
    Alexandre> already.  Although not explicitly stated in section
    Alexandre> [temp.param], this requirement is implied in the last
    Alexandre> sentence of [dcl.type.elab]/3:

    Alexandre>                     If name lookup does not find a
    Alexandre> declaration for the name, the elaborated-type-specifier
    Alexandre> is ill-formed unless it is of the simple form class-key
    Alexandre> identifier in which case the identifier is declared as
    Alexandre> described in _basic.scope.pdecl_.

I think you're misreading this.  It's legal, for example, to say:

  void foo(class A* ap);

with no prior declaration of `A'.  You can't say:

  void foo(class A::B* bp);

without a prior declaration of `A::B'; here the elaborated type
specifier does not have the form `class-key identifier'.

The situation with template parameters is analagous, although I agree
that it is not explicitly discussed by the standard.  The stuff if
[basic.scope.pdecl] discusses the function parameter case explicitly,
but not the template parameter case.

    Alexandre> Perhaps we should take this to comp.std.c++ ?

Perhaps.  But, we want to make sure we implement the right thing, so
we should bring it back here afterwards!

-- 
Mark Mitchell 			mark@markmitchell.com
Mark Mitchell Consulting	http://www.markmitchell.com