Re: c++/8772: Segmentation fault on 3 lines of template code

[Wolfgang Bangerth <bangerth@ticam.utexas.edu>]

The following reply was made to PR c++/8772; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: Volker Reichelt <reichelt@igpm.rwth-aachen.de>
Cc: gcc-gnats@gcc.gnu.org, <sneechy@hotmail.com>, <gcc-bugs@gcc.gnu.org>,
   <gdr@integrable-solutions.net>
Subject: Re: c++/8772: Segmentation fault on 3 lines of template code
Date: Fri, 17 Jan 2003 09:46:45 -0600 (CST)

 > What are we going to do with the PR w.r.t. the how-to-make-to-code-legal
 > issue? Leave it open, close it, suspend it, open a new PR?
 
 Good question. Just to recall this briefly: this code
 ---------------
 template <int> struct A {
     template <int> struct B { enum { v = 1 }; };
 };
 
 template <template <int> class F> struct C {
     enum { v = F<1>::v || 2 };
 };
 
 template <int n> struct D {
     enum { v = C<A<n>::B>::v };
 };
 -----------------------
 generated an ICE (now errors), and the question was: is in the last line
   C<A<n>::B> 
 something meaningful? Wouldn't we have to write
   C<typename A<n>::B>
 ? This doesn't compile either presently. 
 
 Gaby's suggestion was that this needs to be further disambiguated as
   C<typename A<n>::template B>
 which would not be covered by the standard (the oversight Gaby spoke of), 
 but be reasonable. However, this still doesn't compile presently:
   g/a> /home/bangerth/bin/gcc-3.4-pre/bin/gcc -c x.cc
   x.cc:10: error: template argument 1 is invalid
 
 What does compile is (also with icc7, by the way)
   C<A<n>::template B>
 
 Gaby, is the latter the syntax you had in mind to be legal, i.e. put 
 differently: no need for "typename"?
 
 
 If yes, then I would say gcc presently does its best and we should close 
 the report. If the inquire Gaby did with the ISO committee finds some 
 other solution, then this will be put into a DR anyway, and there is no 
 need to keep the report open presently anyway.
 
 Regards
   Wolfgang
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth             email:            bangerth@ticam.utexas.edu
                               www: http://www.ticam.utexas.edu/~bangerth/