Re: c++/3423: "iterator" name lookup trouble

["Artem Khodush" <artem@duma.gov.ru>]

The following reply was made to PR c++/3423; it has been noted by GNATS.

From: "Artem Khodush" <artem@duma.gov.ru>
To: <ak@ixion.net>
Cc: <gcc-gnats@gcc.gnu.org>, <gcc-bugs@gcc.gnu.org>
Subject: Re: c++/3423: "iterator" name lookup trouble
Date: Tue, 26 Jun 2001 16:51:23 +0400

 > #include <vector>
 > -------------------------------------------------------------------------------
 > using namespace std;
 > 
 > template <class T>
 > struct coord_vector {
 >   };
 > 
 > template<class T>
 > struct polygon_segment : public vector<coord_vector<T> > {
 >     void insert_c(iterator it);
 >   };
 > 
 > -------------------------------------------------------------------------------
 > This file results in a parse error in the "insert_c" line, though
 > it should probably find the superclass's iterator. 
 
 No it shouldn't, since the unqualified name 'iterator' does not
 depend on the template parameter, and according to the
 c++ standard, is looked up elsewhere but the base class.
 
 14.6 - Name resolution 
 
 -9- If a name does not depend on a template-parameter (as 
 defined in temp.dep), a declaration (or set of declarations) 
 for that name shall be in scope at the point where the name 
 appears in the template definition; the name is bound to the 
 declaration (or declarations) found at that point and this 
 binding is not affected by declarations that are visible at the 
 point of instantiation. 
 
 14.6.2 - Dependent names 
 
 -3- In the definition of a class template, ...  if a base class 
 of this template depends on a template-parameter, the base 
 class scope is not examined during name lookup until the 
 class template is instantiated. 
 
 
 So the only solution is to fix the code to make iterator
 dependent on the template parameter, as you've 
 mentioned:
 
 > >Fix:
 > qualify "iterator" with superclass name