c++/2288: Variable declared in for-loop-header is in wrong scope

[Wolfgang Bangerth]

The following reply was made to PR c++/2288; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: gcc-gnats@gcc.gnu.org, <gcc-bugs@gcc.gnu.org>
Cc:  
Subject: Re: c++/2288: Variable declared in for-loop-header is in wrong scope
Date: Thu, 14 Nov 2002 18:13:47 -0600 (CST)

 Still happens with recent CVS. A smaller, self-contained testcase is this:
 ------------------------
 void f(int);
 int main() {
    for (int i=0;;++i) {
      int i=5;
      f(i);
    }
    return 0;
 }
 -----------------------
 I don't get an error upon the second declaration of "i", although it 
 should be in the same scope as that declared in the loop-header. If I use 
 -Wshadow, it says
 x.cc: In function `int main()':
 x.cc:4: warning: declaration of `i' shadows a previous local
 x.cc:3: warning: shadowed declaration is here
 
 So one can assume that gcc generates two nested scopes for this construct, 
 in the outer one those variables are placed which are declared in the loop 
 header, in the inner one those go that are declared in the loop body. I 
 think this is not the intent of the standard...
 
 The C frontend in gnu99 mode suffers from the same problem, by the way.
 
 Regards
   Wolfgang
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:           bangerth@ticam.utexas.edu
                                www: http://www.ticam.utexas.edu/~bangerth