[Bug c++/49083] New: g++ should error when a variable declared in a condition is hidden by a variable in the immediately contained block

[howarth at nitro dot med.uc.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49083

           Summary: g++ should error when a variable declared in a
                    condition is hidden by a variable in the immediately
                    contained block
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: howarth@nitro.med.uc.edu


Created attachment 24305
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24305
test case demonstrating the missing error message

Currently g+= 4.6.0 doesn't produce an error for the attached test case,
derived from apt-0.5.4/apt-pkg/deb/deblistparser.cc, despite the fact that a
c++ compiler should error when a variable is declared in a condition that is
hidden by a variable in the immediately contained block. The attached test case
causes the expected compiler errors on HP aCC, AIX xlC, Tru64 cxx and Irix CC.
The g++ compiler only produces a warning if -Wshadow is used. Note that clang
produces the error...

hidden_bug.cc:14:8: error: redefinition of 'I' with a different type
        char *I = S;
              ^
hidden_bug.cc:10:25: note: previous definition is here
      for (const char **I = Sections; *I != 0; I++)
                        ^
hidden_bug.cc:18:21: error: assigning to 'const char *' from incompatible type
'char'
               *I++ = tolower(*Start);
                    ^ ~~~~~~~~~~~~~~~
hidden_bug.cc:20:22: error: assigning to 'const char *' from incompatible type
'char'
                *I++ = '=';
                     ^ ~~~
hidden_bug.cc:22:22: error: assigning to 'const char *' from incompatible type
'char'
                *I++ = '=';
                     ^ ~~~
4 errors generated.