[Bug c++/33124] New: C++ frontend should not warn about new a[0] in template context

["ian at airs dot com" <gcc-bugzilla at gcc dot gnu dot org>]

For this simplified code:

template<int c>
char* f1() { if (c == 0) return 0; else return new char[c]; }
char* f2() { return f1<0>(); }

the C++ frontend issues an unconditional warning.  When compiling with no
options, I get

foo.cc: In function ?char* f1() [with int c = 0]?:
foo.cc:3:   instantiated from here
foo.cc:2: warning: allocating zero-element array

I have no objection to this warning in ordinary usage, but when the argument to
new[] depends on a template parameter, I think this warning does more harm than
good.  Even with properly parameterized code we get a useless and unavoidable
warning.

I recommend both 1) don't warn when the argument depends on a template
parameter; and 2) add an option to control this warning.


-- 
           Summary: C++ frontend should not warn about new a[0] in template
                    context
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ian at airs dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33124