[Bug c++/11512] New: Wrong warning in trivial function template

[jan at etpmod dot phys dot tue dot nl]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11512

           Summary: Wrong warning in trivial function template
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jan at etpmod dot phys dot tue dot nl
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: linux, glibc-2.2.5
  GCC host triplet: linux, glibc-2.2.5
GCC target triplet: linux, glibc-2.2.5

Consider the following code. When compiling with -Wall it generates: 
 
comma.cpp: In function `int foo2()': 
comma.cpp:15: warning: left-hand operand of comma expression has no effect 
 
The 'identical' template-less function (foo1) compiles without warnings. Obviously this warning 
is wrong, and both versions of the code give the expected result. 
 
#include <cassert> 
 
int foo1() 
{ 
        int r=0; 
        for (int i=0; i<1; ++i, ++r) 
                ; 
        return r; 
} 
 
template <class T> 
int foo2() 
{ 
        int r=0; 
        for (int i=0; i<1; ++i, ++r) 
                ; 
        return r; 
} 
 
int main() 
{ 
        assert(foo1()==1); 
        assert(foo2<int>()==1); 
        return 0; 
}