-Wtype-limits should not produce warnings in the following example:
template<class integer>
bool foo(integer x)
{
if(x >= 0)
{
// Do something here if integer is positive.
return false;
}
else if(x < 0) // Used else if() here instead of just else to get 2nd
warning.
{
// Do something else here if integer is negative.
return true;
}
}
int main()
{
foo<unsigned int>(3);
foo<int>(3);
return 0;
}
The first line in the main() function, together with -Wtype-limits (or
-Wextra), produces these warnings:
warning: comparison of unsigned expression >= 0 is always true
warning: comparison of unsigned expression < 0 is always false
While these warnings makes sense for all other cases, they should not occur for
comparison of template types, since it does not easily allow for warning-free
templates which can handle unsigned and signed integers and have different
behavior for negative numbers.
Disabling the warning with -Wno-type-limits works as a temporary solution, but
this also makes finding potential bugs in non-template code more difficult.
Regards,
Jason.
--
Summary: Templates with -Wtype-limits produces warnings.
Product: gcc
Version: 4.3.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: crossroads0000 at googlemail dot com
GCC build triplet: x86_64-linux-elf
GCC host triplet: x86_64-linux-elf
GCC target triplet: x86_64-linux-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44021
