https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92700
Bug ID: 92700
Summary: wrong "unintialized" warning with std::optional
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: f.heckenb...@fh-soft.de
Target Milestone: ---
#include <optional>
#include <string>
int e;
template <typename T> std::optional <size_t> f ()
{
if (auto i = std::string ().find ('a'))
return i;
return { };
}
int main ()
{
size_t j = 1;
while (j)
{
auto i = f <int> ();
if (e != 1 && e != 4 && e != 7)
throw 0;
if (i)
j = *i;
}
}
% g++-9 --version
g++-9 (GCC) 9.1.0
% g++-9 --std=c++17 test.cpp -Wall -O3
test.cpp: In function 'int main()':
test.cpp:10:12: warning: '<anonymous>' may be used uninitialized in this
function [-Wmaybe-uninitialized]
This may be a duplicate, but I can't really tell since this warning seems to
depend on many seemingly unrelated conditions, e.g. f must be a template,
std::string::find seems required (at least a simple external function won't
do),
the seemingly unrelated test of e is required (and must contain at least
3 clauses with specific values -- 1, 2, 3 won't do).
