False positive -Wreturn-stack-address warning with optional

[rogerorr]

Bugzilla Link	44003
Resolution	FIXED
Resolved on	Feb 19, 2020 06:30
Version	trunk
OS	Windows NT
CC	@dwblaikie,@DougGregor,@zygoloid

Extended Description

The following code, with clang trunk and -std=c++17, produces a warning that I believe to be a false positive.

---- code ----
#include
#include <string_view>

std::string_view foo()
{
std::optionalstd::string_view sv("abc");
return *sv; // unwanted [-Wreturn-stack-address] warning
}
---- code ----

See https://godbolt.org/z/vTs3Kk

This is a regression since clang 9.0

[rogerorr]

Re-checking this issue I find that the reproducing test case is now fixed on gcc-trunk.

(Tested with the godbolt link in the original comment on 2020-02-19)

I have marked this particular issue with -Wreturn-stack-address as resolved

[rogerorr]

s/gcc-trunk/clang-trunk/
(Still recovering from WG21 in Prague)