https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79433
Bug ID: 79433
Summary: __has_include reports wrong result headers that #error
on __cplusplus
Product: gcc
Version: 7.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: marc.mutz at kdab dot com
Target Milestone: ---
Code that attempts to detect, say, string_view support by
__has_include(<string_view>) or __has_include(<experimental/string_view>) and
then attempts to #include those headers is greeted with an #error that these
headers require C++17 and C++14, resp.
Since there's no SG-10 SD-6 feature test macro for string_view, this means that
no portable way of detecting string_view support is possible.
Expected behaviour: __has_include should behave consistent with the header's
#error mechanism.
