[Bug libstdc++/109482] New: experimental/net/internet/endpoint/cons.cc FAILs

["ro at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109482

            Bug ID: 109482
           Summary: experimental/net/internet/endpoint/cons.cc FAILs
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
  Target Milestone: ---
              Host: *-*-solaris2.11
            Target: *-*-solaris2.11
             Build: *-*-solaris2.11

Created attachment 54839
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54839&action=edit
32-bit i386-pc-solaris2.11 cons-cons.ii

Between 20230329 (b2f327b9be81326c9e59fc6da98074c909ac7408) and 20230330
(a23b33a1bdeff7bc2289d9ebb7cb7b7ec0a605f5), the
experimental/net/internet/endpoint/cons.cc test began to FAIL on Solaris
(11.3 and 11.4, SPARC and x86):

+FAIL: experimental/net/internet/endpoint/cons.cc (test for excess errors)
+UNRESOLVED: experimental/net/internet/endpoint/cons.cc compilation failed to
produce executable

The log shows

Excess errors:
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:78:
error: non-constant condition for static assertion
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:78:
error: accessing 'in_addr::<unnamed union>::S_addr' member instead of
initialized 'in_addr::<unnamed union>::S_un_b' member in constant expression

The full message is

/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:
In function 'int main()':
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:78:
error: non-constant condition for static assertion
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:78:
  in 'constexpr' expansion of 'test_constexpr()'
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:63:
  in 'constexpr' expansion of 'test_default()'
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:15:
  in 'constexpr' expansion of
'std::experimental::net::v1::ip::basic_endpoint<_InternetProtocol>::address()
const [with _InternetProtocol = std::experimental::net::v1::ip::tcp]()'
/vol/gcc/src/hg/master/local/libstdc++-v3/testsuite/experimental/net/internet/endpoint/cons.cc:78:
error: accessing 'in_addr::<unnamed union>::S_addr' member instead of
initialized 'in_addr::<unnamed union>::S_un_b' member in constant expression

This is no doubt due to

commit e0d77144aaa56ee6e00fd0ba520b0a5c7e052423
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Mar 22 17:00:11 2023 +0000

    libstdc++: Fix constexpr functions in <experimental/internet>

but I don't know what's going on.  I'm attaching the preprocessed testcase.