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Re: [PATCH] Enforce allocator::value_type consistency for containers in C++2a
- From: Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>
- To: Jonathan Wakely <jwakely at redhat dot com>
- Cc: libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Mon, 03 Jun 2019 23:17:08 +0200
- Subject: Re: [PATCH] Enforce allocator::value_type consistency for containers in C++2a
- References: <20190603132311.GA27339@redhat.com>
Hi Jonathan,
> In previous standards it is undefined for a container and its allocator
> to have a different value_type. Libstdc++ has traditionally allowed it
> as an extension, automatically rebinding the allocator to the
> container's value_type. Since GCC 8.1 that extension has been disabled
> for C++11 and later when __STRICT_ANSI__ is defined (i.e. for
> -std=c++11, -std=c++14, -std=c++17 and -std=c++2a).
>
> Since the acceptance of P1463R1 into the C++2a draft an incorrect
> allocator::value_type now requires a diagnostic. This patch implements
> that by enabling the static_assert for -std=gnu++2a as well.
>
> * doc/xml/manual/status_cxx2020.xml: Document P1463R1 status.
> * include/bits/forward_list.h [__cplusplus > 201703]: Enable
> allocator::value_type assertion for C++2a.
> * include/bits/hashtable.h: Likewise.
> * include/bits/stl_deque.h: Likewise.
> * include/bits/stl_list.h: Likewise.
> * include/bits/stl_map.h: Likewise.
> * include/bits/stl_multimap.h: Likewise.
> * include/bits/stl_multiset.h: Likewise.
> * include/bits/stl_set.h: Likewise.
> * include/bits/stl_vector.h: Likewise.
> * testsuite/23_containers/deque/48101-3_neg.cc: New test.
> * testsuite/23_containers/forward_list/48101-3_neg.cc: New test.
> * testsuite/23_containers/list/48101-3_neg.cc: New test.
> * testsuite/23_containers/map/48101-3_neg.cc: New test.
> * testsuite/23_containers/multimap/48101-3_neg.cc: New test.
> * testsuite/23_containers/multiset/48101-3_neg.cc: New test.
> * testsuite/23_containers/set/48101-3_neg.cc: New test.
> * testsuite/23_containers/unordered_map/48101-3_neg.cc: New test.
> * testsuite/23_containers/unordered_multimap/48101-3_neg.cc: New test.
> * testsuite/23_containers/unordered_multiset/48101-3_neg.cc: New test.
> * testsuite/23_containers/unordered_set/48101-3_neg.cc: New test.
> * testsuite/23_containers/vector/48101-3_neg.cc: New test.
>
> Tested x86_64-linux, committed to trunk.
this patch caused a couple of testsuite regressions:
+FAIL: g++.old-deja/g++.other/headers1.C -std=c++98 (test for excess errors)
+UNRESOLVED: g++.old-deja/g++.other/headers1.C -std=c++98 compilation failed to produce executable
Excess errors:
/var/gcc/regression/trunk/11-gcc/build/i386-pc-solaris2.11/libstdc++-v3/include/bits/stl_map.h:122:21: error: 'is_same' has not been declared
/var/gcc/regression/trunk/11-gcc/build/i386-pc-solaris2.11/libstdc++-v3/include/bits/stl_map.h:122:28: error: expected ',' or '...' before '<' token
/var/gcc/regression/trunk/11-gcc/build/i386-pc-solaris2.11/libstdc++-v3/include/bits/stl_multimap.h:121:21: error: 'is_same' has not been declared
/var/gcc/regression/trunk/11-gcc/build/i386-pc-solaris2.11/libstdc++-v3/include/bits/stl_multimap.h:121:28:
error: expected ',' or '...' before '<' token
+FAIL: g++.old-deja/g++.robertl/eb109.C -std=c++98 (test for excess errors)
+FAIL: g++.dg/tree-ssa/copyprop.C (test for excess errors)
Same error, seen everywhere (i386-pc-solaris2.11, sparc-sun-solaris2.11,
aarch64-unknown-linux-gnu, x86_64-pc-linux-gnu, ...).
Rainer
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Rainer Orth, Center for Biotechnology, Bielefeld University