PR libstdc++/89446
* include/bits/char_traits.h (__constant_char_array): Check index is
in range before dereferencing.
(char_traits<char>::compare, char_traits<char>::find)
(char_traits<char8_t>::compare, char_traits<char8_t>::find): Return
immediately if n is zero.
(char_traits<wchar_t>::compare, char_traits<wchar_t>::find): Likewise.
Remove workarounds for PR 67026.
* testsuite/21_strings/basic_string_view/operators/char/89446.cc:
New test.
* testsuite/21_strings/basic_string_view/operators/wchar_t/89446.cc:
New test.
From-SVN: r269148
This patch augments existing tests to validate behavior for char8_t. In
all cases, added test cases are cloned from existing tests for wchar_t
or char16_t.
A few tests required updates to line numbers for diagnostic messages.
2019-02-22 Tom Honermann <tom@honermann.net>
* testsuite/18_support/byte/ops.cc: Validate
std::to_integer<char8_t>, std::to_integer<char16_t>, and
std::to_integer<char32_t>.
* testsuite/18_support/numeric_limits/dr559.cc: Validate
std::numeric_limits<char8_t>.
* testsuite/18_support/numeric_limits/lowest.cc: Validate
std::numeric_limits<char8_t>::lowest().
* testsuite/18_support/numeric_limits/max_digits10.cc: Validate
std::numeric_limits<char8_t>::max_digits10.
* testsuite/18_support/type_info/fundamental.cc: Validate
typeinfo for char8_t.
* testsuite/20_util/from_chars/1_c++20_neg.cc: New test, validating
std::from_chars with char8_t.
* testsuite/20_util/hash/requirements/explicit_instantiation.cc:
Validate explicit instantiation of std::hash<char8_t>.
* testsuite/20_util/is_integral/value.cc: Validate
std::is_integral<char8_t>.
* testsuite/20_util/make_signed/requirements/typedefs-4.cc:
Validate std::make_signed<char8_t>.
* testsuite/21_strings/basic_string/cons/char/deduction.cc:
Validate u8string construction from char8_t sources.
* testsuite/21_strings/basic_string/types/pmr_typedefs.cc: Validate
std::pmr::u8string.
* testsuite/21_strings/basic_string_view/operations/compare/
char/70483.cc: Validate substr operations on u8string_view.
* testsuite/21_strings/basic_string_view/typedefs.cc: Validate that
the u8string_view typedef is defined.
* testsuite/21_strings/char_traits/requirements/
constexpr_functions.cc: Validate char_traits<char8_t> constexpr
member functions.
* testsuite/21_strings/char_traits/requirements/
constexpr_functions_c++17.cc: Validate char_traits<char8_t> C++17
constexpr member functions.
* testsuite/21_strings/headers/string/types_std_c++0x.cc: Validate
that the u8string typedef is defined.
* testsuite/22_locale/locale/cons/unicode.cc: Validate the presence
of the std::codecvt<char16_t, char8_t, std::mbstate_t> and
std::codecvt<char32_t, char8_t, std::mbstate_t> facets.
* testsuite/29_atomics/atomic/cons/assign_neg.cc: Update line
numbers.
* testsuite/29_atomics/atomic/cons/copy_neg.cc: Likewise.
* testsuite/29_atomics/atomic_integral/cons/assign_neg.cc:
Likewise.
* testsuite/29_atomics/atomic_integral/cons/copy_neg.cc: Likewise.
* testsuite/29_atomics/atomic_integral/is_always_lock_free.cc:
Validate std::atomic<char8_t>::is_always_lock_free
* testsuite/29_atomics/atomic_integral/operators/bitwise_neg.cc:
Update line numbers.
* testsuite/29_atomics/atomic_integral/operators/decrement_neg.cc:
Likewise.
* testsuite/29_atomics/atomic_integral/operators/increment_neg.cc:
Likewise.
* testsuite/experimental/polymorphic_allocator/pmr_typedefs_string.cc:
Validate std::experimental::pmr::u8string.
* testsuite/experimental/string_view/typedefs.cc: Validate that the
u8string_view typedef is defined.
* testsuite/util/testsuite_common_types.h: Add char8_t, char16_t and
char32_t to the typelists.
From-SVN: r269089
2019-02-19 Tom Honermann <tom@honermann.net>
* testsuite/18_support/numeric_limits/char8_t.cc: New test cloned
from char16_32_t.cc; validates numeric_limits<char8_t>.
* testsuite/21_strings/basic_string/literals/types-char8_t.cc: New
test cloned from types.cc; validates operator""s for char8_t
returns u8string.
* testsuite/21_strings/basic_string/literals/values-char8_t.cc: New
test cloned from values.cc; validates construction and comparison
of u8string values.
* testsuite/21_strings/basic_string/requirements/
/explicit_instantiation/char8_t/1.cc: New test cloned from
char16_t/1.cc; validates explicit instantiation of
basic_string<char8_t>.
* testsuite/21_strings/basic_string_view/literals/types-char8_t.cc:
New test cloned from types.cc; validates operator""sv for char8_t
returns u8string_view.
* testsuite/21_strings/basic_string_view/literals/
values-char8_t.cc: New test cloned from values.cc; validates
construction and comparison of u8string_view values.
* testsuite/21_strings/basic_string_view/requirements/
explicit_instantiation/char8_t/1.cc: New test cloned from
char16_t/1.cc; validates explicit instantiation of
basic_string_view<char8_t>.
* testsuite/21_strings/char_traits/requirements/char8_t/65049.cc:
New test cloned from char16_t/65049.cc; validates that
char_traits<char8_t> is not vulnerable to the concerns in PR65049.
* testsuite/21_strings/char_traits/requirements/char8_t/
typedefs.cc: New test cloned from char16_t/typedefs.cc; validates
that char_traits<char8_t> member typedefs are present and correct.
* testsuite/21_strings/char_traits/requirements/
explicit_instantiation/char8_t/1.cc: New test cloned from
char16_t/1.cc; validates explicit instantiation of
char_traits<char8_t>.
* testsuite/22_locale/codecvt/char16_t-char8_t.cc: New test cloned
from char16_t.cc: validates
codecvt<char16_t, char8_t, mbstate_t>.
* testsuite/22_locale/codecvt/char32_t-char8_t.cc: New test cloned
from char32_t.cc: validates
codecvt<char32_t, char8_t, mbstate_t>.
* testsuite/22_locale/codecvt/utf8-char8_t.cc: New test cloned from
utf8.cc; validates codecvt<char16_t, char8_t, std::mbstate_t> and
codecvt<char32_t, char8_t, std::mbstate_t>.
* testsuite/27_io/filesystem/path/native/string-char8_t.cc: New
test cloned from string.cc; validates filesystem::path construction
from char8_t input.
* testsuite/experimental/feat-char8_t.cc: New test; validates that
the __cpp_lib_char8_t feature test macro is defined with the
correct value.
* testsuite/experimental/filesystem/path/native/string-char8_t.cc:
New test cloned from string.cc; validates filesystem::path
construction from char8_t input.
* testsuite/experimental/string_view/literals/types-char8_t.cc: New
test cloned from types.cc; validates operator""sv for char8_t
returns u8string_view.
* testsuite/experimental/string_view/literals/values-char8_t.cc:
New test cloned from values.cc; validates construction and
comparison of u8string_view values.
* testsuite/experimental/string_view/requirements/
explicit_instantiation/char8_t/1.cc: New test cloned from
char16_t/1.cc; validates explicit instantiation of
basic_string_view<char8_t>.
* testsuite/ext/char8_t/atomic-1.cc: New test; validates that
ATOMIC_CHAR8_T_LOCK_FREE is not defined if char8_t support is not
enabled.
From-SVN: r269005
Add these constructors from C++11 which were missing from the COW
basic_string. Additionally simplify the definitions of the
basic_string::reference and basic_string::const_reference types as
required by C++11.
This allows filesystem::path::string<Allocator>() to be simplified, so
that the same code is used for both basic_string implementations.
* config/abi/pre/gnu.ver (GLIBCXX_3.4.26): Export allocator-extended
copy/move constructors for old std::basic_string.
* include/bits/basic_string.h [!_GLIBCXX_USE_CXX11_ABI]
(basic_string::reference, basic_string::const_reference): Define
as plain references for C++11 and later.
(basic_string::basic_string()): Put constructor body outside
preprocessor conditional groups.
(basic_string::basic_string(basic_string&&)): Move _Alloc_hider
instead of copying it.
(basic_string::basic_string(const basic_string&, const _Alloc&)):
Define.
(basic_string::basic_string(basic_string&&, const _Alloc&)):
Define.
* include/bits/fs_path.h [!_GLIBCXX_USE_CXX11_ABI]: Remove special
cases for old basic_string.
* testsuite/21_strings/basic_string/cons/char/8.cc: Test
allocator-extended constructors unconditionally. Add extra members to
allocator type when using old string ABI.
* testsuite/21_strings/basic_string/allocator/71964.cc: Enable test
for old string ABI.
* testsuite/21_strings/basic_string/cons/wchar_t/8.cc: Likewise.
From-SVN: r267584
This test started passing with the old ABI with r263808, so doesn't need
to be marked XFAIL now.
* testsuite/21_strings/basic_string/requirements/
explicit_instantiation/debug.cc: Remove XFAIL for old ABI.
From-SVN: r267578
These tests rely on inlining, so if -fno-inline is added to the compiler
flags the tests fail. Use the predefined __NO_INLINE__ macro to detect
that situation, and don't bother testing the move assignment.
* testsuite/21_strings/basic_string/modifiers/assign/char/
move_assign_optim.cc: Avoid spurious failure when -fno-inline added
to test flags.
* testsuite/21_strings/basic_string/modifiers/assign/wchar_t/
move_assign_optim.cc: Likewise.
From-SVN: r267573
* include/std/string_view (basic_string_view::copy): Use traits to
copy.
* testsuite/21_strings/basic_string_view/operations/copy/char/2.cc:
New test.
* testsuite/21_strings/basic_string_view/operations/copy/wchar_t/2.cc:
New test.
From-SVN: r266269
The move constructor for the SSO string uses assign(const basic_string&)
when either:
(1) the source string is "local" and so the contents of the small string
buffer need to be copied, or
(2) the allocator does not propagate and is_always_equal is false.
Case (1) is suboptimal, because the assign member is not noexcept and
the compiler isn't smart enough to see it won't actually throw in this
case. This causes extra code in the move assignment operator so that any
exception will be turned into a call to std::terminate. This can be
fixed by copying small strings inline instead of calling assign.
Case (2) is a bug, because the specific instances of the allocators
could be equal even if is_always_equal is false. This can result in an
unnecessary deep copy (and potentially-throwing allocation) when the
storage should be moved. This can be fixed by simply checking if the
allocators are equal.
PR libstdc++/87749
* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI]
(basic_string::operator=(basic_string&&)): For short strings copy the
buffer inline. Only fall back to using assign(const basic_string&) to
do a deep copy when reallocation is needed.
* testsuite/21_strings/basic_string/modifiers/assign/char/87749.cc:
New test.
* testsuite/21_strings/basic_string/modifiers/assign/char/
move_assign_optim.cc: New test.
* testsuite/21_strings/basic_string/modifiers/assign/wchar_t/87749.cc:
New test.
* testsuite/21_strings/basic_string/modifiers/assign/wchar_t/
move_assign_optim.cc: New test.
From-SVN: r265493
The __gnu_debug string (mostly) implements the C++11 API, but when it
wraps the old COW string many of the member functions in the base class
have the wrong parameter types or return types. This makes the
__gnu_debug::string type adapt itself to the base class API. This
actually makes the debug string slightly more conforming than the
underlying string type when using the old ABI.
* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI]
(basic_string::__const_iterator): Change access to protected.
[!_GLIBCXX_USE_CXX11_ABI] (basic_string::__const_iterator): Define
as typedef for iterator.
* include/debug/string (__const_iterator): Use typedef from base.
(insert(const_iterator, _CharT))
(replace(const_iterator, const_iterator, const basic_string&))
(replace(const_iterator, const_iterator, const _CharT*, size_type))
(replace(const_iterator, const_iterator, const CharT*))
(replace(const_iterator, const_iterator, size_type, _CharT))
(replace(const_iterator, const_iterator, _InputIter, _InputIter))
(replace(const_iterator, const_iterator, initializer_list<_CharT>)):
Change const_iterator parameters to __const_iterator.
(insert(iterator, size_type, _CharT)): Add C++98 overload.
(insert(const_iterator, _InputIterator, _InputIterator)): Change
const_iterator parameter to __const_iterator.
[!_GLIBCXX_USE_CXX11_ABI]: Add workaround for incorrect return type
of base's member function.
(insert(const_iterator, size_type, _CharT)) [!_GLIBCXX_USE_CXX11_ABI]:
Likewise.
(insert(const_iterator, initializer_list<_CharT>))
[!_GLIBCXX_USE_CXX11_ABI]: Likewise.
* testsuite/21_strings/basic_string/init-list.cc: Remove effective
target directive.
From-SVN: r263808
These aliases are placed in the top-level header, e.g. <vector> not
<bits/stl_vector.h>. This ensures that they refer to whichever of
std::vector or __debug::vector or __profile::vector is in use when the
header is included.
* include/std/deque (std::pmr::deque): Declare alias.
* include/std/forward_list (std::pmr::forward_list): Likewise.
* include/std/list (std::pmr::list): Likewise.
* include/std/map (std::pmr::map, std::pmr::multimap): Likewise.
* include/std/regex (std::pmr::match_results, std::pmr::cmatch)
(std::pmr::smatch, std::pmr::wcmatch, std::pmr::wsmatch): Likewise.
* include/std/set (std::pmr::set, std::pmr::multiset): Likewise.
* include/std/string (std::pmr::basic_string, std::pmr::string)
(std::pmr::u16string, std::pmr::u32string, std::pmr::wstring):
Likewise.
* include/std/unordered_map (std::pmr::unordered_map)
(std::pmr::unordered_multimap): Likewise.
* include/std/unordered_set (std::pmr::unordered_set)
(std::pmr::unordered_multiset): Likewise.
* include/std/vector (std::pmr::vector): Likewise.
* testsuite/21_strings/basic_string/types/pmr_typedefs.cc: New test.
* testsuite/23_containers/deque/types/pmr_typedefs.cc: New test.
* testsuite/23_containers/forward_list/pmr_typedefs.cc: New test.
* testsuite/23_containers/list/pmr_typedefs.cc: New test.
* testsuite/23_containers/map/pmr_typedefs.cc: New test.
* testsuite/23_containers/multimap/pmr_typedefs.cc: New test.
* testsuite/23_containers/multiset/pmr_typedefs.cc: New test.
* testsuite/23_containers/set/pmr_typedefs.cc: New test.
* testsuite/23_containers/unordered_map/pmr_typedefs.cc: New test.
* testsuite/23_containers/unordered_multimap/pmr_typedefs.cc: New
test.
* testsuite/23_containers/unordered_multiset/pmr_typedefs.cc: New
test.
* testsuite/23_containers/unordered_set/pmr_typedefs.cc: New test.
* testsuite/23_containers/vector/pmr_typedefs.cc: New test.
* testsuite/28_regex/match_results/pmr_typedefs.cc: New test.
From-SVN: r263456
These tests fail when run with -D_GLIBCXX_USE_CXX11_ABI=0
* testsuite/21_strings/basic_string/cons/char/deduction.cc: XFAIL for
COW strings.
* testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc:
Likewise.
* testsuite/21_strings/basic_string/requirements/
explicit_instantiation/debug.cc: Likewise.
From-SVN: r262448
For COW strings the default constructor does not allocate when
_GLIBCXX_FULLY_DYNAMIC_STRING == 0, so can be noexcept. The move
constructor and swap do not allocate when the allocators are equal, so
add conditional noexcept using allocator_traits::is_always_equal.
PR libstdc++/58265
* include/bits/basic_string.h [!_GLIBCXX_USE_CXX11_ABI]
[_GLIBCXX_FULLY_DYNAMIC_STRING==0] (basic_string::basic_string()):
Add GLIBCXX_NOEXCEPT.
(basic_string::operator=(basic_string&&)): Add _GLIBCXX_NOEXCEPT_IF
to depend on the allocator's is_always_equal property (LWG 2063).
(basic_string::swap(basic_string&)): Likewise.
* include/bits/basic_string.tcc [!_GLIBCXX_USE_CXX11_ABI]
(basic_string::swap(basic_string&)): Likewise.
* testsuite/21_strings/basic_string/allocator/char/move_assign.cc:
Check is_nothrow_move_assignable.
* testsuite/21_strings/basic_string/allocator/wchar_t/move_assign.cc:
Check is_nothrow_move_assignable.
* testsuite/21_strings/basic_string/cons/char/
noexcept_move_construct.cc: Likewise.
* testsuite/21_strings/basic_string/cons/wchar_t/
noexcept_move_construct.cc: Likewise.
From-SVN: r262443
The explicit instantiation declarations for std::basic_string are
disabled for C++17 (and later) so that basic_string symbols get
implicitly instantiated in every translation unit that needs them. On
targets that don't support STB_GNU_UNIQUE this leads to multiple copies
of the empty rep symbol for COW strings. In order to detect whether a
COW string needs to deallocate its storage it compares the address with
the empty rep. When there are multiple copies of the empty rep object
the address is not unique, and so string destructors try to delete the
empty rep, which crashes.
In order to guarantee uniqueness of the _S_empty_rep_storage symbol this
patch adds an explicit instantiation declaration for just that symbol.
This means the other symbols are still implicitly instantiated in C++17
code, but for the empty rep the definition in the library gets used.
Separately, there is no need for C++17 code to implicitly instantiate
the I/O functions for strings, so this also restores the explicit
instantiation declarations for those functions.
PR libstdc++/86138
* include/bits/basic_string.tcc:
[__cplusplus > 201402 && !_GLIBCXX_USE_CXX11_ABI]
(basic_string<char>::_Rep::_S_empty_rep_storage)
(basic_string<wchar_t>::_Rep::_S_empty_rep_storage): Add explicit
instantiation declarations.
[__cplusplus > 201402] (operator>>, operator<<, getline): Re-enable
explicit instantiation declarations.
* testsuite/21_strings/basic_string/cons/char/86138.cc: New.
* testsuite/21_strings/basic_string/cons/wchar_t/86138.cc: New.
From-SVN: r261873
The SSO basic_string has a non-standard insert(iterator, initializer_list)
overload, from a C++0x draft. This adds the correct overload, while also
preserving the old one so that the old symbol is still exported from the
library.
The COW basic_string doesn't have any of the C++11 changes to the insert
overloads (they all still have non-const iterator parameters and the
ones that should return an iterator still return void). This doesn't
make any change to the COW string.
PR libstdc++/83328
* acinclude.m4 (libtool_VERSION): Bump to 6:26:0.
* config/abi/pre/gnu.ver: Add GLIBCXX_3.4.26 and export new symbol.
* configure: Regenerate.
* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI]
(basic_string::insert(const_iterator, initializer_list<C>)): Add.
[_GLIBCXX_USE_CXX11_ABI && !_GLIBCXX_DEFINING_STRING_INSTANTIATIONS]
(basic_string::insert(iterator, initializer_list<C>)): Suppress
definition.
* include/debug/string (basic_string::insert(iterator, C)): Change
first parameter to const_iterator.
(basic_string::insert(iterator, size_type, C)): Likewise. Change
return type to iterator.
(basic_string::insert(iterator, InputIterator, InputIterator)):
Likewise.
(basic_string::insert(iterator, initializer_list<C>)): Change first
parameter to const_iterator and return type to iterator.
* src/c++11/string-inst.cc: Extend comment.
* testsuite/21_strings/basic_string/modifiers/insert/char/83328.cc:
New.
* testsuite/21_strings/basic_string/modifiers/insert/wchar_t/83328.cc:
New.
* testsuite/util/testsuite_abi.cc: Add new symbol version.
From-SVN: r261866
When deduction guides are supported by the compiler (i.e. for C++17 and
later) replace two basic_string constructors by constrained function
templates as required by LWG 3075. In order to ensure that the pre-C++17
non-template constructors are still exported from the shared library
define a macro in src/c++11/string-inst.cc to force the non-template
declarations (this isn't strictly needed yet, because the string
instantiations are compiled with -std=gnu++11, but that is likely to
change).
LWG 3076 basic_string CTAD ambiguity
* doc/xml/manual/intro.xml: Document LWG 3076 change.
* include/bits/basic_string.h
[__cpp_deduction_guides && !_GLIBCXX_DEFINING_STRING_INSTANTIATIONS]
(basic_string(const _CharT*, const _Alloc&)): Turn into a function
template constrained by _RequireAllocator.
(basic_string(size_type, _CharT, const _Alloc&)): Likewise.
* src/c++11/string-inst.cc (_GLIBCXX_DEFINING_STRING_INSTANTIATIONS):
Define.
* testsuite/21_strings/basic_string/cons/char/deduction.cc: Test
deduction
* testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc:
Likewise.
From-SVN: r261670
The C++ committee has confirmed that passing a null pointer to the
unary basic_string_view constructor is undefined. This removes the check
from our implementation, and adds the nonnull attribute to warn when the
compiler can detect undefined input.
* include/std/string_view (basic_string_view(const CharT*)): Remove
check for null pointer and add nonnull attribute.
(compare(const CharT*), compare(size_type, size_type, const CharT*))
(find(const CharT*, size_type), rfind(const CharT*, size_type))
(find_first_of(const CharT*, size_type))
(find_last_of(const CharT*, size_type))
(find_first_not_of(const CharT*, size_type))
(find_last_not_of(const CharT*, size_type)): Add nonnull attribute.
* testsuite/21_strings/basic_string_view/cons/char/nonnull.cc: New.
* testsuite/21_strings/basic_string_view/operations/compare/char/
nonnull.cc: New.
* testsuite/21_strings/basic_string_view/operations/find/char/
nonnull.cc: New.
* testsuite/21_strings/basic_string_view/operations/rfind/char/
nonnull.cc: New.
From-SVN: r261638
PR libstdc++/79162
* include/bits/basic_string.h (basic_string::_If_sv): Remove from the
overload set when the argument is derived from basic_string.
* testsuite/21_strings/basic_string/cons/char/moveable2_c++17.cc: New
test.
* testsuite/21_strings/basic_string/cons/wchar_t/moveable2_c++17.cc:
New test.
From-SVN: r253024
PR libstdc++/81092
* acinclude.m4: Bump libtool_VERSION.
* config/abi/post/i386-linux-gnu/baseline_symbols.txt: Update.
* config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt: Update.
* config/abi/pre/gnu.ver: Add wstring constructor symbols to
GLIBCXX_3.4.24 version and move random_device::_M_get_entropy() symbol
to new GLIBCXX_3.4.25 version.
* doc/xml/manual/abi.xml: Document new versions.
* doc/html/*: Regenerate.
* testsuite/21_strings/basic_string/cons/char/8.cc: Use base object
constructors to ensure required symbols are exported.
* testsuite/21_strings/basic_string/cons/wchar_t/8.cc: Likewise.
* testsuite/util/testsuite_abi.cc: Add new version.
From-SVN: r249246
As discussed in PR c++/80265 ("__builtin_{memcmp,memchr,strlen} are
not usable in constexpr functions"), use __builtin_constant_p to tell
whether we can defer to a constexpr algorithm.
I used __always_inline__ just to be thorough. It isn't really really
necessary as far as I could determine.
Changes like these:
if (__n == 0)
return 0;
- return wmemcmp(__s1, __s2, __n);
+ else
+ return wmemcmp(__s1, __s2, __n);
are necessary otherwise G++ complains that we're calling a
non-constexpr function, which looks like a a manifestation of PR67026
to me.
libstdc++-v3:
2017-06-12 Pedro Alves <palves@redhat.com>
* doc/xml/manual/status_cxx2017.xml: Update C++17 constexpr
char_traits status.
* doc/html/*: Regenerate.
* include/bits/char_traits.h (_GLIBCXX_ALWAYS_INLINE): Define if
not already defined.
(__cpp_lib_constexpr_char_traits): Uncomment.
(__constant_string_p, __constant_char_array_p): New.
(std::char_traits<char>, std::char_traits<wchar_t>): Add
_GLIBCXX17_CONSTEXPR on compare, length and find and use
__constant_string_p, __constant_char_array_p and
__builtin_constant_p to defer to __gnu_cxx::char_traits at compile
time.
* testsuite/21_strings/char_traits/requirements/
constexpr_functions_c++17.cc: Uncomment
__cpp_lib_constexpr_char_traits tests. Uncomment
test_compare<char>, test_length<char>, test_find<char>,
test_compare<wchar_t>, test_length<wchar_t> and test_find<wchar_t>
static_assert tests.
From-SVN: r249137
* include/bits/alloc_traits.h (__is_allocator, _RequireAllocator):
New trait and alias for detecting Allocator-like types.
* include/bits/basic_string.h (basic_string): Add deduction guide
from P0433.
* include/ext/alloc_traits.h (__gnu_cxx::__alloc_traits): Add template
parameter with default template argument that causes substitution
failures for types that cannot be allocators.
* testsuite/21_strings/basic_string/cons/char/deduction.cc: New.
* testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc: New.
From-SVN: r248967
Jonathan Wakely
Tom Honermann
Joel Brobecker
Jakub Jelinek
Edward Smith-Rowland
Sandra Loosemore
François Dumont
Jakub Jelinek
Daniel Kruegler
Rainer Orth
Pedro Alves