Mark 'front()' and 'back()' as noexcept for array/deque/string/string_view. These are just rebranded 'operator[]', and should be noexcept like it is.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@356435 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow 2019-03-19 03:30:07 +00:00
parent e7641c9db9
commit ddb1b0576a
12 changed files with 94 additions and 45 deletions

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@ -197,10 +197,10 @@ struct _LIBCPP_TEMPLATE_VIS array
_LIBCPP_CONSTEXPR_AFTER_CXX14 reference at(size_type __n); _LIBCPP_CONSTEXPR_AFTER_CXX14 reference at(size_type __n);
_LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const; _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const;
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference front() {return __elems_[0];} _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference front() _NOEXCEPT {return __elems_[0];}
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference front() const {return __elems_[0];} _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference front() const _NOEXCEPT {return __elems_[0];}
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference back() {return __elems_[_Size - 1];} _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference back() _NOEXCEPT {return __elems_[_Size - 1];}
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference back() const {return __elems_[_Size - 1];} _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference back() const _NOEXCEPT {return __elems_[_Size - 1];}
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
value_type* data() _NOEXCEPT {return __elems_;} value_type* data() _NOEXCEPT {return __elems_;}
@ -327,25 +327,25 @@ struct _LIBCPP_TEMPLATE_VIS array<_Tp, 0>
} }
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
reference front() { reference front() _NOEXCEPT {
_LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array"); _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
_LIBCPP_UNREACHABLE(); _LIBCPP_UNREACHABLE();
} }
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
const_reference front() const { const_reference front() const _NOEXCEPT {
_LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array"); _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
_LIBCPP_UNREACHABLE(); _LIBCPP_UNREACHABLE();
} }
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
reference back() { reference back() _NOEXCEPT {
_LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array"); _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
_LIBCPP_UNREACHABLE(); _LIBCPP_UNREACHABLE();
} }
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
const_reference back() const { const_reference back() const _NOEXCEPT {
_LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array"); _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
_LIBCPP_UNREACHABLE(); _LIBCPP_UNREACHABLE();
} }

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@ -1338,13 +1338,13 @@ public:
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
const_reference at(size_type __i) const; const_reference at(size_type __i) const;
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
reference front(); reference front() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
const_reference front() const; const_reference front() const _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
reference back(); reference back() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
const_reference back() const; const_reference back() const _NOEXCEPT;
// 23.2.2.3 modifiers: // 23.2.2.3 modifiers:
void push_front(const value_type& __v); void push_front(const value_type& __v);
@ -1785,7 +1785,7 @@ deque<_Tp, _Allocator>::at(size_type __i) const
template <class _Tp, class _Allocator> template <class _Tp, class _Allocator>
inline inline
typename deque<_Tp, _Allocator>::reference typename deque<_Tp, _Allocator>::reference
deque<_Tp, _Allocator>::front() deque<_Tp, _Allocator>::front() _NOEXCEPT
{ {
return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size) return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size)
+ __base::__start_ % __base::__block_size); + __base::__start_ % __base::__block_size);
@ -1794,7 +1794,7 @@ deque<_Tp, _Allocator>::front()
template <class _Tp, class _Allocator> template <class _Tp, class _Allocator>
inline inline
typename deque<_Tp, _Allocator>::const_reference typename deque<_Tp, _Allocator>::const_reference
deque<_Tp, _Allocator>::front() const deque<_Tp, _Allocator>::front() const _NOEXCEPT
{ {
return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size) return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size)
+ __base::__start_ % __base::__block_size); + __base::__start_ % __base::__block_size);
@ -1803,7 +1803,7 @@ deque<_Tp, _Allocator>::front() const
template <class _Tp, class _Allocator> template <class _Tp, class _Allocator>
inline inline
typename deque<_Tp, _Allocator>::reference typename deque<_Tp, _Allocator>::reference
deque<_Tp, _Allocator>::back() deque<_Tp, _Allocator>::back() _NOEXCEPT
{ {
size_type __p = __base::size() + __base::__start_ - 1; size_type __p = __base::size() + __base::__start_ - 1;
return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size); return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
@ -1812,7 +1812,7 @@ deque<_Tp, _Allocator>::back()
template <class _Tp, class _Allocator> template <class _Tp, class _Allocator>
inline inline
typename deque<_Tp, _Allocator>::const_reference typename deque<_Tp, _Allocator>::const_reference
deque<_Tp, _Allocator>::back() const deque<_Tp, _Allocator>::back() const _NOEXCEPT
{ {
size_type __p = __base::size() + __base::__start_ - 1; size_type __p = __base::size() + __base::__start_ - 1;
return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size); return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);

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@ -1060,10 +1060,10 @@ public:
void push_back(value_type __c); void push_back(value_type __c);
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
void pop_back(); void pop_back();
_LIBCPP_INLINE_VISIBILITY reference front(); _LIBCPP_INLINE_VISIBILITY reference front() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY const_reference front() const; _LIBCPP_INLINE_VISIBILITY const_reference front() const _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY reference back(); _LIBCPP_INLINE_VISIBILITY reference back() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY const_reference back() const; _LIBCPP_INLINE_VISIBILITY const_reference back() const _NOEXCEPT;
template <class _Tp> template <class _Tp>
_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
@ -3237,7 +3237,7 @@ basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
template <class _CharT, class _Traits, class _Allocator> template <class _CharT, class _Traits, class _Allocator>
inline inline
typename basic_string<_CharT, _Traits, _Allocator>::reference typename basic_string<_CharT, _Traits, _Allocator>::reference
basic_string<_CharT, _Traits, _Allocator>::front() basic_string<_CharT, _Traits, _Allocator>::front() _NOEXCEPT
{ {
_LIBCPP_ASSERT(!empty(), "string::front(): string is empty"); _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
return *__get_pointer(); return *__get_pointer();
@ -3246,7 +3246,7 @@ basic_string<_CharT, _Traits, _Allocator>::front()
template <class _CharT, class _Traits, class _Allocator> template <class _CharT, class _Traits, class _Allocator>
inline inline
typename basic_string<_CharT, _Traits, _Allocator>::const_reference typename basic_string<_CharT, _Traits, _Allocator>::const_reference
basic_string<_CharT, _Traits, _Allocator>::front() const basic_string<_CharT, _Traits, _Allocator>::front() const _NOEXCEPT
{ {
_LIBCPP_ASSERT(!empty(), "string::front(): string is empty"); _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
return *data(); return *data();
@ -3255,7 +3255,7 @@ basic_string<_CharT, _Traits, _Allocator>::front() const
template <class _CharT, class _Traits, class _Allocator> template <class _CharT, class _Traits, class _Allocator>
inline inline
typename basic_string<_CharT, _Traits, _Allocator>::reference typename basic_string<_CharT, _Traits, _Allocator>::reference
basic_string<_CharT, _Traits, _Allocator>::back() basic_string<_CharT, _Traits, _Allocator>::back() _NOEXCEPT
{ {
_LIBCPP_ASSERT(!empty(), "string::back(): string is empty"); _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
return *(__get_pointer() + size() - 1); return *(__get_pointer() + size() - 1);
@ -3264,7 +3264,7 @@ basic_string<_CharT, _Traits, _Allocator>::back()
template <class _CharT, class _Traits, class _Allocator> template <class _CharT, class _Traits, class _Allocator>
inline inline
typename basic_string<_CharT, _Traits, _Allocator>::const_reference typename basic_string<_CharT, _Traits, _Allocator>::const_reference
basic_string<_CharT, _Traits, _Allocator>::back() const basic_string<_CharT, _Traits, _Allocator>::back() const _NOEXCEPT
{ {
_LIBCPP_ASSERT(!empty(), "string::back(): string is empty"); _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
return *(data() + size() - 1); return *(data() + size() - 1);

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@ -288,13 +288,13 @@ public:
} }
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
const_reference front() const const_reference front() const _NOEXCEPT
{ {
return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0]; return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
} }
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
const_reference back() const const_reference back() const _NOEXCEPT
{ {
return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1]; return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
} }

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@ -68,10 +68,14 @@ int main(int, char**)
typedef std::array<T, 0> C; typedef std::array<T, 0> C;
C c = {}; C c = {};
C const& cc = c; C const& cc = c;
static_assert((std::is_same<decltype(c.front()), T &>::value), ""); ASSERT_SAME_TYPE(decltype( c.back()), typename C::reference);
static_assert((std::is_same<decltype(cc.front()), const T &>::value), ""); ASSERT_SAME_TYPE(decltype(cc.back()), typename C::const_reference);
static_assert((std::is_same<decltype(c.back()), T &>::value), ""); LIBCPP_ASSERT_NOEXCEPT( c.back());
static_assert((std::is_same<decltype(cc.back()), const T &>::value), ""); LIBCPP_ASSERT_NOEXCEPT( cc.back());
ASSERT_SAME_TYPE(decltype( c.front()), typename C::reference);
ASSERT_SAME_TYPE(decltype(cc.front()), typename C::const_reference);
LIBCPP_ASSERT_NOEXCEPT( c.front());
LIBCPP_ASSERT_NOEXCEPT( cc.front());
if (c.size() > (0)) { // always false if (c.size() > (0)) { // always false
TEST_IGNORE_NODISCARD c.front(); TEST_IGNORE_NODISCARD c.front();
TEST_IGNORE_NODISCARD c.back(); TEST_IGNORE_NODISCARD c.back();
@ -84,10 +88,14 @@ int main(int, char**)
typedef std::array<const T, 0> C; typedef std::array<const T, 0> C;
C c = {{}}; C c = {{}};
C const& cc = c; C const& cc = c;
static_assert((std::is_same<decltype(c.front()), const T &>::value), ""); ASSERT_SAME_TYPE(decltype( c.back()), typename C::reference);
static_assert((std::is_same<decltype(cc.front()), const T &>::value), ""); ASSERT_SAME_TYPE(decltype(cc.back()), typename C::const_reference);
static_assert((std::is_same<decltype(c.back()), const T &>::value), ""); LIBCPP_ASSERT_NOEXCEPT( c.back());
static_assert((std::is_same<decltype(cc.back()), const T &>::value), ""); LIBCPP_ASSERT_NOEXCEPT( cc.back());
ASSERT_SAME_TYPE(decltype( c.front()), typename C::reference);
ASSERT_SAME_TYPE(decltype(cc.front()), typename C::const_reference);
LIBCPP_ASSERT_NOEXCEPT( c.front());
LIBCPP_ASSERT_NOEXCEPT( cc.front());
if (c.size() > (0)) { if (c.size() > (0)) {
TEST_IGNORE_NODISCARD c.front(); TEST_IGNORE_NODISCARD c.front();
TEST_IGNORE_NODISCARD c.back(); TEST_IGNORE_NODISCARD c.back();

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@ -54,8 +54,12 @@ int main(int, char**)
{ {
typedef std::deque<int> C; typedef std::deque<int> C;
C c = make<std::deque<int> >(10); C c = make<std::deque<int> >(10);
LIBCPP_ASSERT_NOEXCEPT(c[0]); ASSERT_SAME_TYPE(decltype(c[0]), C::reference);
ASSERT_SAME_TYPE(C::reference, decltype(c[0])); LIBCPP_ASSERT_NOEXCEPT( c[0]);
LIBCPP_ASSERT_NOEXCEPT( c.front());
ASSERT_SAME_TYPE(decltype(c.front()), C::reference);
LIBCPP_ASSERT_NOEXCEPT( c.back());
ASSERT_SAME_TYPE(decltype(c.back()), C::reference);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
assert(c[i] == i); assert(c[i] == i);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
@ -66,8 +70,12 @@ int main(int, char**)
{ {
typedef std::deque<int> C; typedef std::deque<int> C;
const C c = make<std::deque<int> >(10); const C c = make<std::deque<int> >(10);
LIBCPP_ASSERT_NOEXCEPT(c[0]); ASSERT_SAME_TYPE(decltype(c[0]), C::const_reference);
ASSERT_SAME_TYPE(C::const_reference, decltype(c[0])); LIBCPP_ASSERT_NOEXCEPT( c[0]);
LIBCPP_ASSERT_NOEXCEPT( c.front());
ASSERT_SAME_TYPE(decltype(c.front()), C::const_reference);
LIBCPP_ASSERT_NOEXCEPT( c.back());
ASSERT_SAME_TYPE(decltype(c.back()), C::const_reference);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
assert(c[i] == i); assert(c[i] == i);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
@ -79,8 +87,12 @@ int main(int, char**)
{ {
typedef std::deque<int, min_allocator<int>> C; typedef std::deque<int, min_allocator<int>> C;
C c = make<std::deque<int, min_allocator<int>> >(10); C c = make<std::deque<int, min_allocator<int>> >(10);
LIBCPP_ASSERT_NOEXCEPT(c[0]); ASSERT_SAME_TYPE(decltype(c[0]), C::reference);
ASSERT_SAME_TYPE(C::reference, decltype(c[0])); LIBCPP_ASSERT_NOEXCEPT( c[0]);
LIBCPP_ASSERT_NOEXCEPT( c.front());
ASSERT_SAME_TYPE(decltype(c.front()), C::reference);
LIBCPP_ASSERT_NOEXCEPT( c.back());
ASSERT_SAME_TYPE(decltype(c.back()), C::reference);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
assert(c[i] == i); assert(c[i] == i);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
@ -91,8 +103,12 @@ int main(int, char**)
{ {
typedef std::deque<int, min_allocator<int>> C; typedef std::deque<int, min_allocator<int>> C;
const C c = make<std::deque<int, min_allocator<int>> >(10); const C c = make<std::deque<int, min_allocator<int>> >(10);
LIBCPP_ASSERT_NOEXCEPT(c[0]); ASSERT_SAME_TYPE(decltype(c[0]), C::const_reference);
ASSERT_SAME_TYPE(C::const_reference, decltype(c[0])); LIBCPP_ASSERT_NOEXCEPT( c[0]);
LIBCPP_ASSERT_NOEXCEPT( c.front());
ASSERT_SAME_TYPE(decltype(c.front()), C::const_reference);
LIBCPP_ASSERT_NOEXCEPT( c.back());
ASSERT_SAME_TYPE(decltype(c.back()), C::const_reference);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)
assert(c[i] == i); assert(c[i] == i);
for (int i = 0; i < 10; ++i) for (int i = 0; i < 10; ++i)

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@ -25,6 +25,10 @@ void
test(S s) test(S s)
{ {
const S& cs = s; const S& cs = s;
ASSERT_SAME_TYPE(decltype( s.back()), typename S::reference);
ASSERT_SAME_TYPE(decltype(cs.back()), typename S::const_reference);
LIBCPP_ASSERT_NOEXCEPT( s.back());
LIBCPP_ASSERT_NOEXCEPT( cs.back());
assert(&cs.back() == &cs[cs.size()-1]); assert(&cs.back() == &cs[cs.size()-1]);
assert(&s.back() == &s[cs.size()-1]); assert(&s.back() == &s[cs.size()-1]);
s.back() = typename S::value_type('z'); s.back() = typename S::value_type('z');

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@ -25,6 +25,10 @@ void
test(S s) test(S s)
{ {
const S& cs = s; const S& cs = s;
ASSERT_SAME_TYPE(decltype( s.front()), typename S::reference);
ASSERT_SAME_TYPE(decltype(cs.front()), typename S::const_reference);
LIBCPP_ASSERT_NOEXCEPT( s.front());
LIBCPP_ASSERT_NOEXCEPT( cs.front());
assert(&cs.front() == &cs[0]); assert(&cs.front() == &cs[0]);
assert(&s.front() == &s[0]); assert(&s.front() == &s[0]);
s.front() = typename S::value_type('z'); s.front() = typename S::value_type('z');

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@ -26,6 +26,10 @@ int main(int, char**)
typedef std::string S; typedef std::string S;
S s("0123456789"); S s("0123456789");
const S& cs = s; const S& cs = s;
ASSERT_SAME_TYPE(decltype( s[0]), typename S::reference);
ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference);
LIBCPP_ASSERT_NOEXCEPT( s[0]);
LIBCPP_ASSERT_NOEXCEPT( cs[0]);
for (S::size_type i = 0; i < cs.size(); ++i) for (S::size_type i = 0; i < cs.size(); ++i)
{ {
assert(s[i] == static_cast<char>('0' + i)); assert(s[i] == static_cast<char>('0' + i));
@ -40,6 +44,10 @@ int main(int, char**)
typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S; typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
S s("0123456789"); S s("0123456789");
const S& cs = s; const S& cs = s;
ASSERT_SAME_TYPE(decltype( s[0]), typename S::reference);
ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference);
LIBCPP_ASSERT_NOEXCEPT( s[0]);
LIBCPP_ASSERT_NOEXCEPT( cs[0]);
for (S::size_type i = 0; i < cs.size(); ++i) for (S::size_type i = 0; i < cs.size(); ++i)
{ {
assert(s[i] == static_cast<char>('0' + i)); assert(s[i] == static_cast<char>('0' + i));

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@ -18,7 +18,10 @@
template <typename CharT> template <typename CharT>
bool test ( const CharT *s, size_t len ) { bool test ( const CharT *s, size_t len ) {
std::basic_string_view<CharT> sv ( s, len ); typedef std::basic_string_view<CharT> SV;
SV sv ( s, len );
ASSERT_SAME_TYPE(decltype(sv.back()), typename SV::const_reference);
LIBCPP_ASSERT_NOEXCEPT( sv.back());
assert ( sv.length() == len ); assert ( sv.length() == len );
assert ( sv.back() == s[len-1] ); assert ( sv.back() == s[len-1] );
return &sv.back() == s + len - 1; return &sv.back() == s + len - 1;

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@ -18,7 +18,10 @@
template <typename CharT> template <typename CharT>
bool test ( const CharT *s, size_t len ) { bool test ( const CharT *s, size_t len ) {
std::basic_string_view<CharT> sv ( s, len ); typedef std::basic_string_view<CharT> SV;
SV sv ( s, len );
ASSERT_SAME_TYPE(decltype(sv.front()), typename SV::const_reference);
LIBCPP_ASSERT_NOEXCEPT( sv.front());
assert ( sv.length() == len ); assert ( sv.length() == len );
assert ( sv.front() == s[0] ); assert ( sv.front() == s[0] );
return &sv.front() == s; return &sv.front() == s;

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@ -18,7 +18,10 @@
template <typename CharT> template <typename CharT>
void test ( const CharT *s, size_t len ) { void test ( const CharT *s, size_t len ) {
std::basic_string_view<CharT> sv ( s, len ); typedef std::basic_string_view<CharT> SV;
SV sv ( s, len );
ASSERT_SAME_TYPE(decltype(sv[0]), typename SV::const_reference);
LIBCPP_ASSERT_NOEXCEPT( sv[0]);
assert ( sv.length() == len ); assert ( sv.length() == len );
for ( size_t i = 0; i < len; ++i ) { for ( size_t i = 0; i < len; ++i ) {
assert ( sv[i] == s[i] ); assert ( sv[i] == s[i] );