Provide hashers for string_view only if they are using the default char_traits. Seen on SO: test/std/strings/string.view/string.view.hash/char_type.hash.fail.cpp
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@364545 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/string_view b/include/string_view
index aa93e1f..0444831 100644
--- a/include/string_view
+++ b/include/string_view
@@ -776,12 +776,12 @@
typedef basic_string_view<wchar_t> wstring_view;
// [string.view.hash]
-template<class _CharT, class _Traits>
-struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, _Traits> >
- : public unary_function<basic_string_view<_CharT, _Traits>, size_t>
+template<class _CharT>
+struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > >
+ : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
{
_LIBCPP_INLINE_VISIBILITY
- size_t operator()(const basic_string_view<_CharT, _Traits> __val) const _NOEXCEPT {
+ size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
return __do_string_hash(__val.data(), __val.data() + __val.size());
}
};
diff --git a/test/std/strings/basic.string.hash/char_type_hash.fail.cpp b/test/std/strings/basic.string.hash/char_type_hash.fail.cpp
index 542ae05..7857ac7 100644
--- a/test/std/strings/basic.string.hash/char_type_hash.fail.cpp
+++ b/test/std/strings/basic.string.hash/char_type_hash.fail.cpp
@@ -53,7 +53,7 @@
void test() {
typedef std::basic_string<CharT, trait<CharT> > str_t;
std::hash<str_t>
- h; // call to implicitly-deleted default constructor of 'std::hash<str_t>' {{*}}}}
+ h; // expected-error-re 4 {{call to implicitly-deleted default constructor of 'std::hash<str_t>' {{.+}}}}}
}
int main(int, char**) {
diff --git a/test/std/strings/string.view/string.view.hash/char_type.hash.fail.cpp b/test/std/strings/string.view/string.view.hash/char_type.hash.fail.cpp
new file mode 100644
index 0000000..587c989
--- /dev/null
+++ b/test/std/strings/string.view/string.view.hash/char_type.hash.fail.cpp
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <string>
+
+// Test that hash specializations for <string_view> require "char_traits<_CharT>" not just any "_Trait".
+
+#include <string_view>
+#include <string> // for 'mbstate_t'
+
+template <class _CharT>
+struct trait // copied from <__string>
+{
+ typedef _CharT char_type;
+ typedef int int_type;
+ typedef std::streamoff off_type;
+ typedef std::streampos pos_type;
+ typedef std::mbstate_t state_type;
+
+ static inline void assign(char_type& __c1, const char_type& __c2) {
+ __c1 = __c2;
+ }
+ static inline bool eq(char_type __c1, char_type __c2) { return __c1 == __c2; }
+ static inline bool lt(char_type __c1, char_type __c2) { return __c1 < __c2; }
+
+ static int compare(const char_type* __s1, const char_type* __s2, size_t __n);
+ static size_t length(const char_type* __s);
+ static const char_type* find(const char_type* __s, size_t __n,
+ const char_type& __a);
+
+ static char_type* move(char_type* __s1, const char_type* __s2, size_t __n);
+ static char_type* copy(char_type* __s1, const char_type* __s2, size_t __n);
+ static char_type* assign(char_type* __s, size_t __n, char_type __a);
+
+ static inline int_type not_eof(int_type __c) {
+ return eq_int_type(__c, eof()) ? ~eof() : __c;
+ }
+ static inline char_type to_char_type(int_type __c) { return char_type(__c); }
+ static inline int_type to_int_type(char_type __c) { return int_type(__c); }
+ static inline bool eq_int_type(int_type __c1, int_type __c2) {
+ return __c1 == __c2;
+ }
+ static inline int_type eof() { return int_type(EOF); }
+};
+
+template <class CharT>
+void test() {
+ typedef std::basic_string_view<CharT, trait<CharT> > strv_t;
+ std::hash<strv_t>
+ h; // expected-error-re 4 {{call to implicitly-deleted default constructor of 'std::hash<strv_t>' {{.+}}}}}}
+}
+
+int main(int, char**) {
+ test<char>();
+ test<wchar_t>();
+ test<char16_t>();
+ test<char32_t>();
+
+ return 0;
+}
