fix review, simplify implementation

Author: davebayer

libcudacxx/include/cuda/std/string_view

@@ -148,15 +148,14 @@ public:
   {}
 
 #if !_CCCL_COMPILER(NVRTC)
-  _CCCL_HIDE_FROM_ABI constexpr basic_string_view(::std::basic_string_view<_CharT, _Traits> __sv) noexcept
+  _CCCL_TEMPLATE(class _Traits2 = _Traits)
+  _CCCL_REQUIRES(is_same_v<_Traits2, char_traits<_CharT>>)
+  _CCCL_HIDE_FROM_ABI constexpr basic_string_view(::std::basic_string_view<_CharT> __sv) noexcept
       : __data_{__sv.data()}
       , __size_{__sv.size()}
   {}
 
-  _CCCL_TEMPLATE(bool = true)
-  _CCCL_REQUIRES(is_same_v<_Traits, char_traits<_CharT>>)
-  _CCCL_HIDE_FROM_ABI constexpr basic_string_view(
-    ::std::basic_string_view<_CharT, ::std::char_traits<_CharT>> __sv) noexcept
+  _CCCL_HIDE_FROM_ABI constexpr basic_string_view(::std::basic_string_view<_CharT, _Traits> __sv) noexcept
       : __data_{__sv.data()}
       , __size_{__sv.size()}
   {}
@@ -738,16 +737,16 @@ public:
   }
 
 #if !_CCCL_COMPILER(NVRTC)
-  _CCCL_HIDE_FROM_ABI constexpr operator ::std::basic_string_view<_CharT, _Traits>() const noexcept
+  _CCCL_TEMPLATE(class _Traits2 = _Traits)
+  _CCCL_REQUIRES(is_same_v<_Traits2, char_traits<_CharT>>)
+  _CCCL_HIDE_FROM_ABI constexpr operator ::std::basic_string_view<_CharT>() const noexcept
   {
-    return ::std::basic_string_view<_CharT, _Traits>{__data_, __size_};
+    return ::std::basic_string_view<_CharT>{__data_, __size_};
   }
 
-  _CCCL_TEMPLATE(bool = true)
-  _CCCL_REQUIRES(is_same_v<_Traits, char_traits<_CharT>>)
-  _CCCL_HIDE_FROM_ABI constexpr operator ::std::basic_string_view<_CharT, ::std::char_traits<_CharT>>() const noexcept
+  _CCCL_HIDE_FROM_ABI constexpr operator ::std::basic_string_view<_CharT, _Traits>() const noexcept
   {
-    return ::std::basic_string_view<_CharT, ::std::char_traits<_CharT>>{__data_, __size_};
+    return ::std::basic_string_view<_CharT, _Traits>{__data_, __size_};
   }
 #endif // !_CCCL_COMPILER(NVRTC)
 
@@ -779,29 +778,28 @@ _CCCL_REQUIRES(_CUDA_VRANGES::contiguous_range<_Range>)
 _CCCL_HOST_DEVICE basic_string_view(_Range&&) -> basic_string_view<_CUDA_VRANGES::range_value_t<_Range>>;
 
 #if !_CCCL_COMPILER(NVRTC)
+_CCCL_TEMPLATE(class _CharT)
+_CCCL_HOST_DEVICE basic_string_view(::std::basic_string_view<_CharT>) -> basic_string_view<_CharT>;
+
 _CCCL_TEMPLATE(class _CharT, class _Traits)
 _CCCL_HOST_DEVICE basic_string_view(::std::basic_string_view<_CharT, _Traits>) -> basic_string_view<_CharT, _Traits>;
-
-_CCCL_TEMPLATE(class _CharT)
-_CCCL_HOST_DEVICE basic_string_view(::std::basic_string_view<_CharT, ::std::char_traits<_CharT>>)
-  -> basic_string_view<_CharT, char_traits<_CharT>>;
 #endif // !_CCCL_COMPILER(NVRTC)
 
 // operator <<
 
 #if !_CCCL_COMPILER(NVRTC)
 template <class _CharT, class _Traits>
-_CCCL_HIDE_FROM_ABI _CCCL_HOST ::std::basic_ostream<_CharT, _Traits>&
+_CCCL_HIDE_FROM_ABI ::std::basic_ostream<_CharT, _Traits>&
 operator<<(::std::basic_ostream<_CharT, _Traits>& __os, basic_string_view<_CharT, _Traits> __str)
 {
   return __os << ::std::basic_string_view<_CharT, _Traits>{__str};
 }
 
 template <class _CharT>
-_CCCL_HIDE_FROM_ABI _CCCL_HOST ::std::basic_ostream<_CharT, ::std::char_traits<_CharT>>& operator<<(
-  ::std::basic_ostream<_CharT, ::std::char_traits<_CharT>>& __os, basic_string_view<_CharT, char_traits<_CharT>> __str)
+_CCCL_HIDE_FROM_ABI ::std::basic_ostream<_CharT>&
+operator<<(::std::basic_ostream<_CharT>& __os, basic_string_view<_CharT> __str)
 {
-  return __os << ::std::basic_string_view<_CharT, ::std::char_traits<_CharT>>{__str};
+  return __os << ::std::basic_string_view<_CharT>{__str};
 }
 #endif // !_CCCL_COMPILER(NVRTC)