[gcc r12-10242] libstdc++: Add missing noexcept to std::scoped_allocator_adaptor

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:65704fa293ca9d5f9186aa09037fc2869492973b

commit r12-10242-g65704fa293ca9d5f9186aa09037fc2869492973b
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri May 26 21:33:58 2023 +0100

    libstdc++: Add missing noexcept to std::scoped_allocator_adaptor
    
    The standard requires these constructors and accessors to be noexcept.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/scoped_allocator (scoped_allocator_adaptor): Add
            noexcept to all constructors except the default constructor.
            (scoped_allocator_adaptor::inner_allocator): Add noexcept.
            (scoped_allocator_adaptor::outer_allocator): Likewise.
            * testsuite/20_util/scoped_allocator/noexcept.cc: New test.
    
    (cherry picked from commit b960c253e988c68ed3f3829125bc267bdf169356)

Diff:
---
 libstdc++-v3/include/std/scoped_allocator          | 45 ++++++++++++---------
 .../testsuite/20_util/scoped_allocator/noexcept.cc | 47 ++++++++++++++++++++++
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/libstdc++-v3/include/std/scoped_allocator b/libstdc++-v3/include/std/scoped_allocator
index 8ad4c90b694..dd00e8efdbb 100644
--- a/libstdc++-v3/include/std/scoped_allocator
+++ b/libstdc++-v3/include/std/scoped_allocator
@@ -66,7 +66,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct __outermost_type
     {
       using type = _Alloc;
-      static type& _S_outermost(_Alloc& __a) { return __a; }
+      static type& _S_outermost(_Alloc& __a) noexcept { return __a; }
     };
 
   template<typename _Alloc>
@@ -80,7 +80,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       >;
 
       static typename __base::type&
-      _S_outermost(_Alloc& __a)
+      _S_outermost(_Alloc& __a) noexcept
       { return __base::_S_outermost(__a.outer_allocator()); }
     };
 
@@ -105,11 +105,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __inner_type_impl& operator=(__inner_type_impl&&) = default;
 
       template<typename _Alloc>
-      __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
+      __inner_type_impl(const __inner_type_impl<_Alloc>& __other) noexcept
       { }
 
       template<typename _Alloc>
-      __inner_type_impl(__inner_type_impl<_Alloc>&& __other)
+      __inner_type_impl(__inner_type_impl<_Alloc>&& __other) noexcept
       { }
 
       __type&
@@ -138,16 +138,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __inner_type_impl& operator=(__inner_type_impl&&) = default;
 
       template<typename... _Allocs>
-      __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
+      __inner_type_impl(const __inner_type_impl<_Allocs...>& __other) noexcept
       : _M_inner(__other._M_inner) { }
 
       template<typename... _Allocs>
-      __inner_type_impl(__inner_type_impl<_Allocs...>&& __other)
+      __inner_type_impl(__inner_type_impl<_Allocs...>&& __other) noexcept
       : _M_inner(std::move(__other._M_inner)) { }
 
     template<typename... _Args>
       explicit
-      __inner_type_impl(_Args&&... __args)
+      __inner_type_impl(_Args&&... __args) noexcept
       : _M_inner(std::forward<_Args>(__args)...) { }
 
       __type&
@@ -308,31 +308,32 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       template<typename _Outer2, typename = _Constructible<_Outer2>>
         scoped_allocator_adaptor(_Outer2&& __outer,
-                                 const _InnerAllocs&... __inner)
+                                 const _InnerAllocs&... __inner) noexcept
         : _OuterAlloc(std::forward<_Outer2>(__outer)),
           _M_inner(__inner...)
         { }
 
-      scoped_allocator_adaptor(const scoped_allocator_adaptor& __other)
+      scoped_allocator_adaptor(const scoped_allocator_adaptor& __other) noexcept
       : _OuterAlloc(__other.outer_allocator()),
 	_M_inner(__other._M_inner)
       { }
 
-      scoped_allocator_adaptor(scoped_allocator_adaptor&& __other)
+      scoped_allocator_adaptor(scoped_allocator_adaptor&& __other) noexcept
       : _OuterAlloc(std::move(__other.outer_allocator())),
 	_M_inner(std::move(__other._M_inner))
       { }
 
       template<typename _Outer2, typename = _Constructible<const _Outer2&>>
         scoped_allocator_adaptor(
-            const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other)
+	  const scoped_allocator_adaptor<_Outer2, _InnerAllocs...>& __other
+	) noexcept
         : _OuterAlloc(__other.outer_allocator()),
           _M_inner(__other._M_inner)
         { }
 
       template<typename _Outer2, typename = _Constructible<_Outer2>>
         scoped_allocator_adaptor(
-            scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other)
+	  scoped_allocator_adaptor<_Outer2, _InnerAllocs...>&& __other) noexcept
         : _OuterAlloc(std::move(__other.outer_allocator())),
           _M_inner(std::move(__other._M_inner))
         { }
@@ -343,25 +344,31 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       scoped_allocator_adaptor&
       operator=(scoped_allocator_adaptor&&) = default;
 
-      inner_allocator_type& inner_allocator() noexcept
+      inner_allocator_type&
+      inner_allocator() noexcept
       { return _M_inner._M_get(this); }
 
-      const inner_allocator_type& inner_allocator() const noexcept
+      const inner_allocator_type&
+      inner_allocator() const noexcept
       { return _M_inner._M_get(this); }
 
-      outer_allocator_type& outer_allocator() noexcept
+      outer_allocator_type&
+      outer_allocator() noexcept
       { return static_cast<_OuterAlloc&>(*this); }
 
-      const outer_allocator_type& outer_allocator() const noexcept
+      const outer_allocator_type&
+      outer_allocator() const noexcept
       { return static_cast<const _OuterAlloc&>(*this); }
 
-      _GLIBCXX_NODISCARD pointer allocate(size_type __n)
+      _GLIBCXX_NODISCARD pointer
+      allocate(size_type __n)
       { return __traits::allocate(outer_allocator(), __n); }
 
-      _GLIBCXX_NODISCARD pointer allocate(size_type __n, const_void_pointer __hint)
+      _GLIBCXX_NODISCARD pointer
+      allocate(size_type __n, const_void_pointer __hint)
       { return __traits::allocate(outer_allocator(), __n, __hint); }
 
-      void deallocate(pointer __p, size_type __n)
+      void deallocate(pointer __p, size_type __n) noexcept
       { return __traits::deallocate(outer_allocator(), __p, __n); }
 
       size_type max_size() const
diff --git a/libstdc++-v3/testsuite/20_util/scoped_allocator/noexcept.cc b/libstdc++-v3/testsuite/20_util/scoped_allocator/noexcept.cc
new file mode 100644
index 00000000000..16992968d3b
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/scoped_allocator/noexcept.cc
@@ -0,0 +1,47 @@
+// { dg-do compile { target c++11 } }
+
+#include <scoped_allocator>
+
+template<typename T>
+struct Alloc
+{
+  using value_type = T;
+
+  Alloc() noexcept(false) { }
+  Alloc(const Alloc&) noexcept(false) { }
+  template<typename U> Alloc(const Alloc<U>&) noexcept { }
+
+  T* allocate(std::size_t);
+  void deallocate(T*, std::size_t);
+
+  bool operator==(const Alloc&) const noexcept(false) { return true; }
+  bool operator!=(const Alloc&) const noexcept(false) { return false; }
+};
+
+using A1 = std::allocator<int>;
+using A2 = std::allocator<long>;
+using Ax = Alloc<int>;
+using SA1 = std::scoped_allocator_adaptor<A1, Ax>;
+using SA2 = std::scoped_allocator_adaptor<A2, Ax>;
+static_assert( std::is_default_constructible<SA1>::value
+		 && ! std::is_nothrow_default_constructible<SA1>::value,
+	       "default constructor is potentially-throwing" );
+static_assert( std::is_nothrow_constructible<SA1, A1, Ax>::value,
+	       "multi-arg constructor is non-throwing" );
+static_assert( std::is_nothrow_copy_constructible<SA1>::value,
+	       "copy constructor is non-throwing" );
+static_assert( std::is_nothrow_move_constructible<SA1>::value,
+	       "move constructor is non-throwing" );
+static_assert( std::is_nothrow_constructible<SA1, const SA2&>::value,
+	       "converting copy constructor is non-throwing" );
+static_assert( std::is_nothrow_constructible<SA1, SA2>::value,
+	       "converting move constructor is non-throwing" );
+
+static_assert( noexcept(std::declval<SA1&>().inner_allocator()),
+	       "inner_allocator() is non-throwing" );
+static_assert( noexcept(std::declval<const SA1&>().inner_allocator()),
+	       "inner_allocator() const is non-throwing" );
+static_assert( noexcept(std::declval<SA1&>().outer_allocator()),
+	       "outer_allocator() is non-throwing" );
+static_assert( noexcept(std::declval<const SA1&>().outer_allocator()),
+	       "outer_allocator() const is non-throwing" );