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merged 1 commit into from
Aug 22, 2025
Merged

[libc++][NFC] Simplify the special member functions of the node containers #154707

merged 1 commit into from
Aug 22, 2025

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philnik777
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This patch does two things:

  • Remove exception specifications of = defaulted special member functions
  • = default special member functions

The first part is NFC because the explicit specification does exactly the same as the implicit specification. The second is NFC because it does exactly what the = defaulted special member does.

@philnik777 philnik777 marked this pull request as ready for review August 22, 2025 09:24
@philnik777 philnik777 requested a review from a team as a code owner August 22, 2025 09:24
@philnik777 philnik777 merged commit fd52f4d into llvm:main Aug 22, 2025
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@philnik777 philnik777 deleted the simplify_node_smfs branch August 22, 2025 09:24
@llvmbot llvmbot added the libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. label Aug 22, 2025
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llvmbot commented Aug 22, 2025

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

This patch does two things:

  • Remove exception specifications of = defaulted special member functions
  • = default special member functions

The first part is NFC because the explicit specification does exactly the same as the implicit specification. The second is NFC because it does exactly what the = defaulted special member does.

Full diff: https://github.com/llvm/llvm-project/pull/154707.diff

4 Files Affected:

  • (modified) libcxx/include/map (+4-5)
  • (modified) libcxx/include/set (+4-10)
  • (modified) libcxx/include/unordered_map (+4-8)
  • (modified) libcxx/include/unordered_set (+4-17)
diff --git a/libcxx/include/map b/libcxx/include/map
index 4dfce70e50e7f..4bc7e2022f04c 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -978,11 +978,11 @@ public:
 
 #  ifndef _LIBCPP_CXX03_LANG
 
-  _LIBCPP_HIDE_FROM_ABI map(map&& __m) noexcept(is_nothrow_move_constructible<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI map(map&& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI map(map&& __m, const allocator_type& __a);
 
-  _LIBCPP_HIDE_FROM_ABI map& operator=(map&& __m) noexcept(is_nothrow_move_assignable<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI map& operator=(map&& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI map(initializer_list<value_type> __il, const key_compare& __comp = key_compare())
       : __tree_(__vc(__comp)) {
@@ -1646,12 +1646,11 @@ public:
 
 #  ifndef _LIBCPP_CXX03_LANG
 
-  _LIBCPP_HIDE_FROM_ABI multimap(multimap&& __m) noexcept(is_nothrow_move_constructible<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI multimap(multimap&& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI multimap(multimap&& __m, const allocator_type& __a);
 
-  _LIBCPP_HIDE_FROM_ABI multimap&
-  operator=(multimap&& __m) noexcept(is_nothrow_move_assignable<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI multimap& operator=(multimap&& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI multimap(initializer_list<value_type> __il, const key_compare& __comp = key_compare())
       : __tree_(__vc(__comp)) {
diff --git a/libcxx/include/set b/libcxx/include/set
index 05c1939dbbabf..4417d2811eb23 100644
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -667,7 +667,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI set& operator=(const set& __s) = default;
 
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI set(set&& __s) noexcept(is_nothrow_move_constructible<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI set(set&& __s) = default;
 #  endif // _LIBCPP_CXX03_LANG
 
   _LIBCPP_HIDE_FROM_ABI explicit set(const allocator_type& __a) : __tree_(__a) {}
@@ -699,10 +699,7 @@ public:
     return *this;
   }
 
-  _LIBCPP_HIDE_FROM_ABI set& operator=(set&& __s) noexcept(is_nothrow_move_assignable<__base>::value) {
-    __tree_ = std::move(__s.__tree_);
-    return *this;
-  }
+  _LIBCPP_HIDE_FROM_ABI set& operator=(set&& __s) = default;
 #  endif // _LIBCPP_CXX03_LANG
 
   _LIBCPP_HIDE_FROM_ABI ~set() { static_assert(sizeof(std::__diagnose_non_const_comparator<_Key, _Compare>()), ""); }
@@ -1126,7 +1123,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI multiset& operator=(const multiset& __s) = default;
 
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI multiset(multiset&& __s) noexcept(is_nothrow_move_constructible<__base>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI multiset(multiset&& __s) = default;
 
   _LIBCPP_HIDE_FROM_ABI multiset(multiset&& __s, const allocator_type& __a);
 #  endif // _LIBCPP_CXX03_LANG
@@ -1158,10 +1155,7 @@ public:
     return *this;
   }
 
-  _LIBCPP_HIDE_FROM_ABI multiset& operator=(multiset&& __s) _NOEXCEPT_(is_nothrow_move_assignable<__base>::value) {
-    __tree_ = std::move(__s.__tree_);
-    return *this;
-  }
+  _LIBCPP_HIDE_FROM_ABI multiset& operator=(multiset&& __s) = default;
 #  endif // _LIBCPP_CXX03_LANG
 
   _LIBCPP_HIDE_FROM_ABI ~multiset() {
diff --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
index 104dc56a89fea..a934953674967 100644
--- a/libcxx/include/unordered_map
+++ b/libcxx/include/unordered_map
@@ -1049,8 +1049,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u, const allocator_type& __a);
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u)
-      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI unordered_map(initializer_list<value_type> __il);
   _LIBCPP_HIDE_FROM_ABI
@@ -1102,8 +1101,7 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(const unordered_map& __u) = default;
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(unordered_map&& __u)
-      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(unordered_map&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(initializer_list<value_type> __il);
 #  endif // _LIBCPP_CXX03_LANG
 
@@ -1823,8 +1821,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u, const allocator_type& __a);
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u)
-      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI unordered_multimap(initializer_list<value_type> __il);
   _LIBCPP_HIDE_FROM_ABI unordered_multimap(
@@ -1876,8 +1873,7 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(const unordered_multimap& __u) = default;
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(unordered_multimap&& __u)
-      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(unordered_multimap&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(initializer_list<value_type> __il);
 #  endif // _LIBCPP_CXX03_LANG
 
diff --git a/libcxx/include/unordered_set b/libcxx/include/unordered_set
index 09bd81a22eae5..4bc9c1afa2639 100644
--- a/libcxx/include/unordered_set
+++ b/libcxx/include/unordered_set
@@ -706,7 +706,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI unordered_set(const unordered_set& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_set(const unordered_set& __u, const allocator_type& __a);
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_set(unordered_set&& __u) _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+  _LIBCPP_HIDE_FROM_ABI unordered_set(unordered_set&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_set(unordered_set&& __u, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI unordered_set(initializer_list<value_type> __il);
   _LIBCPP_HIDE_FROM_ABI
@@ -735,8 +735,7 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(const unordered_set& __u) = default;
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(unordered_set&& __u)
-      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(unordered_set&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(initializer_list<value_type> __il);
 #  endif // _LIBCPP_CXX03_LANG
 
@@ -1076,11 +1075,6 @@ unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(const unordered_set&
 
 #  ifndef _LIBCPP_CXX03_LANG
 
-template <class _Value, class _Hash, class _Pred, class _Alloc>
-inline unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(unordered_set&& __u)
-    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
-    : __table_(std::move(__u.__table_)) {}
-
 template <class _Value, class _Hash, class _Pred, class _Alloc>
 unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(unordered_set&& __u, const allocator_type& __a)
     : __table_(std::move(__u.__table_), __a) {
@@ -1294,8 +1288,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI unordered_multiset(const unordered_multiset& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multiset(const unordered_multiset& __u, const allocator_type& __a);
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_multiset(unordered_multiset&& __u)
-      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+  _LIBCPP_HIDE_FROM_ABI unordered_multiset(unordered_multiset&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multiset(unordered_multiset&& __u, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI unordered_multiset(initializer_list<value_type> __il);
   _LIBCPP_HIDE_FROM_ABI unordered_multiset(
@@ -1324,8 +1317,7 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(const unordered_multiset& __u) = default;
 #  ifndef _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(unordered_multiset&& __u)
-      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) = default;
+  _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(unordered_multiset&& __u) = default;
   _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(initializer_list<value_type> __il);
 #  endif // _LIBCPP_CXX03_LANG
 
@@ -1675,11 +1667,6 @@ unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
 
 #  ifndef _LIBCPP_CXX03_LANG
 
-template <class _Value, class _Hash, class _Pred, class _Alloc>
-inline unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(unordered_multiset&& __u)
-    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
-    : __table_(std::move(__u.__table_)) {}
-
 template <class _Value, class _Hash, class _Pred, class _Alloc>
 unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
     unordered_multiset&& __u, const allocator_type& __a)

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