[libc++] Remove <functional> includes

Reviewed By: var-const, #libc, ldionne

Spies: #libc_vendors, ldionne, libcxx-commits, miyuki

Differential Revision: https://reviews.llvm.org/D124123

libcxx/docs/ReleaseNotes.rst

@@ -67,10 +67,15 @@ API Changes
   ``<filesystem>`` header. The associated macro
   ``_LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM`` has also been removed.
 
-- Some libc++ headers no longer transitively include all of ``<algorithm>``, ``<chrono>`` and ``<utility>``.
-  If, after updating libc++, you see compiler errors related to missing declarations in
-  namespace ``std``, it might be because one of your source files now needs to
-  ``#include <algorithm>``, ``#include <chrono>`` and/or ``#include <utility>``.
+- Some libc++ headers no longer transitively include all of:
+    - ``<algorithm>``
+    - ``<chrono>``
+    - ``<functional>``
+    - ``<utility>``
+
+  If, after updating libc++, you see compiler errors related to missing declarations
+  in namespace ``std``, it might be because one of your source files now needs to
+  include one or more of the headers listed above.
 
 - The integer distributions ``binomial_distribution``, ``discrete_distribution``,
   ``geometric_distribution``, ``negative_binomial_distribution``, ``poisson_distribution``,

libcxx/include/algorithm

@@ -881,7 +881,6 @@ template <class BidirectionalIterator, class Compare>
 #include <__debug>
 #include <cstddef>
 #include <cstring>
-#include <functional> // TODO: Remove this include
 #include <initializer_list>
 #include <iterator>
 #include <memory>

libcxx/include/experimental/coroutine

@@ -49,7 +49,6 @@ template <class P> struct hash<coroutine_handle<P>>;
 #include <__functional/hash.h>
 #include <cstddef>
 #include <experimental/__config>
-#include <functional> // TODO: Remove this include
 #include <memory> // for hash<T*>
 #include <new>
 #include <type_traits>

libcxx/include/experimental/propagate_const

@@ -113,7 +113,6 @@
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <experimental/__config>
-#include <functional> // TODO: Remove this include
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/experimental/simd

@@ -654,7 +654,6 @@ public:
 #include <array>
 #include <cstddef>
 #include <experimental/__config>
-#include <functional> // TODO: Remove this include
 #include <tuple>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

libcxx/include/ext/hash_map

@@ -206,7 +206,6 @@ template <class Key, class T, class Hash, class Pred, class Alloc>
 #include <__hash_table>
 #include <algorithm>
 #include <ext/__hash>
-#include <functional> // TODO: Remove this include
 #include <stdexcept>
 #include <type_traits>
 

libcxx/include/ext/hash_set

@@ -197,7 +197,6 @@ template <class Value, class Hash, class Pred, class Alloc>
 #include <__hash_table>
 #include <algorithm>
 #include <ext/__hash>
-#include <functional> // TODO: Remove this include
 
 #if defined(__DEPRECATED) && __DEPRECATED
 #if defined(_LIBCPP_WARNING)

libcxx/include/map

@@ -539,7 +539,6 @@ erase_if(multimap<Key, T, Compare, Allocator>& c, Predicate pred);  // C++20
 #include <__utility/forward.h>
 #include <__utility/swap.h>
 #include <compare>
-#include <functional> // TODO: Remove this include
 #include <initializer_list>
 #include <iterator> // __libcpp_erase_if_container
 #include <memory>

libcxx/include/mutex

@@ -192,7 +192,6 @@ template<class Callable, class ...Args>
 #include <__threading_support>
 #include <__utility/forward.h>
 #include <cstdint>
-#include <functional> // TODO: Remove this include
 #include <memory>
 #ifndef _LIBCPP_CXX03_LANG
 # include <tuple>

libcxx/include/numeric

@@ -147,7 +147,6 @@ template<class T>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
 #include <cmath> // for isnormal
-#include <functional> // TODO: Remove this include
 #include <iterator>
 #include <version>
 

libcxx/include/optional

@@ -172,7 +172,6 @@ template<class T>
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <compare>
-#include <functional> // TODO: Remove this include
 #include <initializer_list>
 #include <new>
 #include <stdexcept>

libcxx/include/queue

@@ -227,7 +227,6 @@ template <class T, class Container, class Compare>
 #include <__utility/forward.h>
 #include <compare>
 #include <deque>
-#include <functional> // TODO: Remove this include
 #include <type_traits>
 #include <vector>
 #include <version>

libcxx/include/set

@@ -481,7 +481,6 @@ erase_if(multiset<Key, Compare, Allocator>& c, Predicate pred);  // C++20
 #include <__tree>
 #include <__utility/forward.h>
 #include <compare>
-#include <functional> // TODO: Remove this include
 #include <initializer_list>
 #include <iterator> // __libcpp_erase_if_container
 #include <version>

libcxx/include/thread

@@ -90,7 +90,6 @@ void sleep_for(const chrono::duration<Rep, Period>& rel_time);
 #include <__threading_support>
 #include <__utility/forward.h>
 #include <cstddef>
-#include <functional> // TODO: Remove this include
 #include <iosfwd>
 #include <memory>
 #include <system_error>

libcxx/include/unordered_map

@@ -525,7 +525,6 @@ template <class Key, class T, class Hash, class Pred, class Alloc>
 #include <__node_handle>
 #include <__utility/forward.h>
 #include <compare>
-#include <functional> // TODO: Remove this include
 #include <iterator> // __libcpp_erase_if_container
 #include <stdexcept>
 #include <tuple>

libcxx/include/unordered_set

@@ -469,7 +469,6 @@ template <class Value, class Hash, class Pred, class Alloc>
 #include <__node_handle>
 #include <__utility/forward.h>
 #include <compare>
-#include <functional> // TODO: Remove this include
 #include <iterator> // __libcpp_erase_if_container
 #include <version>
 

libcxx/include/valarray

@@ -357,7 +357,6 @@ template <class T> unspecified2 end(const valarray<T>& v);
 #include <__utility/swap.h>
 #include <cmath>
 #include <cstddef>
-#include <functional> // TODO: Remove this include
 #include <initializer_list>
 #include <new>
 #include <version>