diff --git a/include/boost/unordered/unordered_flat_map.hpp b/include/boost/unordered/unordered_flat_map.hpp
index 46784ac4..e39c194d 100644
--- a/include/boost/unordered/unordered_flat_map.hpp
+++ b/include/boost/unordered/unordered_flat_map.hpp
@@ -35,9 +35,12 @@ namespace boost {
         using init_type = std::pair<Key, T>;
         using moved_type = std::pair<Key&&, T&&>;
         using value_type = std::pair<Key const, T>;
-        static Key const& extract(init_type const& kv) { return kv.first; }
-        static Key const& extract(value_type const& kv) { return kv.first; }
-        static Key const& extract(moved_type const& kv) { return kv.first; }
+
+        template <class K, class V>
+        static K const& extract(std::pair<K, V> const& kv)
+        {
+          return kv.first;
+        }
 
         static moved_type move(value_type& x)
         {
@@ -57,6 +60,7 @@ namespace boost {
       using mapped_type = T;
       using value_type = typename map_types::value_type;
       using size_type = std::size_t;
+      using difference_type = std::ptrdiff_t;
       using hasher = Hash;
       using key_equal = KeyEqual;
       using allocator_type = Allocator;
@@ -79,6 +83,11 @@ namespace boost {
       {
       }
 
+      unordered_flat_map(size_type n, hasher const& h, allocator_type const& a)
+          : unordered_flat_map(n, h, key_equal(), a)
+      {
+      }
+
       explicit unordered_flat_map(allocator_type const& a)
           : unordered_flat_map(0, a)
       {
@@ -93,6 +102,20 @@ namespace boost {
         this->insert(first, last);
       }
 
+      template <class Iterator>
+      unordered_flat_map(
+        Iterator first, Iterator last, size_type n, allocator_type const& a)
+          : unordered_flat_map(first, last, n, hasher(), key_equal(), a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_flat_map(Iterator first, Iterator last, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_map(first, last, n, h, key_equal(), a)
+      {
+      }
+
       unordered_flat_map(unordered_flat_map const& other) : table_(other.table_)
       {
       }
@@ -124,6 +147,18 @@ namespace boost {
       {
       }
 
+      unordered_flat_map(std::initializer_list<value_type> init, size_type n,
+        allocator_type const& a)
+          : unordered_flat_map(init, n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_flat_map(std::initializer_list<value_type> init, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_flat_map(init, n, h, key_equal(), a)
+      {
+      }
+
       ~unordered_flat_map() = default;
 
       unordered_flat_map& operator=(unordered_flat_map const& other)
@@ -165,6 +200,8 @@ namespace boost {
 
       size_type size() const noexcept { return table_.size(); }
 
+      size_type max_size() const noexcept { return table_.max_size(); }
+
       /// Modifiers
       ///
 
@@ -302,6 +339,22 @@ namespace boost {
         table_.swap(rhs.table_);
       }
 
+      template <class H2, class P2>
+      void merge(
+        unordered_flat_map<key_type, mapped_type, H2, P2, allocator_type>&
+          source)
+      {
+        (void)source;
+      }
+
+      template <class H2, class P2>
+      void merge(
+        unordered_flat_map<key_type, mapped_type, H2, P2, allocator_type>&&
+          source)
+      {
+        (void)source;
+      }
+
       /// Lookup
       ///
 
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index fa9d474c..5c15aa0d 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -105,6 +105,7 @@ rule build_foa ( name )
 build_foa fwd_set_test ;
 build_foa fwd_map_test ;
 build_foa compile_set ;
+build_foa compile_map ;
 build_foa constructor_tests ;
 build_foa copy_tests ;
 build_foa move_tests ;
diff --git a/test/unordered/compile_map.cpp b/test/unordered/compile_map.cpp
index 6a84d595..272f7de5 100644
--- a/test/unordered/compile_map.cpp
+++ b/test/unordered/compile_map.cpp
@@ -8,7 +8,12 @@
 
 // clang-format off
 #include "../helpers/prefix.hpp"
+#ifdef BOOST_UNORDERED_FOA_TESTS
+#include <boost/unordered/unordered_flat_map.hpp>
+#include <boost/unordered/detail/implementation.hpp>
+#else
 #include <boost/unordered_map.hpp>
+#endif
 #include "../helpers/postfix.hpp"
 // clang-format on
 
@@ -17,7 +22,28 @@
 #include "./compile_tests.hpp"
 
 // Explicit instantiation to catch compile-time errors
+#ifdef BOOST_UNORDERED_FOA_TESTS
 
+// emulates what was already done for previous tests but without leaking to
+// the detail namespace
+//
+template <typename K, typename T, typename H, typename P, typename A>
+class instantiate_flat_map
+{
+  typedef boost::unordered_flat_map<K, T, H, P, A> container;
+  container x;
+};
+
+template class instantiate_flat_map<int, int, boost::hash<int>,
+  std::equal_to<int>, test::minimal::allocator<int> >;
+
+template class instantiate_flat_map<test::minimal::assignable const,
+  test::minimal::default_assignable const,
+  test::minimal::hash<test::minimal::assignable>,
+  test::minimal::equal_to<test::minimal::assignable>,
+  test::minimal::allocator<int> >;
+
+#else
 #define INSTANTIATE(type)                                                      \
   template class boost::unordered::detail::instantiate_##type
 
@@ -35,6 +61,7 @@ INSTANTIATE(multimap)<test::minimal::assignable, test::minimal::assignable,
   test::minimal::hash<test::minimal::assignable>,
   test::minimal::equal_to<test::minimal::assignable>,
   test::minimal::allocator<int> >;
+#endif
 
 UNORDERED_AUTO_TEST (test0) {
   test::minimal::constructor_param x;
@@ -45,6 +72,19 @@ UNORDERED_AUTO_TEST (test0) {
 
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_map.\n";
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<int, int> int_map;
+
+  boost::unordered_flat_map<int, int, boost::hash<int>, std::equal_to<int>,
+    test::minimal::cxx11_allocator<std::pair<int const, int> > >
+    int_map2;
+
+  boost::unordered_flat_map<test::minimal::assignable,
+    test::minimal::assignable, test::minimal::hash<test::minimal::assignable>,
+    test::minimal::equal_to<test::minimal::assignable>,
+    test::minimal::allocator<value_type> >
+    map;
+#else
   boost::unordered_map<int, int> int_map;
 
   boost::unordered_map<int, int, boost::hash<int>, std::equal_to<int>,
@@ -56,11 +96,13 @@ UNORDERED_AUTO_TEST (test0) {
     test::minimal::equal_to<test::minimal::assignable>,
     test::minimal::allocator<value_type> >
     map;
+#endif
 
   container_test(int_map, std::pair<int const, int>(0, 0));
   container_test(int_map2, std::pair<int const, int>(0, 0));
   container_test(map, value);
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_multimap.\n";
 
   boost::unordered_multimap<int, int> int_multimap;
@@ -78,6 +120,7 @@ UNORDERED_AUTO_TEST (test0) {
   container_test(int_multimap, std::pair<int const, int>(0, 0));
   container_test(int_multimap2, std::pair<int const, int>(0, 0));
   container_test(multimap, value);
+#endif
 }
 
 UNORDERED_AUTO_TEST (equality_tests) {
@@ -85,6 +128,22 @@ UNORDERED_AUTO_TEST (equality_tests) {
     test::minimal::copy_constructible_equality_comparable>
     value_type;
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<int, int> int_map;
+
+  boost::unordered_flat_map<int, int, boost::hash<int>, std::equal_to<int>,
+    test::minimal::cxx11_allocator<std::pair<int const, int> > >
+    int_map2;
+
+  boost::unordered_flat_map<
+    test::minimal::copy_constructible_equality_comparable,
+    test::minimal::copy_constructible_equality_comparable,
+    test::minimal::hash<test::minimal::copy_constructible_equality_comparable>,
+    test::minimal::equal_to<
+      test::minimal::copy_constructible_equality_comparable>,
+    test::minimal::allocator<value_type> >
+    map;
+#else
   boost::unordered_map<int, int> int_map;
 
   boost::unordered_map<int, int, boost::hash<int>, std::equal_to<int>,
@@ -98,11 +157,13 @@ UNORDERED_AUTO_TEST (equality_tests) {
       test::minimal::copy_constructible_equality_comparable>,
     test::minimal::allocator<value_type> >
     map;
+#endif
 
   equality_test(int_map);
   equality_test(int_map2);
   equality_test(map);
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   boost::unordered_multimap<int, int> int_multimap;
 
   boost::unordered_multimap<int, int, boost::hash<int>, std::equal_to<int>,
@@ -121,6 +182,7 @@ UNORDERED_AUTO_TEST (equality_tests) {
   equality_test(int_multimap);
   equality_test(int_multimap2);
   equality_test(multimap);
+#endif
 }
 
 UNORDERED_AUTO_TEST (test1) {
@@ -131,11 +193,19 @@ UNORDERED_AUTO_TEST (test1) {
 
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_map.\n";
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<int, int> map;
+
+  boost::unordered_flat_map<int, int, boost::hash<int>, std::equal_to<int>,
+    test::minimal::cxx11_allocator<std::pair<int const, int> > >
+    map2;
+#else
   boost::unordered_map<int, int> map;
 
   boost::unordered_map<int, int, boost::hash<int>, std::equal_to<int>,
     test::minimal::cxx11_allocator<std::pair<int const, int> > >
     map2;
+#endif
 
   unordered_unique_test(map, map_value);
   unordered_map_test(map, value, value);
@@ -147,6 +217,7 @@ UNORDERED_AUTO_TEST (test1) {
   unordered_copyable_test(map2, value, map_value, hash, equal_to);
   unordered_map_functions(map2, value, value);
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_multimap.\n";
 
   boost::unordered_multimap<int, int> multimap;
@@ -162,6 +233,7 @@ UNORDERED_AUTO_TEST (test1) {
   unordered_equivalent_test(multimap2, map_value);
   unordered_map_test(multimap2, value, value);
   unordered_copyable_test(multimap2, value, map_value, hash, equal_to);
+#endif
 }
 
 UNORDERED_AUTO_TEST (test2) {
@@ -178,28 +250,46 @@ UNORDERED_AUTO_TEST (test2) {
 
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_map.\n";
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<test::minimal::assignable,
+    test::minimal::assignable, test::minimal::hash<test::minimal::assignable>,
+    test::minimal::equal_to<test::minimal::assignable>,
+    test::minimal::allocator<map_value_type> >
+    map;
+#else
   boost::unordered_map<test::minimal::assignable, test::minimal::assignable,
     test::minimal::hash<test::minimal::assignable>,
     test::minimal::equal_to<test::minimal::assignable>,
     test::minimal::allocator<map_value_type> >
     map;
+#endif
 
   unordered_unique_test(map, map_value);
   unordered_map_test(map, assignable, assignable);
   unordered_copyable_test(map, assignable, map_value, hash, equal_to);
   unordered_map_member_test(map, map_value);
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<test::minimal::assignable,
+    test::minimal::default_assignable,
+    test::minimal::hash<test::minimal::assignable>,
+    test::minimal::equal_to<test::minimal::assignable>,
+    test::minimal::allocator<map_value_type> >
+    map2;
+#else
   boost::unordered_map<test::minimal::assignable,
     test::minimal::default_assignable,
     test::minimal::hash<test::minimal::assignable>,
     test::minimal::equal_to<test::minimal::assignable>,
     test::minimal::allocator<map_value_type> >
     map2;
+#endif
 
   test::minimal::default_assignable default_assignable;
 
   unordered_map_functions(map2, assignable, default_assignable);
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   BOOST_LIGHTWEIGHT_TEST_OSTREAM << "Test unordered_multimap.\n";
 
   boost::unordered_multimap<test::minimal::assignable,
@@ -212,6 +302,7 @@ UNORDERED_AUTO_TEST (test2) {
   unordered_map_test(multimap, assignable, assignable);
   unordered_copyable_test(multimap, assignable, map_value, hash, equal_to);
   unordered_map_member_test(multimap, map_value);
+#endif
 }
 
 // Test for ambiguity when using key convertible from iterator
@@ -232,6 +323,11 @@ std::size_t hash_value(lwg2059_key x)
 bool operator==(lwg2059_key x, lwg2059_key y) { return x.value == y.value; }
 
 UNORDERED_AUTO_TEST (lwg2059) {
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  boost::unordered_flat_map<lwg2059_key, int> x;
+  x.emplace(lwg2059_key(10), 5);
+  x.erase(x.begin());
+#else
   {
     boost::unordered_map<lwg2059_key, int> x;
     x.emplace(lwg2059_key(10), 5);
@@ -243,6 +339,7 @@ UNORDERED_AUTO_TEST (lwg2059) {
     x.emplace(lwg2059_key(10), 5);
     x.erase(x.begin());
   }
+#endif
 }
 
 RUN_TESTS()
diff --git a/test/unordered/compile_tests.hpp b/test/unordered/compile_tests.hpp
index 3975cd07..65509e79 100644
--- a/test/unordered/compile_tests.hpp
+++ b/test/unordered/compile_tests.hpp
@@ -360,23 +360,29 @@ void unordered_map_test(X& r, Key const& k, T const& v)
 
   typedef typename X::iterator iterator;
   typedef typename X::const_iterator const_iterator;
+#ifndef BOOST_UNORDERED_FOA_TESTS
   typedef typename X::local_iterator local_iterator;
   typedef typename X::const_local_iterator const_local_iterator;
+#endif
   typedef typename std::iterator_traits<iterator>::pointer iterator_pointer;
   typedef typename std::iterator_traits<const_iterator>::pointer
     const_iterator_pointer;
+#ifndef BOOST_UNORDERED_FOA_TESTS
   typedef typename std::iterator_traits<local_iterator>::pointer
     local_iterator_pointer;
   typedef typename std::iterator_traits<const_local_iterator>::pointer
     const_local_iterator_pointer;
+#endif
 
   BOOST_STATIC_ASSERT((boost::is_same<value_type*, iterator_pointer>::value));
   BOOST_STATIC_ASSERT(
     (boost::is_same<value_type const*, const_iterator_pointer>::value));
+#ifndef BOOST_UNORDERED_FOA_TESTS
   BOOST_STATIC_ASSERT(
     (boost::is_same<value_type*, local_iterator_pointer>::value));
   BOOST_STATIC_ASSERT(
     (boost::is_same<value_type const*, const_local_iterator_pointer>::value));
+#endif
 
   // pointer_traits<iterator>
 
@@ -396,6 +402,7 @@ void unordered_map_test(X& r, Key const& k, T const& v)
   BOOST_STATIC_ASSERT((boost::is_same<std::ptrdiff_t,
     typename boost::pointer_traits<const_iterator>::difference_type>::value));
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   // pointer_traits<local_iterator>
 
   BOOST_STATIC_ASSERT((boost::is_same<local_iterator,
@@ -424,6 +431,7 @@ void unordered_map_test(X& r, Key const& k, T const& v)
   BOOST_STATIC_ASSERT((boost::is_same<T, node_mapped_type>::value));
   // Superfluous,but just to make sure.
   BOOST_STATIC_ASSERT((!boost::is_const<node_key_type>::value));
+#endif
 
   // Calling functions
 
@@ -442,8 +450,12 @@ void unordered_map_test(X& r, Key const& k, T const& v)
   r.emplace(k_lvalue, v_lvalue);
   r.emplace(rvalue(k), rvalue(v));
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  r.emplace(std::piecewise_construct, std::make_tuple(k), std::make_tuple(v));
+#else
   r.emplace(boost::unordered::piecewise_construct, boost::make_tuple(k),
     boost::make_tuple(v));
+#endif
 
   // Emplace with hint
 
@@ -451,9 +463,15 @@ void unordered_map_test(X& r, Key const& k, T const& v)
   r.emplace_hint(r.begin(), k_lvalue, v_lvalue);
   r.emplace_hint(r.begin(), rvalue(k), rvalue(v));
 
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  r.emplace_hint(r.begin(), std::piecewise_construct, std::make_tuple(k),
+    std::make_tuple(v));
+#else
   r.emplace_hint(r.begin(), boost::unordered::piecewise_construct,
     boost::make_tuple(k), boost::make_tuple(v));
+#endif
 
+#ifndef BOOST_UNORDERED_FOA_TESTS
   // Extract
 
   test::check_return_type<node_type>::equals(r.extract(r.begin()));
@@ -476,6 +494,7 @@ void unordered_map_test(X& r, Key const& k, T const& v)
   node_type n = r.extract(r.begin());
   test::check_return_type<node_key_type>::equals_ref(n.key());
   test::check_return_type<node_mapped_type>::equals_ref(n.mapped());
+#endif
 }
 
 template <class X> void equality_test(X& r)