diff --git a/libcxx/include/future b/libcxx/include/future
--- a/libcxx/include/future
+++ b/libcxx/include/future
@@ -44,14 +44,17 @@
 
 const error_category& future_category() noexcept;
 
-class future_error
-    : public logic_error
+class future_error : public logic_error
 {
 public:
     future_error(error_code ec);  // exposition only
-    explicit future_error(future_errc); // C++17
+    explicit future_error(future_errc e); // C++17
+
     const error_code& code() const noexcept;
     const char*       what() const noexcept;
+
+private:
+    error_code ec_;             // exposition only
 };
 
 template <class R>
@@ -500,10 +503,20 @@
 {
     error_code __ec_;
 public:
-    future_error(error_code __ec);
-#if _LIBCPP_STD_VERS > 14
-    explicit future_error(future_errc _Ev) : logic_error(), __ec_(make_error_code(_Ev)) {}
+    struct __tag {
+        explicit __tag() = default;
+    };
+
+    explicit future_error(error_code __ec, __tag)
+        : logic_error(__ec.message()), __ec_(__ec) {}
+
+#if _LIBCPP_STD_VER > 14
+    explicit future_error(future_errc _Ev)
+        : future_error(make_error_code(_Ev), __tag()) {}
+#else
+    future_error(error_code __ec) : logic_error(__ec.message()), __ec_(__ec) {}
 #endif
+
     _LIBCPP_INLINE_VISIBILITY
     const error_code& code() const _NOEXCEPT {return __ec_;}
 
@@ -518,7 +531,7 @@
 void __throw_future_error(future_errc _Ev)
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    throw future_error(make_error_code(_Ev));
+    throw future_error(make_error_code(_Ev), future_error::__tag());
 #else
     ((void)_Ev);
     _VSTD::abort();
@@ -1338,9 +1351,9 @@
     if (__state_)
     {
         if (!__state_->__has_value() && __state_->use_count() > 1)
-            __state_->set_exception(make_exception_ptr(
-                      future_error(make_error_code(future_errc::broken_promise))
-                                                      ));
+          __state_->set_exception(make_exception_ptr(
+              future_error(make_error_code(future_errc::broken_promise),
+                           future_error::__tag())));
         __state_->__release_shared();
     }
 }
@@ -1481,9 +1494,9 @@
     if (__state_)
     {
         if (!__state_->__has_value() && __state_->use_count() > 1)
-            __state_->set_exception(make_exception_ptr(
-                      future_error(make_error_code(future_errc::broken_promise))
-                                                      ));
+          __state_->set_exception(make_exception_ptr(
+              future_error(make_error_code(future_errc::broken_promise),
+                           future_error::__tag())));
         __state_->__release_shared();
     }
 }
diff --git a/libcxx/src/future.cpp b/libcxx/src/future.cpp
--- a/libcxx/src/future.cpp
+++ b/libcxx/src/future.cpp
@@ -71,12 +71,6 @@
     return __f;
 }
 
-future_error::future_error(error_code __ec)
-    : logic_error(__ec.message()),
-      __ec_(__ec)
-{
-}
-
 future_error::~future_error() noexcept
 {
 }
@@ -207,9 +201,9 @@
     {
 #ifndef _LIBCPP_NO_EXCEPTIONS
         if (!__state_->__has_value() && __state_->use_count() > 1)
-            __state_->set_exception(make_exception_ptr(
-                      future_error(make_error_code(future_errc::broken_promise))
-                                                      ));
+          __state_->set_exception(make_exception_ptr(
+              future_error(make_error_code(future_errc::broken_promise),
+                           future_error::__tag())));
 #endif // _LIBCPP_NO_EXCEPTIONS
         __state_->__release_shared();
     }
diff --git a/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp b/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.future_error/code.pass.cpp
@@ -11,10 +11,10 @@
 // <future>
 
 // class future_error
-//     future_error(error_code __ec);  // exposition only
-//     explicit future_error(future_errc _Ev) : __ec_(make_error_code(_Ev)) {} // C++17
+//     future_error(error_code ec);  // exposition only
+//     explicit future_error(future_errc e); // C++17
 
-// const error_code& code() const throw();
+// const error_code& code() const noexcept;
 
 #include <future>
 #include <cassert>
@@ -23,6 +23,7 @@
 
 int main(int, char**)
 {
+#if TEST_STD_VER <= 14
     {
         std::error_code ec = std::make_error_code(std::future_errc::broken_promise);
         std::future_error f(ec);
@@ -43,16 +44,16 @@
         std::future_error f(ec);
         assert(f.code() == ec);
     }
-#if TEST_STD_VER > 14
+#endif
     {
         std::future_error f(std::future_errc::broken_promise);
+        ASSERT_NOEXCEPT(f.code());
         assert(f.code() == std::make_error_code(std::future_errc::broken_promise));
     }
     {
         std::future_error f(std::future_errc::no_state);
         assert(f.code() == std::make_error_code(std::future_errc::no_state));
     }
-#endif
 
   return 0;
 }
diff --git a/libcxx/test/std/thread/futures/futures.future_error/ctor.fail.cpp b/libcxx/test/std/thread/futures/futures.future_error/ctor.fail.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/thread/futures/futures.future_error/ctor.fail.cpp
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: c++03, c++11, c++14
+// UNSUPPORTED: libcpp-has-no-threads
+
+// <future>
+
+// class future_error
+//     explicit future_error(future_errc e); // C++17
+
+#include <future>
+
+int main(int, char**) {
+  auto test_explicit = [](std::future_errc e) -> std::future_error {
+    return {e};
+    // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
+  };
+
+  std::error_code ec = std::make_error_code(std::future_errc::no_state);
+  std::future_error f(ec); // expected-error {{no matching constructor for initialization of 'std::future_error'}}
+
+  return 0;
+}
diff --git a/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp b/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.future_error/what.pass.cpp
@@ -19,7 +19,7 @@
 
 // class future_error
 
-// const char* what() const throw();
+// const char* what() const noexcept;
 
 #include <future>
 #include <cstring>
@@ -30,21 +30,22 @@
 int main(int, char**)
 {
     {
-        std::future_error f(std::make_error_code(std::future_errc::broken_promise));
+        std::future_error f(std::future_errc::broken_promise);
+        ASSERT_NOEXCEPT(f.what());
         LIBCPP_ASSERT(std::strcmp(f.what(), "The associated promise has been destructed prior "
                       "to the associated state becoming ready.") == 0);
     }
     {
-        std::future_error f(std::make_error_code(std::future_errc::future_already_retrieved));
+        std::future_error f(std::future_errc::future_already_retrieved);
         LIBCPP_ASSERT(std::strcmp(f.what(), "The future has already been retrieved from "
                       "the promise or packaged_task.") == 0);
     }
     {
-        std::future_error f(std::make_error_code(std::future_errc::promise_already_satisfied));
+        std::future_error f(std::future_errc::promise_already_satisfied);
         LIBCPP_ASSERT(std::strcmp(f.what(), "The state of the promise has already been set.") == 0);
     }
     {
-        std::future_error f(std::make_error_code(std::future_errc::no_state));
+        std::future_error f(std::future_errc::no_state);
         LIBCPP_ASSERT(std::strcmp(f.what(), "Operation not permitted on an object without "
                       "an associated state.") == 0);
     }