Implement LWG 3065: Make path operators friends.

This prevents things like:

using namespace std::filesystem;
auto x = L"a/b" == std::string("a/b");

5 files changed, 89 insertions, 39 deletions

diff --git a/libcxx/include/filesystem b/libcxx/include/filesystem
index 06a0eb33c4e..af713a06358 100644
--- a/libcxx/include/filesystem
+++ b/libcxx/include/filesystem
@@ -1151,6 +1151,31 @@ public:
     return __is;
   }
 
+  friend _LIBCPP_INLINE_VISIBILITY bool operator==(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) == 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator!=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) != 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator<(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) < 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator<=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) <= 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator>(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) > 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator>=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) >= 0;
+  }
+
+  friend _LIBCPP_INLINE_VISIBILITY path operator/(const path& __lhs,
+                                                  const path& __rhs) {
+    path __result(__lhs);
+    __result /= __rhs;
+    return __result;
+  }
 private:
   inline _LIBCPP_INLINE_VISIBILITY path&
   __assign_view(__string_view const& __s) noexcept {
@@ -1167,43 +1192,6 @@ inline _LIBCPP_INLINE_VISIBILITY void swap(path& __lhs, path& __rhs) noexcept {
 _LIBCPP_FUNC_VIS
 size_t hash_value(const path& __p) noexcept;
 
-inline _LIBCPP_INLINE_VISIBILITY bool operator==(const path& __lhs,
-                                                 const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) == 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY bool operator!=(const path& __lhs,
-                                                 const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) != 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY bool operator<(const path& __lhs,
-                                                const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) < 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY bool operator<=(const path& __lhs,
-                                                 const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) <= 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY bool operator>(const path& __lhs,
-                                                const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) > 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY bool operator>=(const path& __lhs,
-                                                 const path& __rhs) noexcept {
-  return __lhs.compare(__rhs) >= 0;
-}
-
-inline _LIBCPP_INLINE_VISIBILITY path operator/(const path& __lhs,
-                                                const path& __rhs) {
-  path __result(__lhs);
-  __result /= __rhs;
-  return __result;
-}
-
 template <class _Source>
 _LIBCPP_INLINE_VISIBILITY
     typename enable_if<__is_pathable<_Source>::value, path>::type
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp
new file mode 100644
index 00000000000..e0b3a959c29
--- /dev/null
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.fail.cpp
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <filesystem>
+
+#include "filesystem_include.hpp"
+
+using namespace fs;
+
+struct ConvToPath {
+  operator fs::path() const {
+    return "";
+  }
+};
+
+int main() {
+  ConvToPath LHS, RHS;
+  (void)(LHS / RHS); // expected-error {{invalid operands to binary expression}}
+}
\ No newline at end of file
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
index 09498bf2135..2a291d61da7 100644
--- a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/append_op.pass.cpp
@@ -20,7 +20,6 @@
 #include "test_macros.h"
 #include "filesystem_test_helper.hpp"
 
-
 // This is mainly tested via the member append functions.
 int main()
 {
@@ -29,4 +28,7 @@ int main()
   path p2("def");
   path p3 = p1 / p2;
   assert(p3 == "abc/def");
+
+  path p4 = p1 / "def";
+  assert(p4 == "abc/def");
 }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp
new file mode 100644
index 00000000000..00eafe532d0
--- /dev/null
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.nonmember/comparison_ops.fail.cpp
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <filesystem>
+
+
+#include "filesystem_include.hpp"
+
+using namespace fs;
+
+struct ConvToPath {
+  operator fs::path() const {
+    return "";
+  }
+};
+
+int main() {
+  ConvToPath LHS, RHS;
+  (void)(LHS == RHS); // expected-error {{invalid operands to binary expression}}
+  (void)(LHS != RHS); // expected-error {{invalid operands to binary expression}}
+  (void)(LHS < RHS); // expected-error {{invalid operands to binary expression}}
+  (void)(LHS <= RHS); // expected-error {{invalid operands to binary expression}}
+  (void)(LHS > RHS); // expected-error {{invalid operands to binary expression}}
+  (void)(LHS >= RHS); // expected-error {{invalid operands to binary expression}}
+}
\ No newline at end of file
diff --git a/libcxx/www/cxx2a_status.html b/libcxx/www/cxx2a_status.html
index 88aa56e38a8..1a072c9b054 100644
--- a/libcxx/www/cxx2a_status.html
+++ b/libcxx/www/cxx2a_status.html
@@ -270,7 +270,7 @@
 	<tr><td><a href="https://wg21.link/LWG3037">3037</a></td><td><tt>polymorphic_allocator</tt> and incomplete types</td><td>San Diego</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3038">3038</a></td><td><tt>polymorphic_allocator::allocate</tt> should not allow integer overflow to create vulnerabilities</td><td>San Diego</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3054">3054</a></td><td><tt>uninitialized_copy</tt> appears to not be able to meet its exception-safety guarantee</td><td>San Diego</td><td></td></tr>
-	<tr><td><a href="https://wg21.link/LWG3065">3065</a></td><td>LWG 2989 missed that all <tt>path</tt>'s other operators should be hidden friends as well</td><td>San Diego</td><td></td></tr>
+	<tr><td><a href="https://wg21.link/LWG3065">3065</a></td><td>LWG 2989 missed that all <tt>path</tt>'s other operators should be hidden friends as well</td><td>San Diego</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG3096">3096</a></td><td><tt>path::lexically_relative</tt> is confused by trailing slashes</td><td>San Diego</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3116">3116</a></td><td><tt><i>OUTERMOST_ALLOC_TRAITS</i></tt> needs <tt>remove_reference_t</tt></td><td>San Diego</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG3122">3122</a></td><td><tt>__cpp_lib_chrono_udls</tt> was accidentally dropped</td><td>San Diego</td><td><i>We've already made the update; but we don't support all the test macros. When we do, this will be closed</i></td></tr>