Implement filesystem NB comments, relative paths, and related issues.

This is a fairly large patch that implements all of the filesystem NB comments
and the relative paths changes (ex. adding weakly_canonical). These issues
and papers are all interrelated so their implementation couldn't be split up
nicely.

This patch upgrades <experimental/filesystem> to match the C++17 spec and not
the published experimental TS spec. Some of the changes in this patch are both
API and ABI breaking, however libc++ makes no guarantee about stability for
experimental implementations.

The major changes in this patch are:

* Implement NB comments for filesystem (P0492R2), including:
  * Implement `perm_options` enum as part of NB comments, and update the
    `permissions` function to match.
  * Implement changes to `remove_filename` and `replace_filename`
  * Implement changes to `path::stem()` and `path::extension()` which support
    splitting examples like `.profile`.
  * Change path iteration to return an empty path instead of '.' for trailing
    separators.
  * Change `operator/=` to handle absolute paths on the RHS.
  * Change `absolute` to no longer accept a current path argument.

* Implement relative paths according to NB comments (P0219r1)

* Combine `path.cpp` and `operations.cpp` since some path functions require
  access to the operations internals, and some fs operations require access
  to the path parser.

llvm-svn: 329028

10 files changed, 381 insertions, 111 deletions

diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.append.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.append.pass.cpp
index ca072d16114..11bc5dd9b86 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.append.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.append.pass.cpp
@@ -31,6 +31,7 @@
 #include "test_iterators.h"
 #include "count_new.hpp"
 #include "filesystem_test_helper.hpp"
+#include "verbose_assert.h"
 
 
 struct AppendOperatorTestcase {
@@ -45,13 +46,22 @@ const AppendOperatorTestcase Cases[] =
         {S(""),     S(""),      S("")}
       , {S("p1"),   S("p2"),    S("p1/p2")}
       , {S("p1/"),  S("p2"),    S("p1/p2")}
-      , {S("p1"),   S("/p2"),   S("p1/p2")}
-      , {S("p1/"),  S("/p2"),   S("p1//p2")}
+      , {S("p1"),   S("/p2"),   S("/p2")}
+      , {S("p1/"),  S("/p2"),   S("/p2")}
       , {S("p1"),   S("\\p2"),  S("p1/\\p2")}
       , {S("p1\\"), S("p2"),  S("p1\\/p2")}
       , {S("p1\\"), S("\\p2"),  S("p1\\/\\p2")}
-      , {S("p1"),   S(""),      S("p1")}
       , {S(""),     S("p2"),    S("p2")}
+      , {S("/p1"),  S("p2"),    S("/p1/p2")}
+      , {S("/p1"),  S("/p2"),    S("/p2")}
+      , {S("/p1/p3"),  S("p2"),    S("/p1/p3/p2")}
+      , {S("/p1/p3/"),  S("p2"),    S("/p1/p3/p2")}
+      , {S("/p1/"),  S("p2"),    S("/p1/p2")}
+      , {S("/p1/p3/"),  S("/p2/p4"),    S("/p2/p4")}
+      , {S("/"),    S(""),      S("/")}
+      , {S("/p1"), S("/p2/"), S("/p2/")}
+      , {S("p1"),   S(""),      S("p1/")}
+      , {S("p1/"),  S(""),      S("p1/")}
     };
 
 
@@ -59,7 +69,8 @@ const AppendOperatorTestcase LongLHSCases[] =
     {
         {S("p1"),   S("p2"),    S("p1/p2")}
       , {S("p1/"),  S("p2"),    S("p1/p2")}
-      , {S("p1"),   S("/p2"),   S("p1/p2")}
+      , {S("p1"),   S("/p2"),   S("/p2")}
+      , {S("/p1"),  S("p2"),    S("/p1/p2")}
     };
 #undef S
 
@@ -98,7 +109,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       DisableAllocationGuard g;
       LHS /= RHS;
     }
-    assert(LHS == E);
+    ASSERT_PRED(PathEq, LHS , E);
   }
   // basic_string_view
   {
@@ -108,7 +119,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       DisableAllocationGuard g;
       LHS /= RHS;
     }
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
   }
   // CharT*
   {
@@ -118,7 +129,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       DisableAllocationGuard g;
       LHS /= RHS;
     }
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
   }
   {
     path LHS(L); PathReserve(LHS, ReserveSize);
@@ -127,7 +138,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       DisableAllocationGuard g;
       LHS.append(RHS, StrEnd(RHS));
     }
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
   }
   // input iterator - For non-native char types, appends needs to copy the
   // iterator range into a contiguous block of memory before it can perform the
@@ -143,7 +154,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       if (DisableAllocations) g.requireExactly(0);
       LHS /= RHS;
     }
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
   }
   {
     path LHS(L); PathReserve(LHS, ReserveSize);
@@ -154,7 +165,7 @@ void doAppendSourceAllocTest(AppendOperatorTestcase const& TC)
       if (DisableAllocations) g.requireExactly(0);
       LHS.append(RHS, REnd);
     }
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
   }
 }
 
@@ -171,17 +182,18 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
   const Ptr E = TC.expect;
   // basic_string
   {
-    path LHS(L);
+    path Result(L);
     Str RHS(R);
-    path& Ref = (LHS /= RHS);
-    assert(LHS == E);
-    assert(&Ref == &LHS);
+    path& Ref = (Result /= RHS);
+    ASSERT_EQ(Result, E)
+        << DISPLAY(L) << DISPLAY(R);
+    assert(&Ref == &Result);
   }
   {
     path LHS(L);
     Str RHS(R);
     path& Ref = LHS.append(RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   // basic_string_view
@@ -189,14 +201,14 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
     path LHS(L);
     StrView RHS(R);
     path& Ref = (LHS /= RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   {
     path LHS(L);
     StrView RHS(R);
     path& Ref = LHS.append(RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   // Char*
@@ -204,21 +216,22 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
     path LHS(L);
     Str RHS(R);
     path& Ref = (LHS /= RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   {
     path LHS(L);
     Ptr RHS(R);
     path& Ref = LHS.append(RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   {
     path LHS(L);
     Ptr RHS(R);
     path& Ref = LHS.append(RHS, StrEnd(RHS));
-    assert(LHS == E);
+    ASSERT_PRED(PathEq, LHS, E)
+        << DISPLAY(L) << DISPLAY(R);
     assert(&Ref == &LHS);
   }
   // iterators
@@ -226,13 +239,13 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
     path LHS(L);
     InputIter RHS(R);
     path& Ref = (LHS /= RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   {
     path LHS(L); InputIter RHS(R);
     path& Ref = LHS.append(RHS);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
   {
@@ -240,7 +253,7 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
     InputIter RHS(R);
     InputIter REnd(StrEnd(R));
     path& Ref = LHS.append(RHS, REnd);
-    assert(LHS == E);
+    assert(PathEq(LHS, E));
     assert(&Ref == &LHS);
   }
 }
@@ -304,11 +317,14 @@ int main()
   using namespace fs;
   for (auto const & TC : Cases) {
     {
-      path LHS((const char*)TC.lhs);
-      path RHS((const char*)TC.rhs);
-      path& Ref = (LHS /= RHS);
-      assert(LHS == (const char*)TC.expect);
-      assert(&Ref == &LHS);
+      const char* LHS_In = TC.lhs;
+      const char* RHS_In = TC.rhs;
+      path LHS(LHS_In);
+      path RHS(RHS_In);
+      path& Res = (LHS /= RHS);
+      ASSERT_PRED(PathEq, Res, (const char*)TC.expect)
+          << DISPLAY(LHS_In) << DISPLAY(RHS_In);
+      assert(&Res == &LHS);
     }
     doAppendSourceTest<char>    (TC);
     doAppendSourceTest<wchar_t> (TC);
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.compare.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.compare.pass.cpp
index ea356782678..a2af094128d 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.compare.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.compare.pass.cpp
@@ -26,6 +26,7 @@
 //
 // size_t hash_value(path const&) noexcept;
 
+
 #include "filesystem_include.hpp"
 #include <type_traits>
 #include <vector>
@@ -35,7 +36,7 @@
 #include "test_iterators.h"
 #include "count_new.hpp"
 #include "filesystem_test_helper.hpp"
-
+#include "verbose_assert.h"
 
 struct PathCompareTest {
   const char* LHS;
@@ -57,8 +58,9 @@ const PathCompareTest CompareTestCases[] =
     {"a/b/c", "b/a/c", -1},
     {"a/b", "a/b/c", -1},
     {"a/b/c", "a/b", 1},
-    {"a/b/", "a/b/.", 0},
-    {"a/b//////", "a/b/////.", 0},
+    {"a/b/", "a/b/.", -1},
+    {"a/b/", "a/b",    1},
+    {"a/b//////", "a/b/////.", -1},
     {"a/.././b", "a///..//.////b", 0},
     {"//foo//bar///baz////", "//foo/bar/baz/", 0}, // duplicate separators
     {"///foo/bar", "/foo/bar", 0}, // "///" is not a root directory
@@ -94,8 +96,13 @@ int main()
       int ret2 = normalize_ret(p1.compare(R));
       int ret3 = normalize_ret(p1.compare(TC.RHS));
       int ret4 = normalize_ret(p1.compare(RV));
-      assert(ret1 == ret2 && ret1 == ret3 && ret1 == ret4);
-      assert(ret1 == E);
+
+      g.release();
+      ASSERT_EQ(ret1, ret2);
+      ASSERT_EQ(ret1, ret3);
+      ASSERT_EQ(ret1, ret4);
+      ASSERT_EQ(ret1, E)
+          << DISPLAY(TC.LHS) << DISPLAY(TC.RHS);
 
       // check signatures
       ASSERT_NOEXCEPT(p1.compare(p2));
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp
index 377b94e52c7..ecc4c0c30a0 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp
@@ -18,6 +18,7 @@
 // UNSUPPORTED: clang-3.3, clang-3.4, clang-3.5, clang-3.6, clang-3.7, clang-3.8
 
 #include "filesystem_include.hpp"
+
 #include "test_macros.h"
 
 int main ()
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp
index 6dd24b51156..f959e43a304 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp
@@ -53,6 +53,14 @@
 #include "test_iterators.h"
 #include "count_new.hpp"
 #include "filesystem_test_helper.hpp"
+#include "assert_checkpoint.h"
+#include "verbose_assert.h"
+
+struct ComparePathExact {
+  bool operator()(std::string const& LHS, std::string const& RHS) const {
+    return LHS == RHS;
+  }
+};
 
 struct PathDecomposeTestcase
 {
@@ -72,80 +80,89 @@ const PathDecomposeTestcase PathTestCases[] =
     , {".", {"."}, "", "", "", ".", "", "."}
     , {"..", {".."}, "", "", "", "..", "", ".."}
     , {"foo", {"foo"}, "", "", "", "foo", "", "foo"}
-    , {"/", {"/"}, "/", "", "/", "", "", "/"}
+    , {"/", {"/"}, "/", "", "/", "", "/", ""}
     , {"/foo", {"/", "foo"}, "/", "", "/", "foo", "/", "foo"}
-    , {"foo/", {"foo", "."}, "", "", "", "foo/", "foo", "."}
-    , {"/foo/", {"/", "foo", "."}, "/", "", "/", "foo/", "/foo", "."}
+    , {"foo/", {"foo", ""}, "", "", "", "foo/", "foo", ""}
+    , {"/foo/", {"/", "foo", ""}, "/", "", "/", "foo/", "/foo", ""}
     , {"foo/bar", {"foo","bar"}, "",  "", "",  "foo/bar", "foo", "bar"}
     , {"/foo//bar", {"/","foo","bar"}, "/", "", "/", "foo/bar", "/foo", "bar"}
-    , {"//net", {"//net"}, "//net", "//net", "", "", "", "//net"}
-    , {"//net/foo", {"//net", "/", "foo"}, "//net/", "//net", "/", "foo", "//net/", "foo"}
-    , {"///foo///", {"/", "foo", "."}, "/", "", "/", "foo///", "///foo", "."}
+    , {"//net", {"/", "net"}, "/", "", "/", "net", "/", "net"}
+    , {"//net/foo", {"/", "net", "foo"}, "/", "", "/", "net/foo", "/net", "foo"}
+    , {"///foo///", {"/", "foo", ""}, "/", "", "/", "foo///", "///foo", ""}
     , {"///foo///bar", {"/", "foo", "bar"}, "/", "", "/", "foo///bar", "///foo", "bar"}
     , {"/.", {"/", "."}, "/", "", "/", ".", "/", "."}
-    , {"./", {".", "."}, "", "", "", "./", ".", "."}
+    , {"./", {".", ""}, "", "", "", "./", ".", ""}
     , {"/..", {"/", ".."}, "/", "", "/", "..", "/", ".."}
-    , {"../", {"..", "."}, "", "", "", "../", "..", "."}
+    , {"../", {"..", ""}, "", "", "", "../", "..", ""}
     , {"foo/.", {"foo", "."}, "", "", "", "foo/.", "foo", "."}
     , {"foo/..", {"foo", ".."}, "", "", "", "foo/..", "foo", ".."}
-    , {"foo/./", {"foo", ".", "."}, "", "", "", "foo/./", "foo/.", "."}
+    , {"foo/./", {"foo", ".", ""}, "", "", "", "foo/./", "foo/.", ""}
     , {"foo/./bar", {"foo", ".", "bar"}, "", "", "", "foo/./bar", "foo/.", "bar"}
-    , {"foo/../", {"foo", "..", "."}, "", "", "", "foo/../", "foo/..", "."}
+    , {"foo/../", {"foo", "..", ""}, "", "", "", "foo/../", "foo/..", ""}
     , {"foo/../bar", {"foo", "..", "bar"}, "", "", "", "foo/../bar", "foo/..", "bar"}
     , {"c:", {"c:"}, "", "", "", "c:", "", "c:"}
-    , {"c:/", {"c:", "."}, "", "", "", "c:/", "c:", "."}
+    , {"c:/", {"c:", ""}, "", "", "", "c:/", "c:", ""}
     , {"c:foo", {"c:foo"}, "", "", "", "c:foo", "", "c:foo"}
     , {"c:/foo", {"c:", "foo"}, "", "", "", "c:/foo", "c:", "foo"}
-    , {"c:foo/", {"c:foo", "."}, "", "", "", "c:foo/", "c:foo", "."}
-    , {"c:/foo/", {"c:", "foo", "."}, "", "", "", "c:/foo/",  "c:/foo", "."}
+    , {"c:foo/", {"c:foo", ""}, "", "", "", "c:foo/", "c:foo", ""}
+    , {"c:/foo/", {"c:", "foo", ""}, "", "", "", "c:/foo/",  "c:/foo", ""}
     , {"c:/foo/bar", {"c:", "foo", "bar"}, "", "", "", "c:/foo/bar", "c:/foo", "bar"}
     , {"prn:", {"prn:"}, "", "", "", "prn:", "", "prn:"}
     , {"c:\\", {"c:\\"}, "", "", "", "c:\\", "", "c:\\"}
     , {"c:\\foo", {"c:\\foo"}, "", "", "", "c:\\foo", "", "c:\\foo"}
     , {"c:foo\\", {"c:foo\\"}, "", "", "", "c:foo\\", "", "c:foo\\"}
     , {"c:\\foo\\", {"c:\\foo\\"}, "", "", "", "c:\\foo\\", "", "c:\\foo\\"}
-    , {"c:\\foo/",  {"c:\\foo", "."}, "", "", "", "c:\\foo/", "c:\\foo", "."}
+    , {"c:\\foo/",  {"c:\\foo", ""}, "", "", "", "c:\\foo/", "c:\\foo", ""}
     , {"c:/foo\\bar", {"c:", "foo\\bar"}, "", "", "", "c:/foo\\bar", "c:", "foo\\bar"}
-    , {"//", {"//"}, "//", "//", "", "", "", "//"}
+    , {"//", {"/"}, "/", "", "/", "", "/", ""}
   };
 
 void decompPathTest()
 {
   using namespace fs;
   for (auto const & TC : PathTestCases) {
-    path p(TC.raw);
-    assert(p == TC.raw);
+    CHECKPOINT(TC.raw.c_str());
+    fs::path p(TC.raw);
+    ASSERT(p == TC.raw);
 
-    assert(p.root_path() == TC.root_path);
-    assert(p.has_root_path() !=  TC.root_path.empty());
+    ASSERT_EQ(p.root_path(), TC.root_path);
+    ASSERT_NEQ(p.has_root_path(), TC.root_path.empty());
 
-    assert(p.root_name() == TC.root_name);
-    assert(p.has_root_name() !=  TC.root_name.empty());
+    ASSERT(p.root_name().native().empty())
+        << DISPLAY(p.root_name());
+    ASSERT_EQ(p.root_name(),TC.root_name);
+    ASSERT_NEQ(p.has_root_name(), TC.root_name.empty());
 
-    assert(p.root_directory() == TC.root_directory);
-    assert(p.has_root_directory() !=  TC.root_directory.empty());
+    ASSERT_EQ(p.root_directory(), TC.root_directory);
+    ASSERT_NEQ(p.has_root_directory(), TC.root_directory.empty());
 
-    assert(p.relative_path() == TC.relative_path);
-    assert(p.has_relative_path() !=  TC.relative_path.empty());
+    ASSERT_EQ(p.relative_path(), TC.relative_path);
+    ASSERT_NEQ(p.has_relative_path(), TC.relative_path.empty());
 
-    assert(p.parent_path() == TC.parent_path);
-    assert(p.has_parent_path() !=  TC.parent_path.empty());
+    ASSERT_EQ(p.parent_path(), TC.parent_path);
+    ASSERT_NEQ(p.has_parent_path(), TC.parent_path.empty());
 
-    assert(p.filename() == TC.filename);
-    assert(p.has_filename() !=  TC.filename.empty());
+    ASSERT_EQ(p.filename(), TC.filename);
+    ASSERT_NEQ(p.has_filename(), TC.filename.empty());
 
-    assert(p.is_absolute() == p.has_root_directory());
-    assert(p.is_relative() !=  p.is_absolute());
+    ASSERT_EQ(p.is_absolute(), p.has_root_directory());
+    ASSERT_NEQ(p.is_relative(), p.is_absolute());
+    if (p.empty())
+      ASSERT(p.is_relative());
 
-    assert(checkCollectionsEqual(p.begin(), p.end(),
-                                 TC.elements.begin(), TC.elements.end()));
+    ASSERT_COLLECTION_EQ_COMP(
+        p.begin(), p.end(),
+        TC.elements.begin(), TC.elements.end(),
+        ComparePathExact()
+    );
     // check backwards
 
     std::vector<fs::path> Parts;
     for (auto it = p.end(); it != p.begin(); )
       Parts.push_back(*--it);
-    assert(checkCollectionsEqual(Parts.begin(), Parts.end(),
-                                 TC.elements.rbegin(), TC.elements.rend()));
+    ASSERT_COLLECTION_EQ_COMP(Parts.begin(), Parts.end(),
+                                 TC.elements.rbegin(), TC.elements.rend(),
+                              ComparePathExact());
   }
 }
 
@@ -163,10 +180,12 @@ const FilenameDecompTestcase FilenameTestCases[] =
     {"", "", "", ""}
   , {".", ".", ".", ""}
   , {"..", "..", "..", ""}
-  , {"/", "/", "/", ""}
+  , {"/", "", "", ""}
   , {"foo", "foo", "foo", ""}
   , {"/foo/bar.txt", "bar.txt", "bar", ".txt"}
   , {"foo..txt", "foo..txt", "foo.", ".txt"}
+  , {".profile", ".profile", ".profile", ""}
+  , {".profile.txt", ".profile.txt", ".profile", ".txt"}
 };
 
 
@@ -174,18 +193,19 @@ void decompFilenameTest()
 {
   using namespace fs;
   for (auto const & TC : FilenameTestCases) {
-    path p(TC.raw);
-    assert(p == TC.raw);
+    CHECKPOINT(TC.raw.c_str());
+    fs::path p(TC.raw);
+    ASSERT_EQ(p, TC.raw);
     ASSERT_NOEXCEPT(p.empty());
 
-    assert(p.filename() == TC.filename);
-    assert(p.has_filename() != TC.filename.empty());
+    ASSERT_EQ(p.filename(), TC.filename);
+    ASSERT_NEQ(p.has_filename(), TC.filename.empty());
 
-    assert(p.stem() == TC.stem);
-    assert(p.has_stem() != TC.stem.empty());
+    ASSERT_EQ(p.stem(), TC.stem);
+    ASSERT_NEQ(p.has_stem(), TC.stem.empty());
 
-    assert(p.extension() == TC.extension);
-    assert(p.has_extension() != TC.extension.empty());
+    ASSERT_EQ(p.extension(), TC.extension);
+    ASSERT_NEQ(p.has_extension(), TC.extension.empty());
   }
 }
 
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_normal.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_normal.pass.cpp
new file mode 100644
index 00000000000..c897ab60f73
--- /dev/null
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_normal.pass.cpp
@@ -0,0 +1,142 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// <experimental/filesystem>
+
+// class path
+
+// path lexically_normal() const;
+
+#include "filesystem_include.hpp"
+#include <type_traits>
+#include <vector>
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "count_new.hpp"
+#include "filesystem_test_helper.hpp"
+
+
+int main() {
+  // clang-format off
+  struct {
+    std::string input;
+    std::string expect;
+  } TestCases[] = {
+      {"", ""},
+      {"/a/b/c", "/a/b/c"},
+      {"/a/b//c", "/a/b/c"},
+      {"foo/./bar/..", "foo/"},
+      {"foo/.///bar/../", "foo/"},
+      {"/a/b/", "/a/b/"},
+      {"a/b", "a/b"},
+      {"a/b/.", "a/b/"},
+      {"a/b/./", "a/b/"},
+      {"a/..", "."},
+      {".", "."},
+      {"./", "."},
+      {"./.", "."},
+      {"./..", ".."},
+      {"..", ".."},
+      {"../..", "../.."},
+      {"/../", "/"},
+      {"/../..", "/"},
+      {"/../../", "/"},
+      {"..", ".."},
+      {"../", ".."},
+      {"/a/b/c/../", "/a/b/"},
+      {"/a/b/./", "/a/b/"},
+      {"/a/b/c/../d", "/a/b/d"},
+      {"/a/b/c/../d/", "/a/b/d/"},
+      {"//a/", "/a/"},
+      {"//a/b/", "/a/b/"},
+      {"//a/b/.", "/a/b/"},
+      {"//a/..", "/"},
+      ///===---------------------------------------------------------------===//
+      /// Tests specifically for the clauses under [fs.path.generic]p6
+      ///===---------------------------------------------------------------===//
+      // p1: If the path is empty, stop.
+      {"", ""},
+      // p2: Replace each slash character in the root-name with a preferred
+      // separator.
+      {"NO_ROOT_NAME_ON_LINUX", "NO_ROOT_NAME_ON_LINUX"},
+      // p3: Replace each directory-separator with a preferred-separator.
+      // [ Note: The generic pathname grammar ([fs.path.generic]) defines
+      //   directory-separator as one or more slashes and preferred-separators.
+      //   — end note ]
+      {"/", "/"},
+      {"//", "/"},
+      {"///", "/"},
+      {"a/b", "a/b"},
+      {"a//b", "a/b"},
+      {"a///b", "a/b"},
+      {"a/b/", "a/b/"},
+      {"a/b//", "a/b/"},
+      {"a/b///", "a/b/"},
+      {"///a////b//////", "/a/b/"},
+      // p4: Remove each dot filename and any immediately following directory
+      // separators
+      {"foo/.", "foo/"},
+      {"foo/./bar/.", "foo/bar/"},
+      {"./foo/././bar/./", "foo/bar/"},
+      {".///foo//.////./bar/.///", "foo/bar/"},
+      // p5: As long as any appear, remove a non-dot-dot filename immediately
+      // followed by a directory-separator and a dot-dot filename, along with
+      // any immediately following directory separator.
+      {"foo/..", "."},
+      {"foo/../", "."},
+      {"foo/bar/..", "foo/"},
+      {"foo/bar/../", "foo/"},
+      {"foo/bar/../..", "."},
+      {"foo/bar/../../", "."},
+      {"foo/bar/baz/../..", "foo/"},
+      {"foo/bar/baz/../../", "foo/"},
+      {"foo/bar/./..", "foo/"},
+      {"foo/bar/./../", "foo/"},
+      // p6: If there is a root-directory, remove all dot-dot filenames and any
+      // directory-separators immediately following them. [ Note: These dot-dot
+      // filenames attempt to refer to nonexistent parent directories. — end note ]
+      {"/..", "/"},
+      {"/../", "/"},
+      {"/foo/../..", "/"},
+      {"/../foo", "/foo"},
+      {"/../foo/../..", "/"},
+      // p7: If the last filename is dot-dot, remove any trailing
+      // directory-separator.
+      {"../", ".."},
+      {"../../", "../.."},
+      {"foo/../bar/../..///", ".."},
+      {"foo/../bar/..//..///../", "../.."},
+      // p8: If the path is empty, add a dot
+      {".", "."},
+      {"./", "."},
+      {"foo/..", "."}
+  };
+  // clang-format on
+  int ID = 0;
+  bool Failed = false;
+  for (auto& TC : TestCases) {
+    ++ID;
+    fs::path p(TC.input);
+    const fs::path output = p.lexically_normal();
+    if (!PathEq(output, TC.expect)) {
+      Failed = true;
+      std::cerr << "TEST CASE #" << ID << " FAILED: \n";
+      std::cerr << "  Input: '" << TC.input << "'\n";
+      std::cerr << "  Expected: '" << TC.expect << "'\n";
+      std::cerr << "  Output: '" << output.native() << "'";
+      std::cerr << std::endl;
+    }
+  }
+  return Failed;
+}
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp
new file mode 100644
index 00000000000..8b56a19b716
--- /dev/null
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.gen/lexically_relative_and_proximate.pass.cpp
@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// <experimental/filesystem>
+
+// class path
+
+// path lexically_relative(const path& p) const;
+// path lexically_proximate(const path& p) const;
+
+#include "filesystem_include.hpp"
+#include <type_traits>
+#include <vector>
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "count_new.hpp"
+#include "filesystem_test_helper.hpp"
+
+
+int main() {
+  // clang-format off
+  struct {
+    std::string input;
+    std::string base;
+    std::string expect;
+  } TestCases[] = {
+      {"", "", "."},
+      {"/", "a", ""},
+      {"a", "/", ""},
+      {"//net", "a", ""},
+      {"a", "//net", ""},
+      {"//net/", "//net", ""},
+      {"//net", "//net/", ".."},
+      {"//base", "a", ""},
+      {"a", "a", "."},
+      {"a/b", "a/b", "."},
+      {"a/b/c/", "a/b/c/", "."},
+      {"//net", "//net", "."},
+      {"//net/", "//net/", "."},
+      {"//net/a/b", "//net/a/b", "."},
+      {"/a/d", "/a/b/c", "../../d"},
+      {"/a/b/c", "/a/d", "../b/c"},
+      {"a/b/c", "a", "b/c"},
+      {"a/b/c", "a/b/c/x/y", "../.."},
+      {"a/b/c", "a/b/c", "."},
+      {"a/b", "c/d", "../../a/b"}
+  };
+  // clang-format on
+  int ID = 0;
+  bool Failed = false;
+  for (auto& TC : TestCases) {
+    ++ID;
+    const fs::path p(TC.input);
+    const fs::path output = p.lexically_relative(TC.base);
+    auto ReportErr = [&](const char* Testing, fs::path const& Output,
+                                              fs::path const& Expected) {
+      Failed = true;
+      std::cerr << "TEST CASE #" << ID << " FAILED: \n";
+      std::cerr << "  Testing: " << Testing << "\n";
+      std::cerr << "  Input: '" << TC.input << "'\n";
+      std::cerr << "  Base: '" << TC.base << "'\n";
+      std::cerr << "  Expected: '" << Expected << "'\n";
+      std::cerr << "  Output: '" << Output.native() << "'";
+      std::cerr << std::endl;
+    };
+    if (!PathEq(output, TC.expect))
+      ReportErr("path::lexically_relative", output, TC.expect);
+    const fs::path proximate_output = p.lexically_proximate(TC.base);
+    // [path.gen] lexically_proximate
+    // Returns: If the value of lexically_relative(base) is not an empty path,
+    // return it.Otherwise return *this.
+    const fs::path proximate_expected = output.native().empty() ? p
+        : output;
+    if (!PathEq(proximate_expected, proximate_output))
+      ReportErr("path::lexically_proximate", proximate_output, proximate_expected);
+  }
+  return Failed;
+}
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
index 7e329376c93..a757cbb88fd 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/generic_string_alloc.pass.cpp
@@ -28,7 +28,6 @@
 #include "min_allocator.h"
 #include "filesystem_test_helper.hpp"
 
-
 MultiStringType longString = MKSTR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/123456789/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
 
 
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/named_overloads.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
index d3df09ed97e..56b2787fbb6 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.generic.obs/named_overloads.pass.cpp
@@ -30,7 +30,6 @@
 #include "min_allocator.h"
 #include "filesystem_test_helper.hpp"
 
-
 MultiStringType longString = MKSTR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/123456789/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
 
 int main()
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/remove_filename.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/remove_filename.pass.cpp
index 84cdd521429..ec885f15c8c 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/remove_filename.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/remove_filename.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_iterators.h"
 #include "count_new.hpp"
 #include "filesystem_test_helper.hpp"
-
+#include "verbose_assert.h"
 
 struct RemoveFilenameTestcase {
   const char* value;
@@ -33,27 +33,29 @@ struct RemoveFilenameTestcase {
 const RemoveFilenameTestcase TestCases[] =
   {
       {"", ""}
-    , {"/", ""}
-    , {"//", ""}
-    , {"///", ""}
+    , {"/", "/"}
+    , {"//", "//"}
+    , {"///", "///"}
     , {"\\", ""}
     , {".", ""}
     , {"..", ""}
     , {"/foo", "/"}
-    , {"//foo", ""}
-    , {"//foo/", ""}
-    , {"//foo///", ""}
-    , {"///foo", "/"}
-    , {"///foo/", "///foo"}
-    , {"/foo/", "/foo"}
-    , {"/foo/.", "/foo"}
-    , {"/foo/..", "/foo"}
-    , {"/foo/////", "/foo"}
+    , {"foo/bar", "foo/"}
+    , {"foo/", "foo/"}
+    , {"//foo", "//"}
+    , {"//foo/", "//foo/"}
+    , {"//foo///", "//foo///"}
+    , {"///foo", "///"}
+    , {"///foo/", "///foo/"}
+    , {"/foo/", "/foo/"}
+    , {"/foo/.", "/foo/"}
+    , {"/foo/..", "/foo/"}
+    , {"/foo/////", "/foo/////"}
     , {"/foo\\\\", "/"}
-    , {"/foo//\\/", "/foo//\\"}
-    , {"///foo", "/"}
+    , {"/foo//\\/", "/foo//\\/"}
+    , {"///foo", "///"}
     , {"file.txt", ""}
-    , {"bar/../baz/./file.txt", "bar/../baz/."}
+    , {"bar/../baz/./file.txt", "bar/../baz/./"}
   };
 
 int main()
@@ -64,16 +66,8 @@ int main()
     path p(p_orig);
     assert(p == TC.value);
     path& Ref = (p.remove_filename());
-    assert(p == TC.expect);
+    ASSERT_EQ(p, TC.expect) << DISPLAY(p_orig);
     assert(&Ref == &p);
-    {
-      const path parentp = p_orig.parent_path();
-      if (parentp == p_orig.root_name()) {
-
-        assert(p.empty());
-      } else {
-        assert(p == parentp);
-      }
-    }
+    assert(!p.has_filename());
   }
 }
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/replace_filename.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/replace_filename.pass.cpp
index fb7741110cc..bfb3b6a19cd 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/replace_filename.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.modifiers/replace_filename.pass.cpp
@@ -23,7 +23,8 @@
 #include "test_iterators.h"
 #include "count_new.hpp"
 #include "filesystem_test_helper.hpp"
-
+#include "assert_checkpoint.h"
+#include "verbose_assert.h"
 
 struct ReplaceFilenameTestcase {
   const char* value;
@@ -36,9 +37,9 @@ const ReplaceFilenameTestcase TestCases[] =
       {"/foo", "/bar", "bar"}
     , {"/foo", "/", ""}
     , {"foo", "bar", "bar"}
-    , {"/", "bar", "bar"}
+    , {"/", "/bar", "bar"}
     , {"\\", "bar", "bar"}
-    , {"///", "bar", "bar"}
+    , {"///", "///bar", "bar"}
     , {"\\\\", "bar", "bar"}
     , {"\\/\\", "\\/bar", "bar"}
     , {".", "bar", "bar"}
@@ -52,9 +53,11 @@ int main()
   using namespace fs;
   for (auto const & TC : TestCases) {
     path p(TC.value);
-    assert(p == TC.value);
+    ASSERT_EQ(p, TC.value);
     path& Ref = (p.replace_filename(TC.filename));
-    assert(p == TC.expect);
+    ASSERT_EQ(p, TC.expect)
+        << DISPLAY(TC.value)
+        << DISPLAY(TC.filename);
     assert(&Ref == &p);
     // Tests Effects "as-if": remove_filename() append(filename)
     {
@@ -62,7 +65,7 @@ int main()
       path replace(TC.filename);
       p2.remove_filename();
       p2 /= replace;
-      assert(p2 == p);
+      ASSERT_EQ(p, p2);
     }
   }
 }