Implement LWG 2711. Constrain path members.

llvm-svn: 279945

4 files changed, 194 insertions, 0 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 93892fbe10e..f344e115307 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
@@ -246,6 +246,60 @@ void doAppendSourceTest(AppendOperatorTestcase const& TC)
   }
 }
 
+
+
+template <class It, class = decltype(fs::path{}.append(std::declval<It>()))>
+constexpr bool has_append(int) { return true; }
+template <class It>
+constexpr bool has_append(long) { return false; }
+
+template <class It, class = decltype(fs::path{}.operator/=(std::declval<It>()))>
+constexpr bool has_append_op(int) { return true; }
+template <class It>
+constexpr bool has_append_op(long) { return false; }
+
+template <class It>
+constexpr bool has_append() {
+  static_assert(has_append<It>(0) == has_append_op<It>(0), "must be same");
+  return has_append<It>(0) && has_append_op<It>(0);
+}
+
+void test_sfinae()
+{
+  using namespace fs;
+  {
+    using It = const char* const;
+    static_assert(has_append<It>(), "");
+  }
+  {
+    using It = input_iterator<const char*>;
+    static_assert(has_append<It>(), "");
+  }
+  {
+    struct Traits {
+      using iterator_category = std::input_iterator_tag;
+      using value_type = const char;
+      using pointer = const char*;
+      using reference = const char&;
+      using difference_type = std::ptrdiff_t;
+    };
+    using It = input_iterator<const char*, Traits>;
+    static_assert(has_append<It>(), "");
+  }
+  {
+    using It = output_iterator<const char*>;
+    static_assert(!has_append<It>(), "");
+
+  }
+  {
+    static_assert(!has_append<int*>(), "");
+  }
+  {
+    static_assert(!has_append<char>(), "");
+    static_assert(!has_append<const char>(), "");
+  }
+}
+
 int main()
 {
   using namespace fs;
@@ -266,4 +320,5 @@ int main()
     doAppendSourceAllocTest<char>(TC);
     doAppendSourceAllocTest<wchar_t>(TC);
   }
+  test_sfinae();
 }
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.assign/source.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.assign/source.pass.cpp
index ae725a88590..9e48cbf1e7f 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.assign/source.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.assign/source.pass.cpp
@@ -170,6 +170,49 @@ void RunTestCase(MultiStringType const& MS) {
   }
 }
 
+template <class It, class = decltype(fs::path{}.assign(std::declval<It>()))>
+constexpr bool has_assign(int) { return true; }
+template <class It>
+constexpr bool has_assign(long) { return false; }
+template <class It>
+constexpr bool has_assign() { return has_assign<It>(0); }
+
+void test_sfinae() {
+  using namespace fs;
+  {
+    using It = const char* const;
+    static_assert(std::is_assignable<path, It>::value, "");
+    static_assert(has_assign<It>(), "");
+  }
+  {
+    using It = input_iterator<const char*>;
+    static_assert(std::is_assignable<path, It>::value, "");
+    static_assert(has_assign<It>(), "");
+  }
+  {
+    struct Traits {
+      using iterator_category = std::input_iterator_tag;
+      using value_type = const char;
+      using pointer = const char*;
+      using reference = const char&;
+      using difference_type = std::ptrdiff_t;
+    };
+    using It = input_iterator<const char*, Traits>;
+    static_assert(std::is_assignable<path, It>::value, "");
+    static_assert(has_assign<It>(), "");
+  }
+  {
+    using It = output_iterator<const char*>;
+    static_assert(!std::is_assignable<path, It>::value, "");
+    static_assert(!has_assign<It>(), "");
+
+  }
+  {
+    static_assert(!std::is_assignable<path, int*>::value, "");
+    static_assert(!has_assign<int*>(), "");
+  }
+}
+
 int main() {
   for (auto const& MS : PathList) {
     RunTestCase<char>(MS);
@@ -177,4 +220,5 @@ int main() {
     RunTestCase<char16_t>(MS);
     RunTestCase<char32_t>(MS);
   }
+  test_sfinae();
 }
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.concat.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.concat.pass.cpp
index cd627b8c842..89269362d06 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.concat.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.concat.pass.cpp
@@ -265,6 +265,68 @@ void doConcatECharTest(ConcatOperatorTestcase const& TC)
   }
 }
 
+
+template <class It, class = decltype(fs::path{}.concat(std::declval<It>()))>
+constexpr bool has_concat(int) { return true; }
+template <class It>
+constexpr bool has_concat(long) { return false; }
+
+template <class It, class = decltype(fs::path{}.operator+=(std::declval<It>()))>
+constexpr bool has_concat_op(int) { return true; }
+template <class It>
+constexpr bool has_concat_op(long) { return false; }
+template <class It>
+constexpr bool has_concat_op() { return has_concat_op<It>(0); }
+
+template <class It>
+constexpr bool has_concat() {
+  static_assert(has_concat<It>(0) == has_concat_op<It>(0), "must be same");
+  return has_concat<It>(0) && has_concat_op<It>(0);
+}
+
+void test_sfinae() {
+  using namespace fs;
+  {
+    static_assert(has_concat_op<char>(), "");
+    static_assert(has_concat_op<const char>(), "");
+    static_assert(has_concat_op<char16_t>(), "");
+    static_assert(has_concat_op<const char16_t>(), "");
+  }
+  {
+    using It = const char* const;
+    static_assert(has_concat<It>(), "");
+  }
+  {
+    using It = input_iterator<const char*>;
+    static_assert(has_concat<It>(), "");
+  }
+  {
+    struct Traits {
+      using iterator_category = std::input_iterator_tag;
+      using value_type = const char;
+      using pointer = const char*;
+      using reference = const char&;
+      using difference_type = std::ptrdiff_t;
+    };
+    using It = input_iterator<const char*, Traits>;
+    static_assert(has_concat<It>(), "");
+  }
+  {
+    using It = output_iterator<const char*>;
+    static_assert(!has_concat<It>(), "");
+  }
+  {
+    static_assert(!has_concat<int>(0), "");
+    // operator+=(int) is well formed since it converts to operator+=(value_type)
+    // but concat(int) isn't valid because there is no concat(value_type).
+    // This should probably be addressed by a LWG issue.
+    static_assert(has_concat_op<int>(), "");
+  }
+  {
+    static_assert(!has_concat<int*>(), "");
+  }
+}
+
 int main()
 {
   using namespace fs;
@@ -323,4 +385,5 @@ int main()
     doConcatECharTest<char16_t>(TC);
     doConcatECharTest<char32_t>(TC);
   }
+  test_sfinae();
 }
diff --git a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.construct/source.pass.cpp b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.construct/source.pass.cpp
index 402225de11b..a04f35af578 100644
--- a/libcxx/test/std/experimental/filesystem/class.path/path.member/path.construct/source.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.path/path.member/path.construct/source.pass.cpp
@@ -80,6 +80,37 @@ void RunTestCase(MultiStringType const& MS) {
   }
 }
 
+void test_sfinae() {
+  using namespace fs;
+  {
+    using It = const char* const;
+    static_assert(std::is_constructible<path, It>::value, "");
+  }
+  {
+    using It = input_iterator<const char*>;
+    static_assert(std::is_constructible<path, It>::value, "");
+  }
+  {
+    struct Traits {
+      using iterator_category = std::input_iterator_tag;
+      using value_type = const char;
+      using pointer = const char*;
+      using reference = const char&;
+      using difference_type = std::ptrdiff_t;
+    };
+    using It = input_iterator<const char*, Traits>;
+    static_assert(std::is_constructible<path, It>::value, "");
+  }
+  {
+    using It = output_iterator<const char*>;
+    static_assert(!std::is_constructible<path, It>::value, "");
+
+  }
+  {
+    static_assert(!std::is_constructible<path, int*>::value, "");
+  }
+}
+
 int main() {
   for (auto const& MS : PathList) {
     RunTestCase<char>(MS);
@@ -87,4 +118,5 @@ int main() {
     RunTestCase<char16_t>(MS);
     RunTestCase<char32_t>(MS);
   }
+  test_sfinae();
 }