libstdc++/71037 Add base path to filesystem::canonical exceptions

	PR libstdc++/71037
	* src/filesystem/ops.cc (canonical(const path&, const path&)): Add
	base path to exception.
	* testsuite/experimental/filesystem/operations/canonical.cc: Test
	paths contained in exception.

From-SVN: r236074

libstdc++-v3/ChangeLog

 2016-05-10  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/71037
+	* src/filesystem/ops.cc (canonical(const path&, const path&)): Add
+	base path to exception.
+	* testsuite/experimental/filesystem/operations/canonical.cc: Test
+	paths contained in exception.
+
 	* testsuite/experimental/type_erased_allocator/2.cc: Remove unused
 	using declaration.
 

libstdc++-v3/src/filesystem/ops.cc

@@ -220,8 +220,9 @@ fs::canonical(const path& p, const path& base)
 {
   error_code ec;
   path can = canonical(p, base, ec);
-  if (ec.value())
-    _GLIBCXX_THROW_OR_ABORT(filesystem_error("cannot canonicalize", p, ec));
+  if (ec)
+    _GLIBCXX_THROW_OR_ABORT(filesystem_error("cannot canonicalize", p, base,
+					     ec));
   return can;
 }
 

libstdc++-v3/testsuite/experimental/filesystem/operations/canonical.cc

@@ -59,8 +59,28 @@ test01()
   VERIFY( !ec );
 }
 
+void
+test02()
+{
+#if __cpp_exceptions
+  bool test __attribute__((unused)) = false;
+
+  fs::path p = "rel", base = __gnu_test::nonexistent_path();
+  fs::path e1, e2;
+  try {
+    canonical(p, base);
+  } catch (const fs::filesystem_error& e) {
+    e1 = e.path1();
+    e2 = e.path2();
+  }
+  VERIFY( e1 == p );
+  VERIFY( e2 == base );
+#endif
+}
+
 int
 main()
 {
   test01();
+  test02();
 }