fix(#279): fix compilation with older msvc

by avoiding known SFINAE problem in msvc 2017

tests/CMakeLists.txt

@@ -21,6 +21,7 @@ set(TOML11_TEST_NAMES
     test_parse_inline_table
     test_parse_table_keys
     test_parse_table
+    test_parse
     test_result
     test_scanner
     test_serialize

tests/test_parse.cpp

@@ -0,0 +1,50 @@
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+
+#include <toml.hpp>
+
+#include <clocale>
+
+TEST_CASE("testing toml::parse(file)")
+{
+    using namespace toml::literals::toml_literals;
+
+    const std::string spec_example(R"(# This is a TOML document
+
+title = "TOML Example"
+
+[owner]
+name = "Tom Preston-Werner"
+dob = 1979-05-27T07:32:00-08:00
+
+[database]
+enabled = true
+ports = [ 8000, 8001, 8002 ]
+data = [ ["delta", "phi"], [3.14] ]
+temp_targets = { cpu = 79.5, case = 72.0 }
+
+[servers]
+
+[servers.alpha]
+ip = "10.0.0.1"
+role = "frontend"
+
+[servers.beta]
+ip = "10.0.0.2"
+role = "backend"
+)");
+
+    {
+        std::ofstream ofs("test_parse.toml");
+        ofs << spec_example;
+    }
+
+    const auto u = toml::parse_str(spec_example);
+    const auto v = toml::parse("test_parse.toml");
+
+    CHECK_EQ(u, v);
+
+    CHECK_EQ(toml::find<int>(v, "database", "ports", 0), 8000);
+    CHECK_EQ(toml::find<int>(v, "database", "ports", 1), 8001);
+    CHECK_EQ(toml::find<int>(v, "database", "ports", 2), 8002);
+}