diff --git a/include/inja/parser.hpp b/include/inja/parser.hpp
index c4f2a8a..26697b5 100644
--- a/include/inja/parser.hpp
+++ b/include/inja/parser.hpp
@@ -97,7 +97,7 @@ class Parser {
 
     if (config.search_included_templates_in_files) {
       // Build the relative path
-      template_name = path / original_name;
+      template_name = (path / original_name).string();
       if (template_name.compare(0, 2, "./") == 0) {
         template_name.erase(0, 2);
       }
diff --git a/include/inja/renderer.hpp b/include/inja/renderer.hpp
index d3112ee..0f2de46 100644
--- a/include/inja/renderer.hpp
+++ b/include/inja/renderer.hpp
@@ -65,7 +65,7 @@ class Renderer : public NodeVisitor {
 
   static std::string htmlescape(const std::string& data) {
     std::string buffer;
-    buffer.reserve(1.1 * data.size());
+    buffer.reserve((unsigned int)(1.1 * data.size()));
     for (size_t pos = 0; pos != data.size(); ++pos) {
       switch (data[pos]) {
         case '&':  buffer.append("&");       break;
diff --git a/single_include/inja/inja.hpp b/single_include/inja/inja.hpp
index db1dee7..60e1351 100644
--- a/single_include/inja/inja.hpp
+++ b/single_include/inja/inja.hpp
@@ -1542,7 +1542,7 @@ class Parser {
 
     if (config.search_included_templates_in_files) {
       // Build the relative path
-      template_name = path / original_name;
+      template_name = (path / original_name).string();
       if (template_name.compare(0, 2, "./") == 0) {
         template_name.erase(0, 2);
       }
@@ -2172,7 +2172,7 @@ class Renderer : public NodeVisitor {
 
   static std::string htmlescape(const std::string& data) {
     std::string buffer;
-    buffer.reserve(1.1 * data.size());
+    buffer.reserve((unsigned int)(1.1 * data.size()));
     for (size_t pos = 0; pos != data.size(); ++pos) {
       switch (data[pos]) {
         case '&':  buffer.append("&");       break;
diff --git a/test/test-renderer.cpp b/test/test-renderer.cpp
index 36fadb4..d73e4cb 100644
--- a/test/test-renderer.cpp
+++ b/test/test-renderer.cpp
@@ -191,13 +191,13 @@ TEST_CASE("templates") {
     CHECK_THROWS_WITH(env.parse("{% include \"does-not-exist\" %}!"), "[inja.exception.file_error] failed accessing file at 'does-not-exist'");
 
     env.set_search_included_templates_in_files(false);
-    env.set_include_callback([&env](const std::string&, const std::string&) { return env.parse("Hello {{ name }}"); });
+    env.set_include_callback([&env](const std::filesystem::path&, const std::string&) { return env.parse("Hello {{ name }}"); });
 
     const inja::Template t1 = env.parse("{% include \"greeting\" %}!");
     CHECK(env.render(t1, data) == "Hello Peter!");
 
     env.set_search_included_templates_in_files(true);
-    env.set_include_callback([&env](const std::string&, const std::string& name) { return env.parse("Bye " + name); });
+    env.set_include_callback([&env](const std::filesystem::path&, const std::string& name) { return env.parse("Bye " + name); });
 
     const inja::Template t2 = env.parse("{% include \"Jeff\" %}!");
     CHECK(env.render(t2, data) == "Bye Jeff!");