diff --git a/src/libclang/libclang_parser.cpp b/src/libclang/libclang_parser.cpp
index 9eb4c78..bf76159 100644
--- a/src/libclang/libclang_parser.cpp
+++ b/src/libclang/libclang_parser.cpp
@@ -401,17 +401,7 @@ void libclang_compile_config::do_add_macro_definition(std::string name, std::str
 {
     auto str = "-D" + std::move(name);
     if (!definition.empty())
-    {
-        str += "=\"";
-        for (auto c : definition)
-        {
-            if (c == '"')
-                str += "\\\"";
-            else
-                str += c;
-        }
-        str += "\"";
-    }
+        str += "=" + definition;
     add_flag(std::move(str));
 }
 
@@ -517,10 +507,7 @@ detail::cxtranslation_unit get_cxunit(const diagnostic_logger& logger, const det
                                       const libclang_compile_config& config, const char* path,
                                       const std::string& source)
 {
-    CXUnsavedFile file;
-    file.Filename = path;
-    file.Contents = source.c_str();
-    file.Length   = static_cast<unsigned long>(source.length());
+    CXUnsavedFile file{path, source.c_str(), static_cast<unsigned long>(source.length())};
 
     auto args = get_arguments(config);
 
diff --git a/test/cpp_preprocessor.cpp b/test/cpp_preprocessor.cpp
index 5632f98..53ba588 100644
--- a/test/cpp_preprocessor.cpp
+++ b/test/cpp_preprocessor.cpp
@@ -93,6 +93,33 @@ namespace ns2
     }
 }
 
+TEST_CASE("command line macro definition")
+{
+    write_file("command_line_macro_definition.hpp", "NAME foo;");
+    write_file("command_line_macro_definition.cpp",
+               R"(#include "command_line_macro_definition.hpp")");
+
+    struct test_logger : diagnostic_logger
+    {
+        mutable bool error = false;
+
+        bool do_log(const char* source, const diagnostic& d) const override
+        {
+            error = true;
+            default_logger()->log(source, d);
+            return false;
+        }
+    } logger;
+
+    libclang_compile_config config;
+    config.define_macro("NAME", "int");
+
+    libclang_parser parser{type_safe::ref(logger)};
+    parser.parse({}, "command_line_macro_definition.cpp", config);
+    REQUIRE(!parser.error());
+    REQUIRE(!logger.error);
+}
+
 TEST_CASE("cpp_include_directive")
 {
     write_file("cpp_include_directive-header.hpp", R"(
diff --git a/test/libclang_parser.cpp b/test/libclang_parser.cpp
index e5e2ffc..3076f07 100644
--- a/test/libclang_parser.cpp
+++ b/test/libclang_parser.cpp
@@ -25,13 +25,14 @@ void require_flags(const libclang_compile_config& config, const char* flags)
     auto        config_flags = detail::libclang_compile_config_access::flags(config);
     // skip until including __cppast_version__minor__, those are the default options
     auto in_default = true;
-    for (auto iter = config_flags.begin(); iter != config_flags.end(); ++iter)
+    for (auto& config_flag : config_flags)
     {
-        if (*iter == "-D__cppast_version_minor__=\"" CPPAST_VERSION_MINOR "\"")
+        if (config_flag == "-D__cppast_version_minor__=" CPPAST_VERSION_MINOR)
             in_default = false;
         else if (!in_default)
-            result += *iter + ' ';
+            result += config_flag + ' ';
     }
+    REQUIRE(!result.empty());
     result.pop_back();
     REQUIRE(result == flags);
 }