Incorrect warnings when parsing with libclang in Windows mode

diagnostic.cpp

#include <string>
#include <iostream>

#include <clang-c/Index.h>


const char *flags[] = {
   "clang",
   "--driver-mode=cl",
   "-xc++"
};

int main(int argc, const char *argv[]) {
    if (argc != 2) {
        std::cout << argv[0] << " file.cpp" << std::endl;
        return EXIT_FAILURE;
    }

    CXIndex index = clang_createIndex(0, 0);
    if (!index) {
        std::cerr << "createIndex failed\n";
        return EXIT_FAILURE;
    }

    CXTranslationUnit tu;
    CXErrorCode result = clang_parseTranslationUnit2FullArgv(
        index, argv[1], flags, sizeof(flags) / sizeof(flags[0]), nullptr, 0,
        CXTranslationUnit_CreatePreambleOnFirstParse |
        clang_defaultEditingTranslationUnitOptions(),
        &tu);

    if (result != CXError_Success) {
        std::cerr << "clang_parseTranslationUnit2FullArgv failed with code "
                  << result << "\n";
        return EXIT_FAILURE;
    }

    size_t num_diagnostics = clang_getNumDiagnostics(tu);

    for (size_t i = 0; i < num_diagnostics; ++i) {
        CXDiagnostic diagnostic = clang_getDiagnostic(tu, i);
        CXDiagnosticSeverity diagnostic_severity =
            clang_getDiagnosticSeverity(diagnostic);
        CXString raw_string = clang_getDiagnosticSpelling(diagnostic);
        std::string string(clang_getCString(raw_string));
        clang_disposeString(raw_string);
        std::cout << string << "\n";
        clang_disposeDiagnostic(diagnostic);
    }

    return EXIT_SUCCESS;
}