diff --git a/languages/clang/duchain/parsesession.cpp b/languages/clang/duchain/parsesession.cpp
index f42fc6be01..aae06619ba 100644
--- a/languages/clang/duchain/parsesession.cpp
+++ b/languages/clang/duchain/parsesession.cpp
@@ -1,451 +1,453 @@
 /*
     This file is part of KDevelop
 
     Copyright 2013 Olivier de Gaalon <olivier.jg@gmail.com>
     Copyright 2013 Milian Wolff <mail@milianw.de>
     Copyright 2013 Kevin Funk <kfunk@kde.org>
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */
 
 #include "parsesession.h"
 #include <QStandardPaths>
 #include "clangproblem.h"
 #include "clangdiagnosticevaluator.h"
 #include "todoextractor.h"
 #include "clanghelpers.h"
 #include "clangindex.h"
 #include "clangparsingenvironment.h"
 #include "util/clangdebug.h"
 #include "util/clangtypes.h"
 #include "util/clangutils.h"
 
 #include <language/duchain/duchainlock.h>
 #include <language/duchain/duchain.h>
 
 #include <KShell>
 
 #include <QDir>
 #include <QFileInfo>
 #include <QMimeDatabase>
 #include <QMimeType>
 
 #include <algorithm>
 
 using namespace KDevelop;
 
 namespace {
 
 QVector<QByteArray> extraArgs()
 {
     const auto extraArgsString = QString::fromLatin1(qgetenv("KDEV_CLANG_EXTRA_ARGUMENTS"));
     const auto extraArgs = KShell::splitArgs(extraArgsString);
 
     // transform to list of QByteArrays
     QVector<QByteArray> result;
     result.reserve(extraArgs.size());
     foreach (const QString& arg, extraArgs) {
         result << arg.toLatin1();
     }
     clangDebug() << "Passing extra arguments to clang:" << result;
 
     return result;
 }
 
 QVector<QByteArray> argsForSession(const QString& path, ParseSessionData::Options options, const ParserSettings& parserSettings)
 {
     QMimeDatabase db;
     if(db.mimeTypeForFile(path).name() == QStringLiteral("text/x-objcsrc")) {
         return {QByteArrayLiteral("-xobjective-c++")};
     }
 
     if (parserSettings.parserOptions.isEmpty()) {
         // The parserOptions can be empty for some unit tests that use ParseSession directly
         auto defaultArguments = ClangSettingsManager::self()->parserSettings(path).toClangAPI();
         Q_ASSERT(!defaultArguments.isEmpty());
         defaultArguments.append(QByteArrayLiteral("-nostdinc"));
         defaultArguments.append(QByteArrayLiteral("-nostdinc++"));
         defaultArguments.append(QByteArrayLiteral("-xc++"));
         return defaultArguments;
     }
 
     auto result = parserSettings.toClangAPI();
     result.append(QByteArrayLiteral("-nostdinc"));
-    result.append(QByteArrayLiteral("-nostdinc++"));
+    if (parserSettings.isCpp()) {
+        result.append(QByteArrayLiteral("-nostdinc++"));
+    }
 
     if (options & ParseSessionData::PrecompiledHeader) {
         result.append(parserSettings.isCpp() ? QByteArrayLiteral("-xc++-header") : QByteArrayLiteral("-xc-header"));
         return result;
     }
 
     result.append(parserSettings.isCpp() ? QByteArrayLiteral("-xc++") : QByteArrayLiteral("-xc"));
     return result;
 }
 
 void addIncludes(QVector<const char*>* args, QVector<QByteArray>* otherArgs,
                  const Path::List& includes, const char* cliSwitch)
 {
     foreach (const Path& url, includes) {
         if (url.isEmpty()) {
             continue;
         }
         
         QFileInfo info(url.toLocalFile());
         QByteArray path = url.toLocalFile().toUtf8();
 
         if (info.isFile()) {
             path.prepend("-include");
         } else {
             path.prepend(cliSwitch);
         }
         otherArgs->append(path);
         args->append(path.constData());
     }
 }
 
 QVector<CXUnsavedFile> toClangApi(const QVector<UnsavedFile>& unsavedFiles)
 {
     QVector<CXUnsavedFile> unsaved;
     unsaved.reserve(unsavedFiles.size());
     std::transform(unsavedFiles.begin(), unsavedFiles.end(),
                 std::back_inserter(unsaved),
                 [] (const UnsavedFile& file) { return file.toClangApi(); });
     return unsaved;
 }
 
 bool needGccCompatibility(const ClangParsingEnvironment& environment)
 {
     const auto& defines = environment.defines();
     // TODO: potentially do the same for the intel compiler?
     return defines.contains(QStringLiteral("__GNUC__"))
         && !environment.defines().contains(QStringLiteral("__clang__"));
 }
 
 bool hasQtIncludes(const Path::List& includePaths)
 {
     return std::find_if(includePaths.begin(), includePaths.end(), [] (const Path& path) {
         return path.lastPathSegment() == QLatin1String("QtCore");
     }) != includePaths.end();
 }
 
 }
 
 ParseSessionData::ParseSessionData(const QVector<UnsavedFile>& unsavedFiles, ClangIndex* index,
                                    const ClangParsingEnvironment& environment, Options options)
     : m_file(nullptr)
     , m_unit(nullptr)
 {
     unsigned int flags = CXTranslationUnit_CXXChainedPCH
         | CXTranslationUnit_DetailedPreprocessingRecord
 #if CINDEX_VERSION_MINOR >= 34
         | CXTranslationUnit_KeepGoing
 #endif
     ;
     if (options.testFlag(SkipFunctionBodies)) {
         flags |= CXTranslationUnit_SkipFunctionBodies;
     }
     if (options.testFlag(PrecompiledHeader)) {
         flags |= CXTranslationUnit_ForSerialization;
     } else {
         flags |= CXTranslationUnit_CacheCompletionResults
               |  CXTranslationUnit_PrecompiledPreamble;
         if (environment.quality() == ClangParsingEnvironment::Unknown) {
             flags |= CXTranslationUnit_Incomplete;
         }
     }
 
     const auto tuUrl = environment.translationUnitUrl();
     Q_ASSERT(!tuUrl.isEmpty());
 
     const auto arguments = argsForSession(tuUrl.str(), options, environment.parserSettings());
     QVector<const char*> clangArguments;
 
     const auto& includes = environment.includes();
     const auto& pchInclude = environment.pchInclude();
 
     // uses QByteArray as smart-pointer for const char* ownership
     QVector<QByteArray> smartArgs;
     smartArgs.reserve(includes.system.size() + includes.project.size()
                       + pchInclude.isValid() + arguments.size() + 1);
     clangArguments.reserve(smartArgs.size());
 
     std::transform(arguments.constBegin(), arguments.constEnd(),
                    std::back_inserter(clangArguments),
                    [] (const QByteArray &argument) { return argument.constData(); });
 
     // NOTE: the PCH include must come before all other includes!
     if (pchInclude.isValid()) {
         clangArguments << "-include";
         QByteArray pchFile = pchInclude.toLocalFile().toUtf8();
         smartArgs << pchFile;
         clangArguments << pchFile.constData();
     }
 
     if (needGccCompatibility(environment)) {
         const auto compatFile = QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("kdevclangsupport/gcc_compat.h")).toUtf8();
         if (!compatFile.isEmpty()) {
             smartArgs << compatFile;
             clangArguments << "-include" << compatFile.constData();
         }
     }
 
     if (hasQtIncludes(includes.system)) {
         const auto wrappedQtHeaders = QStandardPaths::locate(QStandardPaths::GenericDataLocation,
                                                              QStringLiteral("kdevclangsupport/wrappedQtHeaders"),
                                                              QStandardPaths::LocateDirectory).toUtf8();
         if (!wrappedQtHeaders.isEmpty()) {
             smartArgs << wrappedQtHeaders;
             clangArguments << "-isystem" << wrappedQtHeaders.constData();
             const auto qtCore = wrappedQtHeaders + "/QtCore";
             smartArgs << qtCore;
             clangArguments << "-isystem" << qtCore.constData();
         }
     }
 
     addIncludes(&clangArguments, &smartArgs, includes.system, "-isystem");
     addIncludes(&clangArguments, &smartArgs, includes.project, "-I");
 
     smartArgs << writeDefinesFile(environment.defines());
     clangArguments << "-imacros" << smartArgs.last().constData();
 
     // append extra args from environment variable
     static const auto extraArgs = ::extraArgs();
     foreach (const QByteArray& arg, extraArgs) {
         clangArguments << arg.constData();
     }
 
     QVector<CXUnsavedFile> unsaved;
     //For PrecompiledHeader, we don't want unsaved contents (and contents.isEmpty())
     if (!options.testFlag(PrecompiledHeader)) {
         unsaved = toClangApi(unsavedFiles);
     }
 
     // debugging: print hypothetical clang invocation including args (for easy c&p for local testing)
     if (qEnvironmentVariableIsSet("KDEV_CLANG_DISPLAY_ARGS")) {
         QTextStream out(stdout);
         out << "Invocation: clang";
         foreach (const auto& arg, clangArguments) {
             out << " " << arg;
         }
         out << " " << tuUrl.byteArray().constData() << "\n";
     }
 
     const CXErrorCode code = clang_parseTranslationUnit2(
         index->index(), tuUrl.byteArray().constData(),
         clangArguments.constData(), clangArguments.size(),
         unsaved.data(), unsaved.size(),
         flags,
         &m_unit
     );
     if (code != CXError_Success) {
         qWarning() << "clang_parseTranslationUnit2 return with error code" << code;
         if (!qEnvironmentVariableIsSet("KDEV_CLANG_DISPLAY_DIAGS")) {
             qWarning() << "  (start KDevelop with `KDEV_CLANG_DISPLAY_DIAGS=1 kdevelop` to see more diagnostics)";
         }
     }
 
     if (m_unit) {
         setUnit(m_unit);
         m_environment = environment;
 
         if (options.testFlag(PrecompiledHeader)) {
             clang_saveTranslationUnit(m_unit, (tuUrl.byteArray() + ".pch").constData(), CXSaveTranslationUnit_None);
         }
     } else {
         qWarning() << "Failed to parse translation unit:" << tuUrl;
     }
 }
 
 ParseSessionData::~ParseSessionData()
 {
     clang_disposeTranslationUnit(m_unit);
 }
 
 QByteArray ParseSessionData::writeDefinesFile(const QMap<QString, QString>& defines)
 {
     m_definesFile.open();
     Q_ASSERT(m_definesFile.isWritable());
 
     QTextStream definesStream(&m_definesFile);
     // don't show warnings about redefined macros
     definesStream << "#pragma clang system_header\n";
     for (auto it = defines.begin(); it != defines.end(); ++it) {
         definesStream << QStringLiteral("#define ") << it.key() << ' ' << it.value() << '\n';
     }
 
     return m_definesFile.fileName().toUtf8();
 }
 
 void ParseSessionData::setUnit(CXTranslationUnit unit)
 {
     m_unit = unit;
     if (m_unit) {
         const ClangString unitFile(clang_getTranslationUnitSpelling(unit));
         m_file = clang_getFile(m_unit, unitFile.c_str());
     } else {
         m_file = nullptr;
     }
 }
 
 ClangParsingEnvironment ParseSessionData::environment() const
 {
     return m_environment;
 }
 
 ParseSession::ParseSession(const ParseSessionData::Ptr& data)
     : d(data)
 {
     if (d) {
         ENSURE_CHAIN_NOT_LOCKED
         d->m_mutex.lock();
     }
 }
 
 ParseSession::~ParseSession()
 {
     if (d) {
         d->m_mutex.unlock();
     }
 }
 
 void ParseSession::setData(const ParseSessionData::Ptr& data)
 {
     if (data == d) {
         return;
     }
 
     if (d) {
         d->m_mutex.unlock();
     }
 
     d = data;
 
     if (d) {
         ENSURE_CHAIN_NOT_LOCKED
         d->m_mutex.lock();
     }
 }
 
 ParseSessionData::Ptr ParseSession::data() const
 {
     return d;
 }
 
 IndexedString ParseSession::languageString()
 {
     static const IndexedString lang("Clang");
     return lang;
 }
 
 QList<ProblemPointer> ParseSession::problemsForFile(CXFile file) const
 {
     if (!d) {
         return {};
     }
 
     QList<ProblemPointer> problems;
 
     // extra clang diagnostics
     const uint numDiagnostics = clang_getNumDiagnostics(d->m_unit);
     problems.reserve(numDiagnostics);
     for (uint i = 0; i < numDiagnostics; ++i) {
         auto diagnostic = clang_getDiagnostic(d->m_unit, i);
 
         CXSourceLocation location = clang_getDiagnosticLocation(diagnostic);
         CXFile diagnosticFile;
         clang_getFileLocation(location, &diagnosticFile, nullptr, nullptr, nullptr);
         // missing-include problems are so severe in clang that we always propagate
         // them to this document, to ensure that the user will see the error.
         if (diagnosticFile != file && ClangDiagnosticEvaluator::diagnosticType(diagnostic) != ClangDiagnosticEvaluator::IncludeFileNotFoundProblem) {
             continue;
         }
 
         ProblemPointer problem(ClangDiagnosticEvaluator::createProblem(diagnostic, d->m_unit));
         problems << problem;
 
         clang_disposeDiagnostic(diagnostic);
     }
 
     // other problem sources
 
     TodoExtractor extractor(unit(), file);
     problems << extractor.problems();
 
 #if CINDEX_VERSION_MINOR > 30
     // note that the below warning is triggered on every reparse when there is a precompiled preamble
     // see also TestDUChain::testReparseIncludeGuard
     const QString path = QDir(ClangString(clang_getFileName(file)).toString()).canonicalPath();
     const IndexedString indexedPath(path);
     if (ClangHelpers::isHeader(path) && !clang_isFileMultipleIncludeGuarded(unit(), file)
         && !clang_Location_isInSystemHeader(clang_getLocationForOffset(d->m_unit, file, 0)))
     {
         ProblemPointer problem(new Problem);
         problem->setSeverity(IProblem::Warning);
         problem->setDescription(i18n("Header is not guarded against multiple inclusions"));
         problem->setExplanation(i18n("The given header is not guarded against multiple inclusions, "
             "either with the conventional #ifndef/#define/#endif macro guards or with #pragma once."));
         problem->setFinalLocation({indexedPath, KTextEditor::Range()});
         problem->setSource(IProblem::Preprocessor);
         problems << problem;
         // TODO: Easy to add an assistant here that adds the guards -- any takers?
     }
 #endif
 
     return problems;
 }
 
 CXTranslationUnit ParseSession::unit() const
 {
     return d ? d->m_unit : nullptr;
 }
 
 CXFile ParseSession::file(const QByteArray& path) const
 {
     return clang_getFile(unit(), path.constData());
 }
 
 CXFile ParseSession::mainFile() const
 {
     return d ? d->m_file : nullptr;
 }
 
 bool ParseSession::reparse(const QVector<UnsavedFile>& unsavedFiles, const ClangParsingEnvironment& environment)
 {
     if (!d || environment != d->m_environment) {
         return false;
     }
 
     auto unsaved = toClangApi(unsavedFiles);
 
     const auto code = clang_reparseTranslationUnit(d->m_unit, unsaved.size(), unsaved.data(),
                                                    clang_defaultReparseOptions(d->m_unit));
     if (code != CXError_Success) {
         qWarning() << "clang_reparseTranslationUnit return with error code" << code;
         // if error code != 0 => clang_reparseTranslationUnit invalidates the old translation unit => clean up
         clang_disposeTranslationUnit(d->m_unit);
         d->setUnit(nullptr);
         return false;
     }
 
     // update state
     d->setUnit(d->m_unit);
     return true;
 }
 
 ClangParsingEnvironment ParseSession::environment() const
 {
     return d->m_environment;
 }