diff --git a/plugins/clang/duchain/parsesession.cpp b/plugins/clang/duchain/parsesession.cpp
--- a/plugins/clang/duchain/parsesession.cpp
+++ b/plugins/clang/duchain/parsesession.cpp
@@ -65,6 +65,23 @@
     return result;
 }
 
+void sanitizeArguments(QVector<QByteArray>& arguments)
+{
+    arguments.erase(std::remove_if(
+        arguments.begin(),
+        arguments.end(),
+        [](QByteArray& argument) {
+            if (argument == "-Werror") {
+                return true;
+            }
+
+            argument.replace("-Werror=", "-W");
+
+            return false;
+        }
+    ), arguments.end());
+}
+
 QVector<QByteArray> argsForSession(const QString& path, ParseSessionData::Options options, const ParserSettings& parserSettings)
 {
     QMimeDatabase db;
@@ -87,9 +104,12 @@
     if (parserSettings.parserOptions.isEmpty()) {
         // The parserOptions can be empty for some unit tests that use ParseSession directly
         auto defaultArguments = ClangSettingsManager::self()->parserSettings(path).toClangAPI();
+
         defaultArguments.append(QByteArrayLiteral("-nostdinc"));
         defaultArguments.append(QByteArrayLiteral("-nostdinc++"));
         defaultArguments.append(QByteArrayLiteral("-xc++"));
+
+        sanitizeArguments(defaultArguments);
         return defaultArguments;
     }
 
@@ -101,10 +121,14 @@
 
     if (options & ParseSessionData::PrecompiledHeader) {
         result.append(parserSettings.isCpp() ? QByteArrayLiteral("-xc++-header") : QByteArrayLiteral("-xc-header"));
+
+        sanitizeArguments(result);
         return result;
     }
 
     result.append(parserSettings.isCpp() ? QByteArrayLiteral("-xc++") : QByteArrayLiteral("-xc"));
+
+    sanitizeArguments(result);
     return result;
 }