diff --git a/src/plugins/projectexplorer/gcctoolchain.cpp b/src/plugins/projectexplorer/gcctoolchain.cpp
index a190434efdf..36cab0f8ee5 100644
--- a/src/plugins/projectexplorer/gcctoolchain.cpp
+++ b/src/plugins/projectexplorer/gcctoolchain.cpp
@@ -972,8 +972,13 @@ QList<ToolChain *> GccToolChainFactory::autoDetectToolchains(const QString &comp
                                                return tc->typeId() == requiredTypeId
                                                    && tc->compilerCommand() == compilerPath;
                                            });
-    if (!result.isEmpty())
+    if (!result.isEmpty()) {
+        for (ToolChain *tc : result) {
+            if (tc->isAutoDetected())
+                tc->setLanguage(language);
+        }
         return result;
+    }
 
     result = autoDetectToolChain(compilerPath, language, requiredAbi);
 
diff --git a/src/plugins/projectexplorer/toolchain.cpp b/src/plugins/projectexplorer/toolchain.cpp
index cb636437046..53e03e16ad8 100644
--- a/src/plugins/projectexplorer/toolchain.cpp
+++ b/src/plugins/projectexplorer/toolchain.cpp
@@ -133,7 +133,7 @@ ToolChain::ToolChain(const ToolChain &other) :
 
 void ToolChain::setLanguage(Core::Id language)
 {
-    QTC_ASSERT(!d->m_language.isValid(), return);
+    QTC_ASSERT(!d->m_language.isValid() || isAutoDetected(), return);
     QTC_ASSERT(language.isValid(), return);
     QTC_ASSERT(ToolChainManager::isLanguageSupported(language), return);