C++: Fix crash on invalid function qualified name

Task-number: QTCREATORBUG-14135
Change-Id: I94e850f729bd3dbf4212960c7a980a1f118030b4
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/libs/cplusplus/LookupContext.cpp

@@ -1706,7 +1706,10 @@ bool CreateBindings::visit(Declaration *decl)
 bool CreateBindings::visit(Function *function)
 {
     ClassOrNamespace *previous = _currentClassOrNamespace;
-    _currentClassOrNamespace = lookupType(function, previous);
+    ClassOrNamespace *binding = lookupType(function, previous);
+    if (!binding)
+        return false;
+    _currentClassOrNamespace = binding;
     for (unsigned i = 0, count = function->memberCount(); i < count; ++i) {
         Symbol *s = function->memberAt(i);
         if (Block *b = s->asBlock())

tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp

@@ -194,6 +194,8 @@ private slots:
 
     void test_checksymbols_infiniteLoop_data();
     void test_checksymbols_infiniteLoop();
+
+    void test_parentOfBlock();
 };
 
 void tst_CheckSymbols::test_checksymbols()
@@ -1774,6 +1776,19 @@ void tst_CheckSymbols::test_checksymbols_infiniteLoop()
     TestCase::runCheckSymbols(document1, snapshot);
 }
 
+void tst_CheckSymbols::test_parentOfBlock()
+{
+    const QByteArray source = "void C::f()\n"
+                              "{\n"
+                              "    enum E { e1 };\n"
+                              "}\n";
+
+    const Document::Ptr document = TestCase::createDocument(QLatin1String("file1.cpp"), source);
+    Snapshot snapshot;
+    snapshot.insert(document);
+    TestCase::runCheckSymbols(document, snapshot);
+}
+
 void tst_CheckSymbols::test_checksymbols_infiniteLoop_data()
 {
     QTest::addColumn<QByteArray>("source1");