From 4da91bef8dc3898c155b0b2047a7254a369654d0 Mon Sep 17 00:00:00 2001
From: Nikolai Kosjar <nikolai.kosjar@digia.com>
Date: Wed, 24 Sep 2014 10:18:31 +0200
Subject: [PATCH] C++: Fix endless loop in lookup on Windows

...for templates with typedefs referencing the respectively other
template (basic_ostream <-> ostreambuf_iterator).

Tested with MSVC 2013.

Regression introduced by ba42ceb0cb7827a9bbad29a1e08d4a25339ea57d.

Task-number: QTCREATORBUG-13064
Task-number: QTCREATORBUG-13065
Change-Id: I71a45c720663a73c3302eb7da731e6ad2d8f0fbd
Reviewed-by: Przemyslaw Gorszkowski <pgorszkowski@gmail.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
---
 src/libs/cplusplus/LookupContext.cpp          |  5 +-
 .../checksymbols/tst_checksymbols.cpp         | 46 +++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/libs/cplusplus/LookupContext.cpp b/src/libs/cplusplus/LookupContext.cpp
index 092e48e86de..aa916113b3b 100644
--- a/src/libs/cplusplus/LookupContext.cpp
+++ b/src/libs/cplusplus/LookupContext.cpp
@@ -92,7 +92,10 @@ static bool isNestedInstantiationEnclosingTemplate(
         ClassOrNamespace *nestedClassOrNamespaceInstantiation,
         ClassOrNamespace *enclosingTemplateClassInstantiation)
 {
-    while (enclosingTemplateClassInstantiation) {
+    QList<ClassOrNamespace *> processed;
+    while (enclosingTemplateClassInstantiation
+           && !processed.contains(enclosingTemplateClassInstantiation)) {
+        processed.append(enclosingTemplateClassInstantiation);
         if (enclosingTemplateClassInstantiation == nestedClassOrNamespaceInstantiation)
             return false;
         enclosingTemplateClassInstantiation = enclosingTemplateClassInstantiation->parent();
diff --git a/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp b/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
index fd3ba9ddccd..b2bb282d63c 100644
--- a/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
+++ b/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
@@ -191,6 +191,8 @@ private slots:
 
     void test_checksymbols_macroUses();
     void test_checksymbols_macroUses_data();
+
+    void test_checksymbols_infiniteLoop();
 };
 
 void tst_CheckSymbols::test_checksymbols()
@@ -1751,5 +1753,49 @@ void tst_CheckSymbols::test_checksymbols_macroUses_data()
             << Use(2, 11, 3, Highlighting::MacroUse));
 }
 
+void tst_CheckSymbols::test_checksymbols_infiniteLoop()
+{
+    const QByteArray source1 =
+        "#include \"file2.h\"\n"
+        "\n"
+        "template<class _Elem, class _Traits>\n"
+        "class basic_ios {\n"
+        "        typedef basic_ostream<_Elem, _Traits> _Myos;\n"
+        "};\n"
+        "\n"
+        "template<class _Elem, class _Traits>\n"
+        "class basic_ostream {\n"
+        "        typedef basic_ostream<_Elem, _Traits> _Myt;\n"
+        "        typedef ostreambuf_iterator<_Elem, _Traits> _Iter;\n"
+        "};\n"
+        ;
+    const QString filePath1 = QDir::tempPath() + QLatin1String("/file1.h");
+    CppTools::Tests::TestCase::writeFile(filePath1, source1);
+
+    const QByteArray source2 =
+        "template<class _Elem, class _Traits>\n"
+        "class basic_streambuf {\n"
+        "        typedef basic_streambuf<_Elem, _Traits> _Myt;\n"
+        "};\n"
+        "\n"
+        "template<class _Elem, class _Traits>\n"
+        "class ostreambuf_iterator {\n"
+        "    typedef _Traits traits_type;\n"
+        "        typedef basic_streambuf<_Elem, _Traits> streambuf_type;\n"
+        "        typedef basic_ostream<_Elem, _Traits> ostream_type;\n"
+        "};\n"
+        ;
+    const QString filePath2 = QDir::tempPath() + QLatin1String("/file2.h");
+    CppTools::Tests::TestCase::writeFile(filePath2, source2);
+
+    const Document::Ptr document1 = TestCase::createDocument(filePath1, source1);
+    document1->addIncludeFile(Document::Include("file2.h", filePath2, 1, Client::IncludeLocal));
+    Snapshot snapshot;
+    snapshot.insert(document1);
+    snapshot.insert(TestCase::createDocument(filePath2, source2));
+
+    TestCase::runCheckSymbols(document1, snapshot);
+}
+
 QTEST_APPLESS_MAIN(tst_CheckSymbols)
 #include "tst_checksymbols.moc"