C++: Fix accessing invalid file id of Symbol

Symbol::_fileId can be null if the Symbol was created with a null
translation unit. That is the case for temporary symbols created for
lookup purposes (CreateBindings has a _control with no translation unit
and thus creates symbols with no fileId).

Task-number: QTCREATORBUG-15967
Change-Id: Iee518b39ba3b636fe1658e74179db3aad054d6f2
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

2 files changed, 31 insertions, 2 deletions

diff --git a/src/libs/3rdparty/cplusplus/Symbol.cpp b/src/libs/3rdparty/cplusplus/Symbol.cpp
index ae20b14bb7..e98b33a8a7 100644
--- a/src/libs/3rdparty/cplusplus/Symbol.cpp
+++ b/src/libs/3rdparty/cplusplus/Symbol.cpp
@@ -191,10 +191,10 @@ const StringLiteral *Symbol::fileId() const
 }
 
 const char *Symbol::fileName() const
-{ return fileId()->chars(); }
+{ return _fileId ? _fileId->chars() : ""; }
 
 unsigned Symbol::fileNameLength() const
-{ return fileId()->size(); }
+{ return _fileId ? _fileId->size() : 0; }
 
 const Name *Symbol::unqualifiedName() const
 {
diff --git a/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp b/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
index d2de76e4d8..cf26114d9a 100644
--- a/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
+++ b/tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp
@@ -219,6 +219,8 @@ private slots:
     void test_checksymbols_infiniteLoop_data();
     void test_checksymbols_infiniteLoop();
 
+    void test_checkForValidSymbolFileId();
+
     void test_parentOfBlock();
 
     void findField();
@@ -1165,6 +1167,33 @@ void tst_CheckSymbols::test_checksymbols_infiniteLoop()
     TestCase::runCheckSymbols(document1, snapshot);
 }
 
+void tst_CheckSymbols::test_checkForValidSymbolFileId()
+{
+    const QByteArray contents =
+        "constexpr int parent_of(const int f) { return 1; }\n"
+        "\n"
+        "template <typename T> struct wrapper { const T* ptr; };\n"
+        "template <int> struct Dummy;\n"
+        "\n"
+        "namespace impl {\n"
+        "    template <int f>\n"
+        "    struct dummy_impl {\n"
+        "        wrapper<Dummy<parent_of(f)>> parent;\n"
+        "    };\n"
+        "}\n"
+        "\n"
+        "template <int f>\n"
+        "struct Dummy : impl::dummy_impl<f> {};\n"
+        "\n"
+        "void client()\n"
+        "{\n"
+        "    wrapper<Dummy<1>> a;\n"
+        "    a.ptr->parent.ptr;\n"
+        "}\n";
+
+    BaseTestCase tc(contents);
+}
+
 void tst_CheckSymbols::test_parentOfBlock()
 {
     const QByteArray source = "void C::f()\n"