C++: Add FP test from the work on smart pointers in dataflow.

Author: MathiasVP

cpp/ql/test/query-tests/Likely Bugs/Memory Management/ReturnStackAllocatedMemory/ReturnStackAllocatedMemory.expected

@@ -6,3 +6,4 @@
 | test.cpp:112:2:112:12 | return ... | May return stack-allocated memory from $@. | test.cpp:112:9:112:11 | arr | arr |
 | test.cpp:119:2:119:19 | return ... | May return stack-allocated memory from $@. | test.cpp:119:11:119:13 | arr | arr |
 | test.cpp:171:3:171:24 | return ... | May return stack-allocated memory from $@. | test.cpp:170:35:170:41 | myLocal | myLocal |
+| test.cpp:217:3:217:13 | return ... | May return stack-allocated memory from $@. | test.cpp:216:14:216:17 | port | port |

cpp/ql/test/query-tests/Likely Bugs/Memory Management/ReturnStackAllocatedMemory/test.cpp

@@ -189,3 +189,30 @@ int *&conversionInFlow() {
   int *&pRef = p; // has conversion in the middle of data flow
   return pRef; // BAD [NOT DETECTED]
 }
+
+namespace std {
+	template<typename T>
+	class shared_ptr {
+	public:
+		shared_ptr() noexcept;
+		explicit shared_ptr(T*);
+		shared_ptr(const shared_ptr&) noexcept;
+		template<class U> shared_ptr(const shared_ptr<U>&) noexcept;
+		template<class U> shared_ptr(shared_ptr<U>&&) noexcept;
+
+		shared_ptr<T>& operator=(const shared_ptr<T>&) noexcept;
+		shared_ptr<T>& operator=(shared_ptr<T>&&) noexcept;
+
+		T& operator*() const noexcept;
+		T* operator->() const noexcept;
+
+		T* get() const noexcept;
+	};
+}
+
+auto make_read_port()
+{
+  auto port = std::shared_ptr<int>(new int);
+  auto ptr = port.get();
+  return ptr; // GOOD [FALSE POSITIVE]
+}