Consider temporary object expression to determine type usage

Author: rvermeulen

cpp/common/src/codingstandards/cpp/TypeUses.qll

@@ -132,6 +132,9 @@ private Locatable getATypeUse_i(Type type) {
       result = nq and
       type = nq.getQualifyingElement()
     )
+    // Temporary object creation of type `type`
+    or
+    exists(TemporaryObjectExpr toe | result = toe | type = toe.getType())
   )
   or
   // Recursive case - used by a used type

cpp/common/test/rules/unusedtypedeclarations/test.cpp

@@ -111,3 +111,14 @@ template <typename T> using Z = Y<T>;  // COMPLIANT - used below
 template <typename T> using AA = Y<T>; // NON_COMPLIANT - never instantiated
 
 void test_alias_template() { Z<int> v; }
+
+void test_temporary_object_creation() {
+  auto l1 = [](const auto &p1) noexcept {
+    class C1 { // COMPLIANT - used in temporary object construction
+    public:
+      constexpr static const char *m1() noexcept { return "foo"; }
+    };
+
+    return C1{p1};
+  };
+}