C++: Add a test that demonstrate missing asExpr for aggregate literals.

cpp/ql/test/library-tests/dataflow/asExpr/test.cpp

@@ -21,3 +21,20 @@ A& get_ref();
 void test2() {
   take_ref(get_ref()); // $ asExpr="call to get_ref" asIndirectExpr="call to get_ref"
 }
+
+struct S {
+  int a;
+  int b;
+};
+
+void test_aggregate_literal() {
+  S s1 = {1, 2}; // $ asExpr=1 asExpr=2
+  const S s2 = {3, 4}; // $ asExpr=3 asExpr=4
+  S s3 = (S){5, 6}; // $ asExpr=5 asExpr=6
+  const S s4 = (S){7, 8}; // $ asExpr=7 asExpr=8
+
+  S s5 = {.a = 1, .b = 2}; // $ asExpr=1 asExpr=2
+
+  int xs[] = {1, 2, 3}; // $ asExpr=1 asExpr=2 asExpr=3
+  const int ys[] = {[0] = 4, [1] = 5, [0] = 6}; // $ asExpr=4 asExpr=5 asExpr=6
+}