C++: handle more macros in UseInOwnInitializer

cpp/ql/src/Likely Bugs/UseInOwnInitializer.ql

@@ -27,4 +27,7 @@ where init.getDeclaration() = v
       va = mi.getExpr()
     )
   )
+  and not (
+    va.getEnclosingStmt().isInMacroExpansion()
+  )
 select va, v.getName() + " is used in its own initializer."

cpp/ql/test/query-tests/Likely Bugs/UseInOwnInitializer/test.cpp

@@ -1,23 +1,23 @@
 typedef long size_t;
 
 void test1() {
-	int x = x;
+	int x = x; // BAD
 }
 
 void test2() {
-	int x = x = 2;
+	int x = x = 2; // BAD
 }
 
 void test3() {
-	int x = 2;
+	int x = 2; // GOOD
 }
 
 void test4() {
-	void* x = (void *)&x;
+	void* x = (void *)&x; // GOOD
 }
 
 void test5() {
-	size_t x = sizeof(x);
+	size_t x = sizeof(x); // GOOD
 }
 
 typedef void *voidptr;
@@ -28,7 +28,7 @@ voidptr address_of(voidptr &var) {
 }
 
 void test6() {
-	voidptr x = address_of(x); // initialize to it's own address
+	voidptr x = address_of(x); // GOOD (implicit conversion to reference)
 }
 
 
@@ -38,25 +38,31 @@ struct MyString {
 };
 
 void test7() {
-	MyString ms = {ms.array, {0}}; // initialize to ""
+	MyString ms = {ms.array, {0}}; // GOOD (implicit conversion to pointer)
 }
 
 #define uninitialized(x) x
 
 void test8() {
-	int x = uninitialized(x);
+	int x = uninitialized(x); // GOOD (rval is a macro)
 }
 
 #define uninitialized2(x) x = x
 
 void test9() {
-	int uninitialized2(x);
+	int uninitialized2(x); // GOOD (initializer is a macro)
 }
 
 void test10() {
-	int x = x + 1;
+	int x = x + 1; // BAD: x is evaluated on the right hand side
 }
 
 void test11() {
-	int x = uninitialized(x) + 1;
+	int x = uninitialized(x) + 1; // BAD: x is evaluated on the right hand side
+}
+
+#define self_initialize(t, x) t x = x
+
+void test12() {
+	self_initialize(int, x); // GOOD (statement is from a macro)
 }