CPP: Annotate expr_has_no_effect test.

cpp/ql/test/library-tests/queries/expr_has_no_effect/calls.cpp

@@ -5,11 +5,11 @@ int external();
 class Base {
 public:
   virtual int thingy() {
-    1;
+    1; // BAD
   }
 
   int our_thingy() {
-    Base::thingy();
+    Base::thingy(); // BAD
     return 2;
   }
 };
@@ -17,14 +17,14 @@ public:
 class Derived : public Base {
 public:
   virtual int thingy() {
-    external();
+    external(); // GOOD
     return 3;
   }
 };
 
 void internal() {
   Base* ptr = new Derived();
-  ptr->thingy();
+  ptr->thingy(); // GOOD
 }
 
 }

cpp/ql/test/library-tests/queries/expr_has_no_effect/templatey.cpp

@@ -1,7 +1,7 @@
 template <typename T>
 void foo(T x, T y)
 {
-  x << y;
+  x << y; // GOOD (effect depends on T)
 };
 
 struct streamable
@@ -15,9 +15,9 @@ void operator<<(streamable& lhs, streamable& rhs)
 int main()
 {
   int x = 3;
-  foo(x, x);
+  foo(x, x); // BAD [NOT DETECTED]
   streamable y;
-  foo(y, y);
+  foo(y, y); // BAD [NOT DETECTED]
   return 0;
 }
 
@@ -34,7 +34,7 @@ int pointless_add_numbers(int lhs, int rhs)
 void call_add_numbers()
 {
   int accum = 0;
-  add_numbers(accum, 4);
-  add_numbers(accum, 10);
-  pointless_add_numbers(accum, 20);
+  add_numbers(accum, 4); // GOOD
+  add_numbers(accum, 10); // GOOD
+  pointless_add_numbers(accum, 20); // BAD
 }

cpp/ql/test/library-tests/queries/expr_has_no_effect/volatile.c

@@ -6,18 +6,18 @@ char *pc;
 volatile char *pv;
 
 void f(void) {
-    c;
-    v;
+    c; // BAD
+    v; // (accesses to volatile variables are considered impure)
 
-    pc[5];
+    pc[5]; // BAD
     pv[5];
     ((volatile char *)pc)[5];
 
-    *pc;
+    *pc; // BAD
     *pv;
     *((volatile char *)pc);
 
-    *(pc + 5);
+    *(pc + 5); // BAD
     *(pv + 5);
     *((volatile char *)(pc + 5));
     *(((volatile char *)pc) + 5);