CPP: Apply recommended fix.

Author: geoffw0

cpp/ql/src/Likely Bugs/Arithmetic/PointlessSelfComparison.ql

@@ -18,5 +18,12 @@ from ComparisonOperation cmp
 where pointlessSelfComparison(cmp)
   and not nanTest(cmp)
   and not overflowTest(cmp)
-  and not cmp.isInMacroExpansion()
+  and not exists(MacroInvocation mi | 
+    // cmp is in mi 
+    mi.getAnExpandedElement() = cmp and 
+  
+    // and cmp was apparently not passed in as a macro parameter 
+    cmp.getLocation().getStartLine() = mi.getLocation().getStartLine() and 
+    cmp.getLocation().getStartColumn() = mi.getLocation().getStartColumn() 
+  ) 
 select cmp, "Self comparison."

cpp/ql/test/query-tests/Likely Bugs/Arithmetic/BadAdditionOverflowCheck/PointlessSelfComparison.expected

@@ -3,3 +3,4 @@
 | test.cpp:83:10:83:15 | ... == ... | Self comparison. |
 | test.cpp:90:10:90:15 | ... == ... | Self comparison. |
 | test.cpp:118:7:118:32 | ... != ... | Self comparison. |
+| test.cpp:151:11:151:16 | ... == ... | Self comparison. |

cpp/ql/test/query-tests/Likely Bugs/Arithmetic/BadAdditionOverflowCheck/test.cpp

@@ -148,5 +148,5 @@ void useMarkRange(int offs) {
 #define MY_MACRO(x) (x)
 
 void myMacroTest(int x) {
-	MY_MACRO(x == x); // BAD [NOT DETECTED]
+	MY_MACRO(x == x); // BAD
 }