Merge pull request github#14060 from MathiasVP/fix-compare-where-assign-meant-fp

C++: Fix FP in `cpp/compare-where-assign-meant`

Author: MathiasVP

cpp/ql/src/Likely Bugs/Likely Typos/CompareWhereAssignMeant.ql

@@ -16,6 +16,7 @@ import cpp
 from ExprInVoidContext op
 where
   not op.isUnevaluated() and
+  not inMacroExpansion(op) and
   (
     op instanceof EQExpr
     or

cpp/ql/src/change-notes/2023-08-25-compare-where-assign-meant.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The "Comparison where assignment was intended" query (`cpp/compare-where-assign-meant`) no longer reports comparisons that appear in macro expansions.

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/CompareWhereAssignMeant/CompareWhereAssignMeant.expected

@@ -6,3 +6,5 @@
 | test.cpp:39:23:39:28 | ... == ... | This '==' operator has no effect. The assignment ('=') operator was probably intended. |
 | test.cpp:42:23:42:28 | ... == ... | This '==' operator has no effect. The assignment ('=') operator was probably intended. |
 | test.cpp:51:13:51:13 | call to operator== | This '==' operator has no effect. The assignment ('=') operator was probably intended. |
+| test.cpp:72:3:72:8 | ... == ... | This '==' operator has no effect. The assignment ('=') operator was probably intended. |
+| test.cpp:73:3:73:12 | ... == ... | This '==' operator has no effect. The assignment ('=') operator was probably intended. |

cpp/ql/test/query-tests/Likely Bugs/Likely Typos/CompareWhereAssignMeant/test.cpp

@@ -61,3 +61,14 @@ template<typename T1, typename T2>
 auto sfinaeTrick(T1 x1, T2 x2) -> decltype(x1 == x2, bool()) { // GOOD
   return x1 == x2;
 }
+
+void report_error(const char*);
+
+#define DOES_NOT_THROW(E) do { try { E; } catch (...) { report_error(""); } } while(0)
+#define ID(X) (X)
+
+void test_inside_macro_expansion(int x, int y) {
+  DOES_NOT_THROW(x == y); // GOOD
+  x == y; // BAD
+  x == ID(y); // BAD
+}