C++: Tests (w/ FPs) from MRVA top 1000 run

cpp/ql/test/query-tests/Best Practices/Likely Errors/CommaBeforeMisleadingIndentation/test.cpp

@@ -1,6 +1,22 @@
+// clang-format off
 
-void test(int i, int j, int (*foo)(int))
+typedef unsigned size_t;
+
+struct X {
+	int foo(int y) { return y; }
+} x;
+
+#define FOO(x) ( \
+   (x),          \
+  (x)            \
+)
+
+#define BAR(x, y) ((x), (y))
+
+int test(int i, int j, int (*foo)(int), int (*bar)(int, int))
 {
+	// Comma in simple if statement (prototypical example):
+
 	if (i)
 		(void)i,	// GOOD
 		(void)j;
@@ -9,11 +25,123 @@ void test(int i, int j, int (*foo)(int))
 		(void)i,	// BAD
 	(void)j;
 
-	foo((i++, j++)); // GOOD
-	foo((i++,        // GOOD
-	     j++));
-	foo((i++
-	   , j++));      // GOOD
-	foo((i++,
-	j++));           // BAD (?)
+	// Parenthesized comma (borderline example):
+
+	foo(i++), j++;   // GOOD
+	(foo(i++), j++); // GOOD
+	(foo(i++),       // GOOD
+	 j++);
+	(foo(i++),
+	j++);            // BAD (?)
+
+	x.foo(i++), j++;   // GOOD
+	(x.foo(i++), j++); // GOOD
+	(x.foo(i++),       // GOOD [FALSE POSITIVE]
+	 j++);
+	(x.foo(i++),
+	j++);              // BAD (?)
+
+	FOO(i++), j++;   // GOOD
+	(FOO(i++), j++); // GOOD
+	(FOO(i++),       // GOOD
+	 j++);
+	(FOO(i++),
+	j++);            // BAD (?)
+
+	(void)(i++), j++;   // GOOD
+	((void)(i++), j++); // GOOD
+	((void)(i++),       // GOOD [FALSE POSITIVE]
+	 j++);
+	((void)(i++),
+	j++);               // BAD (?)
+
+	// Comma in argument list doesn't count:
+
+	bar(i++, j++); // GOOD
+	bar(i++,
+	    j++);      // GOOD
+	bar(i++
+	  , j++);      // GOOD
+	bar(i++,
+	j++);          // GOOD: common pattern and unlikely to be misread.
+
+	BAR(i++, j++); // GOOD
+	BAR(i++,
+	    j++);      // GOOD
+	BAR(i++
+	  , j++);      // GOOD
+	BAR(i++,
+	j++);          // GOOD: common pattern and unlikely to be misread.
+
+	using T = decltype(x.foo(i++), // GOOD [FALSE POSITIVE]
+	                   j++);
+	(void)sizeof(x.foo(i++), // GOOD [FALSE POSITIVE]
+	             j++);
+
+	// Comma in loops
+
+    while (i = foo(j++), // GOOD
+           i != j && i != 42 &&
+               !foo(j)) {
+        i = j = i + j;
+    }
+
+    // Mixed tabs and spaces (ugly case):
+
+    for (i = 0,         // GOOD if tab >= 4 spaces else BAD
+		 j = 0;
+		 i + j < 10;
+         i++,           // GOOD if tab >= 4 spaces else BAD
+		 j++);
+
+	if (i)
+	    (void)i,	    // GOOD if tab >= 4 spaces else BAD
+		(void)j;
+
+	// One char difference (common but borderline):
+
+	for (i = 0,         // GOOD? [FALSE POSITIVE]
+	    j = 1;
+		i + j < 10;
+		i++, j++);
+
+	for (i = 0,
+         j = 1; i < 10; i += 2, // GOOD? [FALSE POSITIVE]
+        j++) {}
+
+	// LHS ends on same line RHS begins on:
+
+	int k = (foo(
+		i++
+	), j++); // GOOD? [FALSE POSITIVE]
+
+	// Weird case:
+
+	if (foo(j))
+		return i++
+			, i++ // GOOD(?) [FALSE POSITIVE]
+			? 1
+			: 2;
+
+	return 0;
 }
+
+// Comma in variadic template splice:
+
+namespace std {
+	template <size_t... Is>
+	struct index_sequence {};
+}
+
+template <size_t I>
+struct zip_index {};
+
+template <size_t I>
+int& at(zip_index<I>) { throw 1; }
+
+template <class Fn, class At, size_t... Is>
+void for_each_input(Fn&& fn, std::index_sequence<Is...>) {
+	(fn(zip_index<Is>{}, at(zip_index<Is>{})), ...); // GOOD
+}
+
+// clang-format on