C++: Fix member-call- and C-cast-related FPs

Author: d10c

cpp/ql/src/Best Practices/Likely Errors/CommaBeforeMisleadingIndentation.ql

@@ -9,11 +9,24 @@
  */
 
 import cpp
+import semmle.code.cpp.commons.Exclusions
 
-from CommaExpr ce
+Expr normalizeExpr(Expr e) {
+  if exists(e.(Call).getQualifier())
+  then result = normalizeExpr(e.(Call).getQualifier())
+  else
+    if e.hasExplicitConversion()
+    then result = normalizeExpr(e.getFullyConverted())
+    else result = e
+}
+
+from CommaExpr ce, Expr left, Expr right, int leftStartColumn, int rightStartColumn
 where
   ce.fromSource() and
-  not exists(MacroInvocation me | ce = me.getAnAffectedElement()) and
-  ce.getLeftOperand().getLocation().getStartColumn() >
-    ce.getRightOperand().getLocation().getStartColumn()
-select ce, "Comma before misleading indentation."
+  not isFromMacroDefinition(ce) and
+  left = normalizeExpr(ce.getLeftOperand()) and
+  right = normalizeExpr(ce.getRightOperand()) and
+  leftStartColumn = left.getLocation().getStartColumn() and
+  rightStartColumn = right.getLocation().getStartColumn() and
+  leftStartColumn > rightStartColumn
+select right, "The indentation level after the comma can be misleading (for some tab sizes)."

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

@@ -36,7 +36,7 @@ int test(int i, int j, int (*foo)(int), int (*bar)(int, int))
 
 	x.foo(i++), j++;   // GOOD
 	(x.foo(i++), j++); // GOOD
-	(x.foo(i++),       // GOOD [FALSE POSITIVE]
+	(x.foo(i++),       // GOOD
 	 j++);
 	(x.foo(i++),
 	j++);              // BAD (?)
@@ -50,7 +50,7 @@ int test(int i, int j, int (*foo)(int), int (*bar)(int, int))
 
 	(void)(i++), j++;   // GOOD
 	((void)(i++), j++); // GOOD
-	((void)(i++),       // GOOD [FALSE POSITIVE]
+	((void)(i++),       // GOOD
 	 j++);
 	((void)(i++),
 	j++);               // BAD (?)
@@ -73,9 +73,9 @@ int test(int i, int j, int (*foo)(int), int (*bar)(int, int))
 	BAR(i++,
 	j++);          // GOOD: common pattern and unlikely to be misread.
 
-	using T = decltype(x.foo(i++), // GOOD [FALSE POSITIVE]
+	using T = decltype(x.foo(i++), // GOOD
 	                   j++);
-	(void)sizeof(x.foo(i++), // GOOD [FALSE POSITIVE]
+	(void)sizeof(x.foo(i++), // GOOD
 	             j++);
 
 	// Comma in loops