C++: Behaviour preserving transform.

Author: geoffw0

cpp/ql/src/Likely Bugs/Arithmetic/UnsignedGEZero.qll

@@ -21,13 +21,13 @@ class ConstantZero extends Expr {
  */
 private predicate lookForUnsignedAt(GEExpr ge, Expr candidate) {
   // Base case: `candidate >= 0`
-  ge.getRightOperand() instanceof ConstantZero and
-  candidate = ge.getLeftOperand().getFullyConverted() and
-  // left operand was a signed or unsigned IntegralType before conversions
+  ge.getLesserOperand() instanceof ConstantZero and
+  candidate = ge.getGreaterOperand().getFullyConverted() and
+  // left/greater operand was a signed or unsigned IntegralType before conversions
   // (not a pointer, checking a pointer >= 0 is an entirely different mistake)
   // (not an enum, as the fully converted type of an enum is compiler dependent
   //  so checking an enum >= 0 is always reasonable)
-  ge.getLeftOperand().getUnderlyingType() instanceof IntegralType
+  ge.getGreaterOperand().getUnderlyingType() instanceof IntegralType
   or
   // Recursive case: `...(largerType)candidate >= 0`
   exists(Conversion conversion |