Sync ConditionalExpr changes with csharp

Author: Marcono1234

csharp/ql/src/semmle/code/csharp/dataflow/ModulusAnalysis.qll

@@ -268,9 +268,7 @@ predicate exprModulus(Expr e, Bound b, int val, int mod) {
 private predicate condExprBranchModulus(
   ConditionalExpr cond, boolean branch, Bound b, int val, int mod
 ) {
-  exprModulus(cond.getTrueExpr(), b, val, mod) and branch = true
-  or
-  exprModulus(cond.getFalseExpr(), b, val, mod) and branch = false
+  exprModulus(cond.getBranchExpr(branch), b, val, mod)
 }
 
 private predicate addModulus(Expr add, boolean isLeft, Bound b, int val, int mod) {

csharp/ql/src/semmle/code/csharp/dataflow/internal/rangeanalysis/RangeUtils.qll

@@ -415,5 +415,15 @@ module ExprNode {
 
     /** Gets the "else" expression of this conditional expression. */
     ExprNode getFalseExpr() { hasChild(e, e.getElse(), this, result) }
+
+    /**
+     * If `branch` is `true` gets the "then" expression, if `false` gets the
+     * "else" expression of this conditional expression.
+     */
+    ExprNode getBranchExpr(boolean branch) {
+      branch = true and result = getTrueExpr()
+      or
+      branch = false and result = getFalseExpr()
+    }
   }
 }