C#: Sign analysis support for unsigned right shift.

Author: michaelnebel

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

@@ -404,6 +404,13 @@ module ExprNode {
     override TRShiftOp getOp() { any() }
   }
 
+  /** An unsigned right-shift operation. */
+  class UnsignedRightShiftExpr extends BinaryOperation {
+    override CS::UnsignedRightShiftExpr e;
+
+    override TURShiftOp getOp() { any() }
+  }
+
   /** A conditional expression. */
   class ConditionalExpr extends ExprNode {
     override CS::ConditionalExpr e;

csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/SignAnalysisSpecific.qll

@@ -213,6 +213,7 @@ private module Impl {
     not e.getExpr() instanceof BitwiseXorExpr and
     not e.getExpr() instanceof LeftShiftExpr and
     not e.getExpr() instanceof RightShiftExpr and
+    not e.getExpr() instanceof UnsignedRightShiftExpr and
     not e.getExpr() instanceof ConditionalExpr and
     not e.getExpr() instanceof RefExpr and
     not e.getExpr() instanceof LocalVariableDeclAndInitExpr and