From d37ed4171dedba13b1dcb8c2f5a4aa87a22974cd Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Sat, 2 Jul 2022 13:12:54 -0700
Subject: [PATCH] Update Expr.cs

Add a Dup functionality that allows extending the life-time of expressions that are passed by the UserPropagator callbacks (or other code).
---
 src/api/dotnet/Expr.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/api/dotnet/Expr.cs b/src/api/dotnet/Expr.cs
index f735401d8..7dabc49cd 100644
--- a/src/api/dotnet/Expr.cs
+++ b/src/api/dotnet/Expr.cs
@@ -168,6 +168,16 @@ namespace Microsoft.Z3
         {
             return (Expr)base.Translate(ctx);
         }
+        
+        /// <summary>
+        /// Create a duplicate of expression. 
+        /// This feature is to allow extending the life-time of expressions that were passed down as arguments
+        /// by the user propagator callbacks. By default the life-time of arguments to callbacks is within the
+        /// callback only.
+        /// </summary>
+        public Expr Dup() {
+             return Expr.Create(Context, NativeObject);
+        }
 
         /// <summary>
         /// Returns a string representation of the expression.