diff --git a/src/api/dotnet/Context.cs b/src/api/dotnet/Context.cs
index b4a88add2..c8698277c 100644
--- a/src/api/dotnet/Context.cs
+++ b/src/api/dotnet/Context.cs
@@ -993,7 +993,7 @@ namespace Microsoft.Z3
                         using (r)
                             return MkXor(r, t);
                     })
-                : MkTrue();
+                : MkFalse();
         }
 
         /// <summary>