Made invariant of class 'StructuredCmd' robust by changing the design

(replaced public field by private field + getter/setter)

1 files changed, 18 insertions, 3 deletions

diff --git a/Source/Core/AbsyCmd.cs b/Source/Core/AbsyCmd.cs
index dc57e7fc..e0aae39a 100644
--- a/Source/Core/AbsyCmd.cs
+++ b/Source/Core/AbsyCmd.cs
@@ -705,15 +705,30 @@ namespace Microsoft.Boogie {
 

   [ContractClass(typeof(StructuredCmdContracts))]

   public abstract class StructuredCmd {

-    public IToken/*!*/ tok;

+    private IToken/*!*/ _tok;

+

+    public IToken/*!*/ tok

+    {

+      get

+      {

+        Contract.Ensures(Contract.Result<IToken>() != null);

+        return this._tok;

+      }

+      set

+      {

+        Contract.Requires(value != null);

+        this._tok = value;

+      }

+    }

+

     [ContractInvariantMethod]

     void ObjectInvariant() {

-      Contract.Invariant(tok != null);

+      Contract.Invariant(this._tok != null);

     }

 

     public StructuredCmd(IToken tok) {

       Contract.Requires(tok != null);

-      this.tok = tok;

+      this._tok = tok;

     }

 

     public abstract void Emit(TokenTextWriter/*!*/ stream, int level);