Dafny: added comments for refinements assertions.

1 files changed, 9 insertions, 6 deletions

diff --git a/Source/Dafny/Translator.ssc b/Source/Dafny/Translator.ssc
index dcd1b60f..e80f546b 100644
--- a/Source/Dafny/Translator.ssc
+++ b/Source/Dafny/Translator.ssc
@@ -1738,6 +1738,7 @@ namespace Microsoft.Dafny {
     void AddMethodRefinement(MethodRefinement! m) 

       requires sink != null && predef != null;      

     {

+      // r is abstract, m is concrete 

       Method r = m.Refined;

       assert r != null;

       assert m.EnclosingClass != null;

@@ -1748,7 +1749,7 @@ namespace Microsoft.Dafny {
       ExpressionTranslator etran = new ExpressionTranslator(this, predef, heap, that);      

       

       // TODO: this straight inlining does not handle recursive calls

-      // TODO: we assume frame allows anything to be changed -- we don't include post-conditions in the refinement procedure

+      // TODO: we assume frame allows anything to be changed -- we don't include post-conditions in the refinement procedure, or check refinement of frames      

             

       // generate procedure declaration with pre-condition wp(r, true)

       Bpl.Procedure! proc = AddMethod(r, false, true);

@@ -1792,7 +1793,7 @@ namespace Microsoft.Dafny {
       Bpl.Expr lambda = new Bpl.LambdaExpr(m.tok, new Bpl.TypeVariableSeq(alpha), new Bpl.VariableSeq(oVar, fVar), null, Bpl.Expr.True);    

       builder.Add(Bpl.Cmd.SimpleAssign(m.tok, new Bpl.IdentifierExpr(m.tok, frame), lambda));

       

-      //  assume I($Heap, $Heap)              

+      // assume I($Heap, $Heap)              

       builder.Add(new Bpl.AssumeCmd(m.tok, TrCouplingInvariant(m, heap, "this", heap, that)));     

       

       // assign input formals of m (except "this")

@@ -1840,12 +1841,14 @@ namespace Microsoft.Dafny {
       for (int i = 0; i < k; i++) {

         Bpl.Variable rOut = outParams[i];

         Bpl.Variable mOut = outParams[i+k];

-        assert rOut != null && mOut != null;

-        builder.Add(new Bpl.AssertCmd(m.tok, Bpl.Expr.Eq(new Bpl.IdentifierExpr(m.tok, mOut), new Bpl.IdentifierExpr(m.tok, rOut))));

+        assert rOut != null && mOut != null;        

+        builder.Add(Assert(m.tok, Bpl.Expr.Eq(new Bpl.IdentifierExpr(m.tok, mOut), new Bpl.IdentifierExpr(m.tok, rOut)), 

+          "Refinement method may not produce the same value for output variable " + m.Outs[i].Name));

       }

             

       //  assert I($Heap1, $Heap)      

-      builder.Add(new Bpl.AssertCmd(m.tok, TrCouplingInvariant(m, heap, "this", new Bpl.IdentifierExpr(m.tok, heap2), that)));

+      builder.Add(Assert(m.tok, TrCouplingInvariant(m, heap, "this", new Bpl.IdentifierExpr(m.tok, heap2), that),

+        "Refinement method may not preserve the coupling invariant"));

                                                 

       Bpl.StmtList stmts = builder.Collect(m.tok);            

       Bpl.Implementation impl = new Bpl.Implementation(m.tok, proc.Name,

@@ -2866,7 +2869,7 @@ namespace Microsoft.Dafny {
     

     void AddComment(Bpl.StmtListBuilder! builder, Statement! stmt, string! comment) {

       builder.Add(new Bpl.CommentCmd(string.Format("----- {0} ----- {1}({2},{3})", comment, stmt.Tok.filename, stmt.Tok.line, stmt.Tok.col)));

-    }

+    }    

     

     Bpl.Expr GetWhereClause(IToken! tok, Bpl.Expr! x, Type! type, ExpressionTranslator! etran)

       requires predef != null;