// Remove all let-bindings from the field bindings whose rhs
// contains any of the specified variables
private List <VCExprLetBinding /*!*/> /*!*/ RemoveBindingsWithVars(List <VCExprVar /*!*/> /*!*/ boundVars,
List <TypeVariable /*!*/> /*!*/ boundTypeVars)
{
Contract.Requires(cce.NonNullElements(boundTypeVars));
Contract.Requires(cce.NonNullElements(boundVars));
Contract.Ensures(cce.NonNullElements(Contract.Result <List <VCExprLetBinding> >()));
List <VCExprLetBinding /*!*/> /*!*/
res = new List <VCExprLetBinding /*!*/>();
FreeVariableCollector /*!*/
coll = new FreeVariableCollector();
foreach (KeyValuePair <VCExpr, VCExprVar> pair in Bindings)
{
Contract.Assert(cce.NonNullElements(pair));
coll.Collect(pair.Key);
if (boundVars.Any(var => coll.FreeTermVars.ContainsKey(var)) ||
boundTypeVars.Any(var => coll.FreeTypeVars.Contains(var)))
{
res.Add(Gen.LetBinding(pair.Value, pair.Key));
}
coll.Reset();
}
foreach (VCExprLetBinding b in res)
{
Contract.Assert(b != null);
Bindings.Remove(b.E);
}
return(res);
}
////////////////////////////////////////////////////////////////////////////
public override VCExpr Visit(VCExprQuantifier node, VariableBindings oldBindings)
{
Contract.Requires(oldBindings != null);
Contract.Requires(node != null);
Contract.Ensures(Contract.Result<VCExpr>() != null);
VariableBindings bindings = oldBindings.Clone();
// determine the bound vars that actually occur in the body or
// in any of the triggers (if some variables do not occur, we
// need to take special care of type parameters that only occur
// in the types of such variables)
FreeVariableCollector coll = new FreeVariableCollector();
coll.Collect(node.Body);
foreach (VCTrigger trigger in node.Triggers) {
if (trigger.Pos)
foreach (VCExpr/*!*/ e in trigger.Exprs) {
Contract.Assert(e != null);
coll.Collect(e);
}
}
List<VCExprVar/*!*/> occurringVars = new List<VCExprVar/*!*/>(node.BoundVars.Count);
foreach (VCExprVar var in node.BoundVars)
if (coll.FreeTermVars.ContainsKey(var))
occurringVars.Add(var);
occurringVars.TrimExcess();
// bound term variables are replaced with bound term variables typed in
// a simpler way
List<VCExprVar/*!*/>/*!*/ newBoundVars =
BoundVarsAfterErasure(occurringVars, bindings);
Contract.Assert(cce.NonNullElements(newBoundVars));
VCExpr/*!*/ newNode = HandleQuantifier(node, occurringVars,
newBoundVars, bindings);
Contract.Assert(newNode != null);
if (!(newNode is VCExprQuantifier) || !IsUniversalQuantifier(node))
return newNode;
VariableBindings bindings2;
if (!RedoQuantifier(node, (VCExprQuantifier)newNode, occurringVars, oldBindings,
out bindings2, out newBoundVars))
return newNode;
return HandleQuantifier(node, occurringVars,
newBoundVars, bindings2);
}
