// Add bindings to a formula using an implication or
// conjunction. The bindings themselves will be flattened as well,
// which might introduce further bindings
private VCExpr AddBindings(List <VCExprLetBinding /*!*/> /*!*/ bindings, VCExpr body, FlattenerState state)
{
Contract.Requires(body != null);
Contract.Requires(cce.NonNullElements(bindings));
Contract.Requires((body.Type.IsBool));
Contract.Ensures(Contract.Result <VCExpr>() != null);
List <VCExprLetBinding /*!*/> /*!*/ mutatedBindings = FlattenBindings(bindings, state);
Contract.Assert(mutatedBindings != null);
VCExpr /*!*/ bindingEquations = Gen.AsEquations(mutatedBindings);
Contract.Assert(bindingEquations != null);
switch (state.Polarity)
{
case 1:
return(Gen.Implies(bindingEquations, body));
case -1:
return(Gen.And(bindingEquations, body));
case 0:
// also add explicit quantifiers for the bound variables
List <VCExprVar /*!*/> /*!*/ vars = new List <VCExprVar /*!*/> ();
foreach (VCExprLetBinding /*!*/ binding in mutatedBindings)
{
Contract.Assert(binding != null);
vars.Add(binding.V);
}
return(Gen.Forall(vars, new List <VCTrigger /*!*/>(),
Gen.Implies(bindingEquations, body)));
}
Contract.Assert(false); throw new cce.UnreachableException();
}