public QuantifierExpr RewriteMatchingLoops(QuantifierWithTriggers q)
{
// rewrite quantifier to avoid matching loops
// before:
// assert forall i :: 0 <= i < a.Length-1 ==> a[i] <= a[i+1];
// after:
// assert forall i,j :: j == i+1 ==> 0 <= i < a.Length-1 ==> a[i] <= a[j];
substMap = new List <Tuple <Expression, IdentifierExpr> >();
foreach (var m in q.LoopingMatches)
{
var e = m.OriginalExpr;
if (TriggersCollector.IsPotentialTriggerCandidate(e) && triggersCollector.IsTriggerKiller(e))
{
foreach (var sub in e.SubExpressions)
{
if (triggersCollector.IsTriggerKiller(sub) && (!TriggersCollector.IsPotentialTriggerCandidate(sub)))
{
var entry = substMap.Find(x => ExprExtensions.ExpressionEq(sub, x.Item1));
if (entry == null)
{
var newBv = new BoundVar(sub.tok, "_t#" + substMap.Count, sub.Type);
var ie = new IdentifierExpr(sub.tok, newBv.Name);
ie.Var = newBv;
ie.Type = newBv.Type;
substMap.Add(new Tuple <Expression, IdentifierExpr>(sub, ie));
}
}
}
}
}
var expr = (QuantifierExpr)q.quantifier;
if (substMap.Count > 0)
{
var s = new Translator.ExprSubstituter(substMap);
expr = s.Substitute(q.quantifier) as QuantifierExpr;
}
else
{
// make a copy of the expr
if (expr is ForallExpr)
{
expr = new ForallExpr(expr.tok, expr.TypeArgs, expr.BoundVars, expr.Range, expr.Term, TriggerUtils.CopyAttributes(expr.Attributes))
{
Type = expr.Type, Bounds = expr.Bounds
};
}
else
{
expr = new ExistsExpr(expr.tok, expr.TypeArgs, expr.BoundVars, expr.Range, expr.Term, TriggerUtils.CopyAttributes(expr.Attributes))
{
Type = expr.Type, Bounds = expr.Bounds
};
}
}
return(expr);
}
internal static bool Eq(TriggerMatch t1, TriggerMatch t2)
{
return(ExprExtensions.ExpressionEq(t1.Expr, t2.Expr));
}