bool RewriteMatchingLoop()
{
if (expr is QuantifierExpr)
{
QuantifierExpr quantifier = (QuantifierExpr)expr;
var l = new List <QuantifierWithTriggers>();
List <Expression> splits = new List <Expression>();
bool rewritten = false;
foreach (var q in quantifiers)
{
if (TriggerUtils.NeedsAutoTriggers(q.quantifier) && TriggerUtils.WantsMatchingLoopRewrite(q.quantifier))
{
var matchingLoopRewriter = new MatchingLoopRewriter();
var qq = matchingLoopRewriter.RewriteMatchingLoops(q);
splits.Add(qq);
l.Add(new QuantifierWithTriggers(qq));
rewritten = true;
}
else
{
// don't rewrite the quantifier if we are not auto generate triggers.
// This is because rewriting introduces new boundvars and will cause
// user provided triggers not mention all boundvars
splits.Add(q.quantifier);
l.Add(q);
}
}
if (rewritten)
{
quantifier.SplitQuantifier = splits;
quantifiers = l;
return(true);
}
}
return(false);
}
private void CommitOne(QuantifierWithTriggers q, bool addHeader)
{
var errorLevel = ErrorLevel.Info;
var msg = new StringBuilder();
var indent = addHeader ? " " : "";
bool suppressWarnings = Attributes.Contains(q.quantifier.Attributes, "nowarn");
if (!TriggerUtils.NeedsAutoTriggers(q.quantifier)) // NOTE: split and autotriggers attributes are passed down to Boogie
{
var extraMsg = TriggerUtils.WantsAutoTriggers(q.quantifier) ? "" : " Note that {:autotriggers false} can cause instabilities. Consider using {:nowarn}, {:matchingloop} (not great either), or a manual trigger instead.";
msg.AppendFormat("Not generating triggers for \"{0}\".{1}", Printer.ExprToString(q.quantifier.Term), extraMsg).AppendLine();
}
else
{
if (addHeader)
{
msg.AppendFormat("For expression \"{0}\":", Printer.ExprToString(q.quantifier.Term)).AppendLine();
}
foreach (var candidate in q.Candidates)
{
q.quantifier.Attributes = new Attributes("trigger", candidate.Terms.Select(t => t.Expr).ToList(), q.quantifier.Attributes);
}
AddTriggersToMessage("Selected triggers:", q.Candidates, msg, indent);
AddTriggersToMessage("Rejected triggers:", q.RejectedCandidates, msg, indent, true);
#if QUANTIFIER_WARNINGS
var WARN_TAG = DafnyOptions.O.UnicodeOutput ? "⚠ " : "/!\\ ";
var WARN_TAG_OVERRIDE = suppressWarnings ? "(Suppressed warning) " : WARN_TAG;
var WARN_LEVEL = suppressWarnings ? ErrorLevel.Info : ErrorLevel.Warning;
var WARN = indent + WARN_TAG_OVERRIDE;
if (!q.CandidateTerms.Any())
{
errorLevel = WARN_LEVEL;
msg.Append(WARN).AppendLine("No terms found to trigger on.");
}
else if (!q.Candidates.Any())
{
errorLevel = WARN_LEVEL;
msg.Append(WARN).AppendLine("No trigger covering all quantified variables found.");
}
else if (!q.CouldSuppressLoops && !q.AllowsLoops)
{
errorLevel = WARN_LEVEL;
msg.Append(WARN).AppendLine("Suppressing loops would leave this expression without triggers.");
}
else if (suppressWarnings)
{
errorLevel = ErrorLevel.Warning;
msg.Append(indent).Append(WARN_TAG).AppendLine("There is no warning here to suppress.");
}
#endif
}
if (msg.Length > 0)
{
var msgStr = msg.ToString().TrimEnd("\r\n ".ToCharArray());
reporter.Message(MessageSource.Rewriter, errorLevel, q.quantifier.tok, msgStr);
}
}