RRULE Evaluation: Apply BYYEARDAY=366 only in leap years. (#621)

Author: minichma

Ical.Net/Evaluation/RecurrencePatternEvaluator.cs

@@ -484,7 +484,9 @@ private List<DateTime> GetYearDayVariants(List<DateTime> dates, RecurrencePatter
                     var date1 = date;
                     yearDayDates.AddRange(pattern.ByYearDay.Select(yearDay => yearDay > 0
                         ? date1.AddDays(-date1.DayOfYear + yearDay)
-                        : date1.AddDays(-date1.DayOfYear + 1).AddYears(1).AddDays(yearDay)));
+                        : date1.AddDays(-date1.DayOfYear + 1).AddYears(1).AddDays(yearDay))
+                        // Ignore the BY values that don't fit into the current year (i.e. +-366 in non-leap-years).
+                        .Where(d => d.Year == date1.Year));
                 }
                 return yearDayDates;
             }
@@ -500,7 +502,7 @@ private List<DateTime> GetYearDayVariants(List<DateTime> dates, RecurrencePatter
                         ? date.AddDays(-date.DayOfYear + yearDay)
                         : date.AddDays(-date.DayOfYear + 1).AddYears(1).AddDays(yearDay);
 
-                    if (newDate.DayOfYear == date.DayOfYear)
+                    if (newDate.Date == date.Date)
                     {
                         goto Next;
                     }