Address compiler warnings

Core/Parsers/AssignmentRequirementParser.cs

@@ -15,7 +15,7 @@ public class AssignmentRequirementParser : CsvParserBase
 		CsvReader.Read();
 		CsvReader.ReadHeader();
 		var studentColumns =
-			CsvReader.HeaderRecord.Select(h => h.Trim()).Where(h => !string.IsNullOrEmpty(h)).ToArray();
+			CsvReader.HeaderRecord!.Select(h => h.Trim()).Where(h => !string.IsNullOrEmpty(h)).ToArray();
 
 		var studentArray = 
             studentColumns
@@ -30,21 +30,25 @@ public class AssignmentRequirementParser : CsvParserBase
 				throw new Exception($"Could not find eventDefinition named {eventShortName}");
 			for (int i = 0; i <= studentArray.Length; i++)
 			{
+				var student = studentArray[i];
+				if (student == null)
+					continue;
+
 				var field = CsvReader.GetField(i + 1);
 				switch (field)
 				{
 					case "x":
 					case "X":
-						assumptions.Add(new AssignmentRequirement(evt, studentArray[i], Requirement.Exclude));
+						assumptions.Add(new AssignmentRequirement(evt, student, Requirement.Exclude));
 						break;
 					case "i":
 					case "I":
-						assumptions.Add(new AssignmentRequirement(evt, studentArray[i], Requirement.Include));
+						assumptions.Add(new AssignmentRequirement(evt, student, Requirement.Include));
 						break;
 					default:
 						break;
 				}
-				
+
 			}
 		}
 

Core/Parsers/EventDefinitionParser.cs

@@ -53,8 +53,8 @@ public class EventDefinitionParser : CsvParserBase
 
 			var competitiveEvent = new EventDefinition
 			{
-				Name = name.Trim(), 
-				ShortName = shortName.Trim(), 
+				Name = name.Trim(),
+				ShortName = shortName?.Trim() ?? string.Empty,
 				EventFormat = format,
 				ChapterEligibilityCountState = stateTeams,
 				MinTeamSize = min,
@@ -64,10 +64,10 @@ public class EventDefinitionParser : CsvParserBase
 				//RegionalPresubmit = regionalPresubmit.Trim() == "TRUE",
 				Notes = regionalNotes,
 				Documentation= documentation,
-				Presubmission = statePresubmission.Trim() == "TRUE",
+				Presubmission = statePresubmission?.Trim() == "TRUE",
 				//StatePretesting = statePretesting.Trim() == "TRUE",
 				//StatePreliminaryRound = statePreliminary.Trim() == "TRUE",
-				Eligibility = eligibility,
+				Eligibility = eligibility ?? string.Empty,
 				Theme = theme,
 				Description = description,
 				LevelOfEffort = levelOfEffort

Core/Parsers/EventOccurrenceParser.cs

@@ -31,7 +31,7 @@ public class EventOccurrenceParser
 	public IDictionary<EventDefinition, List<EventOccurrence>> Parse()
     {
         var occurrences = new Dictionary<EventDefinition, List<EventOccurrence>>();
-        EventDefinition currentEventDefinition = null;
+        EventDefinition? currentEventDefinition = null;
 
 		var lines = File.ReadLines(_txtFile.FullName);
         foreach (var line in lines)