Mono.CSharp.ToplevelBlock.AddLabel C# (CSharp) Method

		public void AddLabel (string name, LabeledStatement label)
		{
			if (labels == null)
				labels = new Dictionary<string, object> ();

			object value;
			if (!labels.TryGetValue (name, out value)) {
				labels.Add (name, label);
				return;
			}

			LabeledStatement existing = value as LabeledStatement;
			List<LabeledStatement> existing_list;
			if (existing != null) {
				existing_list = new List<LabeledStatement> ();
				existing_list.Add (existing);
				labels[name] = existing_list;
			} else {
				existing_list = (List<LabeledStatement>) value;
			}

			//
			// A collision checking between labels
			//
			for (int i = 0; i < existing_list.Count; ++i) {
				existing = existing_list[i];
				Block b = existing.Block;

				// Collision at same level
				if (label.Block == b) {
					Report.SymbolRelatedToPreviousError (existing.loc, name);
					Report.Error (140, label.loc, "The label `{0}' is a duplicate", name);
					break;
				}

				// Collision with parent
				b = label.Block;
				while ((b = b.Parent) != null) {
					if (existing.Block == b) {
						Report.Error (158, label.loc,
							"The label `{0}' shadows another label by the same name in a contained scope", name);
						i = existing_list.Count;
						break;
					}
				}

				// Collision with with children
				b = existing.Block;
				while ((b = b.Parent) != null) {
					if (label.Block == b) {
						Report.Error (158, label.loc,
							"The label `{0}' shadows another label by the same name in a contained scope", name);
						i = existing_list.Count;
						break;
					}
				}
			}

			existing_list.Add (label);
		}