Mono.CSharp.Switch.Resolve C# (CSharp) Method

		public override bool Resolve (BlockContext ec)
		{
			Expr = Expr.Resolve (ec);
			if (Expr == null)
				return false;

			new_expr = SwitchGoverningType (ec, Expr);

			if ((new_expr == null) && TypeManager.IsNullableType (Expr.Type)) {
				unwrap = Nullable.Unwrap.Create (Expr, false);
				if (unwrap == null)
					return false;

				new_expr = SwitchGoverningType (ec, unwrap);
			}

			if (new_expr == null){
				ec.Report.Error (151, loc,
					"A switch expression of type `{0}' cannot be converted to an integral type, bool, char, string, enum or nullable type",
					TypeManager.CSharpName (Expr.Type));
				return false;
			}

			// Validate switch.
			SwitchType = new_expr.Type;

			if (RootContext.Version == LanguageVersion.ISO_1 && SwitchType == TypeManager.bool_type) {
				ec.Report.FeatureIsNotAvailable (loc, "switch expression of boolean type");
				return false;
			}

			if (!CheckSwitch (ec))
				return false;

			if (HaveUnwrap)
				Elements.Remove (SwitchLabel.NullStringCase);

			Switch old_switch = ec.Switch;
			ec.Switch = this;
			ec.Switch.SwitchType = SwitchType;

			Report.Debug (1, "START OF SWITCH BLOCK", loc, ec.CurrentBranching);
			ec.StartFlowBranching (FlowBranching.BranchingType.Switch, loc);

			var constant = new_expr as Constant;
			if (constant != null) {
				is_constant = true;
				object key = constant.GetValue ();
				SwitchLabel label;
				if (Elements.TryGetValue (key, out label))
					constant_section = FindSection (label);

				if (constant_section == null)
					constant_section = default_section;
			}

			bool first = true;
			bool ok = true;
			foreach (SwitchSection ss in Sections){
				if (!first)
					ec.CurrentBranching.CreateSibling (
						null, FlowBranching.SiblingType.SwitchSection);
				else
					first = false;

				if (is_constant && (ss != constant_section)) {
					// If we're a constant switch, we're only emitting
					// one single section - mark all the others as
					// unreachable.
					ec.CurrentBranching.CurrentUsageVector.Goto ();
					if (!ss.Block.ResolveUnreachable (ec, true)) {
						ok = false;
					}
				} else {
					if (!ss.Block.Resolve (ec))
						ok = false;
				}
			}

			if (default_section == null)
				ec.CurrentBranching.CreateSibling (
					null, FlowBranching.SiblingType.SwitchSection);

			ec.EndFlowBranching ();
			ec.Switch = old_switch;

			Report.Debug (1, "END OF SWITCH BLOCK", loc, ec.CurrentBranching);

			if (!ok)
				return false;

			if (SwitchType == TypeManager.string_type && !is_constant) {
				// TODO: Optimize single case, and single+default case
				ResolveStringSwitchMap (ec);
			}

			return true;
		}