private BoundPatternSwitchLabel BindPatternSwitchSectionLabel(
            Binder sectionBinder, BoundExpression boundSwitchExpression, SwitchLabelSyntax node, LabelSymbol label, ref BoundPatternSwitchLabel defaultLabel, DiagnosticBag diagnostics)
        {
            switch (node.Kind())
            {
                case SyntaxKind.CaseSwitchLabel:
                    {
                        var caseLabelSyntax = (CaseSwitchLabelSyntax)node;
                        bool wasExpression;
                        var pattern = sectionBinder.BindConstantPattern(
                            node, boundSwitchExpression, boundSwitchExpression.Type, caseLabelSyntax.Value, node.HasErrors, diagnostics, out wasExpression, wasSwitchCase: true);
                        bool hasErrors = pattern.HasErrors;
                        var constantValue = pattern.ConstantValue;
                        if (!hasErrors && (object)constantValue != null && this.FindMatchingSwitchCaseLabel(constantValue, caseLabelSyntax) != label)
                        {
                            diagnostics.Add(ErrorCode.ERR_DuplicateCaseLabel, node.Location, pattern.ConstantValue.GetValueToDisplay() ?? label.Name);
                            hasErrors = true;
                        }
                        return new BoundPatternSwitchLabel(node, label, pattern, null, hasErrors);
                    }

                case SyntaxKind.DefaultSwitchLabel:
                    {
                        var defaultLabelSyntax = (DefaultSwitchLabelSyntax)node;
                        var pattern = new BoundWildcardPattern(node);
                        bool hasErrors = pattern.HasErrors;
                        if (defaultLabel != null)
                        {
                            diagnostics.Add(ErrorCode.ERR_DuplicateCaseLabel, node.Location, "default");
                            hasErrors = true;
                        }

                        // Note that this is semantically last! The caller will place it in the decision tree
                        // in the final position.
                        defaultLabel = new BoundPatternSwitchLabel(node, label, pattern, null, hasErrors);
                        return defaultLabel;
                    }

                case SyntaxKind.CasePatternSwitchLabel:
                    {
                        var matchLabelSyntax = (CasePatternSwitchLabelSyntax)node;
                        var pattern = sectionBinder.BindPattern(
                            matchLabelSyntax.Pattern, boundSwitchExpression, boundSwitchExpression.Type, node.HasErrors, diagnostics, wasSwitchCase: true);
                        return new BoundPatternSwitchLabel(node, label, pattern,
                            matchLabelSyntax.WhenClause != null ? sectionBinder.BindBooleanExpression(matchLabelSyntax.WhenClause.Condition, diagnostics) : null, node.HasErrors);
                    }

                default:
                    throw ExceptionUtilities.UnexpectedValue(node);
            }
        }
예제 #2
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        private BoundPatternSwitchLabel BindPatternSwitchSectionLabel(
            Binder sectionBinder, BoundExpression boundSwitchExpression, SwitchLabelSyntax node, LabelSymbol label, ref BoundPatternSwitchLabel defaultLabel, DiagnosticBag diagnostics)
        {
            switch (node.Kind())
            {
                case SyntaxKind.CaseSwitchLabel:
                    {
                        var caseLabelSyntax = (CaseSwitchLabelSyntax)node;
                        bool wasExpression;
                        var pattern = sectionBinder.BindConstantPattern(
                            node, boundSwitchExpression, boundSwitchExpression.Type, caseLabelSyntax.Value, node.HasErrors, diagnostics, out wasExpression, wasSwitchCase: true);
                        bool hasErrors = pattern.HasErrors;
                        var constantValue = pattern.ConstantValue;
                        if (!hasErrors &&
                            (object)constantValue != null &&
                            pattern.Value.Type == SwitchGoverningType &&
                            this.FindMatchingSwitchCaseLabel(constantValue, caseLabelSyntax) != label)
                        {
                            diagnostics.Add(ErrorCode.ERR_DuplicateCaseLabel, node.Location, pattern.ConstantValue.GetValueToDisplay() ?? label.Name);
                            hasErrors = true;
                        }

                        // Until we've determined whether or not the switch label is reachable, we assume it
                        // is. The caller updates isReachable after determining if the label is subsumed.
                        const bool isReachable = true;
                        return new BoundPatternSwitchLabel(node, label, pattern, null, isReachable, hasErrors);
                    }

                case SyntaxKind.DefaultSwitchLabel:
                    {
                        var defaultLabelSyntax = (DefaultSwitchLabelSyntax)node;
                        var pattern = new BoundWildcardPattern(node);
                        bool hasErrors = pattern.HasErrors;
                        if (defaultLabel != null)
                        {
                            diagnostics.Add(ErrorCode.ERR_DuplicateCaseLabel, node.Location, label.Name);
                            hasErrors = true;
                        }

                        // We always treat the default label as reachable, even if the switch is complete.
                        const bool isReachable = true;

                        // Note that this is semantically last! The caller will place it in the decision tree
                        // in the final position.
                        defaultLabel = new BoundPatternSwitchLabel(node, label, pattern, null, isReachable, hasErrors);
                        return defaultLabel;
                    }

                case SyntaxKind.CasePatternSwitchLabel:
                    {
                        var matchLabelSyntax = (CasePatternSwitchLabelSyntax)node;
                        var pattern = sectionBinder.BindPattern(
                            matchLabelSyntax.Pattern, boundSwitchExpression, boundSwitchExpression.Type, node.HasErrors, diagnostics, wasSwitchCase: true);
                        return new BoundPatternSwitchLabel(node, label, pattern,
                            matchLabelSyntax.WhenClause != null ? sectionBinder.BindBooleanExpression(matchLabelSyntax.WhenClause.Condition, diagnostics) : null,
                            true, node.HasErrors);
                    }

                default:
                    throw ExceptionUtilities.UnexpectedValue(node);
            }
        }
예제 #3
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        private static BoundPatternSwitchLabel BindPatternSwitchSectionLabel(Binder sectionBinder, BoundExpression boundSwitchExpression, SwitchLabelSyntax node, ref DefaultSwitchLabelSyntax defaultLabel, DiagnosticBag diagnostics)
        {
            switch (node.Kind())
            {
                case SyntaxKind.CasePatternSwitchLabel:
                    {
                        var matchLabelSyntax = (CasePatternSwitchLabelSyntax)node;
                        var pattern = sectionBinder.BindPattern(
                            matchLabelSyntax.Pattern, boundSwitchExpression, boundSwitchExpression.Type, node.HasErrors, diagnostics, wasSwitchCase: true);
                        return new BoundPatternSwitchLabel(node, pattern,
                            matchLabelSyntax.WhenClause != null ? sectionBinder.BindBooleanExpression(matchLabelSyntax.WhenClause.Condition, diagnostics) : null, node.HasErrors);
                    }

                case SyntaxKind.CaseSwitchLabel:
                    {
                        var caseLabelSyntax = (CaseSwitchLabelSyntax)node;
                        bool wasExpression;
                        var pattern = sectionBinder.BindConstantPattern(
                            node, boundSwitchExpression, boundSwitchExpression.Type, caseLabelSyntax.Value, node.HasErrors, diagnostics, out wasExpression, wasSwitchCase: true);
                        return new BoundPatternSwitchLabel(node, pattern, null, node.HasErrors);
                    }

                case SyntaxKind.DefaultSwitchLabel:
                    {
                        var defaultLabelSyntax = (DefaultSwitchLabelSyntax)node;
                        var pattern = new BoundWildcardPattern(node);
                        if (defaultLabel != null)
                        {
                            diagnostics.Add(ErrorCode.ERR_DuplicateCaseLabel, node.Location, "default");
                        }

                        defaultLabel = defaultLabelSyntax;
                        return new BoundPatternSwitchLabel(node, pattern, null, node.HasErrors); // note that this is semantically last!
                    }

                default:
                    throw ExceptionUtilities.Unreachable;
            }
        }