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);
}
}
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);
}
}
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;
}
}