private static bool IsFlag(SyntaxNodeAnalysisContext context, EnumMemberDeclarationSyntax declaration)
{
if (context.SemanticModel.GetDeclaredSymbol(declaration, context.CancellationToken) is IFieldSymbol fieldSymbol &&
fieldSymbol.HasConstantValue)
{
EnumFieldSymbolInfo fieldInfo = EnumFieldSymbolInfo.Create(fieldSymbol);
return(fieldInfo.Value > 1 &&
!fieldInfo.HasCompositeValue());
}
return(false);
}
private static async Task <Document> UseBitShiftOperatorAsync(
Document document,
EnumDeclarationSyntax enumDeclaration,
CancellationToken cancellationToken)
{
SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
EnumDeclarationSyntax newEnumDeclaration = enumDeclaration.ReplaceNodes(
GetExpressionsToRewrite(),
(expression, _) =>
{
Optional <object> constantValue = semanticModel.GetConstantValue(expression, cancellationToken);
var power = (int)Math.Log(Convert.ToDouble(constantValue.Value), 2);
BinaryExpressionSyntax leftShift = LeftShiftExpression(NumericLiteralExpression(1), NumericLiteralExpression(power));
return(leftShift.WithTriviaFrom(expression));
});
return(await document.ReplaceNodeAsync(enumDeclaration, newEnumDeclaration, cancellationToken).ConfigureAwait(false));
IEnumerable <ExpressionSyntax> GetExpressionsToRewrite()
{
foreach (EnumMemberDeclarationSyntax member in enumDeclaration.Members)
{
ExpressionSyntax expression = member.EqualsValue?.Value.WalkDownParentheses();
if (expression != null &&
semanticModel.GetDeclaredSymbol(member, cancellationToken) is IFieldSymbol fieldSymbol &&
fieldSymbol.HasConstantValue)
{
EnumFieldSymbolInfo fieldInfo = EnumFieldSymbolInfo.Create(fieldSymbol);
if (fieldInfo.Value > 1 &&
!fieldInfo.HasCompositeValue())
{
yield return(expression);
}
}
}
}
}
public static void ComputeRefactoring(
RefactoringContext context,
EnumDeclarationSyntax enumDeclaration,
SemanticModel semanticModel)
{
SeparatedSyntaxList <EnumMemberDeclarationSyntax> members = enumDeclaration.Members;
if (!members.Any())
{
return;
}
if (members.All(f => f.EqualsValue?.Value == null))
{
return;
}
INamedTypeSymbol enumSymbol = semanticModel.GetDeclaredSymbol(enumDeclaration, context.CancellationToken);
bool isFlags = enumSymbol.HasAttribute(MetadataNames.System_FlagsAttribute);
if (!AreNewValuesDifferentFromExistingValues())
{
return;
}
Document document = context.Document;
context.RegisterRefactoring(
"Declare explicit values (overwrite existing values)",
ct => RefactorAsync(document, enumDeclaration, enumSymbol, semanticModel, ct),
EquivalenceKey);
bool AreNewValuesDifferentFromExistingValues()
{
ulong value = 0;
foreach (EnumMemberDeclarationSyntax member in enumDeclaration.Members)
{
IFieldSymbol fieldSymbol = semanticModel.GetDeclaredSymbol(member, context.CancellationToken);
EnumFieldSymbolInfo fieldSymbolInfo = EnumFieldSymbolInfo.Create(fieldSymbol);
if (!fieldSymbolInfo.HasValue)
{
return(true);
}
if (isFlags &&
fieldSymbolInfo.HasCompositeValue())
{
continue;
}
if (value != fieldSymbolInfo.Value)
{
return(true);
}
if (isFlags)
{
value = (value == 0) ? 1 : value * 2;
}
else
{
value++;
}
if (!ConvertHelpers.CanConvertFromUInt64(value, enumSymbol.EnumUnderlyingType.SpecialType))
{
return(false);
}
}
return(false);
}
}
private static void AnalyzeNamedType(SymbolAnalysisContext context)
{
var typeSymbol = (INamedTypeSymbol)context.Symbol;
if (typeSymbol.IsImplicitlyDeclared)
{
return;
}
if (typeSymbol.TypeKind != TypeKind.Enum)
{
return;
}
bool hasFlagsAttribute = typeSymbol.HasAttribute(MetadataNames.System_FlagsAttribute);
ImmutableArray <ISymbol> members = default;
if (hasFlagsAttribute &&
DiagnosticRules.DeclareEnumMemberWithZeroValue.IsEffective(context))
{
members = typeSymbol.GetMembers();
if (!ContainsFieldWithZeroValue(members))
{
var enumDeclaration = (EnumDeclarationSyntax)typeSymbol.GetSyntax(context.CancellationToken);
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.DeclareEnumMemberWithZeroValue, enumDeclaration.Identifier);
}
}
EnumSymbolInfo enumInfo = default;
if (hasFlagsAttribute &&
DiagnosticRules.CompositeEnumValueContainsUndefinedFlag.IsEffective(context))
{
enumInfo = EnumSymbolInfo.Create(typeSymbol);
foreach (EnumFieldSymbolInfo field in enumInfo.Fields)
{
if (field.HasValue &&
ConvertHelpers.CanConvertFromUInt64(field.Value, typeSymbol.EnumUnderlyingType.SpecialType) &&
!IsMaxValue(field.Value, typeSymbol.EnumUnderlyingType.SpecialType) &&
field.HasCompositeValue())
{
foreach (ulong value in (field.GetFlags()))
{
if (!enumInfo.Contains(value))
{
ReportUndefinedFlag(context, field.Symbol, value.ToString());
}
}
}
}
}
if (hasFlagsAttribute &&
DiagnosticRules.DeclareEnumValueAsCombinationOfNames.IsEffective(context))
{
if (members.IsDefault)
{
members = typeSymbol.GetMembers();
}
foreach (ISymbol member in members)
{
if (!(member is IFieldSymbol fieldSymbol))
{
continue;
}
if (!fieldSymbol.HasConstantValue)
{
break;
}
EnumFieldSymbolInfo fieldInfo = EnumFieldSymbolInfo.Create(fieldSymbol);
if (!fieldInfo.HasCompositeValue())
{
continue;
}
var declaration = (EnumMemberDeclarationSyntax)fieldInfo.Symbol.GetSyntax(context.CancellationToken);
ExpressionSyntax expression = declaration.EqualsValue?.Value.WalkDownParentheses();
if (expression != null &&
(expression.IsKind(SyntaxKind.NumericLiteralExpression) ||
expression
.DescendantNodes()
.Any(f => f.IsKind(SyntaxKind.NumericLiteralExpression))))
{
if (enumInfo.IsDefault)
{
enumInfo = EnumSymbolInfo.Create(typeSymbol);
if (enumInfo.Fields.Any(f => !f.HasValue))
{
break;
}
}
List <EnumFieldSymbolInfo> values = enumInfo.Decompose(fieldInfo);
if (values?.Count > 1)
{
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.DeclareEnumValueAsCombinationOfNames, expression);
}
}
}
}
if (hasFlagsAttribute &&
DiagnosticRules.UseBitShiftOperator.IsEffective(context))
{
if (members.IsDefault)
{
members = typeSymbol.GetMembers();
}
foreach (ISymbol member in members)
{
if (!(member is IFieldSymbol fieldSymbol))
{
continue;
}
if (!fieldSymbol.HasConstantValue)
{
continue;
}
EnumFieldSymbolInfo fieldInfo = EnumFieldSymbolInfo.Create(fieldSymbol);
if (fieldInfo.Value <= 1)
{
continue;
}
if (fieldInfo.HasCompositeValue())
{
continue;
}
var declaration = (EnumMemberDeclarationSyntax)fieldInfo.Symbol.GetSyntax(context.CancellationToken);
ExpressionSyntax expression = declaration.EqualsValue?.Value.WalkDownParentheses();
if (expression.IsKind(SyntaxKind.NumericLiteralExpression))
{
var enumDeclaration = (EnumDeclarationSyntax)typeSymbol.GetSyntax(context.CancellationToken);
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.UseBitShiftOperator, enumDeclaration.Identifier);
break;
}
}
}
if (DiagnosticRules.DuplicateEnumValue.IsEffective(context))
{
if (enumInfo.IsDefault)
{
enumInfo = EnumSymbolInfo.Create(typeSymbol);
}
ImmutableArray <EnumFieldSymbolInfo> fields = enumInfo.Fields;
if (fields.Length > 1)
{
EnumFieldSymbolInfo symbolInfo1 = fields[0];
EnumFieldSymbolInfo symbolInfo2 = default;
for (int i = 1; i < fields.Length; i++, symbolInfo1 = symbolInfo2)
{
symbolInfo2 = fields[i];
if (!symbolInfo1.HasValue ||
!symbolInfo2.HasValue ||
symbolInfo1.Value != symbolInfo2.Value)
{
continue;
}
var enumMember1 = (EnumMemberDeclarationSyntax)symbolInfo1.Symbol.GetSyntax(context.CancellationToken);
if (enumMember1 == null)
{
continue;
}
var enumMember2 = (EnumMemberDeclarationSyntax)symbolInfo2.Symbol.GetSyntax(context.CancellationToken);
if (enumMember2 == null)
{
continue;
}
ExpressionSyntax value1 = enumMember1.EqualsValue?.Value?.WalkDownParentheses();
ExpressionSyntax value2 = enumMember2.EqualsValue?.Value?.WalkDownParentheses();
if (value1 == null)
{
if (value2 != null)
{
ReportDuplicateValue(context, enumMember1, value2);
}
}
else if (value2 == null)
{
ReportDuplicateValue(context, enumMember2, value1);
}
else
{
SyntaxKind kind1 = value1.Kind();
SyntaxKind kind2 = value2.Kind();
if (kind1 == SyntaxKind.NumericLiteralExpression)
{
if (kind2 == SyntaxKind.NumericLiteralExpression)
{
var enumDeclaration = (EnumDeclarationSyntax)enumMember1.Parent;
SeparatedSyntaxList <EnumMemberDeclarationSyntax> enumMembers = enumDeclaration.Members;
if (enumMembers.IndexOf(enumMember1) < enumMembers.IndexOf(enumMember2))
{
ReportDuplicateValue(context, value2);
}
else
{
ReportDuplicateValue(context, value1);
}
}
else if (!string.Equals((value2 as IdentifierNameSyntax)?.Identifier.ValueText, enumMember1.Identifier.ValueText, StringComparison.Ordinal))
{
ReportDuplicateValue(context, value1);
}
}
else if (kind2 == SyntaxKind.NumericLiteralExpression &&
!string.Equals((value1 as IdentifierNameSyntax)?.Identifier.ValueText, enumMember2.Identifier.ValueText, StringComparison.Ordinal))
{
ReportDuplicateValue(context, value2);
}
}
}
}
}
}
