public static async Task ComputeRefactoringAsync(
RefactoringContext context,
LocalDeclarationStatementSyntax localDeclaration)
{
StatementListInfo statementsInfo = SyntaxInfo.StatementListInfo(localDeclaration);
if (!statementsInfo.Success)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
if (!localInfo.Success)
{
return;
}
if (!context.Span.IsEmptyAndContainedInSpan(localInfo.EqualsToken))
{
return;
}
ExpressionSyntax value = localInfo.Value;
if (value == null)
{
return;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
TypeSyntax type = localInfo.Type;
if (type.IsVar)
{
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(value, context.CancellationToken);
if (typeSymbol?.SupportsExplicitDeclaration() != true)
{
return;
}
type = typeSymbol.ToMinimalTypeSyntax(semanticModel, type.SpanStart);
}
else
{
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(type, context.CancellationToken);
if (typeSymbol?.IsErrorType() != false)
{
return;
}
}
context.RegisterRefactoring(
"Split declaration and initialization",
ct => RefactorAsync(context.Document, localInfo, type, statementsInfo, ct),
RefactoringIdentifiers.SplitDeclarationAndInitialization);
}
private static bool CanUseCoalesceExpression(StatementSyntax statement, ExpressionSyntax expression)
{
SyntaxKind kind = statement.Kind();
if (kind == SyntaxKind.LocalDeclarationStatement)
{
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statement);
return(localInfo.Success &&
!localInfo.Type.IsKind(SyntaxKind.RefType) &&
expression.IsKind(SyntaxKind.IdentifierName) &&
string.Equals(localInfo.IdentifierText, ((IdentifierNameSyntax)expression).Identifier.ValueText, StringComparison.Ordinal) &&
!localInfo.Value.GetTrailingTrivia().Any(f => f.IsDirective) &&
!localInfo.SemicolonToken.ContainsDirectives);
}
else if (kind == SyntaxKind.ExpressionStatement)
{
var expressionStatement = (ExpressionStatementSyntax)statement;
SimpleAssignmentStatementInfo assignmentInfo = SyntaxInfo.SimpleAssignmentStatementInfo(expressionStatement);
return(assignmentInfo.Success &&
CSharpFactory.AreEquivalent(expression, assignmentInfo.Left) &&
!assignmentInfo.Right.GetTrailingTrivia().Any(f => f.IsDirective) &&
!expressionStatement.SemicolonToken.ContainsDirectives);
}
return(false);
}
private static Task <Document> ConvertWhileStatementToForStatementAsync(
Document document,
WhileStatementSyntax whileStatement,
CancellationToken cancellationToken)
{
StatementListInfo statementsInfo = SyntaxInfo.StatementListInfo(whileStatement);
SyntaxList <StatementSyntax> statements = statementsInfo.Statements;
int index = statements.IndexOf(whileStatement);
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statements[index - 1]);
var block = (BlockSyntax)whileStatement.Statement;
var expressionStatement = (ExpressionStatementSyntax)block.Statements.Last();
var postIncrementExpression = (PostfixUnaryExpressionSyntax)expressionStatement.Expression;
BlockSyntax newBlock = block.WithStatements(block.Statements.Remove(expressionStatement));
ForStatementSyntax forStatement = CSharpFactory.ForStatement(
declaration: localInfo.Declaration.TrimTrivia(),
condition: whileStatement.Condition,
incrementor: postIncrementExpression.TrimTrivia(),
statement: newBlock);
forStatement = forStatement
.WithLeadingTrivia(localInfo.Statement.GetLeadingTrivia().AddRange(whileStatement.GetLeadingTrivia().EmptyIfWhitespace()))
.WithFormatterAnnotation();
SyntaxList <StatementSyntax> newStatements = statements.ReplaceRange(index - 1, 2, new StatementSyntax[] { forStatement });
return(document.ReplaceStatementsAsync(statementsInfo, newStatements, cancellationToken));
}
public static async Task ComputeRefactoringAsync(RefactoringContext context, VariableDeclarationSyntax variableDeclaration)
{
if (!(variableDeclaration.Parent is LocalDeclarationStatementSyntax localDeclaration))
{
return;
}
if (!CSharpFacts.CanHaveStatements(localDeclaration.Parent.Kind()))
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
if (!localInfo.Success)
{
return;
}
if (!context.Span.IsEmptyAndContainedInSpan(localInfo.Identifier))
{
return;
}
ExpressionSyntax value = localInfo.Value;
if (value == null)
{
return;
}
if (value.Kind() == SyntaxKind.DefaultExpression)
{
return;
}
if (value is LiteralExpressionSyntax)
{
return;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
var typeSymbol = semanticModel.GetTypeSymbol(localInfo.Type, context.CancellationToken) as INamedTypeSymbol;
if (typeSymbol?.Implements(SpecialType.System_IDisposable, allInterfaces: true) != true)
{
return;
}
context.RegisterRefactoring(
$"Using '{localInfo.IdentifierText}'",
cancellationToken => RefactorAsync(context.Document, localInfo, semanticModel, cancellationToken),
RefactoringIdentifiers.WrapInUsingStatement);
}
internal static async Task ComputeRefactoringAsync(RefactoringContext context, VariableDeclarationSyntax variableDeclaration)
{
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(variableDeclaration);
if (!context.Span.IsContainedInSpanOrBetweenSpans(localInfo.Identifier))
{
return;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (!CanRefactor(localInfo, semanticModel, context.CancellationToken))
{
return;
}
RegisterRefactoring(context, IdentifierName(localInfo.Identifier), localInfo.Statement);
}
public static async Task ComputeRefactoringAsync(RefactoringContext context, ConditionalExpressionSyntax conditionalExpression)
{
ExpressionSyntax expression = conditionalExpression.WalkUpParentheses();
SyntaxNode parent = expression.Parent;
if (parent.IsKind(SyntaxKind.ReturnStatement, SyntaxKind.YieldReturnStatement))
{
context.RegisterRefactoring(
Title,
cancellationToken => RefactorAsync(context.Document, (StatementSyntax)parent, conditionalExpression, cancellationToken));
}
else if (parent is AssignmentExpressionSyntax assignment)
{
if (assignment.Parent is ExpressionStatementSyntax expressionStatement)
{
context.RegisterRefactoring(
Title,
cancellationToken => RefactorAsync(context.Document, expressionStatement, conditionalExpression, cancellationToken));
}
}
else
{
SingleLocalDeclarationStatementInfo localDeclarationInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(expression);
if (localDeclarationInfo.Success)
{
TypeSyntax type = localDeclarationInfo.Type;
if (type != null)
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (!type.IsVar ||
semanticModel.GetTypeSymbol(type, context.CancellationToken)?.SupportsExplicitDeclaration() == true)
{
context.RegisterRefactoring(
Title,
cancellationToken => RefactorAsync(context.Document, localDeclarationInfo.Statement, conditionalExpression, semanticModel, cancellationToken));
}
}
}
}
}
internal static async Task ComputeRefactoringAsync(RefactoringContext context, StatementListSelection selectedStatements)
{
if (selectedStatements.Count <= 1)
{
return;
}
StatementSyntax statement = selectedStatements.First();
SyntaxKind kind = statement.Kind();
if (kind == SyntaxKind.LocalDeclarationStatement)
{
var localDeclaration = (LocalDeclarationStatementSyntax)statement;
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (!CanRefactor(localInfo, semanticModel, context.CancellationToken))
{
return;
}
RegisterRefactoring(context, IdentifierName(localInfo.Identifier), localDeclaration, selectedStatements.Count - 1);
}
else if (kind == SyntaxKind.ExpressionStatement)
{
var expressionStatement = (ExpressionStatementSyntax)statement;
SimpleAssignmentStatementInfo assignmentInfo = SyntaxInfo.SimpleAssignmentStatementInfo(expressionStatement);
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (!CanRefactor(assignmentInfo, assignmentInfo.Left, semanticModel, context.CancellationToken))
{
return;
}
RegisterRefactoring(context, assignmentInfo.Left, expressionStatement, selectedStatements.Count - 1);
}
}
public async Task ComputeRefactoringAsync(RefactoringContext context, StatementListSelection selectedStatements)
{
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(selectedStatements.FirstOrDefault() as LocalDeclarationStatementSyntax);
if (!localInfo.Success)
{
return;
}
ExpressionSyntax value = localInfo.Value;
if (value == null)
{
return;
}
if (value.Kind() == SyntaxKind.DefaultExpression)
{
return;
}
if (value is LiteralExpressionSyntax)
{
return;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
var typeSymbol = semanticModel.GetTypeSymbol(localInfo.Type, context.CancellationToken) as INamedTypeSymbol;
if (typeSymbol?.Implements(SpecialType.System_IDisposable, allInterfaces: true) != true)
{
return;
}
context.RegisterRefactoring(
$"Using '{localInfo.IdentifierText}'",
cancellationToken => RefactorAsync(context.Document, selectedStatements, cancellationToken),
RefactoringIdentifiers.WrapInUsingStatement);
}
public static void ComputeRefactoring(RefactoringContext context, StringConcatenationExpressionInfo concatenationInfo)
{
BinaryExpressionSyntax binaryExpression = concatenationInfo.BinaryExpression;
if (binaryExpression.IsParentKind(SyntaxKind.SimpleAssignmentExpression, SyntaxKind.AddAssignmentExpression))
{
var assignment = (AssignmentExpressionSyntax)binaryExpression.Parent;
if (assignment.IsParentKind(SyntaxKind.ExpressionStatement) &&
assignment.Right == binaryExpression)
{
RegisterRefactoring(context, concatenationInfo, (StatementSyntax)assignment.Parent);
}
}
else
{
SingleLocalDeclarationStatementInfo info = SyntaxInfo.SingleLocalDeclarationStatementInfo(binaryExpression);
if (info.Success)
{
RegisterRefactoring(context, concatenationInfo, info.Statement);
}
}
}
private static void AnalyzeSwitchStatement(SyntaxNodeAnalysisContext context)
{
var switchStatement = (SwitchStatementSyntax)context.Node;
SyntaxList <SwitchSectionSyntax> sections = switchStatement.Sections;
if (!sections.Any())
{
return;
}
ExpressionSyntax switchExpression = switchStatement.Expression;
SingleLocalDeclarationStatementInfo localInfo = default;
string name = GetName();
if (name == null)
{
return;
}
ITypeSymbol kindSymbol = context.SemanticModel.GetTypeSymbol(switchExpression, context.CancellationToken);
if (kindSymbol?.HasMetadataName(RoslynMetadataNames.Microsoft_CodeAnalysis_CSharp_SyntaxKind) != true)
{
return;
}
foreach (SwitchSectionSyntax section in sections)
{
SwitchLabelSyntax label = section.Labels.SingleOrDefault(shouldThrow: false);
if (label == null)
{
return;
}
SyntaxKind labelKind = label.Kind();
if (labelKind == SyntaxKind.DefaultSwitchLabel)
{
continue;
}
if (labelKind != SyntaxKind.CaseSwitchLabel)
{
Debug.Assert(labelKind == SyntaxKind.CasePatternSwitchLabel, labelKind.ToString());
return;
}
var caseLabel = (CaseSwitchLabelSyntax)label;
ExpressionSyntax value = caseLabel.Value;
if (!value.IsKind(SyntaxKind.SimpleMemberAccessExpression))
{
return;
}
var memberAccess = (MemberAccessExpressionSyntax)value;
if (memberAccess.Name is not IdentifierNameSyntax identifierName)
{
return;
}
string kindName = identifierName.Identifier.ValueText;
if (!_syntaxKindNames.Contains(kindName))
{
return;
}
SyntaxList <StatementSyntax> statements = section.Statements;
StatementSyntax statement = statements.FirstOrDefault();
if (statement == null)
{
return;
}
if (statement is BlockSyntax block)
{
statement = block.Statements.FirstOrDefault();
}
if (!statement.IsKind(SyntaxKind.LocalDeclarationStatement))
{
return;
}
SingleLocalDeclarationStatementInfo localStatement = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statement);
if (!localStatement.Success)
{
return;
}
if (localStatement.Value is not CastExpressionSyntax castExpression)
{
return;
}
if (castExpression.Expression is not IdentifierNameSyntax localName)
{
return;
}
if (name != localName.Identifier.ValueText)
{
return;
}
if (!IsFixableSyntaxSymbol(castExpression.Type, kindName, context.SemanticModel, context.CancellationToken))
{
return;
}
}
if (localInfo.Success &&
IsLocalVariableReferenced(context, localInfo, switchStatement))
{
return;
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.UsePatternMatching, switchStatement.SwitchKeyword);
string GetName()
{
switch (switchExpression.Kind())
{
case SyntaxKind.IdentifierName:
{
StatementSyntax previousStatement = switchStatement.PreviousStatement();
if (!previousStatement.IsKind(SyntaxKind.LocalDeclarationStatement))
{
return(null);
}
localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)previousStatement);
if (!localInfo.Success)
{
return(null);
}
if (localInfo.IdentifierText != ((IdentifierNameSyntax)switchExpression).Identifier.ValueText)
{
return(null);
}
if (!localInfo.Value.IsKind(SyntaxKind.InvocationExpression))
{
return(null);
}
return(GetName2((InvocationExpressionSyntax)localInfo.Value));
}
case SyntaxKind.InvocationExpression:
{
return(GetName2((InvocationExpressionSyntax)switchExpression));
}
default:
{
return(null);
}
}
}
public static void AnalyzeAsExpression(SyntaxNodeAnalysisContext context)
{
var asExpression = (BinaryExpressionSyntax)context.Node;
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(asExpression);
if (!asExpressionInfo.Success)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(asExpression);
if (!localInfo.Success)
{
return;
}
if (localInfo.Statement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (!(localInfo.Statement.NextStatement() is IfStatementSyntax ifStatement))
{
return;
}
if (!ifStatement.IsSimpleIf())
{
return;
}
if (ifStatement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
StatementSyntax statement = ifStatement.SingleNonBlockStatementOrDefault();
if (statement == null)
{
return;
}
if (!CSharpFacts.IsJumpStatement(statement.Kind()))
{
return;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(ifStatement.Condition, NullCheckStyles.EqualsToNull | NullCheckStyles.IsNull);
if (!nullCheck.Success)
{
return;
}
if (!string.Equals(localInfo.IdentifierText, (nullCheck.Expression as IdentifierNameSyntax)?.Identifier.ValueText, StringComparison.Ordinal))
{
return;
}
context.ReportDiagnostic(DiagnosticDescriptors.UsePatternMatchingInsteadOfAsAndNullCheck, localInfo.Statement);
}
private static void AnalyzeLocalDeclarationStatement(SyntaxNodeAnalysisContext context)
{
var localDeclaration = (LocalDeclarationStatementSyntax)context.Node;
if (localDeclaration.ContainsDiagnostics)
{
return;
}
if (localDeclaration.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (localDeclaration.IsConst)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
if (!localInfo.Success)
{
return;
}
SimpleAssignmentStatementInfo assignmentInfo = SyntaxInfo.SimpleAssignmentStatementInfo(localDeclaration.NextStatement());
if (!assignmentInfo.Success)
{
return;
}
if (assignmentInfo.Statement.ContainsDiagnostics)
{
return;
}
if (assignmentInfo.Statement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
if (assignmentInfo.Left is not IdentifierNameSyntax identifierName)
{
return;
}
string name = identifierName.Identifier.ValueText;
if (!string.Equals(localInfo.IdentifierText, name, StringComparison.Ordinal))
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
if (semanticModel.GetSymbol(identifierName, cancellationToken) is not ILocalSymbol localSymbol)
{
return;
}
if (!SymbolEqualityComparer.Default.Equals(localSymbol, semanticModel.GetDeclaredSymbol(localInfo.Declarator, cancellationToken)))
{
return;
}
ExpressionSyntax value = localInfo.Value;
if (value != null)
{
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(localInfo.Type, cancellationToken);
if (typeSymbol == null)
{
return;
}
if (!semanticModel.IsDefaultValue(typeSymbol, value, cancellationToken))
{
return;
}
if (IsReferenced(localSymbol, assignmentInfo.Right, semanticModel, cancellationToken))
{
return;
}
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticRules.RemoveRedundantAssignment, localInfo.Identifier);
if (value != null)
{
DiagnosticHelpers.ReportNode(context, DiagnosticRules.RemoveRedundantAssignmentFadeOut, localInfo.Initializer);
DiagnosticHelpers.ReportToken(context, DiagnosticRules.RemoveRedundantAssignmentFadeOut, assignmentInfo.OperatorToken);
}
DiagnosticHelpers.ReportToken(context, DiagnosticRules.RemoveRedundantAssignmentFadeOut, localDeclaration.SemicolonToken);
DiagnosticHelpers.ReportNode(context, DiagnosticRules.RemoveRedundantAssignmentFadeOut, assignmentInfo.Left);
}
private static void AnalyzeAsExpression(SyntaxNodeAnalysisContext context)
{
var asExpression = (BinaryExpressionSyntax)context.Node;
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(asExpression);
if (!asExpressionInfo.Success)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(asExpression);
if (!localInfo.Success)
{
return;
}
if (localInfo.Statement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (!(localInfo.Statement.NextStatement() is IfStatementSyntax ifStatement))
{
return;
}
if (!ifStatement.IsSimpleIf())
{
return;
}
if (ifStatement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
StatementSyntax statement = ifStatement.SingleNonBlockStatementOrDefault();
if (statement == null)
{
return;
}
if (!CSharpFacts.IsJumpStatement(statement.Kind()))
{
return;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(ifStatement.Condition, NullCheckStyles.EqualsToNull | NullCheckStyles.IsNull);
if (!nullCheck.Success)
{
return;
}
if (!string.Equals(localInfo.IdentifierText, (nullCheck.Expression as IdentifierNameSyntax)?.Identifier.ValueText, StringComparison.Ordinal))
{
return;
}
if (!localInfo.Type.IsVar)
{
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(asExpressionInfo.Type, cancellationToken);
if (typeSymbol.IsNullableType())
{
return;
}
if (!SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeSymbol(localInfo.Type, cancellationToken), typeSymbol))
{
return;
}
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticDescriptors.UsePatternMatchingInsteadOfAsAndNullCheck, localInfo.Statement);
}
public static void AnalyzeLocalDeclarationStatement(SyntaxNodeAnalysisContext context)
{
var localDeclarationStatement = (LocalDeclarationStatementSyntax)context.Node;
if (localDeclarationStatement.ContainsDiagnostics)
{
return;
}
if (localDeclarationStatement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
SingleLocalDeclarationStatementInfo localDeclarationInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclarationStatement);
if (!localDeclarationInfo.Success)
{
return;
}
ExpressionSyntax value = localDeclarationInfo.Value;
if (value == null)
{
return;
}
SyntaxList <StatementSyntax> statements = SyntaxInfo.StatementListInfo(localDeclarationStatement).Statements;
if (!statements.Any())
{
return;
}
int index = statements.IndexOf(localDeclarationStatement);
if (index == statements.Count - 1)
{
return;
}
StatementSyntax nextStatement = statements[index + 1];
if (nextStatement.ContainsDiagnostics)
{
return;
}
switch (nextStatement.Kind())
{
case SyntaxKind.ExpressionStatement:
{
Analyze(context, statements, localDeclarationInfo, index, (ExpressionStatementSyntax)nextStatement);
break;
}
case SyntaxKind.LocalDeclarationStatement:
{
Analyze(context, statements, localDeclarationInfo, index, (LocalDeclarationStatementSyntax)nextStatement);
break;
}
case SyntaxKind.ReturnStatement:
{
var returnStatement = (ReturnStatementSyntax)nextStatement;
if (!returnStatement.SpanOrLeadingTriviaContainsDirectives())
{
ExpressionSyntax expression = returnStatement.Expression;
if (expression?.Kind() == SyntaxKind.IdentifierName)
{
var identifierName = (IdentifierNameSyntax)expression;
if (string.Equals(localDeclarationInfo.IdentifierText, identifierName.Identifier.ValueText, StringComparison.Ordinal))
{
ReportDiagnostic(context, localDeclarationInfo, expression);
}
}
}
break;
}
case SyntaxKind.ForEachStatement:
{
if (value.IsSingleLine() &&
!value.IsKind(SyntaxKind.ArrayInitializerExpression))
{
var forEachStatement = (ForEachStatementSyntax)nextStatement;
Analyze(context, statements, localDeclarationInfo, forEachStatement.Expression);
}
break;
}
case SyntaxKind.SwitchStatement:
{
if (value.IsSingleLine())
{
var switchStatement = (SwitchStatementSyntax)nextStatement;
Analyze(context, statements, localDeclarationInfo, switchStatement.Expression);
}
break;
}
}
}
private static SingleLocalDeclarationStatementInfo GetLocalInfo(StatementSyntax statement)
{
return((statement.IsKind(SyntaxKind.LocalDeclarationStatement))
? SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statement)
: default);
private static Task <Document> UsePatternMatchingAsync(
Document document,
SwitchStatementSyntax switchStatement,
CancellationToken cancellationToken)
{
SyntaxList <SwitchSectionSyntax> newSections = switchStatement.Sections.Select(section =>
{
if (!(section.Labels.Single() is CaseSwitchLabelSyntax label))
{
return(section);
}
SyntaxList <StatementSyntax> statements = section.Statements;
StatementSyntax statement = statements[0];
if (statement is BlockSyntax block)
{
statement = block.Statements.FirstOrDefault();
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statement);
var castExpression = (CastExpressionSyntax)localInfo.Value;
CasePatternSwitchLabelSyntax newLabel = CasePatternSwitchLabel(
DeclarationPattern(
castExpression.Type,
SingleVariableDesignation(localInfo.Identifier)),
label.ColonToken);
SwitchSectionSyntax newSection = section.RemoveStatement(localInfo.Statement);
newSection = newSection.WithLabels(newSection.Labels.ReplaceAt(0, newLabel));
return(newSection.WithFormatterAnnotation());
})
.ToSyntaxList();
ExpressionSyntax expression = switchStatement.Expression;
ExpressionSyntax newExpression = expression;
LocalDeclarationStatementSyntax localDeclaration = null;
if (expression.IsKind(SyntaxKind.InvocationExpression))
{
SimpleMemberInvocationExpressionInfo invocationInfo = SyntaxInfo.SimpleMemberInvocationExpressionInfo(expression);
newExpression = invocationInfo.Expression;
}
else
{
localDeclaration = (LocalDeclarationStatementSyntax)switchStatement.PreviousStatement();
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
SimpleMemberInvocationExpressionInfo invocationInfo = SyntaxInfo.SimpleMemberInvocationExpressionInfo(localInfo.Value);
newExpression = invocationInfo.Expression;
}
SwitchStatementSyntax newSwitchStatement = switchStatement
.WithExpression(newExpression.WithTriviaFrom(expression))
.WithSections(newSections);
if (localDeclaration != null)
{
StatementListInfo statementsInfo = SyntaxInfo.StatementListInfo(switchStatement);
newSwitchStatement = newSwitchStatement.WithLeadingTrivia(localDeclaration.GetLeadingTrivia());
SyntaxList <StatementSyntax> newStatements = statementsInfo.Statements
.Replace(switchStatement, newSwitchStatement)
.RemoveAt(statementsInfo.IndexOf(localDeclaration));
return(document.ReplaceStatementsAsync(statementsInfo, newStatements, cancellationToken));
}
else
{
return(document.ReplaceNodeAsync(switchStatement, newSwitchStatement, cancellationToken));
}
}
private static void AnalyzeIfStatement(SyntaxNodeAnalysisContext context)
{
var ifStatement = (IfStatementSyntax)context.Node;
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
IsKindExpressionInfo isKindExpression = IsKindExpressionInfo.Create(ifStatement.Condition, semanticModel, cancellationToken: cancellationToken);
if (!isKindExpression.Success)
{
return;
}
Optional <object> optionalConstantValue = semanticModel.GetConstantValue(isKindExpression.KindExpression, cancellationToken);
if (!optionalConstantValue.HasValue)
{
return;
}
if (!(optionalConstantValue.Value is ushort value))
{
return;
}
if (!_syntaxKindValuesToNames.TryGetValue(value, out string name))
{
return;
}
if (!_syntaxKindNames.Contains(name))
{
return;
}
switch (isKindExpression.Style)
{
case IsKindExpressionStyle.IsKind:
case IsKindExpressionStyle.IsKindConditional:
case IsKindExpressionStyle.Kind:
case IsKindExpressionStyle.KindConditional:
{
if (!(ifStatement.Statement is BlockSyntax block))
{
return;
}
Analyze(block.Statements.FirstOrDefault());
break;
}
case IsKindExpressionStyle.NotIsKind:
case IsKindExpressionStyle.NotIsKindConditional:
case IsKindExpressionStyle.NotKind:
case IsKindExpressionStyle.NotKindConditional:
{
if (ifStatement.Else != null)
{
return;
}
StatementSyntax statement = ifStatement.Statement.SingleNonBlockStatementOrDefault();
if (statement == null)
{
return;
}
if (!CSharpFacts.IsJumpStatement(statement.Kind()))
{
return;
}
Analyze(ifStatement.NextStatement());
break;
}
}
void Analyze(StatementSyntax statement)
{
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(statement);
if (!localInfo.Success)
{
return;
}
if (!(localInfo.Value is CastExpressionSyntax castExpression))
{
return;
}
if (!IsFixableSyntaxSymbol(castExpression.Type, name, semanticModel, cancellationToken))
{
return;
}
if (!CSharpFactory.AreEquivalent(isKindExpression.Expression, castExpression.Expression))
{
return;
}
context.ReportDiagnostic(DiagnosticDescriptors.UsePatternMatching, ifStatement.IfKeyword);
}
}
private static async Task <Document> UsePatternMatchingAsync(
Document document,
IfStatementSyntax ifStatement,
CancellationToken cancellationToken)
{
SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
IsKindExpressionInfo isKindExpression = IsKindExpressionInfo.Create(ifStatement.Condition, semanticModel, cancellationToken: cancellationToken);
switch (isKindExpression.Style)
{
case IsKindExpressionStyle.IsKind:
case IsKindExpressionStyle.IsKindConditional:
case IsKindExpressionStyle.Kind:
case IsKindExpressionStyle.KindConditional:
{
var block = (BlockSyntax)ifStatement.Statement;
IsPatternExpressionSyntax isPatternExpression = CreateIsPatternExpression(block.Statements[0]);
BlockSyntax newBlock = block.WithStatements(block.Statements.RemoveAt(0));
IfStatementSyntax newIfStatement = ifStatement.Update(
ifStatement.IfKeyword,
ifStatement.OpenParenToken,
isPatternExpression,
ifStatement.CloseParenToken,
newBlock,
ifStatement.Else);
newIfStatement = newIfStatement.WithFormatterAnnotation();
return(await document.ReplaceNodeAsync(ifStatement, newIfStatement, cancellationToken).ConfigureAwait(false));
}
case IsKindExpressionStyle.NotIsKind:
case IsKindExpressionStyle.NotIsKindConditional:
case IsKindExpressionStyle.NotKind:
case IsKindExpressionStyle.NotKindConditional:
{
StatementListInfo statementsInfo = SyntaxInfo.StatementListInfo(ifStatement);
SyntaxList <StatementSyntax> statements = statementsInfo.Statements;
int index = statements.IndexOf(ifStatement);
IsPatternExpressionSyntax isPatternExpression = CreateIsPatternExpression(statements[index + 1]);
IfStatementSyntax newIfStatement = ifStatement.WithCondition(LogicalNotExpression(isPatternExpression.Parenthesize()).WithTriviaFrom(ifStatement.Condition));
SyntaxList <StatementSyntax> newStatements = statements
.ReplaceAt(index, newIfStatement)
.RemoveAt(index + 1);
return(await document.ReplaceStatementsAsync(statementsInfo, newStatements, cancellationToken).ConfigureAwait(false));
}
default:
{
throw new InvalidOperationException();
}
}
IsPatternExpressionSyntax CreateIsPatternExpression(StatementSyntax statement)
{
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo((LocalDeclarationStatementSyntax)statement);
var castExpression = (CastExpressionSyntax)localInfo.Value;
return(IsPatternExpression(
isKindExpression.Expression,
DeclarationPattern(castExpression.Type, SingleVariableDesignation(localInfo.Identifier))));
}
}
public static async Task ComputeRefactoringAsync(RefactoringContext context, ConditionalExpressionSyntax conditionalExpression)
{
ExpressionSyntax expression = conditionalExpression.WalkUpParentheses();
SyntaxNode parent = expression.Parent;
if (parent.IsKind(SyntaxKind.ReturnStatement, SyntaxKind.YieldReturnStatement))
{
var statement = (StatementSyntax)parent;
RegisterRefactoring(context, conditionalExpression, statement);
if (IsRecursive())
{
RegisterRefactoring(context, conditionalExpression, statement, recursive: true);
}
}
else if (parent is AssignmentExpressionSyntax assignment)
{
if (assignment.Parent is ExpressionStatementSyntax expressionStatement)
{
RegisterRefactoring(context, conditionalExpression, expressionStatement);
if (IsRecursive())
{
RegisterRefactoring(context, conditionalExpression, expressionStatement, recursive: true);
}
}
}
else
{
SingleLocalDeclarationStatementInfo localDeclarationInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(expression);
if (localDeclarationInfo.Success)
{
TypeSyntax type = localDeclarationInfo.Type;
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (!type.IsVar ||
semanticModel.GetTypeSymbol(type, context.CancellationToken)?.SupportsExplicitDeclaration() == true)
{
LocalDeclarationStatementSyntax statement = localDeclarationInfo.Statement;
RegisterRefactoring(context, conditionalExpression, statement, semanticModel);
if (IsRecursive())
{
RegisterRefactoring(context, conditionalExpression, statement, semanticModel, recursive: true);
}
}
}
}
bool IsRecursive()
{
return(conditionalExpression
.WhenFalse
.WalkDownParentheses()
.IsKind(SyntaxKind.ConditionalExpression));
}
}
public static void AnalyzeLocalDeclarationStatement(SyntaxNodeAnalysisContext context)
{
var localDeclarationStatement = (LocalDeclarationStatementSyntax)context.Node;
if (localDeclarationStatement.ContainsDiagnostics)
{
return;
}
if (localDeclarationStatement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
SingleLocalDeclarationStatementInfo localDeclarationInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclarationStatement);
if (!localDeclarationInfo.Success)
{
return;
}
ExpressionSyntax value = localDeclarationInfo.Value;
if (value == null)
{
return;
}
SyntaxList <StatementSyntax> statements = SyntaxInfo.StatementListInfo(localDeclarationStatement).Statements;
if (!statements.Any())
{
return;
}
int index = statements.IndexOf(localDeclarationStatement);
if (index == statements.Count - 1)
{
return;
}
StatementSyntax nextStatement = statements[index + 1];
if (nextStatement.ContainsDiagnostics)
{
return;
}
switch (nextStatement.Kind())
{
case SyntaxKind.ExpressionStatement:
{
Analyze(context, statements, localDeclarationInfo, index, (ExpressionStatementSyntax)nextStatement);
break;
}
case SyntaxKind.LocalDeclarationStatement:
{
Analyze(context, statements, localDeclarationInfo, index, (LocalDeclarationStatementSyntax)nextStatement);
break;
}
case SyntaxKind.ReturnStatement:
{
var returnStatement = (ReturnStatementSyntax)nextStatement;
if (!returnStatement.SpanOrLeadingTriviaContainsDirectives())
{
ExpressionSyntax expression = returnStatement.Expression;
if (expression?.Kind() == SyntaxKind.IdentifierName)
{
var identifierName = (IdentifierNameSyntax)expression;
if (string.Equals(localDeclarationInfo.IdentifierText, identifierName.Identifier.ValueText, StringComparison.Ordinal))
{
ReportDiagnostic(context, localDeclarationInfo, expression);
}
}
}
break;
}
case SyntaxKind.YieldReturnStatement:
{
var yieldStatement = (YieldStatementSyntax)nextStatement;
if (index == statements.Count - 2 &&
!yieldStatement.SpanOrLeadingTriviaContainsDirectives())
{
ExpressionSyntax expression = yieldStatement.Expression;
if (expression?.Kind() == SyntaxKind.IdentifierName)
{
var identifierName = (IdentifierNameSyntax)expression;
if (string.Equals(localDeclarationInfo.IdentifierText, identifierName.Identifier.ValueText, StringComparison.Ordinal))
{
ReportDiagnostic(context, localDeclarationInfo, expression);
}
}
}
break;
}
case SyntaxKind.ForEachStatement:
{
if (value.WalkDownParentheses().IsKind(SyntaxKind.AwaitExpression))
{
return;
}
if (!value.IsSingleLine())
{
return;
}
if (value.IsKind(SyntaxKind.ArrayInitializerExpression))
{
return;
}
var forEachStatement = (ForEachStatementSyntax)nextStatement;
ISymbol localSymbol = GetLocalSymbol(localDeclarationInfo, forEachStatement.Expression, context.SemanticModel, context.CancellationToken);
if (localSymbol?.IsErrorType() != false)
{
return;
}
ContainsLocalOrParameterReferenceWalker walker = ContainsLocalOrParameterReferenceWalker.GetInstance(localSymbol, context.SemanticModel, context.CancellationToken);
walker.Visit(forEachStatement.Statement);
if (!walker.Result &&
index < statements.Count - 2)
{
walker.VisitList(statements, index + 2);
}
if (ContainsLocalOrParameterReferenceWalker.GetResultAndFree(walker))
{
return;
}
ReportDiagnostic(context, localDeclarationInfo, forEachStatement.Expression);
break;
}
case SyntaxKind.SwitchStatement:
{
if (value.WalkDownParentheses().IsKind(SyntaxKind.AwaitExpression))
{
return;
}
if (!value.IsSingleLine())
{
return;
}
var switchStatement = (SwitchStatementSyntax)nextStatement;
ISymbol localSymbol = GetLocalSymbol(localDeclarationInfo, switchStatement.Expression, context.SemanticModel, context.CancellationToken);
if (localSymbol?.IsErrorType() != false)
{
return;
}
ContainsLocalOrParameterReferenceWalker walker = ContainsLocalOrParameterReferenceWalker.GetInstance(localSymbol, context.SemanticModel, context.CancellationToken);
walker.VisitList(switchStatement.Sections);
if (!walker.Result &&
index < statements.Count - 2)
{
walker.VisitList(statements, index + 2);
}
if (ContainsLocalOrParameterReferenceWalker.GetResultAndFree(walker))
{
return;
}
ReportDiagnostic(context, localDeclarationInfo, switchStatement.Expression);
break;
}
}
}
public static void AnalyzeLocalDeclarationStatement(SyntaxNodeAnalysisContext context)
{
var localDeclaration = (LocalDeclarationStatementSyntax)context.Node;
if (localDeclaration.ContainsDiagnostics)
{
return;
}
if (localDeclaration.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (localDeclaration.IsConst)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(localDeclaration);
if (!localInfo.Success)
{
return;
}
SimpleAssignmentStatementInfo assignmentInfo = SyntaxInfo.SimpleAssignmentStatementInfo(localDeclaration.NextStatementOrDefault());
if (!assignmentInfo.Success)
{
return;
}
if (assignmentInfo.Statement.ContainsDiagnostics)
{
return;
}
if (assignmentInfo.Statement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
if (!(assignmentInfo.Left is IdentifierNameSyntax identifierName))
{
return;
}
string name = identifierName.Identifier.ValueText;
if (!string.Equals(localInfo.IdentifierText, name, StringComparison.Ordinal))
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
var localSymbol = semanticModel.GetSymbol(identifierName, cancellationToken) as ILocalSymbol;
if (localSymbol == null)
{
return;
}
if (!localSymbol.Equals(semanticModel.GetDeclaredSymbol(localInfo.Declarator, cancellationToken)))
{
return;
}
EqualsValueClauseSyntax initializer = localInfo.Initializer;
ExpressionSyntax value = initializer?.Value;
if (value != null)
{
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(localInfo.Type, cancellationToken);
if (typeSymbol == null)
{
return;
}
if (!semanticModel.IsDefaultValue(typeSymbol, value, cancellationToken))
{
return;
}
if (IsReferenced(localSymbol, assignmentInfo.Right, semanticModel, cancellationToken))
{
return;
}
}
context.ReportDiagnostic(DiagnosticDescriptors.MergeLocalDeclarationWithAssignment, localInfo.Identifier);
if (value != null)
{
context.ReportNode(DiagnosticDescriptors.MergeLocalDeclarationWithAssignmentFadeOut, initializer);
context.ReportToken(DiagnosticDescriptors.MergeLocalDeclarationWithAssignmentFadeOut, assignmentInfo.OperatorToken);
}
context.ReportToken(DiagnosticDescriptors.MergeLocalDeclarationWithAssignmentFadeOut, localDeclaration.SemicolonToken);
context.ReportNode(DiagnosticDescriptors.MergeLocalDeclarationWithAssignmentFadeOut, assignmentInfo.Left);
}