public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
SyntaxNode root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
ParenthesizedExpressionSyntax parenthesizedExpression = root
.FindNode(context.Span, getInnermostNodeForTie: true)?
.FirstAncestorOrSelf <ParenthesizedExpressionSyntax>();
CodeAction codeAction = CodeAction.Create(
"Remove redundant parentheses",
cancellationToken => RemoveRedundantParenthesesRefactoring.RefactorAsync(context.Document, parenthesizedExpression, cancellationToken),
DiagnosticIdentifiers.RemoveRedundantParentheses + EquivalenceKeySuffix);
context.RegisterCodeFix(codeAction, context.Diagnostics);
}
public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);
if (!TryFindFirstAncestorOrSelf(root, context.Span, out ParenthesizedExpressionSyntax parenthesizedExpression))
{
return;
}
CodeAction codeAction = CodeAction.Create(
"Remove redundant parentheses",
cancellationToken => RemoveRedundantParenthesesRefactoring.RefactorAsync(context.Document, parenthesizedExpression, cancellationToken),
GetEquivalenceKey(DiagnosticIdentifiers.RemoveRedundantParentheses));
context.RegisterCodeFix(codeAction, context.Diagnostics);
}
private void AnalyzeIfStatement(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (IfStatementSyntax)context.Node);
}
private void AnalyzeParenthesizedExpression(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (ParenthesizedExpressionSyntax)context.Node);
}
private void AnalyzeInitializer(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (InitializerExpressionSyntax)context.Node);
}
private void AnalyzeInterpolation(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (InterpolationSyntax)context.Node);
}
private void AnalyzeArrowExpressionClause(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (ArrowExpressionClauseSyntax)context.Node);
}
private void AnalyzeEqualsValueClause(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (EqualsValueClauseSyntax)context.Node);
}
private void AnalyzeAttributeArgument(SyntaxNodeAnalysisContext context)
{
RemoveRedundantParenthesesRefactoring.Analyze(context, (AttributeArgumentSyntax)context.Node);
}
public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
if (!Settings.IsEnabled(CodeFixIdentifiers.AddComparisonWithBooleanLiteral) &&
!Settings.IsEnabled(CodeFixIdentifiers.CreateSingletonArray) &&
!Settings.IsEnabled(CodeFixIdentifiers.UseUncheckedExpression) &&
!Settings.IsEnabled(CodeFixIdentifiers.RemoveConstModifier) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceNullLiteralExpressionWithDefaultValue) &&
!Settings.IsEnabled(CodeFixIdentifiers.UseCoalesceExpression) &&
!Settings.IsEnabled(CodeFixIdentifiers.RemoveConditionThatIsAlwaysEqualToTrueOrFalse) &&
!Settings.IsEnabled(CodeFixIdentifiers.IntroduceLocalVariable) &&
!Settings.IsEnabled(CodeFixIdentifiers.IntroduceField) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceStringLiteralWithCharacterLiteral) &&
!Settings.IsEnabled(CodeFixIdentifiers.UseYieldReturnInsteadOfReturn) &&
!Settings.IsEnabled(CodeFixIdentifiers.ChangeMemberTypeAccordingToReturnExpression) &&
!Settings.IsEnabled(CodeFixIdentifiers.AddArgumentList) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceConditionalExpressionWithIfElse) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceConstantWithField) &&
!Settings.IsEnabled(CodeFixIdentifiers.ChangeTypeAccordingToInitializer) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceYieldReturnWithForEach) &&
!Settings.IsEnabled(CodeFixIdentifiers.ReplaceComparisonWithAssignment) &&
!Settings.IsEnabled(CodeFixIdentifiers.RemoveParentheses))
{
return;
}
SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);
if (!TryFindNode(root, context.Span, out ExpressionSyntax expression))
{
return;
}
foreach (Diagnostic diagnostic in context.Diagnostics)
{
switch (diagnostic.Id)
{
case CompilerDiagnosticIdentifiers.CannotImplicitlyConvertTypeExplicitConversionExists:
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
TypeInfo typeInfo = semanticModel.GetTypeInfo(expression, context.CancellationToken);
ITypeSymbol type = typeInfo.Type;
ITypeSymbol convertedType = typeInfo.ConvertedType;
if ((type is INamedTypeSymbol namedType) &&
namedType.IsNullableType())
{
if (convertedType?.SpecialType == SpecialType.System_Boolean ||
AddComparisonWithBooleanLiteralRefactoring.IsCondition(expression))
{
if (Settings.IsEnabled(CodeFixIdentifiers.AddComparisonWithBooleanLiteral))
{
CodeAction codeAction = CodeAction.Create(
AddComparisonWithBooleanLiteralRefactoring.GetTitle(expression),
cancellationToken => AddComparisonWithBooleanLiteralRefactoring.RefactorAsync(context.Document, expression, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.AddComparisonWithBooleanLiteral));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
else if (namedType.TypeArguments[0].Equals(convertedType))
{
if (Settings.IsEnabled(CodeFixIdentifiers.UseCoalesceExpression))
{
CodeAction codeAction = CodeAction.Create(
"Use coalesce expression",
cancellationToken =>
{
ExpressionSyntax defaultValue = convertedType.GetDefaultValueSyntax(context.Document.GetDefaultSyntaxOptions());
ExpressionSyntax newNode = CoalesceExpression(expression.WithoutTrivia(), defaultValue)
.WithTriviaFrom(expression)
.Parenthesize()
.WithFormatterAnnotation();
return(context.Document.ReplaceNodeAsync(expression, newNode, cancellationToken));
},
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.UseCoalesceExpression));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
}
if (Settings.IsEnabled(CodeFixIdentifiers.ChangeMemberTypeAccordingToReturnExpression) &&
expression.IsParentKind(SyntaxKind.ReturnStatement, SyntaxKind.YieldReturnStatement))
{
ChangeMemberTypeRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
}
if (Settings.IsEnabled(CodeFixIdentifiers.AddCastExpression))
{
CodeFixRegistrator.AddCastExpression(context, diagnostic, expression, convertedType, semanticModel);
}
if (Settings.IsEnabled(CodeFixIdentifiers.ChangeTypeAccordingToInitializer))
{
ChangeTypeAccordingToInitializerRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
}
if (Settings.IsEnabled(CodeFixIdentifiers.CreateSingletonArray) &&
type?.IsErrorType() == false &&
!type.Equals(convertedType) &&
(convertedType is IArrayTypeSymbol arrayType) &&
semanticModel.IsImplicitConversion(expression, arrayType.ElementType))
{
CodeAction codeAction = CodeAction.Create(
"Create singleton array",
cancellationToken => CreateSingletonArrayRefactoring.RefactorAsync(context.Document, expression, arrayType.ElementType, semanticModel, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.CreateSingletonArray));
context.RegisterCodeFix(codeAction, diagnostic);
}
break;
}
case CompilerDiagnosticIdentifiers.ConstantValueCannotBeConverted:
{
if (!Settings.IsEnabled(CodeFixIdentifiers.UseUncheckedExpression))
{
break;
}
CodeAction codeAction = CodeAction.Create(
"Use 'unchecked'",
cancellationToken =>
{
CheckedExpressionSyntax newNode = CSharpFactory.UncheckedExpression(expression.WithoutTrivia());
newNode = newNode.WithTriviaFrom(expression);
return(context.Document.ReplaceNodeAsync(expression, newNode, cancellationToken));
},
GetEquivalenceKey(diagnostic));
context.RegisterCodeFix(codeAction, diagnostic);
break;
}
case CompilerDiagnosticIdentifiers.ExpressionBeingAssignedMustBeConstant:
{
SyntaxNode parent = expression.Parent;
if (parent?.IsKind(SyntaxKind.EqualsValueClause) != true)
{
break;
}
parent = parent.Parent;
if (parent?.IsKind(SyntaxKind.VariableDeclarator) != true)
{
break;
}
parent = parent.Parent;
if (!(parent is VariableDeclarationSyntax variableDeclaration))
{
break;
}
if (Settings.IsEnabled(CodeFixIdentifiers.RemoveConstModifier) &&
variableDeclaration.Parent is LocalDeclarationStatementSyntax localDeclarationStatement)
{
SyntaxTokenList modifiers = localDeclarationStatement.Modifiers;
if (!modifiers.Contains(SyntaxKind.ConstKeyword))
{
break;
}
ModifiersCodeFixRegistrator.RemoveModifier(context, diagnostic, localDeclarationStatement, SyntaxKind.ConstKeyword);
}
else if (Settings.IsEnabled(CodeFixIdentifiers.ReplaceConstantWithField) &&
variableDeclaration.Variables.Count == 1 &&
(variableDeclaration.Parent is FieldDeclarationSyntax fieldDeclaration) &&
fieldDeclaration.Modifiers.Contains(SyntaxKind.ConstKeyword))
{
CodeAction codeAction = CodeAction.Create(
ReplaceConstantWithFieldRefactoring.Title,
cancellationToken => ReplaceConstantWithFieldRefactoring.RefactorAsync(context.Document, fieldDeclaration, cancellationToken),
GetEquivalenceKey(diagnostic));
context.RegisterCodeFix(codeAction, diagnostic);
break;
}
break;
}
case CompilerDiagnosticIdentifiers.CannotConvertNullToTypeBecauseItIsNonNullableValueType:
case CompilerDiagnosticIdentifiers.CannotConvertNullToTypeParameterBecauseItCouldBeNonNullableValueType:
{
if (!Settings.IsEnabled(CodeFixIdentifiers.ReplaceNullLiteralExpressionWithDefaultValue))
{
break;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
CodeFixRegistrator.ReplaceNullWithDefaultValue(context, diagnostic, expression, semanticModel);
break;
}
case CompilerDiagnosticIdentifiers.ResultOfExpressionIsAlwaysConstantSinceValueIsNeverEqualToNull:
{
if (!Settings.IsEnabled(CodeFixIdentifiers.RemoveConditionThatIsAlwaysEqualToTrueOrFalse))
{
break;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(expression, allowedStyles: NullCheckStyles.ComparisonToNull);
if (!nullCheck.Success)
{
break;
}
CodeAction codeAction = CodeAction.Create(
"Remove condition",
cancellationToken =>
{
cancellationToken.ThrowIfCancellationRequested();
SyntaxNode newRoot = RemoveCondition(root, expression, nullCheck.Style == NullCheckStyles.NotEqualsToNull);
cancellationToken.ThrowIfCancellationRequested();
return(Task.FromResult(context.Document.WithSyntaxRoot(newRoot)));
},
GetEquivalenceKey(diagnostic));
context.RegisterCodeFix(codeAction, diagnostic);
break;
}
case CompilerDiagnosticIdentifiers.OnlyAssignmentCallIncrementDecrementAndNewObjectExpressionsCanBeUsedAsStatement:
{
if (Settings.IsEnabled(CodeFixIdentifiers.RemoveParentheses) &&
expression is ParenthesizedExpressionSyntax parenthesizedExpression &&
parenthesizedExpression?.IsMissing == false)
{
CodeAction codeAction = CodeAction.Create(
"Remove parentheses",
cancellationToken => RemoveRedundantParenthesesRefactoring.RefactorAsync(context.Document, parenthesizedExpression, cancellationToken),
GetEquivalenceKey(diagnostic));
context.RegisterCodeFix(codeAction, diagnostic);
break;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (expression.Parent is ArrowExpressionClauseSyntax arrowExpresssionClause)
{
if (!Settings.IsEnabled(CodeFixIdentifiers.ChangeMemberTypeAccordingToReturnExpression))
{
break;
}
ChangeMemberTypeRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
}
else if (expression.Parent is ExpressionStatementSyntax expressionStatement)
{
if (Settings.IsEnabled(CodeFixIdentifiers.AddArgumentList) &&
expression.IsKind(
SyntaxKind.IdentifierName,
SyntaxKind.SimpleMemberAccessExpression))
{
SyntaxNode invocationExpression = InvocationExpression(expression);
if (semanticModel.GetSpeculativeMethodSymbol(expression.SpanStart, invocationExpression) != null)
{
CodeAction codeAction = CodeAction.Create(
"Add argument list",
cancellationToken => context.Document.ReplaceNodeAsync(expression, invocationExpression, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.AddArgumentList));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
if (Settings.IsEnabled(CodeFixIdentifiers.ReplaceComparisonWithAssignment) &&
expression.IsKind(SyntaxKind.EqualsExpression))
{
BinaryExpressionInfo info = SyntaxInfo.BinaryExpressionInfo(expression);
if (!info.Success)
{
break;
}
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(info.Left, context.CancellationToken);
if (typeSymbol?.IsErrorType() != false)
{
break;
}
if (!semanticModel.IsImplicitConversion(info.Right, typeSymbol))
{
break;
}
CodeAction codeAction = CodeAction.Create(
"Replace comparison with assignment",
cancellationToken =>
{
AssignmentExpressionSyntax simpleAssignment = SimpleAssignmentExpression(info.Left, info.Right).WithTriviaFrom(expression);
return(context.Document.ReplaceNodeAsync(expression, simpleAssignment, cancellationToken));
},
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.ReplaceComparisonWithAssignment));
context.RegisterCodeFix(codeAction, diagnostic);
}
if (Settings.IsEnabled(CodeFixIdentifiers.ReplaceConditionalExpressionWithIfElse) &&
(expression is ConditionalExpressionSyntax conditionalExpression) &&
conditionalExpression.Condition != null)
{
ExpressionSyntax whenTrue = conditionalExpression.WhenTrue;
ExpressionSyntax whenFalse = conditionalExpression.WhenFalse;
if (whenTrue != null &&
whenFalse != null &&
semanticModel.GetTypeSymbol(whenTrue, context.CancellationToken)?.SpecialType == SpecialType.System_Void &&
semanticModel.GetTypeSymbol(whenFalse, context.CancellationToken)?.SpecialType == SpecialType.System_Void)
{
CodeAction codeAction = CodeAction.Create(
"Replace ?: with if-else",
cancellationToken =>
{
IfStatementSyntax newNode = IfStatement(
conditionalExpression.Condition.WalkDownParentheses(),
Block(ExpressionStatement(whenTrue)),
ElseClause(Block(ExpressionStatement(whenFalse))));
newNode = newNode
.WithTriviaFrom(expressionStatement)
.WithFormatterAnnotation();
return(context.Document.ReplaceNodeAsync(expressionStatement, newNode, cancellationToken));
},
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.ReplaceConditionalExpressionWithIfElse));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
if (Settings.IsAnyEnabled(
CodeFixIdentifiers.IntroduceLocalVariable,
CodeFixIdentifiers.IntroduceField))
{
if (semanticModel.GetSymbol(expression, context.CancellationToken)?.IsErrorType() != false)
{
break;
}
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(expression, context.CancellationToken);
if (typeSymbol?.IsErrorType() != false)
{
break;
}
if (Settings.IsEnabled(CodeFixIdentifiers.IntroduceLocalVariable) &&
!expressionStatement.IsEmbedded())
{
bool addAwait = typeSymbol.OriginalDefinition.EqualsOrInheritsFromTaskOfT() &&
semanticModel.GetEnclosingSymbol(expressionStatement.SpanStart, context.CancellationToken).IsAsyncMethod();
CodeAction codeAction = CodeAction.Create(
IntroduceLocalVariableRefactoring.GetTitle(expression),
cancellationToken => IntroduceLocalVariableRefactoring.RefactorAsync(context.Document, expressionStatement, typeSymbol, addAwait, semanticModel, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.IntroduceLocalVariable));
context.RegisterCodeFix(codeAction, diagnostic);
}
if (Settings.IsEnabled(CodeFixIdentifiers.IntroduceField))
{
CodeAction codeAction = CodeAction.Create(
$"Introduce field for '{expression}'",
cancellationToken => IntroduceFieldRefactoring.RefactorAsync(context.Document, expressionStatement, typeSymbol, semanticModel, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.IntroduceField));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
}
break;
}
case CompilerDiagnosticIdentifiers.CannotImplicitlyConvertType:
{
if (Settings.IsEnabled(CodeFixIdentifiers.ReplaceYieldReturnWithForEach) &&
expression.IsParentKind(SyntaxKind.YieldReturnStatement))
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
ReplaceYieldReturnWithForEachRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
break;
}
if (Settings.IsEnabled(CodeFixIdentifiers.ChangeMemberTypeAccordingToReturnExpression) &&
expression.IsParentKind(SyntaxKind.ReturnStatement, SyntaxKind.YieldReturnStatement))
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
ChangeMemberTypeRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
break;
}
if (Settings.IsEnabled(CodeFixIdentifiers.ChangeTypeAccordingToInitializer))
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
CodeFixRegistrationResult result = ChangeTypeAccordingToInitializerRefactoring.ComputeCodeFix(context, diagnostic, expression, semanticModel);
if (!result.Success)
{
RemoveAssignmentOfVoidExpression(context, diagnostic, expression, semanticModel);
}
break;
}
if (Settings.IsEnabled(CodeFixIdentifiers.ReplaceStringLiteralWithCharacterLiteral) &&
expression?.Kind() == SyntaxKind.StringLiteralExpression)
{
var literalExpression = (LiteralExpressionSyntax)expression;
if (literalExpression.Token.ValueText.Length == 1)
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (semanticModel.GetTypeInfo(expression, context.CancellationToken).ConvertedType?.SpecialType == SpecialType.System_Char)
{
CodeAction codeAction = CodeAction.Create(
"Replace string literal with character literal",
cancellationToken => ReplaceStringLiteralWithCharacterLiteralRefactoring.RefactorAsync(context.Document, literalExpression, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.ReplaceStringLiteralWithCharacterLiteral));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
}
if (Settings.IsEnabled(CodeFixIdentifiers.UseYieldReturnInsteadOfReturn) &&
expression.IsParentKind(SyntaxKind.ReturnStatement))
{
var returnStatement = (ReturnStatementSyntax)expression.Parent;
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
ISymbol containingSymbol = semanticModel.GetEnclosingSymbol(returnStatement.SpanStart, context.CancellationToken);
if (containingSymbol?.Kind == SymbolKind.Method &&
((IMethodSymbol)containingSymbol).ReturnType.OriginalDefinition.IsIEnumerableOrIEnumerableOfT())
{
CodeAction codeAction = CodeAction.Create(
"Use yield return instead of return",
cancellationToken => UseYieldReturnInsteadOfReturnRefactoring.RefactorAsync(context.Document, returnStatement, SyntaxKind.YieldReturnStatement, semanticModel, cancellationToken),
GetEquivalenceKey(diagnostic, CodeFixIdentifiers.UseYieldReturnInsteadOfReturn));
context.RegisterCodeFix(codeAction, diagnostic);
}
}
break;
}
case CompilerDiagnosticIdentifiers.LeftHandSideOfAssignmentMustBeVariablePropertyOrIndexer:
{
if (!Settings.IsEnabled(CodeFixIdentifiers.RemoveConstModifier))
{
return;
}
if (!expression.IsKind(SyntaxKind.IdentifierName))
{
return;
}
if (!expression.IsParentKind(SyntaxKind.SimpleAssignmentExpression))
{
return;
}
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
SymbolInfo symbolInfo = semanticModel.GetSymbolInfo(expression, context.CancellationToken);
if (symbolInfo.CandidateReason != CandidateReason.NotAVariable)
{
return;
}
if (!(symbolInfo.CandidateSymbols.SingleOrDefault(shouldThrow: false) is ILocalSymbol localSymbol))
{
return;
}
if (!localSymbol.IsConst)
{
return;
}
SyntaxNode node = localSymbol.GetSyntaxOrDefault(context.CancellationToken);
if (!node.IsKind(SyntaxKind.VariableDeclarator))
{
return;
}
node = node.Parent;
if (!node.IsKind(SyntaxKind.VariableDeclaration))
{
return;
}
node = node.Parent;
if (!node.IsKind(SyntaxKind.LocalDeclarationStatement))
{
return;
}
var localDeclaration = (LocalDeclarationStatementSyntax)node;
SyntaxToken constModifier = localDeclaration.Modifiers.Find(SyntaxKind.ConstKeyword);
if (!constModifier.IsKind(SyntaxKind.ConstKeyword))
{
return;
}
ModifiersCodeFixRegistrator.RemoveModifier(context, diagnostic, localDeclaration, constModifier);
break;
}
}
}
}
