public static BlockSyntax AddTrailingBlankLine(BlockSyntax block)
        {
            Debug.Assert(block != null && NeedsTrailingBlankLine(block));

            return block
                .WithTrailingTrivia(block.GetTrailingTrivia().Add(SyntaxFactory.CarriageReturnLineFeed))
                .WithAdditionalAnnotations(Formatter.Annotation);
        }
Beispiel #2
0
        protected bool ExpandWithStatements(SyntaxList <StatementSyntax> statements, out SyntaxList <StatementSyntax> newStatements)
        {
            //check if list contains "with" syntax
            if (!statements.Where(p => (p.Kind == SyntaxKind.WithStatement)).Any())
            {
                newStatements = statements;
                return(false);
            }

            //collect new list of statements
            List <StatementSyntax> newStatementsList = new List <StatementSyntax>();

            foreach (StatementSyntax statementSyntax in statements)
            {
                if (statementSyntax.Kind == SyntaxKind.WithStatement)
                {
                    SyntaxNode newWithNode = this.Visit(statementSyntax);
                    if (newWithNode.Kind == SyntaxKind.Block)
                    {
                        BlockSyntax newWithBlock = (BlockSyntax)newWithNode;

                        if (newWithBlock.Statements.Count > 0)
                        {
                            int newStartIdx = newStatementsList.Count;
                            newStatementsList.AddRange(newWithBlock.Statements);

                            //copy leading and trailing trivia from block to the first and last block statements
                            //as they might contain important information
                            newStatementsList[newStartIdx] = newStatementsList[newStartIdx]
                                                             .WithLeadingTrivia(
                                newWithBlock.GetLeadingTrivia()
                                .AddRange(newStatementsList[newStartIdx].GetLeadingTrivia())
                                .NormalizeSyntaxTriviaList());
                            int newEndIdx = newStatementsList.Count - 1;

                            newStatementsList[newEndIdx] = newStatementsList[newEndIdx]
                                                           .WithTrailingTrivia(
                                newStatementsList[newEndIdx].GetTrailingTrivia()
                                .AddRange(newWithBlock.EndKeywordToken.LeadingTrivia)
                                .AddRange(newWithBlock.GetTrailingTrivia())
                                .NormalizeSyntaxTriviaList());
                        }
                    }
                    else
                    {
                        newStatementsList.Add((StatementSyntax)newWithNode);
                    }
                }
                else
                {
                    newStatementsList.Add(statementSyntax);
                }
            }

            newStatements = SyntaxFactory.List <StatementSyntax>(newStatementsList);
            return(true);
        }
        public static Task <Document> RefactorAsync(
            Document document,
            BlockSyntax block,
            CancellationToken cancellationToken)
        {
            StatementSyntax statement = block
                                        .Statements[0]
                                        .TrimTrivia()
                                        .PrependToLeadingTrivia(block.GetLeadingTrivia())
                                        .AppendToTrailingTrivia(block.GetTrailingTrivia())
                                        .WithFormatterAnnotation();

            return(document.ReplaceNodeAsync(block, statement, cancellationToken));
        }
Beispiel #4
0
        public static Task <Document> RefactorAsync(
            Document document,
            UnsafeStatementSyntax unsafeStatement,
            SyntaxNode containingNode,
            CancellationToken cancellationToken)
        {
            SyntaxToken keyword = unsafeStatement.UnsafeKeyword;

            BlockSyntax block = unsafeStatement.Block;

            SyntaxList <StatementSyntax> statements = block.Statements;

            SyntaxNode newNode = null;

            int count = statements.Count;

            if (count == 0)
            {
                newNode = containingNode.RemoveNode(unsafeStatement);
            }
            else
            {
                StatementSyntax first = statements.First();
                StatementSyntax last  = statements.Last();

                SyntaxTriviaList leadingTrivia = keyword.LeadingTrivia
                                                 .AddRange(keyword.TrailingTrivia.EmptyIfWhitespace())
                                                 .AddRange(block.GetLeadingTrivia().EmptyIfWhitespace())
                                                 .AddRange(block.OpenBraceToken.TrailingTrivia.EmptyIfWhitespace())
                                                 .AddRange(first.GetLeadingTrivia().EmptyIfWhitespace());

                SyntaxTriviaList trailingTrivia = last.GetTrailingTrivia().EmptyIfWhitespace()
                                                  .AddRange(block.CloseBraceToken.LeadingTrivia.EmptyIfWhitespace())
                                                  .AddRange(block.GetTrailingTrivia());

                statements = statements
                             .ReplaceAt(0, first.WithLeadingTrivia(leadingTrivia))
                             .ReplaceAt(count - 1, last.WithTrailingTrivia(trailingTrivia));

                newNode = containingNode.ReplaceNode(unsafeStatement, statements.Select(f => f.WithFormatterAnnotation()));
            }

            newNode = newNode.InsertModifier(SyntaxKind.UnsafeKeyword);

            return(document.ReplaceNodeAsync(containingNode, newNode, cancellationToken));
        }
Beispiel #5
0
        private static async Task <Document> RefactorAsync(
            Document document,
            IfStatementSyntax ifStatement,
            CancellationToken cancellationToken)
        {
            ExpressionSyntax condition = ifStatement.Condition;

            ElseClauseSyntax elseClause = ifStatement.Else;

            if ((ifStatement.Statement as BlockSyntax)?.Statements.Any() == false)
            {
                SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);

                ExpressionSyntax newCondition = Inverter.LogicallyNegate(condition, semanticModel, cancellationToken);

                StatementSyntax statement = elseClause.Statement;

                if (statement is IfStatementSyntax nestedIf)
                {
                    newCondition = LogicalAndExpression(newCondition.Parenthesize(), nestedIf.Condition.Parenthesize());

                    statement = nestedIf.Statement;
                }

                cancellationToken.ThrowIfCancellationRequested();

                IfStatementSyntax newNode = ifStatement.Update(
                    ifStatement.IfKeyword,
                    ifStatement.OpenParenToken,
                    newCondition,
                    ifStatement.CloseParenToken,
                    statement,
                    default(ElseClauseSyntax));

                newNode = newNode.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(ifStatement, newNode, cancellationToken).ConfigureAwait(false));
            }
            else if (elseClause != null)
            {
                WhileStatementSyntax whileStatement;

                if (ifStatement.Parent is BlockSyntax block)
                {
                    whileStatement = (WhileStatementSyntax)block.Parent;
                }
                else
                {
                    block          = Block();
                    whileStatement = (WhileStatementSyntax)ifStatement.Parent;
                }

                cancellationToken.ThrowIfCancellationRequested();

                BlockSyntax newBlock = (ifStatement.Statement is BlockSyntax ifBlock)
                    ? block.WithStatements(ifBlock.Statements)
                    : block.WithStatements(SingletonList(ifStatement.Statement));

                SyntaxNode newNode = whileStatement.Update(
                    whileStatement.WhileKeyword,
                    whileStatement.OpenParenToken,
                    ifStatement.Condition,
                    whileStatement.CloseParenToken,
                    newBlock);

                newNode = newNode.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(whileStatement, newNode, cancellationToken).ConfigureAwait(false));
            }
            else
            {
                var block = (BlockSyntax)ifStatement.Parent;

                SyntaxList <StatementSyntax> statements = block.Statements;

                BlockSyntax newBlock = block.WithStatements(statements.Remove(ifStatement));

                SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);

                ExpressionSyntax newCondition = Inverter.LogicallyNegate(condition, semanticModel, cancellationToken);

                SyntaxNode newNode = block.Parent;

                switch (block.Parent)
                {
                case WhileStatementSyntax whileStatement:
                {
                    cancellationToken.ThrowIfCancellationRequested();

                    if (statements.IsFirst(ifStatement))
                    {
                        newNode = whileStatement.Update(
                            whileStatement.WhileKeyword,
                            whileStatement.OpenParenToken,
                            newCondition,
                            whileStatement.CloseParenToken,
                            newBlock);
                    }
                    else
                    {
                        newNode = DoStatement(
                            Token(whileStatement.WhileKeyword.LeadingTrivia, SyntaxKind.DoKeyword, whileStatement.CloseParenToken.TrailingTrivia),
                            newBlock.WithoutTrailingTrivia(),
                            Token(SyntaxKind.WhileKeyword),
                            OpenParenToken(),
                            newCondition,
                            CloseParenToken(),
                            SemicolonToken().WithTrailingTrivia(newBlock.GetTrailingTrivia()));
                    }

                    break;
                }

                case DoStatementSyntax doStatement:
                {
                    cancellationToken.ThrowIfCancellationRequested();

                    if (statements.IsLast(ifStatement))
                    {
                        newNode = doStatement.Update(
                            doStatement.DoKeyword,
                            newBlock,
                            doStatement.WhileKeyword,
                            doStatement.OpenParenToken,
                            newCondition,
                            doStatement.CloseParenToken,
                            doStatement.SemicolonToken);
                    }
                    else
                    {
                        newNode = WhileStatement(
                            Token(doStatement.DoKeyword.LeadingTrivia, SyntaxKind.WhileKeyword, SyntaxTriviaList.Empty),
                            OpenParenToken(),
                            newCondition,
                            Token(SyntaxTriviaList.Empty, SyntaxKind.CloseParenToken, doStatement.DoKeyword.TrailingTrivia),
                            newBlock.WithTrailingTrivia(doStatement.GetTrailingTrivia()));
                    }

                    break;
                }

                default:
                {
                    Debug.Fail(block.Parent.Kind().ToString());
                    break;
                }
                }

                newNode = newNode.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(block.Parent, newNode, cancellationToken).ConfigureAwait(false));
            }
        }
        SyntaxNode ApplyNodeChange(BlockSyntax blockNode)
        {
            if (blockNode.Parent is ConversionOperatorDeclarationSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is OperatorDeclarationSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is AccessorDeclarationSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is ConstructorDeclarationSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is DestructorDeclarationSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is TryStatementSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is CatchClauseSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is FinallyClauseSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is IfStatementSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is ElseClauseSyntax)
            {
                return(blockNode);
            }
            // if (blockNode.Parent is ParenthesizedExpressionSyntax) return blockNode;
            if (blockNode.Parent is SimpleLambdaExpressionSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is ParenthesizedLambdaExpressionSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is AnonymousMethodExpressionSyntax)
            {
                return(blockNode);
            }
            if (blockNode.Parent is LocalFunctionStatementSyntax)
            {
                return(blockNode);
            }

            if (blockNode.Parent is MethodDeclarationSyntax == false && blockNode.Statements.Count == 1)
            {
                var singleStatement = blockNode.Statements.FirstOrDefault();

                if (singleStatement.Span.Length <= NormalizeWhiteSpace.Options.Block_Single_Statement_Max_Length)
                {
                    if (isReportOnlyMode)
                    {
                        var lineSpan = singleStatement.GetFileLinePosSpan();

                        AddReport(new ChangesReport(singleStatement)
                        {
                            LineNumber = lineSpan.StartLinePosition.Line,
                            Column     = lineSpan.StartLinePosition.Character,
                            Message    = "remove brackets from on line lambda expression",
                            Generator  = nameof(BlockRewriter)
                        });
                    }

                    singleStatement =
                        singleStatement
                        .WithTrailingTrivia(
                            CleanUpListWithExactNumberOfWhiteSpaces(
                                SyntaxFactory.TriviaList(
                                    blockNode.CloseBraceToken.LeadingTrivia
                                    .AddRange(singleStatement.GetTrailingTrivia())
                                    .AddRange(blockNode.GetTrailingTrivia())
                                    ), 1, null)
                            );

                    lastBlockToken = singleStatement.GetLastToken();

                    return(singleStatement);
                }
            }

            return(blockNode);
        }
Beispiel #7
0
        public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.AddArgumentList) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReorderModifiers) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReplaceNullLiteralExpressionWithDefaultValue) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReturnDefaultValue) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.AddMissingType) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.RemoveSemicolon) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.RemoveConditionalAccess) &&
                !Settings.IsCodeFixEnabled(CodeFixIdentifiers.ChangeForEachType))
            {
                return;
            }

            SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);

            if (!TryFindToken(root, context.Span.Start, out SyntaxToken token))
            {
                return;
            }

            SyntaxKind kind = token.Kind();

            foreach (Diagnostic diagnostic in context.Diagnostics)
            {
                switch (diagnostic.Id)
                {
                case CompilerDiagnosticIdentifiers.OperatorCannotBeAppliedToOperandOfType:
                {
                    if (kind == SyntaxKind.QuestionToken &&
                        token.Parent is ConditionalAccessExpressionSyntax conditionalAccess)
                    {
                        SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                        ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(conditionalAccess.Expression, context.CancellationToken);

                        if (typeSymbol?.IsErrorType() == false &&
                            !typeSymbol.IsConstructedFrom(SpecialType.System_Nullable_T))
                        {
                            if (typeSymbol.IsValueType)
                            {
                                if (Settings.IsCodeFixEnabled(CodeFixIdentifiers.RemoveConditionalAccess))
                                {
                                    CodeAction codeAction = CodeAction.Create(
                                        "Remove '?' operator",
                                        cancellationToken =>
                                        {
                                            var textChange = new TextChange(token.Span, "");
                                            return(context.Document.WithTextChangeAsync(textChange, cancellationToken));
                                        },
                                        GetEquivalenceKey(diagnostic));

                                    context.RegisterCodeFix(codeAction, diagnostic);
                                }
                            }
                            else if (typeSymbol.IsReferenceType)
                            {
                                if (Settings.IsCodeFixEnabled(CodeFixIdentifiers.AddArgumentList) &&
                                    conditionalAccess.WhenNotNull is MemberBindingExpressionSyntax memberBindingExpression)
                                {
                                    ConditionalAccessExpressionSyntax newNode = conditionalAccess.WithWhenNotNull(
                                        InvocationExpression(
                                            memberBindingExpression.WithoutTrailingTrivia(),
                                            ArgumentList().WithTrailingTrivia(memberBindingExpression.GetTrailingTrivia())));

                                    CodeAction codeAction = CodeAction.Create(
                                        "Add argument list",
                                        cancellationToken => context.Document.ReplaceNodeAsync(conditionalAccess, newNode, cancellationToken),
                                        GetEquivalenceKey(diagnostic));

                                    context.RegisterCodeFix(codeAction, diagnostic);
                                }
                            }
                        }

                        if (Settings.IsCodeFixEnabled(CodeFixIdentifiers.AddArgumentList))
                        {
                            break;
                        }

                        if (Settings.IsCodeFixEnabled(CodeFixIdentifiers.RemoveConditionalAccess))
                        {
                        }
                    }

                    break;
                }

                case CompilerDiagnosticIdentifiers.PartialModifierCanOnlyAppearImmediatelyBeforeClassStructInterfaceOrVoid:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReorderModifiers))
                    {
                        break;
                    }

                    ModifiersCodeFixRegistrator.MoveModifier(context, diagnostic, token.Parent, token);
                    break;
                }

                case CompilerDiagnosticIdentifiers.ValueCannotBeUsedAsDefaultParameter:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReplaceNullLiteralExpressionWithDefaultValue))
                    {
                        break;
                    }

                    if (!(token.Parent is ParameterSyntax parameter))
                    {
                        break;
                    }

                    ExpressionSyntax value = parameter.Default?.Value;

                    if (value == null)
                    {
                        break;
                    }

                    if (value.Kind() != SyntaxKind.NullLiteralExpression)
                    {
                        break;
                    }

                    SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                    CodeFixRegistrator.ReplaceNullWithDefaultValue(context, diagnostic, value, semanticModel);
                    break;
                }

                case CompilerDiagnosticIdentifiers.ObjectOfTypeConvertibleToTypeIsRequired:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.ReturnDefaultValue))
                    {
                        break;
                    }

                    if (token.Kind() != SyntaxKind.ReturnKeyword)
                    {
                        break;
                    }

                    if (!token.IsParentKind(SyntaxKind.ReturnStatement))
                    {
                        break;
                    }

                    SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                    ISymbol symbol = semanticModel.GetEnclosingSymbol(token.SpanStart, context.CancellationToken);

                    if (symbol == null)
                    {
                        break;
                    }

                    SymbolKind symbolKind = symbol.Kind;

                    ITypeSymbol typeSymbol = null;

                    if (symbolKind == SymbolKind.Method)
                    {
                        var methodSymbol = (IMethodSymbol)symbol;

                        typeSymbol = methodSymbol.ReturnType;

                        if (methodSymbol.IsAsync &&
                            (typeSymbol is INamedTypeSymbol namedTypeSymbol))
                        {
                            ImmutableArray <ITypeSymbol> typeArguments = namedTypeSymbol.TypeArguments;

                            if (typeArguments.Any())
                            {
                                typeSymbol = typeArguments[0];
                            }
                        }
                    }
                    else if (symbolKind == SymbolKind.Property)
                    {
                        typeSymbol = ((IPropertySymbol)symbol).Type;
                    }
                    else
                    {
                        Debug.Fail(symbolKind.ToString());
                    }

                    if (typeSymbol == null)
                    {
                        break;
                    }

                    if (typeSymbol.Kind == SymbolKind.ErrorType)
                    {
                        break;
                    }

                    if (!typeSymbol.SupportsExplicitDeclaration())
                    {
                        break;
                    }

                    var returnStatement = (ReturnStatementSyntax)token.Parent;

                    CodeAction codeAction = CodeAction.Create(
                        "Return default value",
                        cancellationToken =>
                        {
                            ExpressionSyntax expression = typeSymbol.ToDefaultValueSyntax(semanticModel, returnStatement.SpanStart);

                            ReturnStatementSyntax newNode = returnStatement.WithExpression(expression);

                            return(context.Document.ReplaceNodeAsync(returnStatement, newNode, cancellationToken));
                        },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                    break;
                }

                case CompilerDiagnosticIdentifiers.TypeExpected:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.AddMissingType))
                    {
                        break;
                    }

                    if (token.Kind() != SyntaxKind.CloseParenToken)
                    {
                        break;
                    }

                    if (!(token.Parent is DefaultExpressionSyntax defaultExpression))
                    {
                        break;
                    }

                    if (!(defaultExpression.Type is IdentifierNameSyntax identifierName))
                    {
                        break;
                    }

                    if (!identifierName.IsMissing)
                    {
                        break;
                    }

                    SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                    TypeInfo typeInfo = semanticModel.GetTypeInfo(defaultExpression, context.CancellationToken);

                    ITypeSymbol convertedType = typeInfo.ConvertedType;

                    if (convertedType?.SupportsExplicitDeclaration() != true)
                    {
                        break;
                    }

                    CodeAction codeAction = CodeAction.Create(
                        $"Add type '{SymbolDisplay.GetMinimalString(convertedType, semanticModel, defaultExpression.SpanStart)}'",
                        cancellationToken =>
                        {
                            TypeSyntax newNode = convertedType.ToMinimalTypeSyntax(semanticModel, defaultExpression.SpanStart);

                            newNode = newNode
                                      .WithTriviaFrom(identifierName)
                                      .WithFormatterAnnotation();

                            return(context.Document.ReplaceNodeAsync(identifierName, newNode, cancellationToken));
                        },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                    break;
                }

                case CompilerDiagnosticIdentifiers.SemicolonAfterMethodOrAccessorBlockIsNotValid:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.RemoveSemicolon))
                    {
                        break;
                    }

                    if (token.Kind() != SyntaxKind.SemicolonToken)
                    {
                        break;
                    }

                    switch (token.Parent)
                    {
                    case MethodDeclarationSyntax methodDeclaration:
                    {
                        BlockSyntax body = methodDeclaration.Body;

                        if (body == null)
                        {
                            break;
                        }

                        CodeAction codeAction = CodeAction.Create(
                            "Remove semicolon",
                            cancellationToken =>
                                {
                                    SyntaxTriviaList trivia = body
                                                              .GetTrailingTrivia()
                                                              .EmptyIfWhitespace()
                                                              .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                              .AddRange(token.TrailingTrivia);

                                    MethodDeclarationSyntax newNode = methodDeclaration
                                                                      .WithBody(body.WithTrailingTrivia(trivia))
                                                                      .WithSemicolonToken(default(SyntaxToken));

                                    return(context.Document.ReplaceNodeAsync(methodDeclaration, newNode, cancellationToken));
                                },
                            GetEquivalenceKey(diagnostic));

                        context.RegisterCodeFix(codeAction, diagnostic);
                        break;
                    }

                    case PropertyDeclarationSyntax propertyDeclaration:
                    {
                        AccessorListSyntax accessorList = propertyDeclaration.AccessorList;

                        if (accessorList == null)
                        {
                            break;
                        }

                        CodeAction codeAction = CodeAction.Create(
                            "Remove semicolon",
                            cancellationToken =>
                                {
                                    SyntaxTriviaList trivia = accessorList
                                                              .GetTrailingTrivia()
                                                              .EmptyIfWhitespace()
                                                              .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                              .AddRange(token.TrailingTrivia);

                                    PropertyDeclarationSyntax newNode = propertyDeclaration
                                                                        .WithAccessorList(accessorList.WithTrailingTrivia(trivia))
                                                                        .WithSemicolonToken(default(SyntaxToken));

                                    return(context.Document.ReplaceNodeAsync(propertyDeclaration, newNode, cancellationToken));
                                },
                            GetEquivalenceKey(diagnostic));

                        context.RegisterCodeFix(codeAction, diagnostic);
                        break;
                    }

                    case AccessorDeclarationSyntax accessorDeclaration:
                    {
                        BlockSyntax body = accessorDeclaration.Body;

                        if (body == null)
                        {
                            break;
                        }

                        CodeAction codeAction = CodeAction.Create(
                            "Remove semicolon",
                            cancellationToken =>
                                {
                                    SyntaxTriviaList trivia = body
                                                              .GetTrailingTrivia()
                                                              .EmptyIfWhitespace()
                                                              .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                              .AddRange(token.TrailingTrivia);

                                    AccessorDeclarationSyntax newNode = accessorDeclaration
                                                                        .WithBody(body.WithTrailingTrivia(trivia))
                                                                        .WithSemicolonToken(default(SyntaxToken));

                                    return(context.Document.ReplaceNodeAsync(accessorDeclaration, newNode, cancellationToken));
                                },
                            GetEquivalenceKey(diagnostic));

                        context.RegisterCodeFix(codeAction, diagnostic);
                        break;
                    }
                    }

                    break;
                }

                case CompilerDiagnosticIdentifiers.CannotConvertType:
                {
                    if (!Settings.IsCodeFixEnabled(CodeFixIdentifiers.ChangeForEachType))
                    {
                        break;
                    }

                    if (token.Kind() != SyntaxKind.ForEachKeyword)
                    {
                        break;
                    }

                    if (!(token.Parent is ForEachStatementSyntax forEachStatement))
                    {
                        break;
                    }

                    SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                    ForEachStatementInfo info = semanticModel.GetForEachStatementInfo(forEachStatement);

                    ITypeSymbol typeSymbol = info.ElementType;

                    if (typeSymbol.SupportsExplicitDeclaration())
                    {
                        CodeFixRegistrator.ChangeType(context, diagnostic, forEachStatement.Type, typeSymbol, semanticModel, CodeFixIdentifiers.ChangeForEachType);
                    }

                    CodeFixRegistrator.ChangeTypeToVar(context, diagnostic, forEachStatement.Type, CodeFixIdentifiers.ChangeTypeToVar);
                    break;
                }
                }
            }
        }
            SyntaxNode ApplyNodeChange(BlockSyntax blockNode)
            {
                if (blockNode.Parent is ConversionOperatorDeclarationSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is OperatorDeclarationSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is AccessorDeclarationSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is ConstructorDeclarationSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is DestructorDeclarationSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is TryStatementSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is CatchClauseSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is FinallyClauseSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is IfStatementSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is ElseClauseSyntax)
                {
                    return(blockNode);
                }
                //if (blockNode.Parent is ParenthesizedExpressionSyntax) return blockNode;
                if (blockNode.Parent is SimpleLambdaExpressionSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is ParenthesizedLambdaExpressionSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is AnonymousMethodExpressionSyntax)
                {
                    return(blockNode);
                }
                if (blockNode.Parent is MethodDeclarationSyntax == false && blockNode.Statements.Count == 1)
                {
                    var singleStatement = blockNode.Statements.First();

                    if (singleStatement.Span.Length <= BLOCK_SINGLE_STATEMENT_MAX_LENGTH)
                    {
                        singleStatement =
                            singleStatement
                            .WithTrailingTrivia(
                                CleanUpList(
                                    SyntaxFactory.TriviaList(
                                        singleStatement
                                        .GetTrailingTrivia()
                                        .AddRange(blockNode.GetTrailingTrivia())
                                        ), 1)
                                );
                        lastBlockToken = singleStatement.GetLastToken();

                        return(singleStatement);
                    }
                }

                return(blockNode);
            }
Beispiel #9
0
        private static async Task <Document> RefactorAsync(
            Document document,
            IfStatementSyntax ifStatement,
            CancellationToken cancellationToken)
        {
            cancellationToken.ThrowIfCancellationRequested();

            ExpressionSyntax condition = ifStatement.Condition;

            ElseClauseSyntax elseClause = ifStatement.Else;

            SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);

            SimplifyCodeBranchingKind kind = SimplifyCodeBranchingAnalyzer.GetKind(ifStatement, semanticModel, cancellationToken).Value;

            if (kind == SimplifyCodeBranchingKind.IfElseWithEmptyIf)
            {
                ExpressionSyntax newCondition = SyntaxInverter.LogicallyInvert(condition, semanticModel, cancellationToken);

                StatementSyntax statement = elseClause.Statement;

                if (statement is IfStatementSyntax nestedIf)
                {
                    newCondition = LogicalAndExpression(newCondition.Parenthesize(), nestedIf.Condition.Parenthesize());

                    statement = nestedIf.Statement;
                }

                IfStatementSyntax newIfStatement = ifStatement.Update(
                    ifStatement.IfKeyword,
                    ifStatement.OpenParenToken,
                    newCondition,
                    ifStatement.CloseParenToken,
                    statement,
                    default(ElseClauseSyntax));

                newIfStatement = newIfStatement.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(ifStatement, newIfStatement, cancellationToken).ConfigureAwait(false));
            }
            else if (kind == SimplifyCodeBranchingKind.IfElseInsideWhile)
            {
                bool elseContainsBreak = elseClause.SingleNonBlockStatementOrDefault()?.Kind() == SyntaxKind.BreakStatement;

                SyntaxList <StatementSyntax> statements;

                if (elseContainsBreak)
                {
                    statements = (ifStatement.Statement is BlockSyntax block2)
                        ? block2.Statements
                        : SingletonList(ifStatement.Statement);
                }
                else
                {
                    statements = (elseClause.Statement is BlockSyntax block2)
                        ? block2.Statements
                        : SingletonList(elseClause.Statement);
                }

                WhileStatementSyntax whileStatement;

                if (ifStatement.Parent is BlockSyntax block)
                {
                    whileStatement = (WhileStatementSyntax)block.Parent;

                    block = block.WithStatements(block.Statements.ReplaceRange(ifStatement, statements));
                }
                else
                {
                    whileStatement = (WhileStatementSyntax)ifStatement.Parent;

                    block = Block(statements);
                }

                if (!elseContainsBreak)
                {
                    condition = SyntaxInverter.LogicallyInvert(condition, semanticModel, cancellationToken);
                }

                WhileStatementSyntax newWhileStatement = whileStatement.Update(
                    whileStatement.WhileKeyword,
                    whileStatement.OpenParenToken,
                    condition,
                    whileStatement.CloseParenToken,
                    block);

                newWhileStatement = newWhileStatement.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(whileStatement, newWhileStatement, cancellationToken).ConfigureAwait(false));
            }
            else if (kind == SimplifyCodeBranchingKind.SimplifIfInsideWhileOrDo)
            {
                var block = (BlockSyntax)ifStatement.Parent;

                SyntaxList <StatementSyntax> statements = block.Statements;

                BlockSyntax newBlock = block.WithStatements(statements.Remove(ifStatement));

                ExpressionSyntax newCondition = SyntaxInverter.LogicallyInvert(condition, semanticModel, cancellationToken);

                SyntaxNode newNode;

                switch (block.Parent)
                {
                case WhileStatementSyntax whileStatement:
                {
                    if (statements.IsFirst(ifStatement))
                    {
                        newNode = whileStatement.Update(
                            whileStatement.WhileKeyword,
                            whileStatement.OpenParenToken,
                            newCondition,
                            whileStatement.CloseParenToken,
                            newBlock);
                    }
                    else
                    {
                        newNode = DoStatement(
                            Token(whileStatement.WhileKeyword.LeadingTrivia, SyntaxKind.DoKeyword, whileStatement.CloseParenToken.TrailingTrivia),
                            newBlock.WithoutTrailingTrivia(),
                            Token(SyntaxKind.WhileKeyword),
                            OpenParenToken(),
                            newCondition,
                            CloseParenToken(),
                            SemicolonToken().WithTrailingTrivia(newBlock.GetTrailingTrivia()));
                    }

                    break;
                }

                case DoStatementSyntax doStatement:
                {
                    if (statements.IsLast(ifStatement))
                    {
                        newNode = doStatement.Update(
                            doStatement.DoKeyword,
                            newBlock,
                            doStatement.WhileKeyword,
                            doStatement.OpenParenToken,
                            newCondition,
                            doStatement.CloseParenToken,
                            doStatement.SemicolonToken);
                    }
                    else
                    {
                        newNode = WhileStatement(
                            Token(doStatement.DoKeyword.LeadingTrivia, SyntaxKind.WhileKeyword, SyntaxTriviaList.Empty),
                            OpenParenToken(),
                            newCondition,
                            Token(SyntaxTriviaList.Empty, SyntaxKind.CloseParenToken, doStatement.DoKeyword.TrailingTrivia),
                            newBlock.WithTrailingTrivia(doStatement.GetTrailingTrivia()));
                    }

                    break;
                }

                default:
                {
                    throw new InvalidOperationException();
                }
                }

                newNode = newNode.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(block.Parent, newNode, cancellationToken).ConfigureAwait(false));
            }
            else if (kind == SimplifyCodeBranchingKind.SimpleIfContainingOnlyDo)
            {
                StatementSyntax statement = ifStatement.SingleNonBlockStatementOrDefault();

                var doStatement = (DoStatementSyntax)statement;

                WhileStatementSyntax whileStatement = WhileStatement(
                    Token(ifStatement.GetLeadingTrivia(), SyntaxKind.WhileKeyword, SyntaxTriviaList.Empty),
                    OpenParenToken(),
                    doStatement.Condition,
                    Token(SyntaxTriviaList.Empty, SyntaxKind.CloseParenToken, doStatement.DoKeyword.TrailingTrivia),
                    doStatement.Statement.WithTrailingTrivia(ifStatement.GetTrailingTrivia()));

                whileStatement = whileStatement.WithFormatterAnnotation();

                return(await document.ReplaceNodeAsync(ifStatement, whileStatement, cancellationToken).ConfigureAwait(false));
            }
            else
            {
                throw new InvalidOperationException();
            }
        }
        public override async Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);

            if (!TryFindToken(root, context.Span.Start, out SyntaxToken token))
            {
                return;
            }

            SyntaxKind kind       = token.Kind();
            Diagnostic diagnostic = context.Diagnostics[0];
            Document   document   = context.Document;

            switch (diagnostic.Id)
            {
            case CompilerDiagnosticIdentifiers.CS0023_OperatorCannotBeAppliedToOperand:
            {
                if (kind == SyntaxKind.QuestionToken &&
                    token.Parent is ConditionalAccessExpressionSyntax conditionalAccess)
                {
                    SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                    ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(conditionalAccess.Expression, context.CancellationToken);

                    if (typeSymbol?.IsErrorType() == false &&
                        !typeSymbol.IsNullableType())
                    {
                        if (typeSymbol.IsValueType)
                        {
                            if (IsEnabled(diagnostic.Id, CodeFixIdentifiers.RemoveConditionalAccess, document, root.SyntaxTree))
                            {
                                CodeAction codeAction = CodeAction.Create(
                                    "Remove '?' operator",
                                    ct => document.WithTextChangeAsync(token.Span, "", ct),
                                    GetEquivalenceKey(diagnostic));

                                context.RegisterCodeFix(codeAction, diagnostic);
                            }
                        }
                        else if (typeSymbol.IsReferenceType)
                        {
                            if (IsEnabled(diagnostic.Id, CodeFixIdentifiers.AddArgumentList, document, root.SyntaxTree) &&
                                conditionalAccess.WhenNotNull is MemberBindingExpressionSyntax memberBindingExpression)
                            {
                                ConditionalAccessExpressionSyntax newNode = conditionalAccess.WithWhenNotNull(
                                    InvocationExpression(
                                        memberBindingExpression.WithoutTrailingTrivia(),
                                        ArgumentList().WithTrailingTrivia(memberBindingExpression.GetTrailingTrivia())));

                                CodeAction codeAction = CodeAction.Create(
                                    "Add argument list",
                                    ct => document.ReplaceNodeAsync(conditionalAccess, newNode, ct),
                                    GetEquivalenceKey(diagnostic));

                                context.RegisterCodeFix(codeAction, diagnostic);
                            }
                        }
                    }
                }

                break;
            }

            case CompilerDiagnosticIdentifiers.CS0267_PartialModifierCanOnlyAppearImmediatelyBeforeClassStructInterfaceOrVoid:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.OrderModifiers, document, root.SyntaxTree))
                {
                    break;
                }

                ModifiersCodeFixRegistrator.MoveModifier(context, diagnostic, token.Parent, token);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS1750_ValueCannotBeUsedAsDefaultParameter:
            {
                if (token.Parent is not ParameterSyntax parameter)
                {
                    break;
                }

                ExpressionSyntax value = parameter.Default?.Value;

                if (value == null)
                {
                    break;
                }

                if (value.IsKind(SyntaxKind.NullLiteralExpression))
                {
                    if (IsEnabled(diagnostic.Id, CodeFixIdentifiers.ReplaceNullLiteralExpressionWithDefaultValue, document, root.SyntaxTree))
                    {
                        SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                        CodeFixRegistrator.ReplaceNullWithDefaultValue(context, diagnostic, value, semanticModel);
                    }
                }
                else if (!value.IsKind(SyntaxKind.DefaultExpression, SyntaxKind.DefaultLiteralExpression))
                {
                    if (IsEnabled(diagnostic.Id, CodeFixIdentifiers.ChangeParameterType, document, root.SyntaxTree))
                    {
                        SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                        ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(value, context.CancellationToken);

                        if (!typeSymbol.IsKind(SymbolKind.ErrorType))
                        {
                            CodeFixRegistrator.ChangeType(context, diagnostic, parameter.Type, typeSymbol, semanticModel);
                        }
                    }
                }

                break;
            }

            case CompilerDiagnosticIdentifiers.CS0126_ObjectOfTypeConvertibleToTypeIsRequired:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.ReturnDefaultValue, document, root.SyntaxTree))
                {
                    break;
                }

                if (!token.IsKind(SyntaxKind.ReturnKeyword))
                {
                    break;
                }

                if (!token.IsParentKind(SyntaxKind.ReturnStatement))
                {
                    break;
                }

                SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                ISymbol symbol = semanticModel.GetEnclosingSymbol(token.SpanStart, context.CancellationToken);

                if (symbol == null)
                {
                    break;
                }

                SymbolKind symbolKind = symbol.Kind;

                ITypeSymbol typeSymbol = null;

                if (symbolKind == SymbolKind.Method)
                {
                    var methodSymbol = (IMethodSymbol)symbol;

                    typeSymbol = methodSymbol.ReturnType;

                    if (methodSymbol.IsAsync &&
                        (typeSymbol is INamedTypeSymbol namedTypeSymbol))
                    {
                        ImmutableArray <ITypeSymbol> typeArguments = namedTypeSymbol.TypeArguments;

                        if (typeArguments.Any())
                        {
                            typeSymbol = typeArguments[0];
                        }
                    }
                }
                else if (symbolKind == SymbolKind.Property)
                {
                    typeSymbol = ((IPropertySymbol)symbol).Type;
                }
                else
                {
                    Debug.Fail(symbolKind.ToString());
                }

                if (typeSymbol == null)
                {
                    break;
                }

                if (typeSymbol.Kind == SymbolKind.ErrorType)
                {
                    break;
                }

                if (!typeSymbol.SupportsExplicitDeclaration())
                {
                    break;
                }

                var returnStatement = (ReturnStatementSyntax)token.Parent;

                CodeAction codeAction = CodeAction.Create(
                    "Return default value",
                    ct =>
                    {
                        ExpressionSyntax expression = typeSymbol.GetDefaultValueSyntax(document.GetDefaultSyntaxOptions());

                        if (expression.IsKind(SyntaxKind.DefaultExpression) &&
                            document.SupportsLanguageFeature(CSharpLanguageFeature.DefaultLiteral))
                        {
                            expression = CSharpFactory.DefaultLiteralExpression().WithTriviaFrom(expression);
                        }

                        ReturnStatementSyntax newNode = returnStatement.WithExpression(expression);

                        return(document.ReplaceNodeAsync(returnStatement, newNode, ct));
                    },
                    GetEquivalenceKey(diagnostic));

                context.RegisterCodeFix(codeAction, diagnostic);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS1031_TypeExpected:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.AddMissingType, document, root.SyntaxTree))
                {
                    break;
                }

                if (!token.IsKind(SyntaxKind.CloseParenToken))
                {
                    break;
                }

                if (token.Parent is not DefaultExpressionSyntax defaultExpression)
                {
                    break;
                }

                if (defaultExpression.Type is not IdentifierNameSyntax identifierName)
                {
                    break;
                }

                if (!identifierName.IsMissing)
                {
                    break;
                }

                SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                TypeInfo typeInfo = semanticModel.GetTypeInfo(defaultExpression, context.CancellationToken);

                ITypeSymbol convertedType = typeInfo.ConvertedType;

                if (convertedType?.SupportsExplicitDeclaration() != true)
                {
                    break;
                }

                CodeAction codeAction = CodeAction.Create(
                    $"Add type '{SymbolDisplay.ToMinimalDisplayString(convertedType, semanticModel, defaultExpression.SpanStart, SymbolDisplayFormats.DisplayName)}'",
                    ct =>
                    {
                        TypeSyntax newType = convertedType.ToTypeSyntax()
                                             .WithTriviaFrom(identifierName)
                                             .WithFormatterAndSimplifierAnnotation();

                        return(document.ReplaceNodeAsync(identifierName, newType, ct));
                    },
                    GetEquivalenceKey(diagnostic));

                context.RegisterCodeFix(codeAction, diagnostic);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS1597_SemicolonAfterMethodOrAccessorBlockIsNotValid:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.RemoveSemicolon, document, root.SyntaxTree))
                {
                    break;
                }

                if (!token.IsKind(SyntaxKind.SemicolonToken))
                {
                    break;
                }

                switch (token.Parent)
                {
                case MethodDeclarationSyntax methodDeclaration:
                {
                    BlockSyntax body = methodDeclaration.Body;

                    if (body == null)
                    {
                        break;
                    }

                    CodeAction codeAction = CodeAction.Create(
                        "Remove semicolon",
                        ct =>
                            {
                                SyntaxTriviaList trivia = body
                                                          .GetTrailingTrivia()
                                                          .EmptyIfWhitespace()
                                                          .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                          .AddRange(token.TrailingTrivia);

                                MethodDeclarationSyntax newNode = methodDeclaration
                                                                  .WithBody(body.WithTrailingTrivia(trivia))
                                                                  .WithSemicolonToken(default(SyntaxToken));

                                return(document.ReplaceNodeAsync(methodDeclaration, newNode, ct));
                            },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                    break;
                }

                case PropertyDeclarationSyntax propertyDeclaration:
                {
                    AccessorListSyntax accessorList = propertyDeclaration.AccessorList;

                    if (accessorList == null)
                    {
                        break;
                    }

                    CodeAction codeAction = CodeAction.Create(
                        "Remove semicolon",
                        ct =>
                            {
                                SyntaxTriviaList trivia = accessorList
                                                          .GetTrailingTrivia()
                                                          .EmptyIfWhitespace()
                                                          .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                          .AddRange(token.TrailingTrivia);

                                PropertyDeclarationSyntax newNode = propertyDeclaration
                                                                    .WithAccessorList(accessorList.WithTrailingTrivia(trivia))
                                                                    .WithSemicolonToken(default(SyntaxToken));

                                return(document.ReplaceNodeAsync(propertyDeclaration, newNode, ct));
                            },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                    break;
                }

                case AccessorDeclarationSyntax accessorDeclaration:
                {
                    BlockSyntax body = accessorDeclaration.Body;

                    if (body == null)
                    {
                        break;
                    }

                    CodeAction codeAction = CodeAction.Create(
                        "Remove semicolon",
                        ct =>
                            {
                                SyntaxTriviaList trivia = body
                                                          .GetTrailingTrivia()
                                                          .EmptyIfWhitespace()
                                                          .AddRange(token.LeadingTrivia.EmptyIfWhitespace())
                                                          .AddRange(token.TrailingTrivia);

                                AccessorDeclarationSyntax newNode = accessorDeclaration
                                                                    .WithBody(body.WithTrailingTrivia(trivia))
                                                                    .WithSemicolonToken(default(SyntaxToken));

                                return(document.ReplaceNodeAsync(accessorDeclaration, newNode, ct));
                            },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                    break;
                }
                }

                break;
            }

            case CompilerDiagnosticIdentifiers.CS0030_CannotConvertType:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.ChangeForEachType, document, root.SyntaxTree))
                {
                    break;
                }

                if (!token.IsKind(SyntaxKind.ForEachKeyword))
                {
                    break;
                }

                if (token.Parent is not ForEachStatementSyntax forEachStatement)
                {
                    break;
                }

                SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                ForEachStatementInfo info = semanticModel.GetForEachStatementInfo(forEachStatement);

                ITypeSymbol typeSymbol = info.ElementType;

                if (typeSymbol.SupportsExplicitDeclaration())
                {
                    CodeFixRegistrator.ChangeType(context, diagnostic, forEachStatement.Type, typeSymbol, semanticModel, CodeFixIdentifiers.ChangeForEachType);
                }

                CodeFixRegistrator.ChangeTypeToVar(context, diagnostic, forEachStatement.Type, CodeFixIdentifiers.ChangeTypeToVar);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS1737_OptionalParametersMustAppearAfterAllRequiredParameters:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.AddDefaultValueToParameter, document, root.SyntaxTree))
                {
                    break;
                }

                if (token.Parent is not BaseParameterListSyntax parameterList)
                {
                    break;
                }

                SeparatedSyntaxList <ParameterSyntax> parameters = parameterList.Parameters;

                ParameterSyntax parameter = null;

                for (int i = 0; i < parameters.Count; i++)
                {
                    ParameterSyntax p = parameters[i];

                    if (p.FullSpan.End <= token.SpanStart)
                    {
                        parameter = p;
                    }
                    else
                    {
                        break;
                    }
                }

                SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);

                IParameterSymbol parameterSymbol = semanticModel.GetDeclaredSymbol(parameter, context.CancellationToken);

                ITypeSymbol typeSymbol = parameterSymbol.Type;

                if (typeSymbol.Kind == SymbolKind.ErrorType)
                {
                    break;
                }

                CodeAction codeAction = CodeAction.Create(
                    "Add default value",
                    ct =>
                    {
                        ExpressionSyntax defaultValue = typeSymbol.GetDefaultValueSyntax(document.GetDefaultSyntaxOptions());

                        ParameterSyntax newParameter = parameter
                                                       .WithDefault(EqualsValueClause(defaultValue).WithTrailingTrivia(parameter.GetTrailingTrivia()))
                                                       .WithoutTrailingTrivia()
                                                       .WithFormatterAnnotation();

                        return(document.ReplaceNodeAsync(parameter, newParameter, ct));
                    },
                    GetEquivalenceKey(diagnostic));

                context.RegisterCodeFix(codeAction, diagnostic);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS8632_AnnotationForNullableReferenceTypesShouldOnlyBeUsedWithinNullableAnnotationsContext:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.RemoveAnnotationForNullableReferenceTypes, document, root.SyntaxTree))
                {
                    break;
                }

                if (!token.IsKind(SyntaxKind.QuestionToken))
                {
                    return;
                }

                CodeAction codeAction = CodeAction.Create(
                    "Remove 'nullable' annotation",
                    ct =>
                    {
                        var textChange = new TextChange(token.Span, "");

                        return(document.WithTextChangeAsync(textChange, ct));
                    },
                    GetEquivalenceKey(diagnostic));

                context.RegisterCodeFix(codeAction, diagnostic);
                break;
            }

            case CompilerDiagnosticIdentifiers.CS8602_DereferenceOfPossiblyNullReference:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.UseNullForgivingOperator, document, root.SyntaxTree))
                {
                    break;
                }

                Debug.Assert(token.IsKind(SyntaxKind.IdentifierToken), token.Kind().ToString());

                if (!token.IsKind(SyntaxKind.IdentifierToken))
                {
                    return;
                }

                if (!token.IsParentKind(SyntaxKind.IdentifierName))
                {
                    return;
                }

                SyntaxNode node = token.Parent
                                  .WalkUp(f => f.IsKind(SyntaxKind.SimpleMemberAccessExpression, SyntaxKind.InvocationExpression, SyntaxKind.ElementAccessExpression))
                                  .Parent;

                if (node.IsKind(SyntaxKind.ExpressionStatement) &&
                    token.SpanStart == node.SpanStart)
                {
                    CodeAction codeAction = CodeAction.Create(
                        "Use null propagation operator",
                        ct =>
                        {
                            var textChange = new TextChange(new TextSpan(token.Span.End, 0), "?");

                            return(document.WithTextChangeAsync(textChange, ct));
                        },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                }

                return;
            }

            case CompilerDiagnosticIdentifiers.CS8604_PossibleNullReferenceArgumentForParameter:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.UseNullForgivingOperator, document, root.SyntaxTree))
                {
                    break;
                }

                Debug.Assert(token.IsKind(SyntaxKind.IdentifierToken), token.Kind().ToString());

                if (!token.IsKind(SyntaxKind.IdentifierToken))
                {
                    return;
                }

                if (!token.IsParentKind(SyntaxKind.IdentifierName))
                {
                    return;
                }

                CodeAction codeAction = CodeAction.Create(
                    "Use null-forgiving operator",
                    ct =>
                    {
                        var identifierName = (IdentifierNameSyntax)token.Parent;

                        PostfixUnaryExpressionSyntax newExpression = SuppressNullableWarningExpression(identifierName.WithoutTrivia())
                                                                     .WithTriviaFrom(identifierName);

                        return(document.ReplaceNodeAsync(identifierName, newExpression, ct));
                    },
                    GetEquivalenceKey(diagnostic));

                context.RegisterCodeFix(codeAction, diagnostic);
                return;
            }

            case CompilerDiagnosticIdentifiers.CS8618_NonNullableMemberIsUninitialized:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.UseNullForgivingOperator, document, root.SyntaxTree))
                {
                    break;
                }

                Debug.Assert(token.IsKind(SyntaxKind.IdentifierToken), token.Kind().ToString());

                if (!token.IsKind(SyntaxKind.IdentifierToken))
                {
                    return;
                }

                if (token.IsParentKind(SyntaxKind.PropertyDeclaration))
                {
                    CodeAction codeAction = CodeAction.Create(
                        "Use null-forgiving operator",
                        ct =>
                        {
                            var property = (PropertyDeclarationSyntax)token.Parent;

                            PropertyDeclarationSyntax newProperty = property
                                                                    .WithoutTrailingTrivia()
                                                                    .WithInitializer(EqualsValueClause(SuppressNullableWarningExpression(NullLiteralExpression())))
                                                                    .WithSemicolonToken(SemicolonToken().WithTrailingTrivia(property.GetTrailingTrivia()));

                            return(document.ReplaceNodeAsync(property, newProperty, ct));
                        },
                        GetEquivalenceKey(diagnostic));

                    context.RegisterCodeFix(codeAction, diagnostic);
                }
                else
                {
                    SyntaxDebug.Assert(
                        (token.IsParentKind(SyntaxKind.VariableDeclarator) &&
                         token.Parent.IsParentKind(SyntaxKind.VariableDeclaration) &&
                         token.Parent.Parent.IsParentKind(SyntaxKind.FieldDeclaration, SyntaxKind.EventFieldDeclaration)) ||
                        token.IsParentKind(SyntaxKind.ConstructorDeclaration),
                        token);

                    if (token.IsParentKind(SyntaxKind.VariableDeclarator) &&
                        token.Parent.IsParentKind(SyntaxKind.VariableDeclaration) &&
                        token.Parent.Parent.IsParentKind(SyntaxKind.FieldDeclaration))
                    {
                        CodeAction codeAction = CodeAction.Create(
                            "Use null-forgiving operator",
                            ct =>
                            {
                                var declarator = (VariableDeclaratorSyntax)token.Parent;

                                VariableDeclaratorSyntax newDeclarator = declarator
                                                                         .WithoutTrailingTrivia()
                                                                         .WithInitializer(
                                    EqualsValueClause(SuppressNullableWarningExpression(NullLiteralExpression()))
                                    .WithTrailingTrivia(declarator.GetTrailingTrivia()));

                                return(document.ReplaceNodeAsync(declarator, newDeclarator, ct));
                            },
                            GetEquivalenceKey(diagnostic));

                        context.RegisterCodeFix(codeAction, diagnostic);
                    }
                }

                break;
            }

            case CompilerDiagnosticIdentifiers.CS8403_MethodWithIteratorBlockMustBeAsyncToReturnIAsyncEnumerableOfT:
            {
                if (!IsEnabled(diagnostic.Id, CodeFixIdentifiers.AddAsyncModifier, document, root.SyntaxTree))
                {
                    break;
                }

                SyntaxDebug.Assert(token.IsKind(SyntaxKind.IdentifierToken), token);
                SyntaxDebug.Assert(token.IsParentKind(SyntaxKind.MethodDeclaration, SyntaxKind.LocalFunctionStatement), token.Parent);

                if (token.IsParentKind(SyntaxKind.MethodDeclaration, SyntaxKind.LocalFunctionStatement))
                {
                    ModifiersCodeFixRegistrator.AddModifier(
                        context,
                        diagnostic,
                        token.Parent,
                        SyntaxKind.AsyncKeyword,
                        additionalKey: CodeFixIdentifiers.AddAsyncModifier);
                }

                break;
            }
            }
        }
 public static BlockSyntax Trivia(this BlockSyntax node, BlockSyntax that)
 {
     return node.WithLeadingTrivia(that.GetLeadingTrivia()).WithTrailingTrivia(that.GetTrailingTrivia());
 }