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ejballejball
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Publish three new analyzers (#108)
Adds FL0024, FL0025, and FL0026.
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‎AGENTS.md‎

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# Repository Guidance
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* When adding a new analyzer, bump the minor version in `Directory.Build.props` and reset the patch version to zero, for example `1.6.2` to `1.7.0`.
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* Add the release note for a new analyzer under the matching minor-version heading.

‎Directory.Build.props‎

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<Project>
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<PropertyGroup>
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<VersionPrefix>1.6.2</VersionPrefix>
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<VersionPrefix>1.7.0</VersionPrefix>
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<NoWarn>$(NoWarn);1591;1998;NU5105;CA1014;CA1508;CA1859;NU1507</NoWarn>
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<GitHubOrganization>Faithlife</GitHubOrganization>
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<RepositoryName>FaithlifeAnalyzers</RepositoryName>

‎README.md‎

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## Analyzers
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| ID | Description |
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|---|---|
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| --- | --- |
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| [FL0001](docs/FL0001.md) | `AsyncWorkItem.Current` must only be used in methods that return `IEnumerable<AsyncAction>` |
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| [FL0002](docs/FL0002.md) | Optional `StringComparison` arguments must always be specified |
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| [FL0003](docs/FL0003.md) | `UntilCanceled()` may only be used in methods that return `IEnumerable<AsyncAction>` |
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| [FL0021](docs/FL0021.md) | Use null propagation |
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| [FL0022](docs/FL0022.md) | Use AsyncMethodContext.WorkState |
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| [FL0023](docs/FL0023.md) | Replace obsolete Logos.Common.Logging.Extensions extension methods |
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| [FL0024](docs/FL0024.md) | Lambda operators should end the previous line |
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| [FL0025](docs/FL0025.md) | Private fields should be defined last |
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| [FL0026](docs/FL0026.md) | Use `InvariantConvert` |
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## How to Help

‎ReleaseNotes.md‎

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# Release Notes
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## 1.7.0
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* Add [FL0024](https://github.com/Faithlife/FaithlifeAnalyzers/blob/master/docs/FL0024.md): Lambda operators should end the previous line.
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* Add [FL0025](https://github.com/Faithlife/FaithlifeAnalyzers/blob/master/docs/FL0025.md): Private fields should be defined last.
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* Add [FL0026](https://github.com/Faithlife/FaithlifeAnalyzers/blob/master/docs/FL0026.md): Use `InvariantConvert`.
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## 1.6.2
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* Move analyzer documentation from wiki to repository content.

‎docs/FL0024.md‎

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# FL0024: Lambda operators should end the previous line
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Lambda expressions, expression-bodied members, and switch expression arms should keep the `=>` operator at the end of the previous line instead of placing it at the beginning of the next line.
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```csharp
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// discouraged
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public string FormatCustomerDisplayName(CustomerAccountRecord customerAccount)
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=> customerAccount.DisplayName.Trim();
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public IReadOnlyList<string> SelectOrderNumbersForSummary(OrderSummaryMode summaryMode)
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{
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return summaryMode switch
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{
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OrderSummaryMode.PendingFulfillment
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=> customerOrders
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.Where(customerOrderSummaryItem
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=> customerOrderSummaryItem.IsPaid && customerOrderSummaryItem.NeedsFulfillment)
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.Select(customerOrderSummaryItem => customerOrderSummaryItem.OrderNumber)
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.ToList(),
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_ => [],
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};
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}
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```
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```csharp
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// preferred
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public string FormatCustomerDisplayName(CustomerAccountRecord customerAccount) =>
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customerAccount.DisplayName.Trim();
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public IReadOnlyList<string> SelectOrderNumbersForSummary(OrderSummaryMode summaryMode)
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{
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return summaryMode switch
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{
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OrderSummaryMode.PendingFulfillment =>
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customerOrders
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.Where(customerOrderSummaryItem =>
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customerOrderSummaryItem.IsPaid && customerOrderSummaryItem.NeedsFulfillment)
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.Select(customerOrderSummaryItem => customerOrderSummaryItem.OrderNumber)
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.ToList(),
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_ => [],
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};
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}
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```
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This keeps the lambda operator attached to the preceding lambda signature, member declaration, or switch pattern, and follows the Faithlife line-break style for operators.

‎docs/FL0025.md‎

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# FL0025: Private fields should be defined last
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## Summary
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Detects types whose first members are private fields.
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## Example
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### Before
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```csharp
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public sealed class Example
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{
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private readonly int _value;
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public int Value => _value;
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}
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```
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### After
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```csharp
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public sealed class Example
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{
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public int Value => _value;
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private readonly int _value;
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}
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```
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## Rationale
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Keeping private fields at the end of a type makes the public API and higher-level members easier to find first.
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## Severity
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**Warning** - Encourages a consistent member ordering convention.

‎src/Faithlife.Analyzers/LambdaOperatorAnalyzer.cs‎

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using System.Collections.Immutable;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.CSharp.Syntax;
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using Microsoft.CodeAnalysis.Diagnostics;
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using Microsoft.CodeAnalysis.Text;
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namespace Faithlife.Analyzers;
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[DiagnosticAnalyzer(LanguageNames.CSharp)]
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public sealed class LambdaOperatorAnalyzer : DiagnosticAnalyzer
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{
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public override void Initialize(AnalysisContext context)
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{
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context.EnableConcurrentExecution();
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context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
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context.RegisterSyntaxNodeAction(AnalyzeSyntax,
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SyntaxKind.ArrowExpressionClause,
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SyntaxKind.SimpleLambdaExpression,
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SyntaxKind.ParenthesizedLambdaExpression,
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SyntaxKind.SwitchExpressionArm);
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}
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public const string DiagnosticId = "FL0024";
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public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => [s_rule];
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private static void AnalyzeSyntax(SyntaxNodeAnalysisContext context)
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{
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var lambdaOperatorToken = GetLambdaOperatorToken(context.Node);
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if (!lambdaOperatorToken.IsKind(SyntaxKind.EqualsGreaterThanToken))
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return;
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var previousToken = lambdaOperatorToken.GetPreviousToken();
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if (previousToken.IsKind(SyntaxKind.None))
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return;
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var sourceText = lambdaOperatorToken.SyntaxTree.GetText(context.CancellationToken);
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if (!IsFirstNonWhitespaceOnLine(sourceText, lambdaOperatorToken) ||
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!ContainsOnlyWhitespace(sourceText, TextSpan.FromBounds(previousToken.Span.End, lambdaOperatorToken.SpanStart)))
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{
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return;
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}
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context.ReportDiagnostic(Diagnostic.Create(s_rule, lambdaOperatorToken.GetLocation()));
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}
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private static SyntaxToken GetLambdaOperatorToken(SyntaxNode node) =>
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node switch
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{
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ArrowExpressionClauseSyntax arrowExpressionClause => arrowExpressionClause.ArrowToken,
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ParenthesizedLambdaExpressionSyntax parenthesizedLambdaExpression => parenthesizedLambdaExpression.ArrowToken,
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SimpleLambdaExpressionSyntax simpleLambdaExpression => simpleLambdaExpression.ArrowToken,
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SwitchExpressionArmSyntax switchExpressionArm => switchExpressionArm.EqualsGreaterThanToken,
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_ => default,
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};
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private static bool IsFirstNonWhitespaceOnLine(SourceText sourceText, SyntaxToken token)
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{
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var line = sourceText.Lines.GetLineFromPosition(token.SpanStart);
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return ContainsOnlyWhitespace(sourceText, TextSpan.FromBounds(line.Start, token.SpanStart));
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}
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private static bool ContainsOnlyWhitespace(SourceText sourceText, TextSpan span)
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{
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for (int index = span.Start; index < span.End; index++)
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{
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if (!char.IsWhiteSpace(sourceText[index]))
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return false;
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}
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return true;
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}
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private static readonly DiagnosticDescriptor s_rule = new(
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id: DiagnosticId,
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title: "Lambda operator should end the previous line",
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messageFormat: "Move => to the end of the previous line",
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category: "Style",
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defaultSeverity: DiagnosticSeverity.Warning,
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isEnabledByDefault: true,
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helpLinkUri: $"https://github.com/Faithlife/FaithlifeAnalyzers/blob/-/docs/{DiagnosticId}.md");
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}

‎src/Faithlife.Analyzers/LambdaOperatorCodeFixProvider.cs‎

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using System.Collections.Immutable;
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using System.Composition;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CodeActions;
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using Microsoft.CodeAnalysis.CodeFixes;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.Text;
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namespace Faithlife.Analyzers;
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[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(LambdaOperatorCodeFixProvider)), Shared]
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public sealed class LambdaOperatorCodeFixProvider : CodeFixProvider
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{
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public override ImmutableArray<string> FixableDiagnosticIds => [LambdaOperatorAnalyzer.DiagnosticId];
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public override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
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public override async Task RegisterCodeFixesAsync(CodeFixContext context)
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{
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var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
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if (root is null)
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return;
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var diagnostic = context.Diagnostics.First();
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var lambdaOperatorToken = root.FindToken(diagnostic.Location.SourceSpan.Start);
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if (!lambdaOperatorToken.IsKind(SyntaxKind.EqualsGreaterThanToken))
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return;
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var previousToken = lambdaOperatorToken.GetPreviousToken();
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if (previousToken.IsKind(SyntaxKind.None))
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return;
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context.RegisterCodeFix(
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CodeAction.Create(
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title: "Move => to the previous line",
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createChangedDocument: token => MoveLambdaOperatorToPreviousLineAsync(context.Document, previousToken, lambdaOperatorToken, token),
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"move-lambda-operator"),
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diagnostic);
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}
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private static async Task<Document> MoveLambdaOperatorToPreviousLineAsync(Document document, SyntaxToken previousToken, SyntaxToken lambdaOperatorToken, CancellationToken cancellationToken)
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{
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var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
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var nextToken = lambdaOperatorToken.GetNextToken();
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var whitespaceBeforeLambdaOperator = sourceText.ToString(TextSpan.FromBounds(previousToken.Span.End, lambdaOperatorToken.SpanStart));
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var textAfterLambdaOperator = sourceText.ToString(TextSpan.FromBounds(lambdaOperatorToken.Span.End, nextToken.SpanStart));
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var changedText = ContainsOnlyWhitespace(textAfterLambdaOperator) ?
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sourceText.WithChanges(
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new TextChange(TextSpan.FromBounds(previousToken.Span.End, lambdaOperatorToken.SpanStart), " "),
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new TextChange(TextSpan.FromBounds(lambdaOperatorToken.Span.End, nextToken.SpanStart), whitespaceBeforeLambdaOperator)) :
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sourceText.WithChanges(new TextChange(TextSpan.FromBounds(previousToken.Span.End, lambdaOperatorToken.SpanStart), " "));
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return document.WithText(changedText);
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}
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private static bool ContainsOnlyWhitespace(string text) => text.All(char.IsWhiteSpace);
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}

‎src/Faithlife.Analyzers/PrivateFieldsLastAnalyzer.cs‎

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using System.Collections.Immutable;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.CSharp.Syntax;
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using Microsoft.CodeAnalysis.Diagnostics;
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namespace Faithlife.Analyzers;
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[DiagnosticAnalyzer(LanguageNames.CSharp)]
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public sealed class PrivateFieldsLastAnalyzer : DiagnosticAnalyzer
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{
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public const string DiagnosticId = "FL0025";
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public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => [s_rule];
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public override void Initialize(AnalysisContext context)
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{
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context.EnableConcurrentExecution();
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context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
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context.RegisterSyntaxNodeAction(AnalyzeType, SyntaxKind.ClassDeclaration, SyntaxKind.StructDeclaration, SyntaxKind.RecordDeclaration, SyntaxKind.RecordStructDeclaration);
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}
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private static void AnalyzeType(SyntaxNodeAnalysisContext context)
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{
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var typeDeclaration = (TypeDeclarationSyntax) context.Node;
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if (typeDeclaration.Members.Count < 2)
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return;
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var leadingPrivateFieldCount = GetLeadingPrivateFieldCount(typeDeclaration.Members, member => IsPrivateField(context.SemanticModel, member, context.CancellationToken));
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if (leadingPrivateFieldCount is 0 || leadingPrivateFieldCount == typeDeclaration.Members.Count)
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return;
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context.ReportDiagnostic(Diagnostic.Create(s_rule, typeDeclaration.Members[0].GetLocation()));
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}
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internal static int GetLeadingPrivateFieldCount(SyntaxList<MemberDeclarationSyntax> members, Func<MemberDeclarationSyntax, bool> isPrivateField)
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{
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var privateFieldCount = 0;
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while (privateFieldCount < members.Count && isPrivateField(members[privateFieldCount]))
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privateFieldCount++;
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return privateFieldCount;
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}
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internal static bool IsPrivateField(SemanticModel semanticModel, MemberDeclarationSyntax member, CancellationToken cancellationToken)
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{
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if (member is not FieldDeclarationSyntax { Declaration.Variables.Count: > 0 } field)
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return false;
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return semanticModel.GetDeclaredSymbol(field.Declaration.Variables[0], cancellationToken) is IFieldSymbol
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{
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DeclaredAccessibility: Accessibility.Private,
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};
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}
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private static readonly DiagnosticDescriptor s_rule = new(
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id: DiagnosticId,
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title: "Private fields should be defined last",
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messageFormat: "Move private fields to the end of the type",
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category: "Usage",
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defaultSeverity: DiagnosticSeverity.Warning,
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isEnabledByDefault: true,
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helpLinkUri: $"https://github.com/Faithlife/FaithlifeAnalyzers/blob/-/docs/{DiagnosticId}.md");
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}

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