feat: ignore diagnostics for generated code

src/OmniSharp.Host/Services/OmniSharpEnvironment.cs

@@ -38,6 +38,11 @@ public OmniSharpEnvironment(
                 throw new ArgumentException("OmniSharp only supports being launched with a directory path or a path to a solution (.sln, .slnf) file.", nameof(path));
             }
 
+            if (TargetDirectory[TargetDirectory.Length - 1] != Path.DirectorySeparatorChar)
+            {
+                TargetDirectory += Path.DirectorySeparatorChar;
+            }
+
             HostProcessId = hostPid;
             LogLevel = logLevel;
             AdditionalArguments = additionalArguments;

src/OmniSharp.Roslyn.CSharp/Helpers/SyntaxTreeExtensions.cs

@@ -0,0 +1,50 @@
+using System.Threading;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace OmniSharp.Roslyn.CSharp.Helpers
+{
+    public static class SyntaxTreeExtensions
+    {
+        private static readonly string[] _autoGeneratedStrings = new[] { "<autogenerated", "<auto-generated" };
+
+        public static bool IsAutoGenerated(this SyntaxTree syntaxTree, CancellationToken cancellationToken = default)
+        {
+            SyntaxNode root = syntaxTree.GetRoot(cancellationToken);
+            if (!root.HasLeadingTrivia)
+            {
+                return false;
+            }
+
+            SyntaxTriviaList leadingTrivia = root.GetLeadingTrivia();
+
+            foreach (SyntaxTrivia trivia in leadingTrivia)
+            {
+                if (!IsCommentTrivia(trivia))
+                {
+                    continue;
+                }
+
+                foreach (string autoGenerated in _autoGeneratedStrings)
+                {
+                    if (!trivia.ToString().Contains(autoGenerated))
+                    {
+                        continue;
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        private static bool IsCommentTrivia(SyntaxTrivia trivia) =>
+            trivia.IsKind(SyntaxKind.MultiLineCommentTrivia) ||
+            trivia.IsKind(SyntaxKind.SingleLineCommentTrivia) ||
+            trivia.IsKind(SyntaxKind.SingleLineDocumentationCommentTrivia) ||
+            trivia.IsKind(SyntaxKind.MultiLineDocumentationCommentTrivia) ||
+            trivia.IsKind(SyntaxKind.ShebangDirectiveTrivia);
+
+    }
+}

src/OmniSharp.Roslyn.CSharp/Workers/Diagnostics/CSharpDiagnosticWorkerBase.cs

@@ -0,0 +1,78 @@
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.Extensions.FileSystemGlobbing;
+using OmniSharp.FileSystem;
+using OmniSharp.Roslyn.CSharp.Services.Diagnostics;
+
+namespace OmniSharp.Roslyn.CSharp.Workers.Diagnostics;
+
+public abstract class CSharpDiagnosticWorkerBase : ICsDiagnosticWorker
+{
+    private readonly OmniSharpWorkspace _workspace;
+    private readonly FileSystemHelper _fileSystemHelper;
+    private readonly Matcher _fileSystemMatcher;
+
+    public CSharpDiagnosticWorkerBase(
+            OmniSharpWorkspace workspace,
+            FileSystemHelper fileSystemHelper)
+    {
+        _workspace = workspace;
+        _fileSystemHelper = fileSystemHelper;
+        _fileSystemMatcher = _fileSystemHelper.BuildExcludeMatcher();
+    }
+
+    public abstract bool AnalyzersEnabled { get; }
+
+    public abstract Task<IEnumerable<Diagnostic>> AnalyzeDocumentAsync(Document document, CancellationToken cancellationToken);
+
+    public abstract Task<IEnumerable<Diagnostic>> AnalyzeProjectsAsync(Project project, CancellationToken cancellationToken);
+
+    public abstract Task<ImmutableArray<DocumentDiagnostics>> GetAllDiagnosticsAsync();
+
+    public abstract Task<ImmutableArray<DocumentDiagnostics>> GetDiagnostics(ImmutableArray<string> documentPaths);
+
+    public abstract ImmutableArray<DocumentId> QueueDocumentsForDiagnostics(IEnumerable<Document> documents, AnalyzerWorkType workType);
+
+    public ImmutableArray<DocumentId> QueueDocumentsForDiagnostics()
+    {
+        IEnumerable<Document> documents = _workspace.CurrentSolution.Projects.SelectMany(x => x.Documents);
+        documents = FilterDocuments(documents);
+        return QueueDocumentsForDiagnostics(documents, AnalyzerWorkType.Background);
+    }
+
+    public ImmutableArray<DocumentId> QueueDocumentsForDiagnostics(ImmutableArray<ProjectId> projectId)
+    {
+        IEnumerable<Document> documents = projectId.SelectMany(projectId => _workspace.CurrentSolution.GetProject(projectId).Documents);
+        documents = FilterDocuments(documents);
+        return QueueDocumentsForDiagnostics(documents, AnalyzerWorkType.Background);
+    }
+
+    protected ImmutableArray<DocumentId> QueueDocumentsForDiagnostics(Project project)
+    {
+        IEnumerable<Document> documents = project.Documents;
+        documents = FilterDocuments(documents);
+        return QueueDocumentsForDiagnostics(documents, AnalyzerWorkType.Background);
+    }
+
+    protected ImmutableArray<DocumentId> QueueDocumentsForDiagnostics(IEnumerable<DocumentId> documentsIds, AnalyzerWorkType workType)
+    {
+        IEnumerable<Document> documents = documentsIds.Select(x => _workspace.CurrentSolution.GetDocument(x));
+        documents = FilterDocuments(documents);
+        return QueueDocumentsForDiagnostics(documents, workType);
+    }
+
+    private ImmutableArray<Document> FilterDocuments(IEnumerable<Document> documents) =>
+        documents
+            .Where(x => !FileSystemHelper.AutoGenerated(x.FilePath))
+            .Where(x => !_fileSystemMatcher
+                    .Match(FileSystemHelper
+                        .GetRelativePath(x.FilePath, _fileSystemHelper.TargetDirectory)
+                        ?? x.FilePath)
+                    .HasMatches)
+            .ToImmutableArray();
+}