Add suppressor support for dotnet-format

Author: sailro

src/BuiltInTools/dotnet-format/Analyzers/AnalyzerFormatter.cs

@@ -315,6 +315,13 @@ internal static async Task<ImmutableDictionary<ProjectId, ImmutableArray<Diagnos
                     .Where(analyzer => DoesAnalyzerSupportLanguage(analyzer, project.Language));
                 foreach (var analyzer in filteredAnalyzer)
                 {
+                    // Allow suppressors unconditionally
+                    if (analyzer is DiagnosticSuppressor suppressor)
+                    {
+                        analyzers.Add(suppressor);
+                        continue;
+                    }
+
                     // Filter by excluded diagnostics
                     if (!excludeDiagnostics.IsEmpty &&
                         analyzer.SupportedDiagnostics.All(descriptor => excludeDiagnostics.Contains(descriptor.Id)))

src/BuiltInTools/dotnet-format/Analyzers/CodeStyleInformationProvider.cs

@@ -33,16 +33,28 @@ public ImmutableDictionary<ProjectId, AnalyzersAndFixers> GetAnalyzersAndFixers(
                 .Select(path => new AnalyzerFileReference(path, analyzerAssemblyLoader));
 
             var analyzersByLanguage = new Dictionary<string, AnalyzersAndFixers>();
+
+            // We need AnalyzerReferenceInformationProvider to load all local project suppressors
+            var referenceProvider =  new AnalyzerReferenceInformationProvider();
+            var projectsReferenceAnalyzersAndFixers = referenceProvider.GetAnalyzersAndFixers(workspace, solution, formatOptions, logger);
+
             return solution.Projects
                 .ToImmutableDictionary(
                     project => project.Id,
                     project =>
                     {
                         if (!analyzersByLanguage.TryGetValue(project.Language, out var analyzersAndFixers))
                         {
-                            var analyzers = references.SelectMany(reference => reference.GetAnalyzers(project.Language)).ToImmutableArray();
+                            var analyzers = references.SelectMany(reference => reference.GetAnalyzers(project.Language));
                             var codeFixes = AnalyzerFinderHelpers.LoadFixers(references.Select(reference => reference.GetAssembly()), project.Language);
-                            analyzersAndFixers = new AnalyzersAndFixers(analyzers, codeFixes);
+
+                            // Add local project suppressors to global analyzers
+                            if (projectsReferenceAnalyzersAndFixers.TryGetValue(project.Id, out var referenceAnalyzersAndFixers))
+                            {
+                                analyzers = referenceAnalyzersAndFixers.Analyzers.OfType<DiagnosticSuppressor>().Aggregate(analyzers, (current, suppressor) => current.Append(suppressor));
+                            }
+
+                            analyzersAndFixers = new AnalyzersAndFixers(analyzers.ToImmutableArray(), codeFixes);
                             analyzersByLanguage.Add(project.Language, analyzersAndFixers);
                         }