Address feedback + update DocumentAnalysisExecutor to use the new...

Address feedback + update DocumentAnalysisExecutor to use the new GetAnalysisResultAsync APIs as an outcome of design change in https://github.com/dotnet/roslyn/pull/45347

src/Features/Core/Portable/Diagnostics/DocumentAnalysisExecutor.cs

@@ -169,13 +169,15 @@ private async Task<ImmutableArray<Diagnostic>> GetSyntaxDiagnosticsAsync(SyntaxT
 
             if (isCompilerAnalyzer)
             {
+                // TODO: Move this invocation to OOP
                 return await _compilationWithAnalyzers.GetAnalyzerSyntaxDiagnosticsAsync(tree, ImmutableArray.Create(analyzer), cancellationToken).ConfigureAwait(false);
             }
 
             if (_lazySyntaxDiagnostics == null)
             {
                 // TODO: Move this invocation to OOP
-                var treeDiagnostics = await _compilationWithAnalyzers.GetCategorizedAnalyzerSyntaxDiagnosticsAsync(tree, _compilationBasedAnalyzersInAnalysisScope, cancellationToken).ConfigureAwait(false);
+                var analysisResult = await _compilationWithAnalyzers.GetAnalysisResultAsync(tree, _compilationBasedAnalyzersInAnalysisScope, cancellationToken).ConfigureAwait(false);
+                var treeDiagnostics = analysisResult.SyntaxDiagnostics.TryGetValue(tree, out var value) ? value : ImmutableDictionary<DiagnosticAnalyzer, ImmutableArray<Diagnostic>>.Empty;
                 Interlocked.CompareExchange(ref _lazySyntaxDiagnostics, treeDiagnostics, null);
             }
 
@@ -202,13 +204,16 @@ private async Task<ImmutableArray<Diagnostic>> GetSemanticDiagnosticsAsync(Seman
 #endif
 
                 var adjustedSpan = await GetAdjustedSpanForCompilerAnalyzerAsync().ConfigureAwait(false);
+
+                // TODO: Move this invocation to OOP
                 return await _compilationWithAnalyzers.GetAnalyzerSemanticDiagnosticsAsync(model, adjustedSpan, ImmutableArray.Create(analyzer), cancellationToken).ConfigureAwait(false);
             }
 
             if (_lazySemanticDiagnostics == null)
             {
                 // TODO: Move this invocation to OOP
-                var treeDiagnostics = await _compilationWithAnalyzers.GetCategorizedAnalyzerSemanticDiagnosticsAsync(model, span, _compilationBasedAnalyzersInAnalysisScope, cancellationToken).ConfigureAwait(false);
+                var analysisResult = await _compilationWithAnalyzers.GetAnalysisResultAsync(model, span, _compilationBasedAnalyzersInAnalysisScope, cancellationToken).ConfigureAwait(false);
+                var treeDiagnostics = analysisResult.SemanticDiagnostics.TryGetValue(model.SyntaxTree, out var value) ? value : ImmutableDictionary<DiagnosticAnalyzer, ImmutableArray<Diagnostic>>.Empty;
                 Interlocked.CompareExchange(ref _lazySemanticDiagnostics, treeDiagnostics, null);
             }
 

src/Features/Core/Portable/Diagnostics/EngineV2/DiagnosticIncrementalAnalyzer_IncrementalAnalyzer.cs

@@ -47,6 +47,13 @@ private async Task AnalyzeDocumentForKindAsync(Document document, AnalysisKind k
                 var stateSets = _stateManager.GetOrUpdateStateSets(document.Project);
                 var compilationWithAnalyzers = await GetOrCreateCompilationWithAnalyzersAsync(document.Project, stateSets, cancellationToken).ConfigureAwait(false);
 
+                // We split the diagnostic computation for document into following steps:
+                //  1. Try to get cached diagnostics for each analyzer, while computing the set of analyzers that do not have cached diagnostics.
+                //  2. Execute all the non-cached analyzers with a single invocation into CompilationWithAnalyzers.
+                //  3. Fetch computed diagnostics per-analyzer from the above invocation, and cache and raise diagnostic reported events.
+                // In near future, the diagnostic computation invocation into CompilationWithAnalyzers will be moved to OOP.
+                // This should help simplify and/or remove the IDE layer diagnostic caching in devenv process.
+
                 // First attempt to fetch diagnostics from the cache, while computing the state sets for analyzers that are not cached.
                 using var _ = ArrayBuilder<StateSet>.GetInstance(out var nonCachedStateSets);
                 foreach (var stateSet in stateSets)
@@ -63,7 +70,7 @@ private async Task AnalyzeDocumentForKindAsync(Document document, AnalysisKind k
                     }
                 }
 
-                // Then, compute the diagnostics for non-cached state sets.
+                // Then, compute the diagnostics for non-cached state sets, and cache and raise diagnostic reported events for these diagnostics.
                 if (nonCachedStateSets.Count > 0)
                 {
                     var analysisScope = new DocumentAnalysisScope(document, span: null, nonCachedStateSets.SelectAsArray(s => s.Analyzer), kind);