Use helper methods to transform DiagnosticAnalysisResult

src/Features/Core/Portable/Diagnostics/EngineV2/DiagnosticIncrementalAnalyzer.Executor.cs

@@ -165,15 +165,7 @@ public IEnumerable<DiagnosticData> ConvertToLocalDiagnostics(Document targetDocu
                 Logger.Log(FunctionId.Diagnostics_ProjectDiagnostic, p => $"Failed to Load Successfully ({p.FilePath ?? p.Name})", project);
 
                 // get rid of any result except syntax from compiler analyzer result
-                var newCompilerAnalysisResult = new DiagnosticAnalysisResult(
-                    analysisResult.ProjectId,
-                    analysisResult.Version,
-                    analysisResult.SyntaxLocals,
-                    semanticLocals: ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>>.Empty,
-                    nonLocals: ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>>.Empty,
-                    others: ImmutableArray<DiagnosticData>.Empty,
-                    documentIds: null,
-                    fromBuild: false);
+                var newCompilerAnalysisResult = analysisResult.DropExceptSyntax();
 
                 // return new result
                 return result.SetItem(compilerAnalyzer, newCompilerAnalysisResult);

src/Features/Core/Portable/Diagnostics/EngineV2/DiagnosticIncrementalAnalyzer.ProjectState.cs

@@ -232,7 +232,7 @@ public async Task SaveAsync(Project project, DiagnosticAnalysisResult result)
             public void ResetVersion()
             {
                 // reset version of cached data so that we can recalculate new data (ex, OnDocumentReset)
-                _lastResult = new DiagnosticAnalysisResult(_lastResult.ProjectId, VersionStamp.Default, _lastResult.DocumentIds, _lastResult.IsEmpty, _lastResult.FromBuild);
+                _lastResult = _lastResult.Reset();
             }
 
             public async Task MergeAsync(ActiveFileState state, Document document)
@@ -280,7 +280,7 @@ public async Task MergeAsync(ActiveFileState state, Document document)
                 await SerializeAsync(serializer, document, document.Id, _owner.SemanticStateName, semantic.Items).ConfigureAwait(false);
 
                 // save last aggregated form of analysis result
-                _lastResult = new DiagnosticAnalysisResult(_lastResult.ProjectId, version, _lastResult.DocumentIdsOrEmpty.Add(state.DocumentId), isEmpty: false, fromBuild: fromBuild);
+                _lastResult = _lastResult.UpdateAggregatedResult(version, state.DocumentId, fromBuild);
             }
 
             public bool OnDocumentRemoved(DocumentId id)

src/Workspaces/Core/Portable/Diagnostics/DiagnosticAnalysisResult.cs

@@ -30,7 +30,7 @@ internal struct DiagnosticAnalysisResult
         private readonly ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>> _nonLocals;
         private readonly ImmutableArray<DiagnosticData> _others;
 
-        public DiagnosticAnalysisResult(
+        private DiagnosticAnalysisResult(
             ProjectId projectId, VersionStamp version, ImmutableHashSet<DocumentId> documentIds, bool isEmpty, bool fromBuild)
         {
             ProjectId = projectId;
@@ -45,7 +45,7 @@ internal struct DiagnosticAnalysisResult
             _others = default;
         }
 
-        public DiagnosticAnalysisResult(
+        private DiagnosticAnalysisResult(
             ProjectId projectId, VersionStamp version,
             ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>> syntaxLocals,
             ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>> semanticLocals,
@@ -180,6 +180,29 @@ public DiagnosticAnalysisResult ToAggregatedForm()
             return new DiagnosticAnalysisResult(ProjectId, Version, DocumentIds, IsEmpty, FromBuild);
         }
 
+        public DiagnosticAnalysisResult UpdateAggregatedResult(VersionStamp version, DocumentId documentId, bool fromBuild)
+        {
+            return new DiagnosticAnalysisResult(ProjectId, version, DocumentIdsOrEmpty.Add(documentId), isEmpty: false, fromBuild: fromBuild);
+        }
+
+        public DiagnosticAnalysisResult Reset()
+        {
+            return new DiagnosticAnalysisResult(ProjectId, VersionStamp.Default, DocumentIds, IsEmpty, FromBuild);
+        }
+
+        public DiagnosticAnalysisResult DropExceptSyntax()
+        {
+            return new DiagnosticAnalysisResult(
+               ProjectId,
+               Version,
+               SyntaxLocals,
+               semanticLocals: ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>>.Empty,
+               nonLocals: ImmutableDictionary<DocumentId, ImmutableArray<DiagnosticData>>.Empty,
+               others: ImmutableArray<DiagnosticData>.Empty,
+               documentIds: null,
+               fromBuild: false);
+        }
+
         private T ReturnIfNotDefault<T>(T value)
         {
             if (object.Equals(value, default))