Fix #2807: Detect when a compiler-generated/hidden type needs to be decompiled in WholeProjectDecompiler.

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -32,6 +32,7 @@ using ICSharpCode.Decompiler.CSharp.Syntax;
 using ICSharpCode.Decompiler.CSharp.Transforms;
 using ICSharpCode.Decompiler.DebugInfo;
 using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.Semantics;
 using ICSharpCode.Decompiler.Solution;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.Util;
@@ -206,8 +207,28 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		IEnumerable<(string itemType, string fileName)> WriteCodeFilesInProject(Metadata.PEFile module, IList<PartialTypeInfo> partialTypes, CancellationToken cancellationToken)
 		{
 			var metadata = module.Metadata;
-			var files = module.Metadata.GetTopLevelTypeDefinitions().Where(td => IncludeTypeWhenDecompilingProject(module, td)).GroupBy(
-				delegate (TypeDefinitionHandle h) {
+			var files = module.Metadata.GetTopLevelTypeDefinitions().Where(td => IncludeTypeWhenDecompilingProject(module, td))
+				.GroupBy(GetFileFileNameForHandle, StringComparer.OrdinalIgnoreCase).ToList();
+			var progressReporter = ProgressIndicator;
+			var progress = new DecompilationProgress { TotalUnits = files.Count, Title = "Exporting project..." };
+			DecompilerTypeSystem ts = new DecompilerTypeSystem(module, AssemblyResolver, Settings);
+			var workList = new HashSet<TypeDefinitionHandle>();
+			var processedTypes = new HashSet<TypeDefinitionHandle>();
+			ProcessFiles(files);
+			while (workList.Count > 0)
+			{
+				var additionalFiles = workList
+					.GroupBy(GetFileFileNameForHandle, StringComparer.OrdinalIgnoreCase).ToList();
+				workList.Clear();
+				ProcessFiles(additionalFiles);
+				files.AddRange(additionalFiles);
+				progress.TotalUnits = files.Count;
+			}
+
+			return files.Select(f => ("Compile", f.Key)).Concat(WriteAssemblyInfo(ts, cancellationToken));
+
+			string GetFileFileNameForHandle(TypeDefinitionHandle h)
+			{
 				var type = metadata.GetTypeDefinition(h);
 				string file = CleanUpFileName(metadata.GetString(type.Name)) + ".cs";
 				string ns = metadata.GetString(type.Namespace);
@@ -222,10 +243,11 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 						Directory.CreateDirectory(Path.Combine(TargetDirectory, dir));
 					return Path.Combine(dir, file);
 				}
-				}, StringComparer.OrdinalIgnoreCase).ToList();
-			var progressReporter = ProgressIndicator;
-			var progress = new DecompilationProgress { TotalUnits = files.Count, Title = "Exporting project..." };
-			DecompilerTypeSystem ts = new DecompilerTypeSystem(module, AssemblyResolver, Settings);
+			}
+
+			void ProcessFiles(List<IGrouping<string, TypeDefinitionHandle>> files)
+			{
+				processedTypes.AddRange(files.SelectMany(f => f));
 				Parallel.ForEach(
 					Partitioner.Create(files, loadBalance: true),
 					new ParallelOptions {
@@ -245,7 +267,27 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 								}
 
 								decompiler.CancellationToken = cancellationToken;
-							var syntaxTree = decompiler.DecompileTypes(file.ToArray());
+								var declaredTypes = file.ToArray();
+								var syntaxTree = decompiler.DecompileTypes(declaredTypes);
+
+								foreach (var node in syntaxTree.Descendants)
+								{
+									var td = (node.GetResolveResult() as TypeResolveResult)?.Type.GetDefinition();
+									if (td?.ParentModule != ts.MainModule)
+										continue;
+									while (td?.DeclaringTypeDefinition != null)
+									{
+										td = td.DeclaringTypeDefinition;
+									}
+									if (td != null && td.MetadataToken is { IsNil: false } token && !processedTypes.Contains((TypeDefinitionHandle)token))
+									{
+										lock (workList)
+										{
+											workList.Add((TypeDefinitionHandle)token);
+										}
+									}
+								}
+
 								syntaxTree.AcceptVisitor(new CSharpOutputVisitor(w, Settings.CSharpFormattingOptions));
 							}
 							catch (Exception innerException) when (!(innerException is OperationCanceledException || innerException is DecompilerException))
@@ -257,7 +299,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 						Interlocked.Increment(ref progress.UnitsCompleted);
 						progressReporter?.Report(progress);
 					});
-			return files.Select(f => ("Compile", f.Key)).Concat(WriteAssemblyInfo(ts, cancellationToken));
+			}
 		}
 		#endregion