Fix #1340: infinite recursion in DelegateConstruction due to recursive local function being mistreated as delegate construction.

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -517,11 +517,14 @@ namespace ICSharpCode.Decompiler.CSharp
 				var part = method;
 
 				var connectedMethods = new Queue<MethodDefinitionHandle>();
+				var processedMethods = new HashSet<MethodDefinitionHandle>();
 				var processedNestedTypes = new HashSet<TypeDefinitionHandle>();
 				connectedMethods.Enqueue(part);
 
 				while (connectedMethods.Count > 0) {
 					part = connectedMethods.Dequeue();
+					if (!processedMethods.Add(part))
+						continue;
 					try {
 						ReadCodeMappingInfo(module, declaringType, info, parent, part, connectedMethods, processedNestedTypes);
 					} catch (BadImageFormatException) {

ICSharpCode.Decompiler/IL/Transforms/DelegateConstruction.cs

@@ -155,6 +155,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			var targetMethod = ((IInstructionWithMethodOperand)value.Arguments[1]).Method;
 			if (!IsAnonymousMethod(decompilationContext.CurrentTypeDefinition, targetMethod))
 				return null;
+			if (LocalFunctionDecompiler.IsLocalFunctionMethod(targetMethod.ParentModule.PEFile, (MethodDefinitionHandle)targetMethod.MetadataToken))
+				return null;
 			target = value.Arguments[0];
 			if (targetMethod.MetadataToken.IsNil)
 				return null;

ICSharpCode.Decompiler/IL/Transforms/LocalFunctionDecompiler.cs

@@ -21,8 +21,9 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		{
 			var metadata = module.Metadata;
 			var method = metadata.GetMethodDefinition(methodHandle);
+			var declaringType = method.GetDeclaringType();
 
-			if ((method.Attributes & MethodAttributes.Assembly) == 0 || !method.IsCompilerGenerated(metadata))
+			if ((method.Attributes & MethodAttributes.Assembly) == 0 || !(method.IsCompilerGenerated(metadata) || declaringType.IsCompilerGenerated(metadata)))
 				return false;
 
 			if (!ParseLocalFunctionName(metadata.GetString(method.Name), out _, out _))