cherrypick/cherrypick_generator/lib/module_generator.dart

// ... остальные импорты ...
import 'package:analyzer/dart/element/element.dart';
import 'package:build/build.dart';
import 'package:source_gen/source_gen.dart';
import 'package:cherrypick_annotations/cherrypick_annotations.dart' as ann;

class ModuleGenerator extends GeneratorForAnnotation<ann.module> {
  @override
  String generateForAnnotatedElement(
      Element element, ConstantReader annotation, BuildStep buildStep) {
    if (element is! ClassElement) {
      throw InvalidGenerationSourceError(
        '@module() может быть применён только к классам.',
        element: element,
      );
    }

    final classElement = element;
    final className = classElement.displayName;
    final generatedClassName = r'$' + className;
    final buffer = StringBuffer();

    //buffer.writeln("part of '${buildStep.inputId.uri.pathSegments.last}';\n");
    buffer.writeln('final class $generatedClassName extends $className {');
    buffer.writeln('  @override');
    buffer.writeln('  void builder(Scope currentScope) {');

    for (final method in classElement.methods.where((m) => !m.isAbstract)) {
      final hasSingleton = method.metadata.any(
        (m) =>
            m
                .computeConstantValue()
                ?.type
                ?.getDisplayString(withNullability: false)
                .toLowerCase()
                .contains('singleton') ??
            false,
      );
      if (!hasSingleton) continue;

      final returnType =
          method.returnType.getDisplayString(withNullability: false);
      final methodName = method.displayName;
      final args = method.parameters
          .map((p) =>
              "currentScope.resolve<${p.type.getDisplayString(withNullability: false)}>()")
          .join(', ');

      buffer.write('    bind<$returnType>()'
          '.toProvide(() => $methodName($args))'
          '.singleton();\n');
    }

    buffer.writeln('  }\n}');
    return buffer.toString();
  }
}

Builder moduleBuilder(BuilderOptions options) =>
    PartBuilder([ModuleGenerator()], '.cherrypick.g.dart');