| # Specify analysis options. | 
 | # | 
 | # Until there are meta linter rules, each desired lint must be explicitly enabled. | 
 | # See: https://github.com/dart-lang/linter/issues/288 | 
 | # | 
 | # For a list of lints, see: http://dart-lang.github.io/linter/lints/ | 
 | # See the configuration guide for more | 
 | # https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer | 
 | # | 
 | # There are other similar analysis options files in the flutter repos, | 
 | # which should be kept in sync with this file: | 
 | # | 
 | #   - analysis_options.yaml (this file) | 
 | #   - packages/flutter/lib/analysis_options_user.yaml | 
 | #   - https://github.com/flutter/plugins/blob/master/analysis_options.yaml | 
 | #   - https://github.com/flutter/engine/blob/master/analysis_options.yaml | 
 | # | 
 | # This file contains the analysis options used by Flutter tools, such as IntelliJ, | 
 | # Android Studio, and the `flutter analyze` command. | 
 |  | 
 | analyzer: | 
 |   strong-mode: | 
 |     implicit-dynamic: false | 
 |   errors: | 
 |     # treat missing required parameters as a warning (not a hint) | 
 |     missing_required_param: warning | 
 |     # treat missing returns as a warning (not a hint) | 
 |     missing_return: warning | 
 |     # allow having TODOs in the code | 
 |     todo: ignore | 
 |     # Ignore analyzer hints for updating pubspecs when using Future or | 
 |     # Stream and not importing dart:async | 
 |     # Please see https://github.com/flutter/flutter/pull/24528 for details. | 
 |     sdk_version_async_exported_from_core: ignore | 
 |   exclude: | 
 |     - "bin/cache/**" | 
 |     # the following two are relative to the stocks example and the flutter package respectively | 
 |     # see https://github.com/dart-lang/sdk/issues/28463 | 
 |     - "lib/i18n/stock_messages_*.dart" | 
 |     - "lib/src/http/**" | 
 |  | 
 | linter: | 
 |   rules: | 
 |     # these rules are documented on and in the same order as | 
 |     # the Dart Lint rules page to make maintenance easier | 
 |     # https://github.com/dart-lang/linter/blob/master/example/all.yaml | 
 |     - always_declare_return_types | 
 |     - always_put_control_body_on_new_line | 
 |     # - always_put_required_named_parameters_first # we prefer having parameters in the same order as fields https://github.com/flutter/flutter/issues/10219 | 
 |     - always_require_non_null_named_parameters | 
 |     - always_specify_types | 
 |     - annotate_overrides | 
 |     # - avoid_annotating_with_dynamic # conflicts with always_specify_types | 
 |     - avoid_as | 
 |     - avoid_bool_literals_in_conditional_expressions | 
 |     # - avoid_catches_without_on_clauses # we do this commonly | 
 |     # - avoid_catching_errors # we do this commonly | 
 |     - avoid_classes_with_only_static_members | 
 |     # - avoid_double_and_int_checks # only useful when targeting JS runtime | 
 |     - avoid_empty_else | 
 |     - avoid_field_initializers_in_const_classes | 
 |     - avoid_function_literals_in_foreach_calls | 
 |     # - avoid_implementing_value_types # not yet tested | 
 |     - avoid_init_to_null | 
 |     # - avoid_js_rounded_ints # only useful when targeting JS runtime | 
 |     - avoid_null_checks_in_equality_operators | 
 |     # - avoid_positional_boolean_parameters # not yet tested | 
 |     # - avoid_private_typedef_functions # we prefer having typedef (discussion in https://github.com/flutter/flutter/pull/16356) | 
 |     - avoid_relative_lib_imports | 
 |     - avoid_renaming_method_parameters | 
 |     - avoid_return_types_on_setters | 
 |     # - avoid_returning_null # there are plenty of valid reasons to return null | 
 |     # - avoid_returning_null_for_future # not yet tested | 
 |     - avoid_returning_null_for_void | 
 |     # - avoid_returning_this # there are plenty of valid reasons to return this | 
 |     # - avoid_setters_without_getters # not yet tested | 
 |     # - avoid_shadowing_type_parameters # not yet tested | 
 |     # - avoid_single_cascade_in_expression_statements # not yet tested | 
 |     - avoid_slow_async_io | 
 |     - avoid_types_as_parameter_names | 
 |     # - avoid_types_on_closure_parameters # conflicts with always_specify_types | 
 |     - avoid_unused_constructor_parameters | 
 |     - avoid_void_async | 
 |     - await_only_futures | 
 |     - camel_case_types | 
 |     - cancel_subscriptions | 
 |     # - cascade_invocations # not yet tested | 
 |     # - close_sinks # not reliable enough | 
 |     # - comment_references # blocked on https://github.com/flutter/flutter/issues/20765 | 
 |     # - constant_identifier_names # needs an opt-out https://github.com/dart-lang/linter/issues/204 | 
 |     - control_flow_in_finally | 
 |     # - curly_braces_in_flow_control_structures # not yet tested | 
 |     # - diagnostic_describe_all_properties # not yet tested | 
 |     - directives_ordering | 
 |     - empty_catches | 
 |     - empty_constructor_bodies | 
 |     - empty_statements | 
 |     # - file_names # not yet tested | 
 |     - flutter_style_todos | 
 |     - hash_and_equals | 
 |     - implementation_imports | 
 |     # - invariant_booleans # too many false positives: https://github.com/dart-lang/linter/issues/811 | 
 |     - iterable_contains_unrelated_type | 
 |     # - join_return_with_assignment # not yet tested | 
 |     - library_names | 
 |     - library_prefixes | 
 |     # - lines_longer_than_80_chars # not yet tested | 
 |     - list_remove_unrelated_type | 
 |     # - literal_only_boolean_expressions # too many false positives: https://github.com/dart-lang/sdk/issues/34181 | 
 |     - no_adjacent_strings_in_list | 
 |     - no_duplicate_case_values | 
 |     - non_constant_identifier_names | 
 |     # - null_closures  # not yet tested | 
 |     # - omit_local_variable_types # opposite of always_specify_types | 
 |     # - one_member_abstracts # too many false positives | 
 |     # - only_throw_errors # https://github.com/flutter/flutter/issues/5792 | 
 |     - overridden_fields | 
 |     - package_api_docs | 
 |     - package_names | 
 |     - package_prefixed_library_names | 
 |     # - parameter_assignments # we do this commonly | 
 |     - prefer_adjacent_string_concatenation | 
 |     - prefer_asserts_in_initializer_lists | 
 |     # - prefer_asserts_with_message # not yet tested | 
 |     - prefer_collection_literals | 
 |     - prefer_conditional_assignment | 
 |     - prefer_const_constructors | 
 |     - prefer_const_constructors_in_immutables | 
 |     - prefer_const_declarations | 
 |     - prefer_const_literals_to_create_immutables | 
 |     # - prefer_constructors_over_static_methods # not yet tested | 
 |     - prefer_contains | 
 |     # - prefer_double_quotes # opposite of prefer_single_quotes | 
 |     - prefer_equal_for_default_values | 
 |     # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#consider-using--for-short-functions-and-methods | 
 |     - prefer_final_fields | 
 |     # - prefer_final_in_for_each # not yet tested | 
 |     - prefer_final_locals | 
 |     # - prefer_for_elements_to_map_fromIterable # not yet tested | 
 |     - prefer_foreach | 
 |     # - prefer_function_declarations_over_variables # not yet tested | 
 |     - prefer_generic_function_type_aliases | 
 |     # - prefer_if_elements_to_conditional_expressions # not yet tested | 
 |     - prefer_if_null_operators | 
 |     - prefer_initializing_formals | 
 |     - prefer_inlined_adds | 
 |     # - prefer_int_literals # not yet tested | 
 |     # - prefer_interpolation_to_compose_strings # not yet tested | 
 |     - prefer_is_empty | 
 |     - prefer_is_not_empty | 
 |     - prefer_iterable_whereType | 
 |     # - prefer_mixin # https://github.com/dart-lang/language/issues/32 | 
 |     # - prefer_null_aware_operators # disable until NNBD, see https://github.com/flutter/flutter/pull/32711#issuecomment-492930932 | 
 |     - prefer_single_quotes | 
 |     - prefer_spread_collections | 
 |     - prefer_typing_uninitialized_variables | 
 |     - prefer_void_to_null | 
 |     # - provide_deprecation_message # not yet tested | 
 |     # - public_member_api_docs # enabled on a case-by-case basis; see e.g. packages/analysis_options.yaml | 
 |     - recursive_getters | 
 |     - slash_for_doc_comments | 
 |     # - sort_child_properties_last # not yet tested | 
 |     - sort_constructors_first | 
 |     - sort_pub_dependencies | 
 |     - sort_unnamed_constructors_first | 
 |     - test_types_in_equals | 
 |     - throw_in_finally | 
 |     # - type_annotate_public_apis # subset of always_specify_types | 
 |     - type_init_formals | 
 |     # - unawaited_futures # too many false positives | 
 |     # - unnecessary_await_in_return # not yet tested | 
 |     - unnecessary_brace_in_string_interps | 
 |     - unnecessary_const | 
 |     - unnecessary_getters_setters | 
 |     # - unnecessary_lambdas # has false positives: https://github.com/dart-lang/linter/issues/498 | 
 |     - unnecessary_new | 
 |     - unnecessary_null_aware_assignments | 
 |     - unnecessary_null_in_if_null_operators | 
 |     - unnecessary_overrides | 
 |     - unnecessary_parenthesis | 
 |     - unnecessary_statements | 
 |     - unnecessary_this | 
 |     - unrelated_type_equality_checks | 
 |     # - unsafe_html # not yet tested | 
 |     - use_full_hex_values_for_flutter_colors | 
 |     # - use_function_type_syntax_for_parameters # not yet tested | 
 |     - use_rethrow_when_possible | 
 |     # - use_setters_to_change_properties # not yet tested | 
 |     # - use_string_buffers # has false positives: https://github.com/dart-lang/sdk/issues/34182 | 
 |     # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review | 
 |     - valid_regexps | 
 |     # - void_checks # not yet tested |