| # 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 | 
 | # | 
 | # This file is derived from the master file in the flutter repo, and should be | 
 | # kept in sync with it. | 
 |  | 
 | 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 | 
 |     # Turned off until null-safe rollout is complete. | 
 |     unnecessary_null_comparison: ignore | 
 |  | 
 | 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 | 
 |     # - always_use_package_imports # we do this commonly | 
 |     - annotate_overrides | 
 |     # - avoid_annotating_with_dynamic # conflicts with always_specify_types | 
 |     - 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_dynamic_calls # not yet tested | 
 |     - avoid_empty_else | 
 |     - avoid_equals_and_hash_code_on_mutable_classes | 
 |     # - avoid_escaping_inner_quotes # not yet tested | 
 |     - 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_print # not yet tested | 
 |     # - avoid_private_typedef_functions # we prefer having typedef (discussion in https://github.com/flutter/flutter/pull/16356) | 
 |     # - avoid_redundant_argument_values # not yet tested | 
 |     - 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 | 
 |     - avoid_single_cascade_in_expression_statements | 
 |     - avoid_slow_async_io | 
 |     - avoid_type_to_string | 
 |     - avoid_types_as_parameter_names | 
 |     # - avoid_types_on_closure_parameters # conflicts with always_specify_types | 
 |     - avoid_unnecessary_containers | 
 |     - avoid_unused_constructor_parameters | 
 |     - avoid_void_async | 
 |     # - avoid_web_libraries_in_flutter # not yet tested | 
 |     - await_only_futures | 
 |     - camel_case_extensions | 
 |     - camel_case_types | 
 |     - cancel_subscriptions | 
 |     # - cascade_invocations # not yet tested | 
 |     - cast_nullable_to_non_nullable | 
 |     # - close_sinks # not reliable enough | 
 |     # - comment_references # blocked on https://github.com/dart-lang/linter/issues/1142 | 
 |     # - 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 required by flutter style | 
 |     - deprecated_consistency | 
 |     # - diagnostic_describe_all_properties # not yet tested | 
 |     - directives_ordering | 
 |     # - do_not_use_environment # we do this commonly | 
 |     - empty_catches | 
 |     - empty_constructor_bodies | 
 |     - empty_statements | 
 |     - exhaustive_cases | 
 |     - file_names | 
 |     - 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 required by flutter style | 
 |     - leading_newlines_in_multiline_strings | 
 |     - library_names | 
 |     - library_prefixes | 
 |     # - lines_longer_than_80_chars # not required by flutter style | 
 |     - list_remove_unrelated_type | 
 |     # - literal_only_boolean_expressions # too many false positives: https://github.com/dart-lang/sdk/issues/34181 | 
 |     - missing_whitespace_between_adjacent_strings | 
 |     - no_adjacent_strings_in_list | 
 |     # - no_default_cases # too many false positives | 
 |     - no_duplicate_case_values | 
 |     - no_logic_in_create_state | 
 |     # - no_runtimeType_toString # ok in tests; we enable this only in packages/ | 
 |     - non_constant_identifier_names | 
 |     - null_check_on_nullable_type_parameter | 
 |     - null_closures | 
 |     # - 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 required by flutter style | 
 |     - 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 # far too many false positives | 
 |     - 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 | 
 |     - prefer_final_locals | 
 |     - prefer_for_elements_to_map_fromIterable | 
 |     - prefer_foreach | 
 |     - prefer_function_declarations_over_variables | 
 |     - prefer_generic_function_type_aliases | 
 |     - prefer_if_elements_to_conditional_expressions | 
 |     - prefer_if_null_operators | 
 |     - prefer_initializing_formals | 
 |     - prefer_inlined_adds | 
 |     # - prefer_int_literals # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#use-double-literals-for-double-constants | 
 |     # - prefer_interpolation_to_compose_strings # doesn't work with raw strings, see https://github.com/dart-lang/linter/issues/2490 | 
 |     - prefer_is_empty | 
 |     - prefer_is_not_empty | 
 |     - prefer_is_not_operator | 
 |     - prefer_iterable_whereType | 
 |     # - prefer_mixin # https://github.com/dart-lang/language/issues/32 | 
 |     - prefer_null_aware_operators | 
 |     # - prefer_relative_imports # incompatible with sub-package imports | 
 |     - prefer_single_quotes | 
 |     - prefer_spread_collections | 
 |     - prefer_typing_uninitialized_variables | 
 |     - prefer_void_to_null | 
 |     - provide_deprecation_message | 
 |     - public_member_api_docs | 
 |     - recursive_getters | 
 |     - sized_box_for_whitespace | 
 |     - 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 | 
 |     - tighten_type_of_initializing_formals | 
 |     # - type_annotate_public_apis # subset of always_specify_types | 
 |     - type_init_formals | 
 |     # - unawaited_futures # too many false positives | 
 |     - unnecessary_await_in_return | 
 |     - unnecessary_brace_in_string_interps | 
 |     - unnecessary_const | 
 |     # - unnecessary_final # conflicts with prefer_final_locals | 
 |     - unnecessary_getters_setters | 
 |     # - unnecessary_lambdas # has false positives: https://github.com/dart-lang/linter/issues/498 | 
 |     - unnecessary_new | 
 |     - unnecessary_null_aware_assignments | 
 |     # - unnecessary_null_checks # not yet tested | 
 |     - unnecessary_null_in_if_null_operators | 
 |     - unnecessary_nullable_for_final_variable_declarations | 
 |     - unnecessary_overrides | 
 |     - unnecessary_parenthesis | 
 |     # - unnecessary_raw_strings # not yet tested | 
 |     - unnecessary_statements | 
 |     - unnecessary_string_escapes | 
 |     - unnecessary_string_interpolations | 
 |     - unnecessary_this | 
 |     - unrelated_type_equality_checks | 
 |     # - unsafe_html # not yet tested | 
 |     - use_full_hex_values_for_flutter_colors | 
 |     - use_function_type_syntax_for_parameters | 
 |     # - use_if_null_to_convert_nulls_to_bools # not yet tested | 
 |     - use_is_even_rather_than_modulo | 
 |     - use_key_in_widget_constructors | 
 |     - use_late_for_private_fields_and_variables | 
 |     # - use_named_constants # not yet yested | 
 |     - use_raw_strings | 
 |     - 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 | 
 |     ### Local flutter/packages changes ### | 
 |     # Flutter has a specific use case for dependencies that are intentionally | 
 |     # not sorted, which doesn't apply to this repo. | 
 |     - sort_pub_dependencies |