Dart & Flutter lint rules

Patterns that make applications harder to use with assistive technology.

• accessible-widget-labelsflutter

  Warn about unlabeled interactive gesture targets.

• avoid-missing-image-altflutter

  Requires semanticLabel on Flutter Image and imageSemanticLabel on FadeInImage.

• minimum-touch-targetflutter

  Warn about explicitly undersized Flutter touch targets.

• prefer-action-button-tooltipflutter

  Requires useful tooltips on Flutter floating action buttons and icon buttons.

Needlessly complex code that is harder to read and maintain.

• avoid-classes-with-only-static-membersavoid_classes_with_only_static_members

  Flags a class that declares only static members.

• avoid-collapsible-if

  Flags an else-free if whose only then-statement is another else-free if.

• avoid-complex-arithmetic-expressions

  Reports arithmetic expressions containing too many terms.

• avoid-complex-conditions

  Flags boolean expressions with more logical operands than the configured threshold.

• avoid-complex-loop-conditions

  Flags loop conditions with more logical operands than the configured threshold.

• avoid-function-literals-in-foreach-callsavoid_function_literals_in_foreach_calls

  Flags a function literal passed to an Iterable's forEach.

• avoid-if-with-many-branches

  Reports long if/else-if chains; replace them with a switch or extracted helpers.

• avoid-inverted-boolean-expressionsavoid_inverted_boolean_expressionsrecommended

  Flags a doubly-negated boolean expression such as !!x.

• avoid-long-records

  Reports record values and record types with too many fields.

• avoid-nested-conditional-expressionsavoid-nested-conditional-expressions

  Flags a ternary conditional expression nested inside another ternary.

• avoid-nested-ifavoid_nested_if

  Flags an if statement whose then-branch contains nested if statements.

• avoid-nested-switch-expressions

  Reports deeply nested switch expressions.

• avoid-nested-switches

  Reports deeply nested switch statements.

• avoid-nested-try-statements

  Reports deeply nested try statements.

• avoid-redundant-asyncavoid-redundant-asyncrecommended

  Flags an async function whose body is a single return await ...;.

• avoid-unnecessary-containersavoid_unnecessary_containersrecommendedflutter

  Flags a Container whose only argument is a child.

• avoid-unnecessary-type-assertionsavoid-unnecessary-type-assertionsrecommended

  Flags an is check whose result is already guaranteed by the resolved static type.

• avoid-unnecessary-type-castsavoid-unnecessary-type-castsrecommended

  Flags an as cast to the operand's resolved static type.

• cascade-invocationscascade_invocations

  Flags consecutive statements that invoke members on the same variable.

• cognitive-complexity

  Reports function bodies with excessive nesting-weighted control flow.

• cyclomatic-complexitycyclomatic_complexity

  Flags a function whose cyclomatic complexity exceeds the configured threshold.

• join-return-with-assignmentjoin_return_with_assignment

  Flags an assignment immediately followed by return of the same variable.

• max-lines-for-filemax_lines_for_file

  Flags a file longer than the configured line limit.

• max-lines-for-functionmax_lines_for_function

  Flags a function or method longer than the configured line limit.

• max-parameters-for-functionmax_parameters_for_function

  Flags callable declarations and function types with more than the configured number of parameters.

• max-statements

  Reports function bodies with too many statements.

• max-switch-casesmax_switch_cases

  Flags a switch statement with more than the configured number of cases.

• maximum-nesting-levelmaximum_nesting_level

  Flags a function whose control-flow nesting runs deeper than the configured level.

• no-boolean-literal-compareno-boolean-literal-comparerecommended

  Don't compare boolean values to boolean literals.

• one-member-abstractsone_member_abstracts

  Flags abstract classes whose only member is a single abstract method.

• prefer-conditional-assignmentprefer_conditional_assignmentrecommended

  Flags if (x == null) { x = y; } with no else branch.

• prefer-conditional-expressionsprefer-conditional-expressions

  Flags an if/else whose branches each reduce to a single return or a single assignment to the same target.

• prefer-expression-function-bodiesprefer_expression_function_bodies

  Flags block function bodies that consist of a single return of a value.

• prefer-extracting-callbacksprefer-extracting-callbacksflutter

  Flags inline block-body callbacks passed to Widget constructors.

• prefer-for-elements-to-map-from-iterableprefer_for_elements_to_map_fromIterablerecommended

  Flags Map.fromIterable(x, key: ..., value: ...).

• prefer-if-elements-to-conditional-expressionsprefer_if_elements_to_conditional_expressions

  Prefers collection if elements to conditional expressions in list and set literals.

• prefer-if-null-operatorsprefer_if_null_operatorsrecommended

  Flags x == null ? y : x (and the inverted x != null ? x : y).

• prefer-immediate-returnprefer-immediate-return

  Flags a local variable that is returned on the immediately following statement.

• prefer-iterable-anyprefer_iterable_anyrecommended

  Flags iterable.where(...).isNotEmpty.

• prefer-iterable-everyprefer_iterable_everyrecommended

  Flags iterable.where(predicate).isEmpty and filtered-length comparisons.

• prefer-moving-to-variableprefer-moving-to-variable

  Flags repeated property/getter chains in local variable initializers.

• prefer-null-aware-operatorsprefer_null_aware_operatorsrecommended

  Flags x == null ? null : x.y (and the inverted x != null ? x.y : null).

• unnecessary-constunnecessary_constrecommended

  Flags a redundant const keyword inside an already-const context.

• unnecessary-getters-settersunnecessary_getters_settersrecommended

  Flags a trivial getter/setter pair that only reads and writes a private field.

• unnecessary-lambdasunnecessary_lambdasrecommended

  Flags a closure that only forwards its parameters to a function a tear-off could name.

• unnecessary-overridesunnecessary_overridesrecommended

  Flags a member that does nothing but forward to super with the same arguments and resolved contract.

• widget-tree-depthflutter

  Limits the depth of an inline Flutter widget construction tree.

Code that is outright wrong or will not behave as intended.

• add-equatable-propsrecommendedequatable

  Flags concrete Equatable subclasses that do not declare an instance props property.

• always-pass-global-keyflutter

  Keep GlobalKeys stable and pass owned State fields to widgets.

• always-remove-listenerrecommendedflutter

  Requires Flutter Listenable registrations in State to be removed.

• always-use-package-importsalways_use_package_imports

  Disallow relative imports in libraries under a package's lib/ directory.

• avoid-assigning-to-static-field

  Flags instance methods writing resolved static fields, including compound assignments and increments.

• avoid-calling-notifier-members-inside-buildrecommendedriverpod

  Flags calls to Riverpod notifier methods during widget build.

• avoid-collection-equality-checksrecommended

  Flags equality comparisons between non-constant SDK collections.

• avoid-conditional-hooksrecommendedflutter_hooks

  Flags hook calls in conditional branches, short-circuit operands, and loops.

• avoid-constant-assert-conditions

  Flags assertions whose Boolean condition is statically constant.

• avoid-constant-conditions

  Flags statically constant binary branch, loop, collection, and expression conditions.

• avoid-constant-switches

  Flags switch statements and expressions with a statically constant subject.

• avoid-contradictory-expressionsrecommended

  Flags pairs of conditions that are always false with && or true with ||.

• avoid-disposing-late-fieldsflutter

  Avoid releasing late State fields that may be unset or initialized only by cleanup.

• avoid-duplicate-bloc-event-handlersrecommendedbloc

  Flags later registrations of the same event type in a Bloc constructor.

• avoid-duplicate-cascades

  Flags repeated field or index assignment targets within one cascade.

• avoid-duplicate-collection-elements

  Flags repeated scalar literals and stable local reads in list and set literals.

• avoid-duplicate-exports

  Flags export directives whose visible names are already covered by another export.

• avoid-duplicate-factories

  Flags factories in one type with the same implementation, ignoring factory names and alpha-renaming parameters by position.

• avoid-duplicate-initializers

  Flags final/const variables with identical initializers in the same scope.

• avoid-duplicate-map-keysrecommended

  Flags repeated literal keys in map literals, including literal spreads and collection if entries.

• avoid-duplicate-mixins

  Flags repeated mixins in a with clause or a same-library superclass chain.

• avoid-duplicate-named-imports

  Flags imports of the same library that differ only in their name prefix.

• avoid-duplicate-switch-case-conditionsrecommended

  Flags repeated when guards on syntactically identical switch patterns.

• avoid-duplicate-test-assertionsrecommendedtest

  Reports repeated identical, side-effect-free assertions in a straight-line block.

• avoid-dynamic-callsavoid_dynamic_callsrecommended

  Avoid method calls or property accesses on a dynamic target.

• avoid-emit-outside-blocrecommendedbloc

  Flags external calls and tear-offs of a Bloc or Cubit's emit method.

• avoid-empty-setstaterecommendedflutter

  Avoid setState callbacks with empty block bodies.

• avoid-empty-test-groupstest

  Reports inline framework groups without any test registrations.

• avoid-global-stateavoid-global-state

  Disallow mutable global and static state.

• avoid-hooks-outside-buildrecommendedflutter_hooks

  Flags confirmed Flutter hooks outside hook builds, custom hooks, and HookBuilder/HookConsumer builders.

• avoid-incorrect-image-opacityflutter

  Flags Opacity directly wrapping a Flutter Image, including named constructors.

• avoid-inherited-widget-in-initstaterecommendedflutter

  Avoid inherited-widget subscriptions during initState.

• avoid-instantiating-in-value-providerprovider

  Value providers borrow existing instances; newly constructed values need create.

• avoid-late-contextrecommendedflutter

  Avoid storing BuildContext in late fields or reading it in late initializers.

• avoid-missing-completer-stack-trace

  Preserve error origins when calling SDK Completer.completeError.

• avoid-missing-controllerflutter

  Require Flutter text fields to expose their updated value.

• avoid-missing-enum-constant-in-map

  Require enum-keyed map literals to include every declared enum value.

• avoid-missing-interpolationrecommended

  Flags missing interpolation around visible String variables or member accesses and calls.

• avoid-misused-hooksrecommendedflutter_hooks

  Flags confirmed Flutter hooks called directly in non-hook Flutter widget builds.

• avoid-mounted-in-setstateflutter

  Check mounted before invoking Flutter State.setState, never inside its callback.

• avoid-mutable-equatable-subclass-fieldsrecommendedequatable

  Flags mutable instance fields on subclasses inheriting Equatable equality.

• avoid-mutable-global-variablesavoid_mutable_global_variables

  Disallow mutable top-level variables.

• avoid-nested-futures

  Avoid Future<Future<T>>, FutureOr<Future<T>>, and other directly nested future wrappers.

• avoid-nested-streams-and-futures

  Avoid directly nesting SDK streams and futures: Stream<Future<T>> and Future<Stream<T>> complicate consumption.

• avoid-read-inside-buildrecommendedprovider

  Flags non-listening Provider reads directly inside Flutter widget builds.

• avoid-recursive-calls

  Reports direct self-calls in functions and methods, including guarded recursion.

• avoid-recursive-widget-callsrecommendedflutter

  Warns when a widget's build method constructs the same widget again.

• avoid-ref-inside-state-disposeriverpod

  Rejects Riverpod widget references used during State.dispose.

• avoid-ref-read-inside-buildrecommendedriverpod

  Flags one-time Riverpod reads of provider state during widget build.

• avoid-ref-watch-outside-buildrecommendedriverpod

  Flags Riverpod WidgetRef.watch subscriptions outside synchronous widget build bodies.

• avoid-relative-lib-importsavoid_relative_lib_importsrecommended

  Disallow relative imports that reach into a lib/ directory.

• avoid-returning-widgetsavoid-returning-widgetsflutter

  Disallow functions and methods that return a Widget.

• avoid-type-to-stringavoid_type_to_stringrecommended

  Avoid Type.toString() in production code, where type names may be minified.

• avoid-uncaught-future-errorsrecommended

  Flags local futures first awaited after another await inside a try/catch.

• avoid-unconditional-break

  Reports unconditional break, continue, return or throw in a for-loop body.

• avoid-undisposed-instancesrecommendedflutter

  Warns when a disposable constructor result is discarded.

• avoid-unmodified-loop-conditionrecommended

  Flags loop conditions whose local scalar inputs are never modified by the loop.

• avoid-unnecessary-setstaterecommendedflutter

  Avoid setState during build, initState, or didUpdateWidget.

• avoid-unnecessary-stateful-widgetsrecommendedflutter

  Warns when a StatefulWidget's local State contains only a pure build method.

• avoid-unreachable-for-loop

  Reports iteration of a collection in a branch that requires it to be empty.

• avoid-unrelated-type-castsrecommended

  Flags casts between types proven unrelated by canonical type resolution.

• avoid-unsafe-collection-methods

  Flags potentially throwing element access on SDK collections.

• avoid-unsafe-reduce

  Warn when SDK Iterable.reduce can receive an empty collection.

• avoid-unused-after-null-check

  Reports a null-checked local ignored by a branch that passes another local of the same resolved type to a call.

• avoid-unused-parametersavoid-unused-parametersrecommended

  Disallow declared parameters that are never used, excluding primary constructors.

• avoid-watch-outside-buildrecommendedprovider

  Flags listening Provider accesses proven to run outside Flutter builds.

• avoid-web-libraries-in-flutteravoid_web_libraries_in_flutterrecommendedflutter

  Disallow importing web-only dart: libraries from Flutter code.

• await-only-futuresawait_only_futuresrecommended

  Await only values assignable to futures; FutureOr, dynamic, bottom types and extension types are accepted like the analyzer.

• cancel-subscriptionscancel_subscriptionsrecommended

  Cancel instances of dart:async StreamSubscription.

• check-is-not-closed-after-async-gaprecommendedbloc

  Flags Bloc add and emit calls after an await without a fresh isClosed check.

• close-sinksclose_sinksrecommended

  Close instances of dart:core Sink.

• collection-methods-unrelated-typecollection_methods_unrelated_typerecommended

  Reports collection lookups whose argument type is unrelated to the collection's type argument.

• comment-referencescomment_referencesrecommended

  Flags doc-comment references [name] that resolve to nothing in scope.

• correct-order-for-super-disposecorrect_order_for_super_disposerecommendedflutter

  Require super.dispose() to be the last call in dispose.

• deprecated-member-use-from-same-packagedeprecated_member_use_from_same_package

  Reports uses of deprecated declarations from their own package.

• diagnostic-describe-all-propertiesdiagnostic_describe_all_propertiesflutter

  Requires every public property of a Diagnosticable class to be referenced in its debug methods.

• discarded-futuresdiscarded_futures

  Don't discard Futures returned by calls in synchronous functions.

• dispose-fieldsrecommendedflutter

  Requires other owned disposable State fields to be released in dispose().

• dispose-focus-node-and-timerrecommendedflutter

  Requires owned FocusNode and Timer fields to be released in State.dispose().

• dispose-provided-instancesrecommendedriverpod

  Flags provider-created instances with a dispose method that lack ref.onDispose cleanup.

• dispose-provider-resourcesrecommendedriverpod

  Flags provider-created resources without autoDispose or ref.onDispose cleanup.

• dispose-providersrecommendedprovider

  Requires cleanup callbacks for disposable values created by package:provider's Provider.

• emit-new-bloc-state-instancesrecommendedbloc

  Flags Bloc and Cubit emissions that reuse their current state instance.

• exhaustive-casesexhaustive_casesrecommended

  Require switch statements over enum-like classes to cover every constant value.

• function-always-returns-null

  Flags value functions with a proven explicit null return on every path.

• function-always-returns-same-value

  Warns when distinct return paths in a function produce the same scalar constant.

• handle-bloc-event-subclassesbloc

  Warns when a Bloc constructor leaves a concrete event subclass without a handler.

• hash-and-equalshash_and_equalsrecommended

  Require hashCode and == to be overridden together.

• implementation-importsimplementation_importsrecommended

  Disallow importing another package's private src/ libraries.

• implicit-reopenimplicit_reopen

  Flags classes that implicitly reopen a supertype declared in the same library.

• invalid-case-patternsinvalid_case_patternsrecommended

  Flags pre-3.0 switch case expressions that change meaning or break under Dart 3 patterns.

• invalid-runtime-check-with-js-interop-typesinvalid_runtime_check_with_js_interop_typesrecommended

  Reject platform-dependent runtime checks involving JavaScript interop types.

• library-private-types-in-public-apilibrary_private_types_in_public_apirecommended

  Avoid using library-private types in public APIs.

• list-all-equatable-fieldsrecommendedequatable

  Flags declared instance fields omitted from a statically understood Equatable props list.

• literal-only-boolean-expressionsliteral_only_boolean_expressionsrecommended

  Flags conditions built only from literals, whose value never changes.

• match-getter-setter-field-names

  Detect likely copy-paste errors in trivial accessors when a different field matching the accessor name is declared.

• missing-test-assertionrecommendedtest

  Reports inline test callbacks that contain no recognized assertion calls.

• no-adjacent-strings-in-listno_adjacent_strings_in_listrecommended

  Flags adjacent string literals used as an element of a list or set literal.

• no-logic-in-create-stateno_logic_in_create_staterecommendedflutter

  Require StatefulWidget.createState to return only a fresh zero-argument Flutter State construction.

• no-self-assignmentsno_self_assignmentsrecommended

  Flags assignments of a variable to itself, such as x = x;.

• null-check-on-nullable-type-parameternull_check_on_nullable_type_parameterrecommended

  Flags a null assertion x! on a nullable type parameter T? whose expected type is T or T? for a potentially nullable T, and null-assert patterns whose matched value is a nullable type parameter.

• null-closuresnull_closuresrecommended

  Reject literal null in the closure slots of curated SDK APIs.

• prefer-correct-json-casts

  Decode JSON containers using their actual runtime generic types.

• prefer-define-hero-tagflutter

  Require an explicit heroTag on Flutter FloatingActionButton constructors.

• prefer-expect-latertest

  Requires expectLater when a canonical expect call receives an unawaited Future.

• prefer-immutable-bloc-eventsrecommendedbloc

  Flags Bloc event classes without an explicit @immutable annotation.

• prefer-immutable-bloc-staterecommendedbloc

  Flags Bloc state classes without an explicit @immutable annotation.

• prefer-immutable-provider-argumentsriverpod

  Requires stable value equality for freshly created Riverpod family keys.

• prefer-read-for-methodsrecommendedprovider

  Flags void method actions on a listening Provider lookup during build.

• prefer-ref-read-for-methodsrecommendedriverpod

  Flags watching a Riverpod notifier solely to invoke one of its methods.

• prefer-relative-importsprefer_relative_imports

  Prefer relative imports for libraries of the same package under lib/.

• prefer-sealed-bloc-eventsrecommendedbloc

  Flags Bloc event classes without a sealed or final modifier.

• prefer-sealed-bloc-staterecommendedbloc

  Flags Bloc state classes without a sealed or final modifier.

• prefer-void-to-nullprefer_void_to_nullrecommended

  Flags uses of the Null type where void is meant.

• proper-controller-disposeproper_controller_disposerecommendedflutter

  Requires Flutter controllers owned by a State field to be disposed.

• proper-expanded-and-flexibleproper_expanded_and_flexiblerecommendedflutter

  Require Expanded and Flexible to sit directly inside a flex widget.

• proper-from-environmentproper_from_environmentrecommended

  Require fromEnvironment to be evaluated in a const context.

• proper-super-init-stateproper_super_init_staterecommendedflutter

  Require super.initState() to be the first statement of a resolved Flutter State subclass's initState override.

• require-super-disposerecommendedflutter

  Require super.dispose() in Flutter State dispose overrides.

• test-types-in-equalstest_types_in_equalsrecommended

  Flags casting the parameter of operator == instead of testing its type.

• throw-in-finallythrow_in_finallyrecommended

  Flags throw inside a finally block.

• type-literal-in-constant-patterntype_literal_in_constant_patternrecommended

  Don't use constant patterns whose expressions have the core Type type.

• unnecessary-flutter-importsrecommendedflutter

  Disallow unused Flutter framework and dart:async imports.

• unnecessary-nullable-return-typeunnecessary_nullable_return_type

  Disallow nullable return types on functions that never return null.

• unnecessary-statementsunnecessary_statementsrecommended

  Flags expression statements whose expression has no clear effect.

• unrelated-type-equality-checksunrelated_type_equality_checksrecommended

  Reports ==/!= comparisons and relational ==/!= patterns whose operand types are unrelated.

• use-build-context-synchronouslyuse_build_context_synchronouslyrecommendedflutter

  Flags BuildContext use after an asynchronous gap without a mounted guard.

• use-closest-build-contextrecommendedflutter

  Use the nearest BuildContext parameter inside nested callbacks.

• use-key-in-widget-constructorsuse_key_in_widget_constructorsrecommendedflutter

  Require public widget constructors to accept or initialize a Flutter Key.

• use-once-constructors-once-provideruse_once_constructors_once_providerflutter

  Require Riverpod once-providers to be created through .once().

• use-ref-and-state-synchronouslyrecommendedriverpod

  Flags notifier ref and state accesses after an async gap without ref.mounted.

• use-ref-read-synchronouslyrecommendedriverpod

  Flags Riverpod WidgetRef.read calls after an async gap without a mounted guard.

• use-setstate-synchronouslyrecommendedflutter

  Require a mounted check before calling setState after an async gap.

• valid-regexpsvalid_regexpsrecommended

  Disallow statically known invalid dart:core regular expressions.

• void-checksvoid_checksrecommended

  Don't pass or assign values to void (or FutureOr<void>) locations.

Patterns with avoidable runtime or build cost.

• avoid-border-allflutter

  Avoids Flutter's non-const Border.all factory.

• avoid-shrink-wrap-in-listsflutter

  Avoids shrink-wrapped Flutter lists nested in rows, columns, or other lists.

• avoid-slow-async-ioavoid_slow_async_io

  Avoid the slow asynchronous dart:io file-system queries.

• avoid-slow-collection-methods

  Reports filtered iterable searches that have a direct search-method alternative.

• avoid-unnecessary-collections

  Avoid singleton collection literals where SDK APIs accept a single value.

• avoid-unnecessary-consumer-widgetsriverpod

  Flags Riverpod consumer widgets whose build reference is unused.

• avoid-unnecessary-futures

  Prefer synchronous declarations when an async Future only returns scalars.

• avoid-unnecessary-gesture-detectorflutter

  Flags handler-free Flutter GestureDetectors and tap-only wrappers around enabled Flutter buttons.

• avoid-unnecessary-hook-widgetsflutter_hooks

  Flags confirmed hook widgets and HookBuilder callbacks that do not use hooks.

• move-variable-closer-to-its-usage

  Move final/const scalar literals into their only branch, or after an if.

• move-variable-outside-iteration

  Reports loop-local final variables whose computation is independent of the loop.

• noop-primitive-operationsnoop_primitive_operationsrecommended

  Flags primitive operations that return their receiver unchanged.

• prefer-const-border-radiusprefer-const-border-radiusrecommendedflutter

  Flags BorderRadius.only(...) whose four corner radii are all equal.

• prefer-containsprefer_containsrecommended

  Prefers contains to comparing the result of indexOf with a constant.

• prefer-correct-edge-insets-constructorprefer-correct-edge-insets-constructorrecommendedflutter

  Flags an EdgeInsets.only(...) that a more specific constructor expresses better.

• prefer-declaring-const-constructorprefer_declaring_const_constructorflutter

  Flags a generative constructor that is legally eligible to be const.

• prefer-foreachprefer_foreach

  Prefers forEach to a for-in loop that only passes each element to a function.

• prefer-return-await

  Await returned SDK Futures inside a try body protected by a catch clause.

• prefer-single-setstateflutter

  Merge consecutive Flutter State.setState statements in the same block.

• prefer-use-callbackflutter_hooks

  Prefer useCallback for synchronous memoized function literals.

• prefer-use-memoflutter_hooks

  Prefer memoizing freshly allocated collection values used as hook keys.

• prefer-using-list-viewflutter

  Suggests considering ListView for a SingleChildScrollView containing a plain Flutter Column with at least two unconditional children in a list literal.

• sized-box-for-whitespacesized_box_for_whitespacerecommendedflutter

  Flags a Container used only to add fixed width/height whitespace.

• unnecessary-to-list-in-spreadsunnecessary_to_list_in_spreadsrecommended

  Flags a .toList() call on the operand of a spread, e.g.

• use-is-even-rather-than-modulouse_is_even_rather_than_modulo

  Prefers isEven/isOdd to comparing x % 2 with 0 or 1.

• use-string-buffersuse_string_buffersrecommended

  Prefers a StringBuffer to growing a String with + inside a loop.

Patterns that expose applications or their users to security risks.

• avoid-hardcoded-credentials

  Warns when credential-like variables, fields, or parameter defaults use nonempty string or numeric literals.

• avoid-sensitive-query-params

  Detect explicit secret-bearing URL query keys, not arbitrary occurrences of words such as token in paths, fragments, map values, or prose.

• avoid-weak-cryptographic-algorithmsrecommended

  Flags references to MD5, SHA-1, DES, triple DES, and RC4 package APIs.

• prefer-random-secure

  Prefer the cryptographically secure dart:math random generator.

Idiomatic, consistent Dart and Flutter style.

• always-declare-return-typesalways_declare_return_typesrecommended

  Flags functions and methods declared without a return type.

• always-put-control-body-on-new-linealways_put_control_body_on_new_line

  Flags a control-flow body that starts on the same line as its control clause.

• always-put-required-named-parameters-firstalways_put_required_named_parameters_first

  Flags a required named parameter declared after an optional named one.

• always-specify-typesalways_specify_types

  Requires explicit type annotations everywhere a type could be inferred.

• annotate-overridesannotate_overridesrecommended

  Requires @override on members that override an inherited declaration.

• arguments-ordering

  Named arguments follow their resolved parameter declaration order by default.

• avoid-abbreviations-in-doc-commentsavoid_abbreviations_in_doc_comments

  Flags Latin abbreviations in doc comments.

• avoid-annotating-with-dynamicavoid_annotating_with_dynamic

  Flags parameters explicitly annotated with dynamic.

• avoid-bloc-public-fieldsbloc

  Keep package-confirmed Bloc instance fields private; inherited API overrides are allowed.

• avoid-bloc-public-methodsbloc

  Enforce the package-confirmed Bloc convention.

• avoid-bool-literals-in-conditional-expressionsavoid_bool_literals_in_conditional_expressionsrecommended

  Flags conditional expressions over bool that have a bool literal branch.

• avoid-catches-without-on-clausesavoid_catches_without_on_clauses

  Avoid catch clauses without an on type.

• avoid-catching-errorsavoid_catching_errors

  Don't explicitly catch Error or types that implement it.

• avoid-double-and-int-checksavoid_double_and_int_checksrecommended

  Avoid checking a value for double and then for int.

• avoid-equals-and-hash-code-on-mutable-classesavoid_equals_and_hash_code_on_mutable_classes

  Flags == and hashCode overrides in classes not marked @immutable.

• avoid-escaping-inner-quotesavoid_escaping_inner_quotes

  Flags a string literal that escapes its own quote character when switching the outer quotes would remove every escape.

• avoid-field-initializers-in-const-classesavoid_field_initializers_in_const_classes

  Flags field initializers in classes with a const constructor.

• avoid-final-parametersavoid_final_parameters

  Flags parameters declared final.

• avoid-implementing-value-typesavoid_implementing_value_types

  Flags implements of a class that overrides ==.

• avoid-init-to-nullavoid_init_to_nullrecommended

  Flags explicit = null initializers on declarations that already default to null.

• avoid-js-rounded-intsavoid_js_rounded_intsrecommended

  Avoid integer literals that JavaScript would round.

• avoid-late-keywordavoid-late-keyword

  Flags use of the late keyword on variables and fields.

• avoid-multiple-declarations-per-lineavoid_multiple_declarations_per_linerecommended

  Flags a variable declaration that declares more than one variable.

• avoid-non-null-assertionavoid-non-null-assertion

  Flags the null-assertion operator ! except on a resolved Map index.

• avoid-null-checks-in-equality-operatorsavoid_null_checks_in_equality_operatorsrecommended

  Flags null checks of the parameter inside a custom operator ==.

• avoid-positional-boolean-parametersavoid_positional_boolean_parameters

  Flags a positional bool parameter in a public signature.

• avoid-positional-fields-in-recordsavoid_positional_fields_in_records

  Flags positional fields in record types.

• avoid-private-typedef-functionsavoid_private_typedef_functions

  Flags a private function typedef that is used at most once.

• avoid-public-notifier-propertiesriverpod

  Keeps notifier state behind Riverpod's observable state property.

• avoid-redundant-argument-valuesavoid_redundant_argument_values

  Flags arguments that pass exactly the parameter's default value.

• avoid-redundant-else

  Flags else branches after an if body that unconditionally returns or throws.

• avoid-redundant-pattern-field-namesavoid_redundant_pattern_field_namesrecommended

  Flags redundant field names in object and record patterns.

• avoid-renaming-method-parametersavoid_renaming_method_parameters

  Requires overriding methods to keep the positional parameter names of the member they inherit.

• avoid-return-types-on-settersavoid_return_types_on_settersrecommended

  Flags setters declared with an explicit return type.

• avoid-returning-thisavoid_returning_this

  Flags methods that return this only to enable a fluent interface.

• avoid-setters-without-gettersavoid_setters_without_getters

  Flags a setter that has no corresponding getter.

• avoid-single-cascade-in-expression-statementsavoid_single_cascade_in_expression_statementsrecommended

  Flags an expression statement that is a cascade with a single section.

• avoid-single-child-column-or-rowavoid_single_child_column_or_rowflutter

  Flags a Column, Row, or Flex widget built with a single child.

• avoid-top-level-member-access

  Flags mutable global state: non-const, non-final top-level variables and static fields, plus every read of mutable top-level variables.

• avoid-types-on-closure-parametersavoid_types_on_closure_parameters

  Flags type annotations on closure parameters whose types come from context.

• avoid-unnecessary-block

  Flags standalone nested blocks that introduce no lexical declarations.

• avoid-unnecessary-call

  Prefer direct invocation of functions and resolved callable instances.

• avoid-unnecessary-continue

  Flags an unlabeled continue at the end of a loop body or its final branch.

• avoid-unnecessary-getter

  Flags a getter that only exposes a private final field.

• avoid-unnecessary-if

  Flags an if branch that only returns the same expression as the following return.

• avoid-unnecessary-length-check

  Empty collections already skip for-in and forEach bodies.

• avoid-unnecessary-local-variable

  Reports a single-use local used only to initialize the next local.

• avoid-unnecessary-negations

  Simplifies negated bool literals and equality comparisons with a logical negation on both sides.

• avoid-unnecessary-overrides-in-stateflutter

  Redundant Flutter State overrides that drop inherited @protected.

• avoid-unnecessary-reassignment

  Reports an eager local initializer immediately overwritten without a read.

• avoid-unnecessary-return

  Flags bare returns at the end of a function or its final if/block branches.

• avoid-unnecessary-super

  Omit implicit super() initializers and provably redundant member prefixes.

• avoid-unused-constructor-parametersavoid_unused_constructor_parameters

  Flags constructor parameters that are never used.

• avoid-void-asyncavoid_void_asyncrecommended

  Avoid async functions and methods declared to return void.

• avoid-wrapping-in-paddingflutter

  Flags Padding directly wrapping a Flutter Container that can own the padding.

• binary-expression-operand-orderbinary-expression-operand-order

  Flags comparison expressions with a literal on the left-hand side.

• boolean-prefixesboolean_prefixes

  Flags boolean identifiers that lack a conventional interrogative prefix.

• camel-case-extensionscamel_case_extensionsrecommended

  Flags named extensions whose name is not UpperCamelCase.

• camel-case-typescamel_case_typesrecommended

  Flags type names that are not UpperCamelCase.

• cast-nullable-to-non-nullablecast_nullable_to_non_nullable

  Flags e as T casts of a nullable value to a non-nullable type.

• class-members-orderingclass_members_ordering

  Flags class members declared out of a canonical order.

• combinators-orderingcombinators_ordering

  Flags show/hide combinators whose names are not sorted alphabetically.

• conditional-uri-does-not-existconditional_uri_does_not_existrecommended

  Require the targets of conditional import and export URIs to exist.

• constant-identifier-namesconstant_identifier_namesrecommended

  Flags constant identifiers that are not lowerCamelCase.

• curly-braces-in-flow-control-structurescurly_braces_in_flow_control_structuresrecommended

  Requires curly braces around the bodies of flow-control statements.

• dangling-library-doc-commentsdangling_library_doc_commentsrecommended

  Attach library documentation to an explicit library directive.

• deprecated-consistencydeprecated_consistencyrecommended

  Flags deprecations that are not carried through to related declarations.

• directives-orderingdirectives_ordering

  Flags import and export directives that break the Effective Dart ordering.

• do-not-use-environmentdo_not_use_environment

  Disallow reading compilation environment declarations, including type aliases.

• double-literal-formatdouble-literal-format

  Flags double literals written with redundant or missing digits.

• empty-constructor-bodiesempty_constructor_bodiesrecommended

  Flags constructors with an empty block body {}.

• enum-constants-ordering

  Flags enum constants whose declared names violate the configured order.

• eol-at-end-of-fileeol_at_end_of_filerecommended

  Flags a non-empty file that does not end with exactly one line break.

• extend-equatableequatable

  Require Equatable semantics for configured class/file name patterns.

• file-namesfile_namesrecommended

  Enforces lowercase_with_underscores for source file names.

• flutter-style-todosflutter_style_todos

  Flags TODO comments that do not follow the Flutter style // TODO(username): message, https://URL-to-issue.

• format-commentformat-comment

  Flags comments that are not formatted as complete sentences.

• implicit-call-tearoffsimplicit_call_tearoffs

  Explicitly tear off callable objects' call methods.

• initializers-ordering

  Requires field initializers to follow their containing type's field declaration order by default.

• leading-newlines-in-multiline-stringsleading_newlines_in_multiline_strings

  Flags a multiline string spanning several lines whose text does not start with a line break right after the opening quotes.

• library-annotationslibrary_annotationsrecommended

  Requires library-targeted metadata to attach to a library directive.

• library-nameslibrary_namesrecommended

  Flags a library name that is not lowercase_with_underscores.

• library-prefixeslibrary_prefixesrecommended

  Flags import prefixes that are not lower_case_with_underscores.

• lines-longer-than-80-charslines_longer_than_80_chars

  Flags source lines longer than 80 characters.

• map-keys-ordering

  Flags literal string map keys that violate the configured order.

• matching-super-parametersmatching_super_parameters

  Flags positional super parameters named differently from the super constructor's corresponding parameter.

• member-orderingmember-ordering

  Flags class members declared out of the configured order.

• missing-whitespace-between-adjacent-stringsmissing_whitespace_between_adjacent_stringsrecommended

  Flags adjacent string literals that join two words without a space between them.

• newline-before-break

  Requires a blank line before a break that follows another statement.

• newline-before-case

  Requires a blank line between successive switch statement case clauses.

• newline-before-constructor

  Requires a blank line before constructors following another member.

• newline-before-continue

  Requires a blank line before a continue that follows another statement.

• newline-before-method

  Requires a blank line before method declarations following another member.

• newline-before-returnnewline-before-return

  Flags return statements that are not preceded by a blank line.

• newline-before-throw

  Requires a blank line before a throw that follows another statement.

• no-default-casesno_default_cases

  Flags default: in switch statements over enums and enum-like classes.

• no-leading-underscores-for-library-prefixesno_leading_underscores_for_library_prefixesrecommended

  Flags import prefixes that begin with an underscore.

• no-leading-underscores-for-local-identifiersno_leading_underscores_for_local_identifiersrecommended

  Flags local variables and parameters whose names begin with an underscore.

• no-literal-bool-comparisonsno_literal_bool_comparisons

  Flags boolean literals compared or combined with a non-nullable bool.

• no-magic-numberno-magic-number

  Flags unnamed numeric literals (magic numbers) used inline in expressions.

• no-object-declarationno-object-declaration

  Flags class members declared with the type Object (or Object?).

• no-runtime-type-to-stringno_runtimeType_toString

  Avoid calling toString() on runtimeType.

• non-constant-identifier-namesnon_constant_identifier_namesrecommended

  Flags non-constant identifiers that are not written in lowerCamelCase.

• omit-local-variable-typesomit_local_variable_types

  Flags local variable type annotations that repeat the initializer's type.

• only-throw-errorsonly_throw_errorsrecommended

  Only throw instances of classes that extend Exception or Error.

• parameter-assignmentsparameter_assignments

  Don't reassign parameters of functions, methods, or constructors.

• parameters-ordering

  Requires named parameters to follow the explicitly configured alphabetical order.

• pattern-fields-ordering

  Flags named object and record pattern fields that violate the configured order.

• prefer-adjacent-string-concatenationprefer_adjacent_string_concatenationrecommended

  Flags two string literals joined with the + operator.

• prefer-align-over-containerflutter

  Prefers Align over a Container used only for alignment.

• prefer-asserts-in-initializer-listsprefer_asserts_in_initializer_lists

  Flags leading constructor-body asserts that could live in the initializer list.

• prefer-asserts-with-messageprefer_asserts_with_message

  Flags assert statements and assert initializers that have no message.

• prefer-async-awaitprefer-async-await

  Flags .then(...) future chains that should use async/await.

• prefer-async-callbackprefer_async_callbackflutter

  Flags the type Future<void> Function() in favor of Flutter's AsyncCallback.

• prefer-bloc-event-suffixbloc

  Enforce the package-confirmed Bloc convention.

• prefer-bloc-extensionsbloc

  Prefer context.read/watch over package:flutter_bloc's provider lookups.

• prefer-bloc-state-suffixbloc

  Enforce the package-confirmed Bloc convention.

• prefer-center-over-alignflutter

  Prefers Center over an Align whose alignment is known to be centered.

• prefer-collection-literalsprefer_collection_literalsrecommended

  Flags no-argument collection constructor calls that a literal would express.

• prefer-commenting-analyzer-ignores

  Require explanations for analyzer ignore: and ignore_for_file: comments.

• prefer-const-constructorsprefer_const_constructors

  Prefers const when invoking a const constructor with constant arguments.

• prefer-const-constructors-in-immutablesprefer_const_constructors_in_immutablesflutter

  Prefers const constructors in immutable classes and extension types.

• prefer-const-declarationsprefer_const_declarationsrecommended

  Flags final declarations whose initializers are all constant expressions.

• prefer-const-literals-to-create-immutablesprefer_const_literals_to_create_immutables

  Prefers const list, set, and map literals as arguments to constructors of @immutable classes.

• prefer-constrained-box-over-containerflutter

  Prefers ConstrainedBox over a Container used only for constraints.

• prefer-constructors-over-static-methodsprefer_constructors_over_static_methods

  Flags static methods that create and return an instance of their own class.

• prefer-containerflutter

  Suggests collapsing compatible nested layout widgets into one Container.

• prefer-correct-callback-field-name

  Match callback field names to a configured regular expression.

• prefer-correct-error-name

  Require configured error parameter names in catches and SDK error callbacks.

• prefer-correct-handler-name

  Match callback handler methods to a configured regular expression.

• prefer-correct-identifier-lengthprefer-correct-identifier-length

  Flags declared identifiers that are shorter or longer than the allowed range.

• prefer-correct-notifier-file-nameriverpod

  Requires snake_case file names ending in _notifier.dart for resolved Riverpod notifier classes.

• prefer-correct-provider-file-nameriverpod

  Requires snake_case file names ending in _provider.dart for resolved Riverpod provider declarations, including annotated generator functions.

• prefer-correct-test-file-nametest

  Requires entry-point files under package-root test/ or integration_test/ to use the _test.dart suffix.

• prefer-correct-type-nameprefer-correct-type-name

  Flags type declarations whose name is not well-formed UpperCamelCase.

• prefer-dedicated-media-query-methodsprefer_dedicated_media_query_methodsrecommendedflutter

  Flags MediaQuery.of(context).size access in favor of MediaQuery.sizeOf.

• prefer-double-quotesprefer_double_quotes

  Flags single-quoted string literals that could use double quotes without needing an escape.

• prefer-early-return

  Flags a trailing if that wraps multiple statements in a void function.

• prefer-equatable-mixinequatable

  Prefer EquatableMixin to directly extending package:equatable's Equatable.

• prefer-final-fieldsprefer_final_fieldsrecommended

  Flags a private field that is initialized but never reassigned, so it could be final (prefer-final-fields, adopted from package:lints).

• prefer-final-in-for-eachprefer_final_in_for_eachrecommended

  Prefer final for a for-each loop variable that is never reassigned.

• prefer-final-localsprefer_final_localsrecommended

  Prefer final for local variable declarations that are never reassigned.

• prefer-final-parametersprefer_final_parameters

  Prefer final for parameters that are never reassigned.

• prefer-firstprefer-first

  Flags [0] index access that should use the .first getter.

• prefer-for-in

  Flags zero-based, unit-step index loops over a syntactically known list.

• prefer-for-loop-in-childrenflutter

  Prefers collection-for elements over eager map/toList chains in Flutter children.

• prefer-function-declarations-over-variablesprefer_function_declarations_over_variablesrecommended

  Flags a local variable bound to a function literal that should be a local function declaration.

• prefer-generic-function-type-aliasesprefer_generic_function_type_aliasesrecommended

  Flags old-style function typedefs written with inline parameter syntax.

• prefer-getter-over-method

  Prefer getters for synchronous, zero-argument methods that only read a field.

• prefer-initializing-formalsprefer_initializing_formalsrecommended

  Prefer initializing formals when a parameter is copied directly into its field.

• prefer-inlined-addsprefer_inlined_addsrecommended

  Flags an add cascade on a list literal whose element could be written inline.

• prefer-int-literalsprefer_int_literals

  Flags a whole-number double literal, such as 1.0, where the context type is double so the int literal 1 means the same value.

• prefer-interpolation-to-compose-stringsprefer_interpolation_to_compose_stringsrecommended

  Prefers string interpolation to composing strings with +.

• prefer-is-emptyprefer_is_emptyrecommended

  Flags .length comparisons equivalent to a .isEmpty check.

• prefer-is-not-emptyprefer_is_not_emptyrecommended

  Flags .length comparisons equivalent to a .isNotEmpty check.

• prefer-is-not-operatorprefer_is_not_operatorrecommended

  Flags a negated type test !(x is T) that should use the is! operator.

• prefer-iterable-ofprefer-iterable-ofrecommended

  Flags .from collection constructors in favor of the .of constructor.

• prefer-iterable-where-typeprefer_iterable_whereTyperecommended

  Flags .where((e) => e is T), which .whereType<T>() expresses directly.

• prefer-lastprefer-last

  Flags manual last-element indexing in favor of the .last getter.

• prefer-match-file-name

  Match a file's sole class or enum name to its snake-case basename.

• prefer-mixinprefer_mixinrecommended

  Flags with clauses that mix in a plain class instead of a mixin.

• prefer-multi-bloc-providerbloc

  Flatten directly nested package:flutter_bloc BlocProviders with MultiBlocProvider.

• prefer-multi-providerprovider

  Prefer a flat MultiProvider to directly nested provider widgets.

• prefer-named-boolean-parameters

  Flags explicit positional bool parameters in private declarations and unconstrained closures.

• prefer-named-parameters

  Prefer named parameters when a declaration exceeds max-number (default 1).

• prefer-null-aware-method-callsprefer_null_aware_method_callsrecommended

  Prefers f?.call() to calling a null-checked function after a != null test.

• prefer-padding-over-containerflutter

  Prefers Padding over a Container used only for padding.

• prefer-provider-extensionsprovider

  Prefer context.read/watch when provider extensions are in scope.

• prefer-returning-condition

  Flags an if returning a boolean literal followed by the opposite literal.

• prefer-riverpod-notifier-suffixriverpod

  Requires a Notifier suffix on classes extending resolved Riverpod notifiers.

• prefer-riverpod-provider-suffixriverpod

  Requires a Provider suffix on resolved Riverpod top-level providers and static fields.

• prefer-single-quotesprefer_single_quotes

  Flags double-quoted string literals that could use single quotes without needing an escape.

• prefer-sized-box-squareflutter

  Prefers SizedBox.square for an unnamed Flutter SizedBox whose explicit width and height are stable variable reads or numeric literals with identical token spelling.

• prefer-spread-collectionsprefer_spread_collectionsrecommended

  Flags an addAll cascade on a collection literal that a spread would express.

• prefer-switch-expression

  Prefer switch expressions for exhaustive switches that only return or assign a value.

• prefer-test-matcherstest

  Recommends Matcher expectations and direct type, equality, or ordering matchers.

• prefer-trailing-commaprefer-trailing-comma

  Flags multi-line argument lists that are missing a trailing comma.

• prefer-transform-over-containerflutter

  Prefers Transform over a Container used only for transform.

• prefer-type-over-var

  Prefer explicit types over var in ordinary variable declarations.

• prefer-typing-uninitialized-variablesprefer_typing_uninitialized_variablesrecommended

  Flags uninitialized variables declared without a type annotation.

• prefer-underscore-for-unused-callback-parametersprefer_underscore_for_unused_callback_parameters

  Flags unused closure parameters that are not named with underscores.

• prefer-void-callbackflutter

  Prefers Flutter's VoidCallback alias over a nongeneric void Function() type.

• provide-deprecation-messageprovide_deprecation_messagerecommended

  Flags @deprecated and @Deprecated() annotations that carry no message.

• public-member-api-docspublic_member_api_docs

  Documents public declarations and members in package libraries.

• record-fields-ordering

  Flags named record type fields that violate the configured order.

• require-trailing-commasrequire_trailing_commas

  Flags a multi-line call, declaration, assert, or collection literal that is missing a trailing comma.

• sized-box-shrink-expandsized_box_shrink_expandrecommendedflutter

  Prefers SizedBox.shrink() / SizedBox.expand() over a SizedBox sized to zero or infinity.

• slash-for-doc-commentsslash_for_doc_commentsrecommended

  Flags /** ...

• sort-child-properties-lastsort_child_properties_lastrecommendedflutter

  Sort Widget-valued child properties last, except before closure arguments.

• sort-constructors-firstsort_constructors_first

  Flags a constructor declared after a non-constructor member.

• sort-unnamed-constructors-firstsort_unnamed_constructors_first

  Flags an unnamed constructor declared after a named constructor.

• tighten-type-of-initializing-formalstighten_type_of_initializing_formals

  Flags a nullable this.x or super.x initializing formal whose constructor asserts x != null.

• type-annotate-public-apistype_annotate_public_apisrecommended

  Requires type annotations on public declarations.

• type-init-formalstype_init_formalsrecommended

  Flags a *redundant* type annotation on an initializing formal or super parameter (type-init-formals, adopted from package:lints).

• unawaited-futuresunawaited_futuresrecommended

  Future results in async bodies must be awaited or marked unawaited.

• unintended-html-in-doc-commentunintended_html_in_doc_commentrecommended

  Flags angle-bracket text in doc comments that Markdown would render as an HTML tag.

• unnecessary-await-in-returnunnecessary_await_in_return

  Avoid await on a returned Future the function's own Future already covers.

• unnecessary-brace-in-string-interpsunnecessary_brace_in_string_interpsrecommended

  Flags ${x} string interpolations whose braces can be dropped.

• unnecessary-breaksunnecessary_breaksrecommended

  Flags a trailing break in a switch case that already ends implicitly.

• unnecessary-constructor-nameunnecessary_constructor_namerecommended

  Flags a redundant .new on constructor declarations and invocations.

• unnecessary-finalunnecessary_final

  Don't use final for local variables and parameters.

• unnecessary-lateunnecessary_laterecommended

  Flags a redundant late modifier on an initialized static or top-level variable.

• unnecessary-library-directiveunnecessary_library_directiverecommended

  Flags a library directive that has neither a doc comment nor annotations.

• unnecessary-library-nameunnecessary_library_namerecommended

  Flags a library directive that carries an explicit name.

• unnecessary-newunnecessary_newrecommended

  Flags an explicit new keyword in an instance-creation expression.

• unnecessary-null-aware-operator-on-extension-on-nullableunnecessary_null_aware_operator_on_extension_on_nullable

  Flags a null-aware access whose member comes from an extension on a nullable type.

• unnecessary-null-checksunnecessary_null_checks

  Flags a null assertion ! on a value that flows into a nullable context.

• unnecessary-nullable-for-final-variable-declarationsunnecessary_nullable_for_final_variable_declarationsrecommended

  Flags a final or const variable given a nullable type but initialized to a provably non-null value.

• unnecessary-parenthesisunnecessary_parenthesisrecommended

  Flags parentheses that can be removed without changing the meaning or hurting readability.

• unnecessary-raw-stringsunnecessary_raw_stringsrecommended

  Flags raw string literals that contain no backslash or $.

• unnecessary-string-escapesunnecessary_string_escapesrecommended

  Flags backslashes that do not affect a string's value.

• unnecessary-string-interpolationsunnecessary_string_interpolationsrecommended

  Flags a string literal whose entire content is a single interpolation of a provably non-nullable String.

• unnecessary-thisunnecessary_thisrecommended

  Flags a redundant this. qualifier on member access.

• unreachable-from-mainunreachable_from_main

  Report public declarations that no entry point of an executable library reaches.

• use-colored-boxuse_colored_boxrecommendedflutter

  Prefers ColoredBox over a Container that only paints a color behind its child.

• use-decorated-boxuse_decorated_boxrecommendedflutter

  Prefers DecoratedBox over a Container that only decorates its child.

• use-design-system-itemuse-design-system-itemflutter

  Flags construction of a widget or type that should be replaced by its design-system equivalent.

• use-enumsuse_enums

  Flags classes that emulate an enum and could be declared as one.

• use-existing-destructuring

  Reuse or extend an existing record destructuring instead of rereading a field.

• use-existing-variable

  Reuse a local for stable SDK arithmetic and String.length/int parity getters.

• use-full-hex-values-for-flutter-colorsuse_full_hex_values_for_flutter_colorsrecommendedflutter

  Require an eight-digit hexadecimal integer for the canonical Flutter Color default constructor.

• use-function-type-syntax-for-parametersuse_function_type_syntax_for_parametersrecommended

  Flags an old-style function-typed parameter written with inline parameter syntax.

• use-if-null-to-convert-nulls-to-boolsuse_if_null_to_convert_nulls_to_boolsrecommended

  Prefers ?? to comparing a nullable bool against a boolean literal.

• use-late-for-private-fields-and-variablesuse_late_for_private_fields_and_variables

  Flags a private nullable field or top-level variable that is only ever assigned non-null values and read through !, so it could be late with a non-nullable type.

• use-named-constantsuse_named_constantsrecommended

  Prefers a class's predefined static constant to constructing an equal constant.

• use-raw-stringsuse_raw_strings

  Flags string literals whose only escapes are \\ and \$, which a raw string would express without any backslash.

• use-setters-to-change-propertiesuse_setters_to_change_properties

  Flags one-parameter void methods that only assign that parameter to a field.

• use-spacer-as-expanded-childuse_spacer_as_expanded_childrecommendedflutter

  Flags an Expanded wrapping an empty SizedBox or Container that should be a Spacer.

• use-string-in-part-of-directivesuse_string_in_part_of_directivesrecommended

  Flags a part of directive that names its library instead of using a string URI.

• use-super-parametersuse_super_parametersrecommended

  Prefer super parameters when a constructor only forwards parameters to its superclass.

• use-test-throws-matchersuse_test_throws_matchersrecommended

  Prefers throwsA matchers over try { ...; fail(...); } catch (...) {}.

• use-to-and-as-if-applicableuse_to_and_as_if_applicable

  Flags conversion methods not named to… or as….

Patterns that are probably a mistake or a latent bug.

• avoid-accessing-other-classes-private-members

  Enforces class-level encapsulation even inside one Dart library.

• avoid-assignments-as-conditions

  Flags assignments evaluated inside control-flow conditions.

• avoid-banned-annotations

  Ban configured dotted annotation names, without the leading @.

• avoid-banned-exports

  Ban decoded export URIs, including all conditional alternatives.

• avoid-banned-names

  Ban declaration names, exempting references, initializing/super formals, and @override-annotated members and their parameters.

• avoid-banned-types

  Ban resolved explicit type annotations, including nested generic arguments.

• avoid-barrel-files

  Discourage files containing only re-exports, without declarations or parts.

• avoid-bitwise-operators-with-booleans

  Flags & and | applied to two non-nullable boolean operands.

• avoid-commented-out-code

  Flags ordinary comments that contain recognizable Dart statements.

• avoid-double-slash-imports

  Reject repeated path separators in directive URIs (import, export and part).

• avoid-dynamicavoid-dynamic

  Flags explicit dynamic type annotations.

• avoid-empty-elseavoid_empty_elserecommended

  Flags an else clause whose body is an empty statement (else ;).

• avoid-ignoring-return-valuesavoid-ignoring-return-values

  Flags a discarded call whose resolved return type is non-void.

• avoid-incorrect-uri

  Reject runtime-invalid Uri constructor arguments: conflicting path or query inputs and query parameter values that are neither null, strings nor iterables of strings.

• avoid-inverted-boolean-checks

  Prefer direct equality comparisons and De Morgan forms in control-flow conditions.

• avoid-multi-assignment

  Split chained assignments into separate statements.

• avoid-mutating-parameters

  Detects writes through named function, method and constructor parameter objects.

• avoid-negated-conditions

  Prefer positive conditions when both branches can be swapped.

• avoid-nested-assignments

  Require assignments to be standalone statements, arrow bodies or loop operations.

• avoid-non-final-exception-class-fields

  Exception and Error payloads should not change after construction.

• avoid-passing-async-when-sync-expectedavoid-passing-async-when-sync-expectedrecommended

  Flags an async closure passed to a proven synchronous callback parameter.

• avoid-passing-bloc-to-blocbloc

  Rejects direct Bloc and Cubit arguments to other blocs.

• avoid-passing-bloc-to-widgetbloc

  Rejects direct Bloc and Cubit arguments to Flutter widget constructors.

• avoid-passing-build-context-to-blocsbloc

  Keeps Flutter BuildContext arguments outside Bloc and Cubit APIs.

• avoid-printavoid_printrecommendedflutter

  Flags calls and callback arguments resolving to dart:core's print.

• avoid-referencing-subclasses

  Keeps base classes independent from their transitive subclasses.

• avoid-returning-null-for-voidavoid_returning_null_for_voidrecommended

  Flags return null; (and => null bodies) in synchronous void functions and asynchronous Future<void> functions.

• avoid-shadowed-extension-methods

  Flags extension instance methods and accessors hidden by their target's members.

• avoid-shadowing

  Flags local bindings and parameters that hide an enclosing type's member.

• avoid-shadowing-type-parametersavoid_shadowing_type_parametersrecommended

  Flags a type parameter that shadows a type parameter of an enclosing declaration.

• avoid-suspicious-super-overrides

  Finds getters hiding fields supplied via the immediate super constructor's this. formals or declaring primary-constructor parameters.

• avoid-throw-in-catch-blockavoid-throw-in-catch-block

  Flags throw statements inside a catch block.

• avoid-top-level-members-in-teststest

  Requires public declarations in test files, except main, to be private.

• avoid-types-as-parameter-namesavoid_types_as_parameter_namesrecommended

  Flags implicit formal parameters, catch variables, and type parameters that shadow a type in their enclosing scope.

• avoid-unrelated-type-assertionsavoid-unrelated-type-assertionsrecommended

  Flags an is check proven impossible by canonical resolved types.

• banned-usage

  Ban resolved API references, not identifiers that merely share their spelling.

• cascade-after-null-coalescing

  Flags a cascade after an unparenthesized null-coalescing expression.

• control-flow-in-finallycontrol_flow_in_finallyrecommended

  Flags return, break, or continue that escapes a finally block.

• empty-catchesempty_catchesrecommended

  Flags empty catch blocks.

• empty-statementsempty_statementsrecommended

  Flags stray empty statements (a lone ;).

• no-duplicate-case-valuesno_duplicate_case_valuesrecommended

  Flags semantically equal constant values within one switch.

• no-empty-blockno-empty-block

  Flags empty blocks ({}).

• no-equal-argumentsno-equal-arguments

  Flags an argument passed more than once in the same invocation.

• no-equal-then-elseno-equal-then-elserecommended

  Flags an if/else or ternary whose two branches are identical.

• no-magic-string

  Extract inline string literals into named variables or constants.

• no-self-comparisonsno_self_comparisonsrecommended

  Flags proven self-comparisons of side-effect-free scalar values.

• no-wildcard-variable-usesno_wildcard_variable_usesrecommended

  Flags references to a wildcard variable or parameter (a name made solely of underscores, such as _ or __).

• overridden-fieldsoverridden_fieldsrecommended

  Flags instance fields that redeclare an inherited field.

• prefer-unique-test-namestest

  Reports duplicate test descriptions within a group and constant names in loops.

• recursive-gettersrecursive_gettersrecommended

  Flags a getter that unconditionally returns itself.

• unnecessary-null-aware-assignmentsunnecessary_null_aware_assignmentsrecommended

  Flags x ??= null, which can never have an effect.

• unnecessary-null-in-if-null-operatorsunnecessary_null_in_if_null_operatorsrecommended

  Flags x ?? null and null ?? x, where the null operand is redundant.

• use-rethrow-when-possibleuse_rethrow_when_possiblerecommended

  Flags throw e inside a catch (e) by matching the exception parameter's name.

Rules that analyze relationships between files, run in falcon's whole-project pass.

• banned-importscross-file

  Report imports forbidden by package-relative architectural boundaries.

• depend-on-referenced-packagesdepend_on_referenced_packagesrecommendedcross-file

  Require imported packages to be declared in pubspec.yaml.

• no-import-cyclescross-file

  Report mutually dependent components of imported or exported library files.

• package-namespackage_namesrecommendedcross-file

  Require package names to be valid lower_case_with_underscores identifiers.

• secure-pubspec-urlssecure_pubspec_urlsrecommendedcross-file

  Disallow insecure URL schemes in pubspec.yaml string values.

• sort-pub-dependenciessort_pub_dependenciescross-file

  Require pubspec.yaml dependency sections to be sorted alphabetically.

• undeclared-dependenciescross-file

  Report package imports and exports missing from the enclosing pubspec.

• unnecessary-nullablecheck-unnecessary-nullablecross-file

  Flags private function or method parameters whose nullable type is unnecessary.

• unused-codecheck-unused-codecross-file

  Report public top-level declarations that nothing references.

• unused-dependenciescross-file

  Report regular pubspec dependencies with no Dart import or export in the analyzed package.

• unused-filescheck-unused-filescross-file

  Report lib/ files that no project entrypoint can reach.