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Dart rules

Codiga provides multiple sets of rules for 12+ languages. Below we provide a link and a description for all the rules supported by our platform. Note that not all the rules are being listed and described below.

ALWAYS_DECLARE_RETURN_TYPES

Code style
Error

Method should have return type

always_specify_types

Code style
Informational

Always specify types

ARGUMENT_TYPE_NOT_ASSIGNABLE

Code style
Warning

Invalid assignments

ASSET_DOES_NOT_EXIST

Code style
Warning

Asset does not exists

AVOID_BOOL_LITERALS_IN_CONDITIONAL_EXPRESSIONS

Code style
Informational

Avoid bool literals in condition

AVOID_CLASSES_WITH_ONLY_STATIC_MEMBERS

Code style
Informational

Avoid defining a class that contains only static members.

AVOID_ESCAPING_INNER_QUOTES

Code style
Informational

Avoid escaping inner quotes by converting surrounding quotes.

AVOID_FUNCTION_LITERALS_IN_FOREACH_CALLS

Code style
Informational

Avoid using `forEach` with a function literal.

avoid_init_to_null

Code style
Informational

Don't explicitly initialize variables to null.

AVOID_POSITIONAL_BOOLEAN_PARAMETERS

Code style
Informational

Avoid positional boolean parameters.

AVOID_PRINT

Code style
Error

Avoid `print` calls in production code.

AVOID_REDUNDANT_ARGUMENT_VALUES

Code style
Informational

Avoid redundant argument values.

AVOID_RETURN_TYPES_ON_SETTERS

Code style
Informational

Avoid return types on setters.

AVOID_UNNECESSARY_CONTAINERS

Code style
Informational

Avoid unnecessary containers.

AVOID_VOID_ASYNC

Code style
Informational

Avoid async functions that return void.

AVOID_WEB_LIBRARIES_IN_FLUTTER

Code style
Informational

Avoid using web-only libraries outside Flutter web plugin packages.

AWAIT_ONLY_FUTURES

Code style
Informational

await' should only apply to futures

BODY_MIGHT_COMPLETE_NORMALLY

Code style
Warning

The body might complete normally

CAMEL_CASE_TYPES

Code style
Informational

Name types using UpperCamelCase.

CAST_NULLABLE_TO_NON_NULLABLE

Code style
Informational

Don't cast a nullable value to a non nullable type.

CAST_TO_NON_TYPE

Code style
Warning

The name isn't a type

close_sinks

Code style
Informational

Close instances of `dart.core.Sink`.\n

CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE

Code style
Warning

Const variables must be initialized with a constant value.

CONST_WITH_NON_CONSTANT_ARGUMENT

Code style
Warning

Arguments of a constant creation must be constant expressions.

COULD_NOT_INFER

Code style
Warning

Cannot infer type

CREATION_WITH_NON_TYPE

Code style
Warning

The name 'BubbleStyle' isn't a class.\n

DEAD_CODE

Code style
Informational

Dead code.

DEAD_CODE_ON_CATCH_SUBTYPE

Code style
Informational

Dead code on catch subtype.

DEAD_NULL_AWARE_EXPRESSION

Code style
Informational

The left operand can't be null.

DEFAULT_LIST_CONSTRUCTOR

Code style
Warning

The default 'List' constructor isn't available when null safety is enabled.

DEPEND_ON_REFERENCED_PACKAGES

Code style
Informational

Depend on referenced packages.

DEPRECATED_MEMBER_USE

Code style
Informational

Member is deprecated and shouldn't be used. This property is no longer used

DIRECTIVES_ORDERING

Code style
Informational

Import ordering

DUPLICATE_IMPORT

Code style
Informational

Duplicate import.

EMPTY_CATCHES

Code style
Informational

Avoid empty catch blocks.

empty_constructor_bodies

Code style
Informational

Use `;` instead of `{}` for empty constructor bodies.

empty_statements

Code style
Informational

Detect empty statements (dead code)

EOL_AT_END_OF_FILE

Code style
Informational

Put a single newline at end of file.

EXPECTED_TOKEN

Code style
Warning

Expected to find '['.

EXTENDS_NON_CLASS

Code style
Warning

Classes can only extend other classes.

EXTRA_POSITIONAL_ARGUMENTS

Code style
Warning

Too many positional arguments.

FILE_NAMES

Code style
Informational

Name source files using `lowercase\_with\_underscores`.

GETTER_NOT_SUBTYPE_SETTER_TYPES

Code style
Warning

Invalid return type

HASH_AND_EQUALS

Code style
Informational

Override `hashCode` if overriding `==`

ILLEGAL_ASSIGNMENT_TO_NON_ASSIGNABLE

Code style
Error

Illegal assignment to non-assignable expression.

implementation_imports

Code style
Informational

Don't import implementation files from another package.

IMPLEMENTS_NON_CLASS

Code style
Warning

Classes and mixins can only implement other classes and mixins.

IMPORT_OF_LEGACY_LIBRARY_INTO_NULL_SAFE

Code style
Informational

Legacy library

INCLUDE_FILE_NOT_FOUND

Code style
Warning

Include file not found

INVALID_ANNOTATION_TARGET

Code style
Informational

Invalid annotation target

INVALID_ASSIGNMENT

Code style
Warning

Invalid assignments

INVALID_CONSTANT

Code style
Warning

Invalid constant value

INVALID_NULL_AWARE_OPERATOR

Code style
Informational

The receiver can't be null because of short-circuiting

INVALID_OVERRIDE

Code style
Warning

Invalid override

INVALID_USE_OF_PROTECTED_MEMBER

Code style
Informational

Invalid use of protected members

INVARIANT_BOOLEANS

Code style
Informational

Conditions should not unconditionally evaluate to `true` or to `false`.

JOIN_RETURN_WITH_ASSIGNMENT

Code style
Informational

Join return statement with assignment when possible.

LIBRARY_PREFIXES

Code style
Informational

Use `lowercase\_with\_underscores` when specifying a library prefix.

LIST_ELEMENT_TYPE_NOT_ASSIGNABLE

Code style
Warning

List element type not assignable

MISSING_ASSIGNABLE_SELECTOR

Code style
Error

Missing selector

MISSING_DEFAULT_VALUE_FOR_PARAMETER

Code style
Warning

Missing default value for parameter

MISSING_ENUM_CONSTANT_IN_SWITCH

Code style
Informational

Missing case clause for 'null'.

MISSING_IDENTIFIER

Code style
Warning

Expected an identifier.

MISSING_REQUIRED_ARGUMENT

Code style
Error

Missing required argument

MISSING_REQUIRED_PARAM

Code style
Warning

Missing required parameters

MISSING_RETURN

Code style
Informational

Missing return value

MIXIN_OF_NON_CLASS

Code style
Warning

Classes can only mix in mixins and classes.

MIXIN_WITH_NON_CLASS_SUPERCLASS

Code style
Warning

Mixin can only be applied to class.

MUST_BE_IMMUTABLE

Code style
Informational

Must be immutable

MUST_CALL_SUPER

Code style
Informational

This method overrides a method annotated as '@mustCallSuper' in 'State'

NEW_WITH_UNDEFINED_CONSTRUCTOR_DEFAULT

Code style
Warning

The class doesn't have a default constructor.

NO_DEFAULT_SUPER_CONSTRUCTOR

Code style
Error

No default super constructor

NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER

Code style
Warning

Missing concrete implementations of methods

NON_BOOL_CONDITION

Code style
Warning

Conditions must have a static type of 'bool'

NON_CONSTANT_CASE_EXPRESSION

Code style
Warning

Case expressions must be constant

NON_CONSTANT_DEFAULT_VALUE

Code style
Warning

The default value of an optional parameter must be constant

non_constant_identifier_names

Code style
Informational

Name non-constant identifiers using lowerCamelCase

NON_CONSTANT_LIST_ELEMENT

Code style
Warning

The values in a const list literal must be constants

NON_CONSTANT_MAP_VALUE

Code style
Warning

The values in a const map literal must be constant

NON_TYPE_AS_TYPE_ARGUMENT

Code style
Warning

The name isn't a type so it can't be used as a type argument

NON_TYPE_IN_CATCH_CLAUSE

Code style
Warning

The name isn't a type and can't be used in an on-catch clause.

NOOP_PRIMITIVE_OPERATIONS

Code style
Informational

Noop primitive operations.

NOT_ASSIGNED_POTENTIALLY_NON_NULLABLE_LOCAL_VARIABLE

Code style
Warning

The non-nullable local variable must be assigned before it can be used.

NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD

Code style
Warning

Non-nullable instance field must be initialized.

NOT_INITIALIZED_NON_NULLABLE_VARIABLE

Code style
Warning

The non-nullable variable must be initialized.

NULLABLE_TYPE_IN_CATCH_CLAUSE

Code style
Informational

A potentially nullable type can't be used in an 'on' clause because it isn't valid to throw a nullable expression.

OVERRIDDEN_FIELDS

Code style
Informational

Don't override fields.

OVERRIDE_ON_NON_OVERRIDING_MEMBER

Code style
Informational

The field doesn't override an inherited getter or setter.

POSITIONAL_AFTER_NAMED_ARGUMENT

Code style
Warning

Positional arguments must occur before named arguments.

PREFER_CONST_CONSTRUCTORS

Code style
Informational

Prefer const with constant constructors.

PREFER_CONST_CONSTRUCTORS_IN_IMMUTABLES

Code style
Informational

Prefer declaring const constructors on `@immutable` classes

PREFER_CONST_DECLARATIONS

Code style
Error

Prefer const over final for declarations

PREFER_CONST_LITERALS_TO_CREATE_IMMUTABLES

Code style
Informational

Prefer const literals as parameters of constructors on @immutable classes.

PREFER_FINAL_IN_FOR_EACH

Code style
Informational

Prefer final in for-each loop variable if reference is not reassigned.

PREFER_FINAL_LOCALS

Code style
Error

Prefer final for variable declarations if they are not reassigned.

PREFER_IF_ELEMENTS_TO_CONDITIONAL_EXPRESSIONS

Code style
Informational

Prefer if elements to conditional expressions where possible.

PREFER_IF_NULL_OPERATORS

Code style
Informational

Prefer using if null operators.

PREFER_INITIALIZING_FORMALS

Code style
Informational

Use initializing formals when possible.

PREFER_INTERPOLATION_TO_COMPOSE_STRINGS

Code style
Informational

Use interpolation to compose strings and values.

PREFER_IS_EMPTY

Code style
Informational

Use isEmpty instead of length\n

PREFER_IS_NOT_EMPTY

Code style
Informational

Use `isNotEmpty` for Iterables and Maps.

PREFER_NULL_AWARE_METHOD_CALLS

Code style
Informational

Prefer null aware method calls.

PREFER_TYPING_UNINITIALIZED_VARIABLES

Code style
Informational

Prefer typing uninitialized variables and fields.

REDIRECT_TO_NON_CLASS

Code style
Error

Name isn't a type and can't be used in a redirected constructor.

REQUIRE_TRAILING_COMMAS

Code style
Informational

Missing a required trailing comma.

RETURN_OF_INVALID_TYPE

Code style
Warning

Invalid return type

RETURN_OF_INVALID_TYPE_FROM_CLOSURE

Code style
Warning

Invalid return type from closure

SIZED_BOX_FOR_WHITESPACE

Code style
Informational

SizedBox for whitespace.

SORT_CHILD_PROPERTIES_LAST

Code style
Error

Sort child properties last in widget instance creations.

SORT_PUB_DEPENDENCIES

Code style
Informational

Sort pub dependencies.

TYPE_ANNOTATE_PUBLIC_APIS

Code style
Error

Type annotate public APIs.

TYPE_ARGUMENT_NOT_MATCHING_BOUNDS

Code style
Error

Type arguments do not match bounds

TYPE_TEST_WITH_UNDEFINED_NAME

Code style
Warning

Undefined name

UNCHECKED_USE_OF_NULLABLE_VALUE

Code style
Warning

Method can't be unconditionally invoked because the receiver can be 'null'.

UNDEFINED_CONSTRUCTOR_IN_INITIALIZER

Code style
Warning

Undefined constructor

UNDEFINED_GETTER

Code style
Warning

Undefined getter

UNDEFINED_NAMED_PARAMETER

Code style
Warning

Named parameter undefined

UNDEFINED_OPERATOR

Code style
Error

Undefined operator

UNDEFINED_SETTER

Code style
Warning

Undefined setter

UNDEFINED_SUPER_MEMBER

Code style
Warning

Undefined super member

unnecessary_brace_in_string_interps

Code style
Informational

Avoid using braces in interpolation when not needed.

UNNECESSARY_CAST

Code style
Informational

Unnecessary cast.

UNNECESSARY_NEW

Code style
Informational

Unnecessary new keyword.

UNNECESSARY_NON_NULL_ASSERTION

Code style
Warning

Uneccessary non null assertion

UNNECESSARY_NULL_CHECKS

Code style
Informational

Unnecessary null checks

UNNECESSARY_NULL_COMPARISON

Code style
Informational

The operand can't be null

UNNECESSARY_PARENTHESIS

Code style
Informational

Unnecessary parenthesis

unnecessary_statements

Code style
Informational

Avoid using unnecessary statements

UNNECESSARY_STRING_INTERPOLATIONS

Code style
Informational

Unnecessary string interpolation

UNNECESSARY_THIS

Code style
Error

Unecessary this

UNSUPPORTED_OPERATOR

Code style
Error

The '===' operator is not supported

UNUSED_CATCH_CLAUSE

Code style
Informational

Unused catch clause

UNUSED_CATCH_STACK

Code style
Informational

Stack trace not used

UNUSED_ELEMENT

Code style
Informational

Unused element

UNUSED_FIELD

Code style
Informational

Unused fiel

UNUSED_IMPORT

Code style
Informational

Unused import

UNUSED_LABEL

Code style
Informational

Unused label

UNUSED_LOCAL_VARIABLE

Code style
Informational

Unused local variable

URI_HAS_NOT_BEEN_GENERATED

Code style
Warning

URI has not been generated

USE_BUILD_CONTEXT_SYNCHRONOUSLY

Code style
Informational

Use build context synchronuously

USE_LATE_FOR_PRIVATE_FIELDS_AND_VARIABLES

Code style
Informational

Use late for private members with non-nullable type.

USE_NAMED_CONSTANTS

Code style
Informational

Use named constants

USE_OF_VOID_RESULT

Code style
Error

Use of void results

USE_STRING_BUFFERS

Code style
Informational

Use string buffers to compose strings

NO_LEADING_UNDERSCORES_FOR_LOCAL_IDENTIFIERS

Code style
Warning

Avoid leading underscores for local identifiers.

Learn more

CONSTANT_IDENTIFIER_NAMES

Code style
Warning

Prefer using lowerCamelCase for constant names.

Learn more

DIRECTIVE_AFTER_DECLARATION

Code style
Informational

Directives must appear before any declarations.

FLUTTER_STYLE_TODOS

Code style
Informational

Use Flutter TODO format.

Learn more

NO_LEADING_UNDERSCORES_FOR_LIBRARY_PREFIXES

Code style
Informational

Avoid leading underscores for library prefixes.

INVALID_FACTORY_NAME_NOT_A_CLASS

Code style
Informational

The name of a factory constructor must be the same as the name of the immediately enclosing class.

Learn more

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