Rules
General rules configuration is described here.
Rules are grouped by category to help you understand their purpose. Each rule has emojis denoting:
- ⚙️ - this rule is configurable
- 🛠 - some problems reported by this rule can be fixed by editor suggestions
- ⚠️ - this rule is deprecated and will be removed in the next major release
Common
Enforces named argument order in function and constructor invocations to be the same as corresponding named parameter declaration order.
Warns when a cascade expression is used after if null (??) binary expression without parentheses.
Avoid using collection methods with unrelated types, such as accessing a map of integers using a string key.
Warns when an import/export directive contains a double slash.
Warns when a file has multiple exports declarations with the same URI.
Warns when dynamic type is used as variable type in declaration, return type of a function, etc.
Warns when a return value of a method or function invocation or a class instance property access is not used.
Warns when a field or variable is declared with a late keyword.
Warns when a enum constant is missing in a map declaration.
Warns when a string literal contains non ascii characters.
Warns when non null assertion operator ! (or “bang” operator) is used for a property access or method invocation. The operator check works at runtime and it may fail and throw a runtime exception.
Warns when an asynchronous function is used as an argument where a synchronous function is expected.
Checks for redundant async in a method or function body.
Warns when a public top-level member (except the entrypoint) is declared inside a test file.
Warns about unnecessary usage of is and whereType operators.
Checks for unused parameters inside a function or method body.
Warns when a literal value is on the left hand side in a binary expressions.
Checks that double literals should begin with 0. instead of just ., and should not end with a trailing 0.
Warns when a field is not added to props getter of a class that extends Equatable or EquatableMixin.
Enforces blank line between statements and return in a block.
Warns on comparison to a boolean literal, as in x == true.
Warns when equal arguments are passed to a function or method invocation.
Warns when if statement has equal then and else statements or conditional expression has equal then and else expressions.
Warns against using number literals outside of named constants or variables.
Recommends to use async/await syntax to handle a Future result instead of .then() invocation.
Warns when // ignore: comments are left without any additional description why this ignore is applied.
Recommends to use a conditional expression instead of assigning to the same thing or return statement in each branch of an if statement.
Warns when an identifier name length is very short or long.
Warns if the file within /test contains a main, but the file name doesn't end with _test.dart.
Type name should only contain alphanumeric characters, start with an uppercase character and span between min-length and max-length characters in length.
Since Dart 2.15 it's possible to use byName method on enum values prop instead of searching the value with firstWhere.
Warns when a method or a function returns a variable declared right before the return statement.
Warns when List.from() factory is used instead of List.of().
Warns when a property access or a method invocation start with duplicated chains of other invocations / accesses inside a single function or method block.
Suggests to use static class member instead of global constants, variables and functions.
Checks for a trailing comma for arguments, parameters, enum values and collections.
Flutter specific
Warns when an event listener is added but never removed.
Warns when a method or function returns a Widget or subclass of a Widget.
Warns when a ListView widget with shrinkWrap parameter is wrapped in a Column, Row or another ListView widget.
Warns when setState is called inside initState, didUpdateWidget or build methods and when it is called from a sync method that is called inside those methods.
Warns when a widget is wrapped in a Padding widget but has a padding settings by itself.
Warns when a RenderObject setter doesn't have an equality check for the new value.
Warns when an updateRenderObject method is absent or doesn't update all fields set in createRenderObject.
Warns about inline callbacks in a widget tree and suggest to extract them to a widget method.
Warns when a file contains more than a single widget.
Warns when a Column widget with only children parameter is wrapped in a SingleChildScrollView widget.
Flame
Lints for the Flame package.
Warns when a Vector2 is created inside a Component's update method.
Warns when a late final variable is being initialized in the Component's onMount method.
Warns when a Component's onLoad method can be made sync.
Warns when a game is instantiated in a stateless widget build method.
Intl specific
Recommends to use ClassName_ClassMemberName pattern for Intl methods name argument.
Warns when a Intl method invoked without a description.
Warns when the Intl.message() invocation has incorrect args.
Angular specific
Warns when a @Component annotation has explicit false value for preserveWhitespace.
Enforces Angular @Component annotation arguments ordering.
Prefer setting changeDetection: ChangeDetectionStrategy.OnPush in Angular @Component annotations.