Rules overview

Rules are grouped by a category to help you understand their purpose.

Rules configuration is described here.

Common

• avoid-collection-methods-with-unrelated-types

  Avoid using collection methods with unrelated types, such as accessing a map of integers using a string key.

• avoid-dynamic

  Warns when dynamic type is used as variable type in declaration, return type of a function, etc.

• avoid-global-state

  Warns about usage mutable global variables.

• avoid-ignoring-return-values

  Warns when a return value of a method or function invocation or a class instance property access is not used.

• avoid-late-keyword

  Warns when a field or variable is declared with a late keyword.

• avoid-missing-enum-constant-in-map

  Warns when a enum constant is missing in a map declaration.

• avoid-nested-conditional-expressions  

  Warns about nested conditional expressions.

• avoid-non-ascii-symbols

  Warns when a string literal contains non ascii characters.

• avoid-non-null-assertion

  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.

• avoid-throw-in-catch-block

  Warns when call throw in a catch block.

• avoid-unnecessary-type-assertions

  Warns about unnecessary usage of 'is' and 'whereType' operators.

• avoid-unnecessary-type-casts

  Warns about unnecessary usage of 'as' operators.

• avoid-unrelated-type-assertions

  Warns about unrelated usages of 'is' operators.

• avoid-unused-parameters

  Checks for unused parameters inside a function or method body.

• ban-name  

  Configure some names that you want to ban.

• binary-expression-operand-order  

  Warns when a literal value is on the left hand side in a binary expressions.

• double-literal-format  

  Checks that double literals should begin with 0. instead of just ., and should not end with a trailing 0.

• format-comment  

  Prefer format comments like sentences.

• member-ordering  

  Enforces ordering for a class members.

• member-ordering-extended  

  Enforces ordering for a class members.

• newline-before-return

  Enforces blank line between statements and return in a block.

• no-boolean-literal-compare  

  Warns on comparison to a boolean literal, as in x == true.

• no-empty-block

  Disallows empty blocks except catch clause block.

• no-equal-arguments  

  Warns when equal arguments passed to a function or method invocation.

• no-equal-then-else

  Warns when if statement has equal then and else statements or conditional expression has equal then and else expressions.

• no-magic-number  

  Warns against using number literals outside of named constants or variables.

• no-object-declaration

  Warns when a class member is declared with Object type.

• prefer-async-await

  Recommends to use async/await syntax to handle Futures result instead of .then() invocation.

• prefer-commenting-analyzer-ignores

  Warns when // ignore: comments are left without any additional description why this ignore is applied.

• prefer-conditional-expressions  

  Recommends to use a conditional expression instead of assigning to the same thing or return statement in each branch of an if statement.

• prefer-correct-identifier-length  

  Warns when identifier name length very short or long.

• prefer-correct-type-name  

  Type name should only contain alphanumeric characters, start with an uppercase character and span between min-length and max-length characters in length.

• prefer-first  

  Use first to gets the first element.

• prefer-immediate-return  

  Warns when a method or a function returns a variable declared right before the return statement.

• prefer-last  

  Use last to gets the last element.

• prefer-match-file-name

  Warns when file name does not match class name.

• prefer-trailing-comma    

  Check for trailing comma for arguments, parameters, enum values and collections.

• tag-name    

  Warns when tag name does not match class name.

Flutter specific

• always-remove-listener

  Warns when an event listener is added but never removed.

• avoid-border-all

  Avoid using Border.all constructor.

• avoid-returning-widgets  

  Warns when a method or function returns a Widget or subclass of a Widget.

• avoid-unnecessary-setstate

  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.

• avoid-wrapping-in-padding

  Warns when a widget is wrapped in a Padding widget but has a padding settings by itself.

• prefer-const-border-radius  

  Warns when used non const border radius.

• prefer-extracting-callbacks  

  Warns about inline callbacks in a widget tree and suggest to extract them to a widget method.

• prefer-single-widget-per-file  

  Warns when a file contains more than a single widget.

Intl specific

• prefer-intl-name  

  Recommends to use ClassName_ClassMemberName pattern for Intl methods name argument.

• provide-correct-intl-args

  Warns when the Intl.message() invocation has incorrect args.

Angular specific

• avoid-preserve-whitespace-false

  Warns when a @Component annotation has explicit false value for preserveWhitespace.

• component-annotation-arguments-ordering  

  Enforces Angular @Component annotation arguments ordering.

• prefer-on-push-cd-strategy

  Prefer setting changeDetection: ChangeDetectionStrategy.OnPush in Angular @Component annotations.