omit_obvious_property_types

Omit obvious type annotations for top-level and static variables.

Don't type annotate initialized top-level or static variables when the type is obvious.

BAD:

final int myTopLevelVariable = 7;

class A {
  static String myStaticVariable = 'Hello';
}

GOOD:

final myTopLevelVariable = 7;

class A {
  static myStaticVariable = 'Hello';
}

Sometimes the inferred type is not the type you want the variable to have. For example, you may intend to assign values of other types later. You may also wish to write a type annotation explicitly because the type of the initializing expression is non-obvious and it will be helpful for future readers of the code to document this type. Or you may wish to commit to a specific type such that future updates of dependencies (in nearby code, in imports, anywhere) will not silently change the type of that variable, thus introducing compile-time errors or run-time bugs in locations where this variable is used. In those cases, go ahead and annotate the variable with the type you want.

GOOD:

final num myTopLevelVariable = 7;

class A {
  static String? myStaticVariable = 'Hello';
}

This rule is experimental. It is being evaluated, and it may be changed or removed. Feedback on its behavior is welcome! The main issue is here: https://github.com/dart-lang/linter/issues/5101.

The omit_obvious_property_types rule is incompatible with the following rules:

• always_specify_types

To enable the omit_obvious_property_types rule, add omit_obvious_property_types under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - omit_obvious_property_types

If you're instead using the YAML map syntax to configure linter rules, add omit_obvious_property_types: true under linter > rules:

linter:
  rules:
    omit_obvious_property_types: true

Unless stated otherwise, the documentation on this site reflects Dart 3.6.0. Page last updated on 2025-01-27. View source or report an issue.