type_literal_in_constant_pattern

Don't use constant patterns with type literals.

If you meant to test if the object has type Foo, instead write Foo _.

BAD:

void f(Object? x) {
  if (x case num) {
    print('int or double');
  }
}

GOOD:

void f(Object? x) {
  if (x case num _) {
    print('int or double');
  }
}

If you do mean to test that the matched value (which you expect to have the type Type) is equal to the type literal Foo, then this lint can be silenced using const (Foo).

BAD:

void f(Object? x) {
  if (x case int) {
    print('int');
  }
}

GOOD:

void f(Object? x) {
  if (x case const (int)) {
    print('int');
  }
}

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

linter:
  rules:
    - type_literal_in_constant_pattern

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

linter:
  rules:
    type_literal_in_constant_pattern: 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.