use_sliver_prefix

v0.4.0WarningFixConfigurableWidget Best Practices

This rule warns when a widget’s build method returns a sliver widget (like SliverList, SliverAppBar, SliverToBoxAdapter) but the class name does not start with Sliver. Slivers and non-sliver widgets are not interchangeable, so making the distinction visible in the name prevents layout errors.

Why use this rule

If you drop a sliver-returning widget into a Column or Row, Flutter throws a confusing runtime error about “RenderSliver” not being a “RenderBox”. A Sliver prefix on the class name makes it immediately obvious that the widget belongs inside a CustomScrollView, not a regular box layout. This naming convention is used throughout the Flutter framework itself.

See also: Slivers

Don’t

// Returns a sliver but name does not indicate it
class MyAdapter extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverToBoxAdapter(child: Text('hello'));
  }
}

class ProductList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverList(delegate: SliverChildListDelegate([]));
  }
}

Do

// Sliver prefix makes the contract clear
class SliverMyAdapter extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverToBoxAdapter(child: Text('hello'));
  }
}

class SliverProductList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverList(delegate: SliverChildListDelegate([]));
  }
}

Turning this rule off

This rule is in the pedantic preset, so it is enabled by preset: pedantic or by name:

many_lints.yaml

rules:
  use_sliver_prefix: true

To turn it off again:

many_lints.yaml

rules:
  use_sliver_prefix: false

To keep the rule on but skip certain paths, use per-rule exclude.

Options

Projects with a state abstraction that does not extend Flutter’s State can opt that base class into this rule:

analysis_options.yaml

analysis_options.yaml

many_lints:
  rules:
    use_sliver_prefix:
      state_base_classes: [AppState]

many_lints.yaml

many_lints.yaml

rules:
  use_sliver_prefix:
    state_base_classes: [AppState]

Option	Type	Default	Description
state_base_classes	list of strings	[]	Additional non-State base classes whose subclasses should be treated as state classes

Related rules

• always_pass_global_key — Don’t create a GlobalKey inside build.
• avoid_conditional_hooks — Never call hooks inside conditionals, loops, or ternaries.
• avoid_deep_widget_nesting — Keep a widget tree within a nesting budget.
• avoid_flexible_outside_flex — Only use Flexible and Expanded as direct children of Row, Column, or Flex.