# no_leading_underscores_for_library_prefixes

> Details about the no_leading_underscores_for_library_prefixes diagnostic produced by the Dart analyzer.



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_The library prefix '{0}' starts with an underscore._

## Description

The analyzer produces this diagnostic when the name of a prefix declared
on an import starts with an underscore.

Library prefixes are inherently not visible outside the declaring library,
so a leading underscore indicating private adds no value.

## Example

The following code produces this diagnostic because the prefix `_core`
starts with an underscore:

```dart
import 'dart:core' as [!_core!];
```

## Common fixes

Remove the underscore:

```dart
import 'dart:core' as core;
```

