# deprecated_colon_for_default_value

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



_Using a colon as the separator before a default value is deprecated and will not be supported in language version 3.0 and later._

## Description

The analyzer produces this diagnostic when a colon (`:`) is used as the
separator before the default value of an optional named parameter.
While this syntax is allowed, it is deprecated in favor of
using an equal sign (`=`).

## Example

The following code produces this diagnostic because a colon is being used
before the default value of the optional parameter `i`:

```dart
void f({int i [!:!] 0}) {}
```

## Common fixes

Replace the colon with an equal sign.

```dart
void f({int i = 0}) {}
```

