deprecated_optional

Omitting an argument for the '{0}' parameter is deprecated.

The analyzer produces this diagnostic when an argument is omitted for an optional parameter annotated with @Deprecated.optional. This annotation indicates that omitting an argument for the parameter is deprecated, and the parameter will soon become required.

Given a library p that defines a function with an optional parameter annotated with @Deprecated.optional:

void f({@Deprecated.optional() int a = 0}) {}

The following code produces this diagnostic, because the invocation doesn't pass a value for the parameter a:

import 'package:p/p.dart';
​
void g() {
  f();
}

Follow any specific instructions provided in the @Deprecated.optional annotation.

If no instructions are present, pass an appropriate argument for the corresponding parameter:

import 'package:p/p.dart';
​
void g() {
  f(a: 0);
}

Using the default value will preserve the current behavior of the code.