prefer_final_parameters

The parameter '{0}' should be final.

NOTE: This rule is removed in Dart 3.13.0; it is no longer functional.

The analyzer produces this diagnostic when a parameter of a constructor, method, function, or closure isn't marked as being final.

The following code produces this diagnostic because the parameter s isn't a final parameter:

// @dart=3.12
String f(String s) => s;

Add the modifier final to the parameter:

// @dart=3.12
String f(final String s) => s;