shared_deferred_prefix

The prefix of a deferred import can't be used in other import directives.

The analyzer produces this diagnostic when a prefix in a deferred import is also used as a prefix in other imports (whether deferred or not). The prefix in a deferred import can't be shared with other imports because the prefix is used to load the imported library.

The following code produces this diagnostic because the prefix x is used as the prefix for a deferred import and is also used for one other import:

import 'dart:math' deferred as x;
import 'dart:convert' as x;

var y = x.json.encode(x.min(0, 1));

If you can use a different name for the deferred import, then do so:

import 'dart:math' deferred as math;
import 'dart:convert' as x;

var y = x.json.encode(math.min(0, 1));

If you can use a different name for the other imports, then do so:

import 'dart:math' deferred as x;
import 'dart:convert' as convert;

var y = convert.json.encode(x.min(0, 1));

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.