use_string_in_part_of_directives

The part-of directive uses a library name.

The analyzer produces this diagnostic when a part of directive uses a library name to refer to the library that the part is a part of.

Given a file named lib.dart that contains the following:

library lib;
​
part 'test.dart';

The following code produces this diagnostic because the part of directive uses the name of the library rather than the URI of the library it's part of:

part of lib;

Use a URI to reference the library:

part of 'lib.dart';