nullable_type_in_implements_clause
A class, mixin, or extension type can't implement a nullable type.
Description
#The analyzer produces this diagnostic when a class, mixin, or
extension type declaration has an implements clause, and an
interface is followed by a ?.
It isn't valid to specify a nullable interface because doing so would have
no meaning; it wouldn't change the interface being inherited by the class
containing the implements clause.
Note, however, that it is valid to use a nullable type as a type argument
to the interface, such as class A implements B<C?> {}.
Example
#The following code produces this diagnostic because A? is a nullable
type, and nullable types can't be used in an implements clause:
class A {}
class B implements A? {}Common fixes
#Remove the question mark from the type:
class A {}
class B implements A {}除非另有说明，文档之所提及适用于 Dart 3.7.3 版本，本页面最后更新时间: 2025-05-08。 查看文档源码 或者 报告页面问题。