invalid_use_of_covariant_in_extension
Can't have modifier '{0}' in an extension.
Description
#
The analyzer produces this diagnostic when a member declared inside an
extension uses the keyword covariant in the declaration of a parameter.
Extensions aren't classes and don't have subclasses, so the keyword serves
no purpose.
Example
#
The following code produces this diagnostic because i is marked as being
covariant:
dart
extension E on String {
void a(covariant int i) {}
}
Common fixes
#Remove the covariant keyword:
dart
extension E on String {
void a(int i) {}
}