Readonly class Bar cannot extend non-readonly class Foo¶
Description¶
A readonly class cannot extends a non-readonly class; a non-readonly class cannot extends a readonly class. Both classes must be readonly or non-readonly to be able to extends one another. This is due to readonly being applied to all available properties, which is ambiguous with class hierarchies.
Example¶
<?php
class Foo
{
}
readonly class Bar extends Foo
{
}
?>
Solutions¶
Make both classes readonly.
Make both classes non-readonly.
Make both classes non-readonly and apply readonly per properties.