The 'override' decorator must have a Contracted class in it's ancestry

[mlhaufe]

// okay
@Contracted(fooContract)
class Foo {
    method(){...}
}

class Bar extends Foo {
    @override
    method(){...}
}

// Not okay
class Foo {
    method(){...}
}

class Bar extends Foo {
    @override
    method(){...}
}

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