Unsuccessful assignment of a readonly variable does not return 1

[Laur Aliste]

Hi,
is it accepted behavior for a failing assignment of a readonly variable to return successfully?

See following code:

fail() {
    return 1
}

o() {
    local i j

    i="$(fail)" || echo "i init failed"
    readonly j="$(fail)" || echo "j init failed"  # this echo is not executed
}


Expected assignment of a variable j to return 1 as well, but it doesn't.