make X::Placeholder::Mainline a subclass of X::Placeholder::Block
make X::Placeholder::Mainline a subclass of X::Placeholder::Block

it really is just a specialization of the general "block" case

prammer/specs,prammer/specs,tokuhirom/specs,tokuhirom/specs,tokuhirom/specs,perl6/specs,perl6/specs,prammer/specs