module type S = Optional_syntax_intf.Smodule type S1 = Optional_syntax_intf.S1module type S2 = Optional_syntax_intf.S2Core_kernel.Optional_syntaxInterfaces for use with the match%optional syntax, provided by ppx_optional.
module type S = Optional_syntax_intf.Smodule type S1 = Optional_syntax_intf.S1module type S2 = Optional_syntax_intf.S2