Feature #16275

Updated by nobu (Nobuyoshi Nakada) 10 months ago

`obj.:method` obj.:method is introduced at r66667 by #12125 and #13581. 
 It encourages the functional programming style in Ruby. 

 But this shorthand syntax is just for methods of `self` without arguments. 
 It causes another feature requests like #16273 (and lambda compositions like #15428). 

 Such features will introduce a new view of Ruby but no one illustrates the whole picture yet. 
 I worried about such patch work may cause a conflict with future expansion of functional programing style or a just a garbage feature. 

 `.:` .: syntax is introduced introduce in 2.7.0 preview1, not released in production yet. 
 How about reverting at this time and re-introduce with a big picture.