For loop modifier blocks

[newpavlov]

Take a look at this proposal, which is somewhat alternative to that you propose:

[Pre-RFC]: Generator integration with for loops

Motivation Although Generator was initially introduced with async story in mind, it can be also used for enhancing core for loop functionality. Integration of Generator with for loops looks quite natural: for value in generator { // .. } Here we iterate over yielded values and discard return value of the generator. Introduction of this feature will also prevent a lot of confusion for people coming from Python, as syntax of for loops and generators are quite close, thus it will be natural …