[perl #131593] [BUG][REGRESSION] Failure to sink values in for loops

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# New Ticket Created by  Zoffix Znet 
# Please include the string:  [perl #131593]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=131593 >


This a two part report:

1) It appears in some cases a for loop doesn't sink stuff. Which causes, for 
example, a .map call to never be evaluated:

    <Zoffix__> m: sub foo($?) { ^2 .map: &say }; foo() for 1
    <camelia> rakudo-moar c252b3: ( no output )
    <Zoffix__> m: sub foo($?) { ^2 .map: &say }; foo().sink for 1
    <camelia> rakudo-moar c252b3: OUTPUT: «0␤1␤»

2) It actually works for the case when the sub is called as .&foo:

    <Zoffix__> c: 2017.05,HEAD sub foo($?) { ^2 .map: &say }; foo() for 1
    <committable6> Zoffix__, ¦2017.05,HEAD(8074966): «»

    <Zoffix__> c: 2017.05,HEAD sub foo($) { ^2 .map: &say }; .&foo for 1
    <committable6> Zoffix__, ¦2017.05: «0␤1» ¦HEAD(8074966): «»

This worked since summer of 2016, however, commit 9b0b9e made it not work again.

[1] 
https://github.com/rakudo/rakudo/commit/9b0b9effe5fee1f35497cf97a5e7bda9bb083507