[perl #124331] hyperop'd -= won't DWIM a single element on the right

[via RT]

# New Ticket Created by  Timo Paulssen 
# Please include the string:  [perl #124331]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=124331 >


This code:

    my @sizes = 100, 110, 120, 130; @sizes >>-=>> @sizes[0]; say @sizes

gives 0, 110, 120, 130.

    my @sizes = 100, 110, 120, 130; @sizes = @sizes >>-=>> (@sizes[0] xx
4); say @sizes

gives 0, 10, 20, 30 (which is what I expect the other one to work, too).

    my @sizes = 100, 110, 120, 130; @sizes >>-=>> (@sizes[0] xx 4); say
@sizes

gives the expected result, too.