[perl #71514] Calling .subst in a reduction method destroys the effect of make()

[via RT]

# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #71514]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=71514 >


grammar ActionsTestGrammar {
    token TOP {
        ^ .+ $ {*}
    }
}
class TestActions {
    method TOP($/) {
        "a\nb".subst(/\n+/, '', :g);
        make 123;
    }
}

say ActionsTestGrammar.parse("ab\ncd", :action(TestActions.new)).ast;

Prints:
ab
cd

commenting out the line with the call to .subst makes it print 123 as
expected.

Found by takadonet++

Cheers,
Moritz