# New Ticket Created by James E Keenan # Please include the string: [perl #134252] # in the subject line of all future correspondence about this issue. # <URL: https://rt.perl.org/Ticket/Display.html?id=134252 > This was first reported to me off list by Carlos Guevara, based on his smoke testing rigs. http://matrix.cpantesters.org/?dist=Data-Alias http://matrix.cpantesters.org/?dist=Syntax-Keyword-Try Carlos also reported that test(s) in the latter distro hung. I can confirm that on FreeBSD-11, Syntax::Keyword::Try's test t/11loop.t hung indefinitely and had to be Ctrl-C-ed for smoking to proceed. I was consequently not able to get a definitive bisection for that module. On Linux I was able to bisect the problem with Data::Alias to: ##### f23e164367e8b9494783181262bf4a1a16d26961 is the first bad commit commit f23e164367e8b9494783181262bf4a1a16d26961 Author: David Mitchell <davem@iabyn.com> Date: Tue Jun 18 15:11:12 2019 +0100 Perl_list() tail-call optimise The part of this function that scans the children of e.g. @a = do { void; void; list } applying list context only to the last child, tail call optimise that call to list(). (See also a few commits later entitled "Perl_scalar() tail-call optimise" for a discourse on setting PL_curcop (in)correctly.) :100644 100644 77dc177ec9bfd8c488d2a62aacaaaedc4f2658b7 a30740f2a5a449b1644665331ba560cbc9c167ee M op.c ##### No further diagnose yet attempted. Thank you very much. Jim Keenan perl perl perlThread Previous