#!/usr/bin/perl use strict; use warnings; use Test::More; =pod See this for some details: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=476579 Here is the basic test case, it segfaults, so I am going to leave it commented out. Basically it seems that there is some bad interaction between the ??{} construct that is used in the "parser" for type definitions and threading so probably the fix would involve removing the ??{} usage for something else. use threads; { package Foo; use Moose; has "bar" => (is => 'rw', isa => "Str | Num"); } my $thr = threads->create(sub {}); $thr->join(); =cut { local $TODO = 'This is just a stub for the test, see the POD'; fail('Moose type constraints and threads dont get along'); } done_testing;