From @usev6

I get a segmentation fault with moar when I run the following command (tested on Debian 7 and FreeBSD 10.0)​:

$ PERL6LIB=$(pwd)/lib​:. ./perl6-m t/spec/S05-transliteration/trans.rakudo.moar
1..60
ok 1 - Each side can be individual characters
ok 2 - The two sides of the any pair can be strings interpreted as tr/// would multichar
ok 3 - The two sides of the any pair can be strings interpreted as tr/// would range
ok 4 - If the first character is a dash it isn't part of a range
Segmentation fault

Other values for PERL6LIB ('lib​:.' or '/path/to/rakudo/lib​:/path/to/rakudo) seem to work​: http://pastebin.com/cAzk213S

Also setting MVM_SPESH_INLINE_DISABLE=1 avoids the segfault as FROGGS pointed out (link below)​:
$ PERL6LIB=$(pwd)/lib​:. MVM_SPESH_INLINE_DISABLE=1 ./perl6-m t/spec/S05-transliteration/trans.rakudo.moar
[... runs as expected, no segfault]

For further discussion see http://irclog.perlgeek.de/perl6/2014-09-24#i_9403093

From @usev6

I tried to narrow the problem down, but was not very successful.

With the attached file "trans.t" I can reproduce the segfault​:

$ PERL6LIB=$(pwd)/lib​:. ./perl6-m trans.t
alive
Segmentation fault

If I remove some variable declarations or the last say in that file, the segfault goes away. Even changing the quotation (s/'/"/g or s/"/'/g) avoids the segfault.

(On a second system I had to declare some more empty variables to get a segfault. But otherwise it behaves identically.)

From @usev6

use v6;
use Test;

'ABC'.trans( ('A'=>'a'), ('B'=>'b'), ('C'=>'c') );

'XYZ'.trans( ('XYZ' => 'xyz') );

'ABC-DEF'.trans( ('- A..Z' => '_ a..z') );

my ($var1,$var2,$var3,$var4,$var5,$var6,$var7,$var8,$var9,$var10);
my ($var11,$var12,$var13,$var14,$var15,$var16,$var17);
say "alive"; ## no segfault when commenting this line or not declaring one of those variables

From @usev6

This was fixed in MoarVM today (cmp. http://irclog.perlgeek.de/perl6/2014-10-02#i_9446636 and http://irclog.perlgeek.de/perl6/2014-10-02#i_9447562).

@usev6 - Status changed from 'new' to 'resolved'