EOF check in MoarVM breaks process substitution and opening of devices

[p6rt]

Migrated from rt.perl.org#127423 (status was 'new')

Searchable as RT127423$

[p6rt]

From vittore.scolari@pasteur.fr

Typing the following on the command line​:

perl6 -e 'say @​*ARGS[0].IO.open(​:r).lines' <(head /etc/hosts)

causes the software to abort with the error message​:

Failed to seek in filehandle​: 29

This is caused by MoarVM/src/io/syncfile.c at the end of the mvm_eof
function.

same for​:
perl6 -e 'say @​*ARGS[0].IO.lines' /dev/tty

[p6rt]

From @zoffixznet

Still present today in Rakudo 2016.07.1-88-g15ee3c3​:

$ perl6 -e 'say @​*ARGS[0].IO.open(​:r).lines' <(head /etc/hosts)
Failed to seek in filehandle​: 29
  in block <unit> at -e line 1

--
Cheers,
ZZ | https://twitter.com/zoffix

[p6rt]

From vittore.scolari@pasteur.fr

The bugs seems fixed as of today - 2017.06-13-g6b634a3

Thank you

[p6rt]

From @zoffixznet

Tests needed