[perl #123834] LTA error for putting 'is rw' in the wrong spot in sub signatures

[via RT]

# New Ticket Created by  Adrian Kreher 
# Please include the string:  [perl #123834]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=123834 >


I wrote 'sub f($x=60 is rw)' instead of 'sub f($x is rw = 60)'. STD
gives a much better error:

143824       avuserow | m: sub f($x=60 is rw) {$x++; say $x}; f
143825       +camelia | rakudo-moar 949b80:
OUTPUT«?31m===?0mSORRY!?31m===?0m Error while compiling
/tmp/KK124_JoHD␤Missing block␤at /tmp/KK124_JoHD:1␤------> ?32msub
f($x=60 ?33m⏏?31mis rw) {$x++; say
$x}; f?0m␤»
143828       avuserow | std: sub f($x=60 is rw) {$x++; say $x}; f
143830       +camelia | std f9b7f55:
OUTPUT«?31m===?0mSORRY!?31m===?0m␤Default expression must come last at
/tmp/W6d6MA7gbZ line 1:␤------> ?32msub f($x=60 ?33m⏏?31mis rw) {$x++;
say $x}; f?0m␤Unable to
parse signature at /tmp/W6d6MA7gbZ line 1:␤------> ?32msub
f?33m⏏?31m($x=60 is rw…»

My local build's version: This is perl6 version 2015.01-141-gfec2339
built on MoarVM version 2015.01-34-g2d7eddb