From @masak

<LoRe> rakudo​: print ([1..3] <<->> [1..3]).perl
<p6eval> rakudo fdae00​: OUTPUT«Bool​::False»
<LoRe> rakudo​: print ([1..3] <<+>> -<< [1..3]).perl
<p6eval> rakudo fdae00​: OUTPUT«[0, 0, 0]»
<masak> LoRe​: huh.
<masak> rakudo​: say ((1, 2, 3) <<->> (1, 2, 3)).perl
<p6eval> rakudo fdae00​: OUTPUT«Bool​::False␤»
<masak> rakudo​: say ((1, 2, 3) >>-<< (1, 2, 3)).perl
<p6eval> rakudo fdae00​: OUTPUT«[0, 0, 0]␤»
<masak> should those two differ? the arrays are of the same length.
<LoRe> rakudo​: print ([1..3] <<[-]>> [1..3]).perl
<p6eval> rakudo fdae00​: OUTPUT«[0, 0, 0]»
<LoRe> ok
<masak> oh!
<masak> it parses as either < or > and something.
<masak> I'm not sure how it manages to do that.
* masak submits rakudobug
<masak> LoRe++

From @kyleha

This is an automatically generated mail to inform you that tests are now available in S03-metaops/hyper.t

commit 71fdf1d837b6869d9826d6f4d058678eb62c668a
Author​: Kodi Arfer <hippo@​Thoth.(none)>
Date​: Wed Sep 29 20​:06​:05 2010 -0400

  [hyper.t] Added tests for RT #​77800.

diff --git a/S03-metaops/hyper.t b/S03-metaops/hyper.t
index fbfc5bd..b9a2780 100644
--- a/S03-metaops/hyper.t
+++ b/S03-metaops/hyper.t
@@ -8,7 +8,7 @@ use Test;
 
 =end pod
 
-plan 265;
+plan 269;
 
 # L<S03/Hyper operators>
  # binary infix
@@ -717,7 +717,16 @@ my @e;
 
 # RT #74530
 {
-    is ~(-<<(1..3)), '-1 -2 -3', 'ranges and hyper ops mix';;
+    is ~(-<<(1..3)), '-1 -2 -3', 'ranges and hyper ops mix';
+}
+
+# RT #77800
+# Parsing hyper-subtraction
+{
+    is ((9, 8) <<-<< (1, 2, 3, 4)), (8, 6, 6, 4), '<<-<<';
+    is ((9, 8, 10, 12) >>->> (1, 2)), (8, 6, 9, 10), '>>->>';
+    is ((9, 8) >>-<< (1, 2)), (8, 6), '>>-<<';
+    is ((9, 8) <<->> (1, 2, 5)), (8, 6, 4), '<<->>';
 }
 
 done_testing;

The RT System itself - Status changed from 'new' to 'open'

From @Kodiologist

Fixed in fb57ef1. The culprit was an assertion in Grammar.pm that was
intended to prevent the "-" in "if $a -> { ... }" from parsing as
subtraction.

@Kodiologist - Status changed from 'open' to 'resolved'