From gerd.r.devel@googlemail.com

<not_gerd> rn​: sub ($ = 42 --> Int) { ... }
<p6eval> niecza v19-4-g12b71c7​: ( no output )
<p6eval> ..rakudo 88a9d6​: OUTPUT«===SORRY!===␤Missing block␤at
/tmp/rjG5cSGHkE​:1␤»

From @ronaldxs

On Thu Jun 28 01​:11​:14 2012, gerd.r.devel@​googlemail.com wrote​:

<not_gerd> rn​: sub ($ = 42 --> Int) { ... }
<p6eval> niecza v19-4-g12b71c7​: ( no output )
<p6eval> ..rakudo 88a9d6​: OUTPUT«===SORRY!===␤Missing block␤at
/tmp/rjG5cSGHkE​:1␤»

I ran into this with a named subroutine but noticed there that the
prefix form of declaring the return type seems to be effective as a
workaround.

So

sub foo(Int $x = 3 --> Rat) { return $x / 2}

unsurprisingly gives the same error but

my/our Rat sub foo(Int $x = 3) { return $x / 2}

seems to work as expected.

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

From @masak

<lizmat> r​: sub a ( $a=1, --> Hash ) { say $a; my %h }; say a(2)
<camelia> rakudo 8d2ec9​: OUTPUT«2␤().hash␤»
<lizmat> r​: sub a ( $a=1 --> Hash ) { say $a; my %h }; say a(2)
<camelia> rakudo 8d2ec9​: OUTPUT«===SORRY!===␤Missing block␤at
/tmp/NxD226NWlT​:1␤------> sub a ( $a=1 --> Hash ⏏) { say $a; my %h };
say a(2)␤ expecting any of​:␤ postfix␤ infix stopper␤
  infix or meta-infix␤ prefix or term␤ …
<lizmat> for some reason, if we have a default, we need a comma there
<lizmat> r​: sub a ( $a --> Hash ) { say $a; my %h }; say a(2)
<camelia> rakudo 8d2ec9​: OUTPUT«2␤().hash␤»
* masak submits rakudobug for the required comma

I have a feeling I know what's up. The default puts the parser in EXPR
mode. The '-->' should be a stopper, but it isn't, so it gets parsed
as '- ->', binary minus and a pointy. The Hash gets gobbled up as a
parameter, and then the parser expects a block, not ')'. This is
consistent with the error message.

From @usev6

This works now without the comma​:

$ perl6-m -e 'sub a ( $a=1 --> Hash ) { say $a; my %h }; say a(2)'
2

^^ empty string here ;-)

I added a test to S06-signature/defaults.t with the following commit​: Raku/roast@4485db4547

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