From @masak

<jnthn> rakudo​: sub foo( &x) { say "ok" }; foo({ say "lol" })
<p6eval> rakudo 0d4fe0​: OUTPUT«ok␤»
<jnthn> rakudo​: sub foo(Callable &x) { say "ok" }; foo({ say "lol" })
<p6eval> rakudo 0d4fe0​: OUTPUT«ok␤»
<jnthn> wtf
<jnthn> rakudo​: sub foo(&x) { }; say &foo.signature.perl;
<p6eval> rakudo 0d4fe0​: OUTPUT«​:(x)␤»
<masak> something wrong?
<jnthn> rakudo​: sub foo(Callable &x) { }; say &foo.signature.perl;
<p6eval> rakudo 0d4fe0​: OUTPUT«​:(x where all(Callable))␤»
<jnthn> :-/
<masak> please state the nature of your medical emergency.
<jnthn> masak​: Callable &x should mean I can only pass something that
does Callable[Callable]
* masak submits rakudobug
<jnthn> Damm, just when I think I've got something right.
<wolverian> is the type parameter the return type?
<jnthn> The type parameter indicates the return type constraint.

From @kyleha

This is an automatically generated mail to inform you that tests are now available in t/spec/S06-signature/code.t

commit 7b90df932029168b1169472c623a5f015c91e54b
Author​: kyle <kyle@​c213334d-75ef-0310-aa23-eaa082d1ae64>
Date​: Fri Oct 9 17​:14​:06 2009 +0000

  [t/spec] Test for RT #​68578
 
  git-svn-id​: http://svn.pugscode.org/pugs@&#8203;28679 c213334d-75ef-0310-aa23-eaa082d1ae64

diff --git a/t/spec/S06-signature/code.t b/t/spec/S06-signature/code.t
index 2ff20ee..26f8660 100644
--- a/t/spec/S06-signature/code.t
+++ b/t/spec/S06-signature/code.t
@@ -1,6 +1,6 @@
 use v6;
 use Test;
-plan 4;
+plan 6;
 
 # TODO: move this test to closure-parameters.t if it works in the future
 
@@ -28,4 +28,12 @@ sub not_returns_a_sub { 3 };
 dies_ok {tester2(not_returns_a_sub)}, 
         "can't pass thing that doesn't do Callable";
 
+is tester2({ 'block' }), 1, 'Can pass a block to a &parameter';
+
+# RT #68578
+{
+    sub rt68578( Callable &x ) {}
+    dies_ok { rt68578({ 'block' }) }, "Can't pass block that doesn't do Callable";
+}
+
 # vim: ft=perl6

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

From @kyleha

The new tests for this pass, so I'm marking this resolved.

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