From @masak

<timotimo> r​: sub test(@​a[10]) { say +@​a }; test((1, 2, 3, 4, 5, 6, 7,
8, 9, 10))
<camelia> rakudo e7ce6b​: OUTPUT«Constraint type check failed for
parameter '' in sub-signature of parameter @​a [...]
<timotimo> i got nothin'
<masak> timotimo​: that doesn't mean what you think it means.
<masak> r​: sub test(@​a [10]) { say "it's alive!" }; test([10])
<camelia> rakudo e7ce6b​: OUTPUT«it's alive!␤»
<TimToady> masak​: @​a[10] is supposed to mean something different than @​a [10]
<masak> TimToady​: that may be. it clearly doesn't in Rakudo ;)
<jnthn> r​: sub foo(@​a[10]) { }; foo([10])
<camelia> rakudo e7ce6b​: ( no output )
<jnthn> r​: sub foo(@​a[10]) { }; foo([9])
<camelia> rakudo e7ce6b​: OUTPUT«Constraint type check failed for
parameter '' in sub-signature of parameter @​a [...]
<jnthn> hm :)
<TimToady> it's not parsing it as a shape
<jnthn> aye, I don't think it expects to parse a shape there... :P
<jnthn> Does STD? What does it mean to parse a shape there? :)
<TimToady> I can think of two interpretation
<TimToady> one, a constraint on what you can pass in
<TimToady> secondly, one might allow @​a[$size] to bind $size to the
size, but that's a little there, and probably a bad idea
<jnthn> pobably ;)
<TimToady> STD parses it as a shape
<TimToady> in any case, the syntax @​a[] should be reserved for
shape-related declarations, not treated as a subbinding
<TimToady> anyway, if we let people write subbinding with @​a[], people
will, and then their code will break later when we require whitespace;
so better to require it now

From @usev6

Nowadays @​a[10] in a signature is parsed as a shaped array (and gives a fitting error message since shape declaration is NYI)​:

$ perl6 -e 'sub foo(@​a[10]) { }'
===SORRY!=== Error while compiling -e
Shape declaration is not yet implemented; please use whitespace if you meant a subsignature for unpacking
at -e​:1
------> sub foo(@​a⏏[10]) { }
  expecting any of​:
  shape declaration

Should we add a test for this error message and close this ticket or should the ticket stay open until shape declaration is implemented?

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

From @jnthn

On Sat Jan 03 08​:12​:50 2015, bartolin@​gmx.de wrote​:

Nowadays @​a[10] in a signature is parsed as a shaped array (and gives
a fitting error message since shape declaration is NYI)​:

$ perl6 -e 'sub foo(@​a[10]) { }'
===SORRY!=== Error while compiling -e
Shape declaration is not yet implemented; please use whitespace if you
meant a subsignature for unpacking
at -e​:1
------> sub foo(@​a⏏[10]) { }
expecting any of​:
shape declaration

Should we add a test for this error message and close this ticket or
should the ticket stay open until shape declaration is implemented?

I implemented it and added tests in S06-signature/shape.t.

/jnthn

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