From @smls

S07 [https://github.com/perl6/specs/blob/master/S07-lists.pod] claims​:

  "The single argument rule does respect Scalar containers."
  "The single argument rule is implemented consistently throughout the language."

It lists 'for', '.push', 'infix​:<,>' and 'postcircumfix​:<[ ]>' as examples of
things that consistently follow the rule.

Since it does not explicitly mention the X and Z meta-operators as exceptions,
it stands to reason that they too should follow this rule.

But in current Rakudo they only follow it partially​: They treat each operand as
a single argument whose elements to act on, but they do *not* respect Scalar-containerization of said arguments.

Example​:

  say $(1, 2) X <a b c>

Output​:

  ((1 a) (1 b) (1 c) (2 a) (2 b) (2 c))

Expected output​:

  (((1 2) a) ((1 2) b) ((1 2) c))

TL;DR​: This is either a Rakudo bug, or a case where S07 needs more clarification.

From @jnthn

On Sat Oct 31 14​:12​:36 2015, smls75@​gmail.com wrote​:

S07 [https://github.com/perl6/specs/blob/master/S07-lists.pod] claims​:

"The single argument rule does respect Scalar containers."
"The single argument rule is implemented consistently throughout the
language."

It lists 'for', '.push', 'infix​:<,>' and 'postcircumfix​:<[ ]>' as
examples of
things that consistently follow the rule.

Since it does not explicitly mention the X and Z meta-operators as
exceptions,
it stands to reason that they too should follow this rule.

But in current Rakudo they only follow it partially​: They treat each
operand as
a single argument whose elements to act on, but they do *not* respect
Scalar-containerization of said arguments.

Example​:

say $(1, 2) X <a b c>

Output​:

((1 a) (1 b) (1 c) (2 a) (2 b) (2 c))

Expected output​:

(((1 2) a) ((1 2) b) ((1 2) c))

TL;DR​: This is either a Rakudo bug, or a case where S07 needs more
clarification.

Rakudo bug, and fixed now. Also roundrobin was vulnerable to a similar problem, and has also been fixed. Tests in S03-metaops/cross.t, S03-metaops/zip.t, and S32-container/roundrobin.t.

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

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