No error when multiplying inequality constraints

[extemporalgenome]

What version of CUE are you using (cue version)?

$ cue version
v0.3.0-alpha6

Does this issue reproduce with the latest release?

yes

What did you do?

I was exploring a more concise/expressive way of minimum and maximum list length:

x: (>0) * [y]
x: (<5) * [y]

y: -1
x: [1,2,3,4]

https://cuelang.org/play/?id=CXTDnET25_-#cue@export@cue

What did you expect to see?

If this were a feature/operation in cue, I would expect so see x fail to validate because it does not have between 1 and 5 elements, and because those elements aren't all the value -1.

If this is not a feature of cue (and it appears not to be), I would expect to see a language-level error indicating that inequality constraints are not compatible with the multiplication operator.

What did you see instead?

cue eval results in:

x: [1, 2, 3, 4]
y: -1

The first two lines appear not to contribute any constraint, though commenting out the last line of the input yields:

x: >0*[y] & <5*[y]
y: -1

(so cue is parsing, rather than discarding, these constraints).

Note that multiplying inequality constraints together (such as <5 * >10) is also accepted by cue, but appears to have no validation effect either.

[mpvl]

Duplicate of #680, but leaving because of the more descriptive title.

[cueckoo]

This issue has been migrated to cue-lang/cue#684.

For more details about CUE's migration to a new home, please see cue-lang/cue#1078.