Type match error in object literal with set keys

[tsandall]

The following policy is rejected by the type checker:

package bin

a := {1, 2, 3, 4}

b := {3, 4, 5}

c := {4, 5, 6}

d := {
	a: b,
	[1, 2]: c,
}

# this results in a compile error due to type mismatch
output {
	d == {
		[1, 2]: {4, 5, 6},
		{1, 2, 3, 4}: {3, 4, 5}
	}
}

The error:

1 error occurred: policy.rego:16: rego_type_error: match error
	left  : object<[1 2]: set[number]>[set[number]: set[number]]
	right : object<[1 2]: set[number], [1 2 3 4]: set[number]>

It looks like the type checker is rejecting the equals expression because the static property on the RHS does not unify with the dynamic property on the LHS.

[johanfylling]

Changing a to define an array a := [1, 2, 3, 4] makes the type-checker happy. Naturally, this will however make the equality in output fail (set != array, even though their members are the same).

The key of a static object property is a JSON value; could this be the culprit? Static properties with a set key will be turned into an array key, which then fails the comparison to the corresponding dynamic set-key property.

[stale[bot]]

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