Subsetting uniqueness conformance is not checked for an implicit subsetting

[someshSandbox]

validateSubsettingUniquenessConformance is checked for a subsetting written in the source (:>, subsets), but not for one the feature gets implicitly.

package N {
    action def A {
        action b[*] nonunique;
    }
}

b is a composite action owned by an action definition, so it implicitly subsets Actions::Action::subactions (checkActionUsageSubactionSpecialization). subactions is declared Action[0..*] with no nonunique (Systems Library/Actions.sysml:57), so it is unique, and a nonunique b cannot subset it.

model	sysml -validate (develop d9a97d6d8)	expected (validateSubsettingUniquenessConformance)
action b[*] nonunique;	no errors	the same error, at b: its implicit subsetting of subactions breaks the constraint
action b[*] nonunique :> subactions;	3:34: error: Subsetting/redefining feature cannot be nonunique if subsetted/redefined feature is unique	this error
action b[*];	no errors	no errors

The constraint is on the Subsetting, and an implied Subsetting is one too. Model.ConformanceViolations (internal/semantic/semantics/redefinition_conformance.go) walks only the written RelSubsets/RelRedefines relationships, plus the positional parameter counterparts for direction. validation-constraints.md lists the constraint as faithful, with only the written case (xpect/p04-nonunique-subsets-unique.kerml).

Other implicit subsettings of a unique library feature would be missed the same way. Examples are the other subactions-style features in Actions.sysml and Transfer::payload (Anything[1..*]) for a flow's payload.