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  1. OMG Issue

SYSML21 — Interface derivations select ReferenceUsage

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  • Key: SYSML21-715
  • Status: open  
  • Source: Diversitas Systems Engineering Ltd ( Geoffrey Tullener)
  • Summary: 
    Usage::deriveUsageNestedInterface: Interface derivations select ReferenceUsage

Where:          SysML 2.0 (formal/2026-03-02), ยง8.3.6.4 Usage (also 8.3.6.2 Definition), PDF p.306 (printed 274)
Published OCL:  nestedInterface = nestedUsage->selectByKind(ReferenceUsage)
Correction:     nestedInterface = nestedUsage->selectByKind(InterfaceUsage)
Proof of fault: The derivation selects ReferenceUsages for a property declared InterfaceUsage; the two metaclasses are unrelated.
Likely cause:   Copy, edit left incomplete. Property name edited, type not: still the sibling's ReferenceUsage. Same slip in the Definition family (ownedInterface / ownedReference).
Nearest rule:   Usage::deriveUsageNestedReference (SysML 2.0 PDF p.307 (printed 275)): nestedReference = nestedUsage->selectByKind(ReferenceUsage)
Same defect in: Usage::deriveUsageNestedInterface, Definition::deriveDefinitionOwnedInterface
Basis of fix:   The property's type and the prose both name InterfaceUsage.

    Provenance: found by deterministic checks of the OCL against the metamodel and OMG's reference implementation; the argument was reviewed and challenged by the reporter before filing. Further information on these methods is available on request.

    Not blocking: we are proceeding with the correction above in our own implementation.
  • Reported: SysML 2.0 — Tue, 27 Oct 2026 18:51 GMT
  • Updated: Fri, 30 Oct 2026 21:19 GMT