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  1. OMG Issue

SYSML21 — oclIsType does not exist in OCL

Open Closed All
  • Key: SYSML21-710
  • Status: open  
  • Source: Diversitas Systems Engineering Ltd ( Geoffrey Tullener)
  • Summary: 
    ObjectiveMembership::validateObjectiveMembershipOwningType: oclIsType does not exist in OCL

Where:          SysML 2.0 (formal/2026-03-02), ยง8.3.22.4 ObjectiveMembership (also 8.3.21.11 SubjectMembership, 8.3.26.2 Expose), PDF p.402 (printed 370)
Published OCL:  owningType.oclIsType(CaseDefinition) or owningType.oclIsType(CaseUsage)
Correction proposed (one of two readings): owningType.oclIsKindOf(CaseDefinition) or owningType.oclIsKindOf(CaseUsage)
Proof of fault: oclIsType is not an OCL operation, so the rule has no meaning as written.
Likely cause:   Non-existent operator used consistently. The same non-existent oclIsType appears in three unrelated rules: an authoring habit, not a slip. The Subject rule also has a garbled type name (RequiremenCaseRequirementDefinition).
Nearest rule:   SubjectMembership::validateSubjectMembershipOwningType (SysML 2.0 PDF p.396 (printed 364)): owningType.oclIsType(RequirementDefinition) or owningType.oclIsType(RequiremenCaseRequirementDefinition) or owningType.oclIsType(CaseDefinition) or owningType.oclIsType(CaseUsage)
Same defect in: ObjectiveMembership::validateObjectiveMembershipOwningType, SubjectMembership::validateSubjectMembershipOwningType, Expose::validateExposeOwningNamespace
Basis of fix:   Two candidates (oclIsKindOf, oclIsTypeOf); the language's use of objectives in analysis cases decides for oclIsKindOf.
Also:           SubjectMembership::validateSubjectMembershipOwningType names a garbled type, RequiremenCaseRequirementDefinition; its prose lists RequirementDefinition, RequirementUsage, CaseDefinition and CaseUsage, so RequirementUsage is meant.

    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 18:41 GMT
  • Updated: Fri, 30 Oct 2026 21:31 GMT