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C.3.A:4.3 - Guard_TypedJoin — compose typed producers and consumers

Intent. Compose producer A, which declares output kind k_A, with consumer B, which expects input kind k_B.

Guard_TypedJoin(A, k_A, edition_A; B, k_B, edition_B; TargetSlice) SHALL:

  1. pin both declaration episteme editions;
  2. establish output-to-input compatibility in the covariant flow direction:
    • the kinds are identical or SubkindOfObtains(k_A, k_B; effectiveReferenceScheme) holds; or
    • for a bridged flow, an obtaining KindBridge maps k_A to exact, independently identified distinct target-side kind k_A', its separate assertion carries the current mapping and loss basis, and k_A' is identical to k_B or SubkindOfObtains(k_A', k_B; targetReferenceScheme) holds;
  3. compute serial scope as the intersection of the two governed scopes and require coverage of TargetSlice;
  4. route bridge consequences to R and check freshness separately; and
  5. when an actual produced candidate enters B, evaluate J(candidate, k_B, edition_B, TargetSlice) and continue only on true, preserving false and unknown separately from refusal.

Declaration compatibility alone MUST NOT classify a future or actual output. Scope widening MUST NOT repair a type mismatch. The universal-claim variance rule in Guard_TypedClaim does not reverse this producer-to-consumer direction.