The entry type for a SUBSCRIPTION resolver stored in a
TypeResolverMap.
The bivariant counterpart of AnyFieldResolver, for the same
reason and by the same mechanism: TypeResolverMap bound the bare
SubscriptionResolver, whose defaults are all unknown, so a typed
subscription entry — resolve: (payload: Book) => payload.title — was
rejected under strictFunctionTypes with
Type 'unknown' is not assignable to type 'Book'. That is X6-4's defect
surviving on the subscription arm.
subscribe is declared with method syntax (bivariant) and resolve reuses
AnyFieldResolver, so a typed subscription assigns while an
unannotated one still gets its parameters contextually. Instantiating
SubscriptionResolver at never would buy the first and lose the second,
which is the regression the field arm already hit.
The entry type for a SUBSCRIPTION resolver stored in a
TypeResolverMap.The bivariant counterpart of
AnyFieldResolver, for the same reason and by the same mechanism:TypeResolverMapbound the bareSubscriptionResolver, whose defaults are allunknown, so a typed subscription entry —resolve: (payload: Book) => payload.title— was rejected understrictFunctionTypeswithType 'unknown' is not assignable to type 'Book'. That is X6-4's defect surviving on the subscription arm.subscribeis declared with method syntax (bivariant) andresolvereusesAnyFieldResolver, so a typed subscription assigns while an unannotated one still gets its parameters contextually. InstantiatingSubscriptionResolveratneverwould buy the first and lose the second, which is the regression the field arm already hit.