Function check_body 

pub fn check_body(
    input: &ResolvedCommons,
    body: &Block,
    return_ty: TyId,
    return_ty_span: Span,
    scope: HashMap<String, TyId>,
    caps: CapabilityCtx,
    test_services: HashMap<String, TestServiceSig>,
    test_actors: HashMap<String, ActorDecl>,
    where_pred: Option<&Expr>,
    sinks: CheckSinks<'_>,
) -> Option<TyId>

Type-check a bare body against return_ty in scope, with caps available as both in-scope and declared capabilities and (if non-empty) test_services/test_actors in scope for a test-case body’s svc.call/ by <Actor>(...) resolution (§32/#33: the one shape every hand-rolled Ctx outside this crate needed, letting Ctx itself stay pub(crate)). where_pred, if present, is checked first against Bool (a property’s optional for all ... where filter — bynk.property.where_not_bool on mismatch), sharing ctx with the main body so both populate the same expr_types/errors sinks. Unlike check_handler_body, this skips the linearity pass, the return-type-mismatch diagnostic, and the unused-given diagnostic — nothing outside this crate that built its own Ctx ran those either, and adding them here would be a behaviour change, not a refactor.