pub fn validate_explicit_origin_required(d: &Descriptor) -> Result<(), Error>Expand description
Validate that every @N in a non-canonical wrapper has an explicit
origin path on the wire — either via OriginPathOverrides[idx] or
via a non-empty entry in the path_decl (shared or divergent).
Per spec v0.13 §6.3: when canonical_origin(&d.tree) is None, the
wrapper is “non-canonical” and the encoder must emit an explicit
origin for every @N. The decoder enforces the same as defense in
depth: failure → Error::MissingExplicitOrigin { idx }.
If canonical_origin(&d.tree) is Some(_), this validator is a
no-op — any origin spec (elided or explicit) is allowed.