code: func ReferencesInExpr(expr hcl.Expression) ([]*addrs.Reference, tfdiags.Diagnostics) {
  	if expr == nil {
  		return nil, nil
  	}
  	traversals := expr.Variables()
  	return References(traversals)
  }
docs: // ReferencesInExpr is a helper wrapper around References that first searches
  // the given expression for traversals, before converting those traversals
  // to references.