Macro frame_support::decl_error

macro_rules! decl_error {
    (
		$(#[$attr:meta])*
		pub enum $error:ident
			for $module:ident<
				$generic:ident: $trait:path
				$(, $inst_generic:ident: $instance:path)?
			>
			$( where $( $where_ty:ty: $where_bound:path ),* $(,)? )?
		{
			$(
				$( #[doc = $doc_attr:tt] )*
				$name:ident
			),*
			$(,)?
		}
	) => { ... };
}

👎Deprecated: Will be removed after July 2023; use the attribute #[pallet] macro instead. For more info, see: https://github.com/paritytech/substrate/pull/13705

Declare an error type for a runtime module.