Fixes

frame/support/src/dispatch.rs

@@ -2169,7 +2169,8 @@ macro_rules! decl_module {
 			for $mod_type<$trait_instance $(, $instance)?> where $( $other_where_bounds )*
 		{
 			fn count() -> usize { 1 }
-			fn accumulate(acc: &mut $crate::traits::PalletInfoData) {
+			fn accumulate(acc: &mut Vec<$crate::traits::PalletInfoData>) {
+				use $crate::traits::PalletInfoAccess;
 				let item = $crate::traits::PalletInfoData {
 					index: Self::index(),
 					name: Self::name(),

frame/support/src/traits/metadata.rs

@@ -18,7 +18,6 @@
 //! Traits for managing information attached to pallets and their constituents.
 
 use codec::{Decode, Encode};
-use impl_trait_for_tuples::impl_for_tuples;
 use sp_runtime::RuntimeDebug;
 use sp_std::prelude::*;
 
@@ -80,8 +79,8 @@ pub trait PalletsInfoAccess {
 
 	/// All of the pallets' information that this type represents. Relevant for tuples.
 	fn infos() -> Vec<PalletInfoData> {
-		let mut result = Vec::with_capacity(Self::infos_len());
-		Self::accumulate_infos(&mut result);
+		let mut result = Vec::with_capacity(Self::count());
+		Self::accumulate(&mut result);
 		result
 	}
 }
@@ -95,8 +94,8 @@ impl<T: PalletsInfoAccess> PalletsInfoAccess for (T,) {
 impl<T1: PalletsInfoAccess, T2: PalletsInfoAccess> PalletsInfoAccess for (T1, T2) {
 	fn count() -> usize { T1::count() + T2::count() }
 	fn accumulate(acc: &mut Vec<PalletInfoData>) {
-		T1::accumulate(acc);
 		T2::accumulate(acc);
+		T1::accumulate(acc);
 	}
 }
 

frame/support/test/tests/pallet_instance.rs

@@ -507,12 +507,18 @@ fn storage_expand() {
 
 #[test]
 fn pallet_metadata_expands() {
-	use frame_support::traits::{CrateVersion, PalletInfoAccess, PalletInfoData};
+	use frame_support::traits::{CrateVersion, PalletsInfoAccess, PalletInfoData};
 	let mut infos = AllPalletsWithSystem::infos();
 	infos.sort_by_key(|x| x.index);
 	assert_eq!(
 		infos,
 		vec![
+			PalletInfoData {
+				index: 0,
+				name: "System",
+				module_name: "frame_system",
+				crate_version: CrateVersion { major: 4, minor: 0, patch: 0 },
+			},
 			PalletInfoData {
 				index: 1,
 				name: "Example",