pallet-vesting: Support multiple, merge-able vesting schedules

bin/node/runtime/src/lib.rs

@@ -1009,6 +1009,7 @@ impl pallet_society::Config for Runtime {
 
 parameter_types! {
 	pub const MinVestedTransfer: Balance = 100 * DOLLARS;
+	pub const MaxVestingSchedules: u32 = 3;
 }
 
 impl pallet_vesting::Config for Runtime {
@@ -1017,6 +1018,7 @@ impl pallet_vesting::Config for Runtime {
 	type BlockNumberToBalance = ConvertInto;
 	type MinVestedTransfer = MinVestedTransfer;
 	type WeightInfo = pallet_vesting::weights::SubstrateWeight<Runtime>;
+	type MaxVestingSchedules = MaxVestingSchedules;
 }
 
 impl pallet_mmr::Config for Runtime {

frame/support/src/traits/tokens/currency/lockable.rs

@@ -99,6 +99,9 @@ pub trait VestingSchedule<AccountId> {
 
 	/// Remove a vesting schedule for a given account.
 	///
+	/// Parameter `schedule_index` is only applicable for implementations that
+	/// support multiple schedules.
+	///
 	/// NOTE: This doesn't alter the free balance of the account.
-	fn remove_vesting_schedule(who: &AccountId);
+	fn remove_vesting_schedule(who: &AccountId, schedule_index: Option<u32>) -> DispatchResult;
 }

frame/vesting/README.md

@@ -15,6 +15,8 @@ equivalent to the amount remaining to be vested. This is done through a dispatch
 either `vest` (in typical case where the sender is calling on their own behalf) or `vest_other`
 in case the sender is calling on another account's behalf.
 
+A user can have multiple vesting schedules, which are capped by an upper bound. With an upper bound
+>= 2, users can merge 2 schedules.
 ## Interface
 
 This module implements the `VestingSchedule` trait.
@@ -24,8 +26,9 @@ This module implements the `VestingSchedule` trait.
 - `vest` - Update the lock, reducing it in line with the amount "vested" so far.
 - `vest_other` - Update the lock of another account, reducing it in line with the amount
   "vested" so far.
+- `merge_schedules` - Merge two vesting schedules together, creating a new vesting schedule that
+   over the "worst case" duration.
 
 [`Call`]: ./enum.Call.html
 [`Config`]: ./trait.Config.html
-
 License: Apache-2.0