Make use of assimilate_storage for GenesisConfig (#1982)

* Make use of `assimilate_storage` for `GenesisConfig`

Fixes incorrect initialization of the staking gensis storage.

* Add some documentation

substrate/srml/staking/src/lib.rs

@@ -270,6 +270,7 @@ decl_storage! {
 		build(|storage: &mut primitives::StorageOverlay, _: &mut primitives::ChildrenStorageOverlay, config: &GenesisConfig<T>| {
 			with_storage(storage, || {
 				for &(ref stash, ref controller, balance) in &config.stakers {
+					assert!(T::Currency::free_balance(&stash) >= balance);
 					let _ = <Module<T>>::bond(T::Origin::from(Some(stash.clone()).into()), T::Lookup::unlookup(controller.clone()), balance, RewardDestination::Staked);
 					let _ = <Module<T>>::validate(T::Origin::from(Some(controller.clone()).into()), Default::default());
 				}

substrate/srml/staking/src/mock.rs

@@ -137,7 +137,16 @@ impl ExtBuilder {
 		let _ = balances::GenesisConfig::<Test>{
 			balances: if self.monied {
 				if self.reward > 0 {
-					vec![(1, 10 * balance_factor), (2, 20 * balance_factor), (3, 300 * balance_factor), (4, 400 * balance_factor), (10, balance_factor), (11, balance_factor * 1000), (20, balance_factor), (21, balance_factor * 2000)]
+					vec![
+						(1, 10 * balance_factor),
+						(2, 20 * balance_factor),
+						(3, 300 * balance_factor),
+						(4, 400 * balance_factor),
+						(10, balance_factor),
+						(11, balance_factor * 1000),
+						(20, balance_factor),
+						(21, balance_factor * 2000)
+					]
 				} else {
 					vec![(1, 10 * balance_factor), (2, 20 * balance_factor), (3, 300 * balance_factor), (4, 400 * balance_factor)]
 				}

substrate/srml/support/procedural/src/storage/transformation.rs

@@ -389,21 +389,6 @@ fn decl_store_extra_genesis(
 
 			#[cfg(feature = "std")]
 			impl#fparam #scrate::runtime_primitives::BuildStorage for GenesisConfig#sparam {
-
-				fn build_storage(self) -> ::std::result::Result<(#scrate::runtime_primitives::StorageOverlay, #scrate::runtime_primitives::ChildrenStorageOverlay), String> {
-					let mut r: #scrate::runtime_primitives::StorageOverlay = Default::default();
-					let mut c: #scrate::runtime_primitives::ChildrenStorageOverlay = Default::default();
-
-					{
-						use #scrate::rstd::{cell::RefCell, marker::PhantomData};
-						let storage = (RefCell::new(&mut r), PhantomData::<Self>::default());
-						#builders
-					}
-
-					#scall(&mut r, &mut c, &self);
-
-					Ok((r, c))
-				}
 				fn assimilate_storage(self, r: &mut #scrate::runtime_primitives::StorageOverlay, c: &mut #scrate::runtime_primitives::ChildrenStorageOverlay) -> ::std::result::Result<(), String> {
 					use #scrate::rstd::{cell::RefCell, marker::PhantomData};
 					let storage = (RefCell::new(r), PhantomData::<Self>::default());

substrate/srml/support/src/runtime.rs

@@ -62,6 +62,11 @@
 /// - `Inherent $( (CALL) )*` - If the module provides/can check inherents. The optional parameter
 ///                             is for modules that use a `Call` from a different module as
 ///                             inherent.
+///
+/// # Note
+///
+/// The population of the genesis storage depends on the order of modules. So, if one of your
+/// modules depends on another module. The dependent module need to come before the module depending on it.
 #[macro_export]
 macro_rules! construct_runtime {