Define ss58 prefix inside the runtime (#7810)

* Add SS58Prefix type to the frame_system config trait

* Remove unused chain_id runtime interface

substrate/frame/system/src/lib.rs

@@ -257,6 +257,13 @@ pub trait Config: 'static + Eq + Clone {
 	type OnKilledAccount: OnKilledAccount<Self::AccountId>;
 
 	type SystemWeightInfo: WeightInfo;
+
+	/// The designated SS85 prefix of this chain.
+	///
+	/// This replaces the "ss58Format" property declared in the chain spec. Reason is
+	/// that the runtime should know about the prefix in order to make use of it as
+	/// an identifier of the chain.
+	type SS58Prefix: Get<u8>;
 }
 
 pub type DigestOf<T> = generic::Digest<<T as Config>::Hash>;
@@ -516,6 +523,13 @@ decl_module! {
 		/// The weight configuration (limits & base values) for each class of extrinsics and block.
 		const BlockWeights: limits::BlockWeights = T::BlockWeights::get();
 
+		/// The designated SS85 prefix of this chain.
+		///
+		/// This replaces the "ss58Format" property declared in the chain spec. Reason is
+		/// that the runtime should know about the prefix in order to make use of it as
+		/// an identifier of the chain.
+		const SS58Prefix: u8 = T::SS58Prefix::get();
+
 		fn on_runtime_upgrade() -> frame_support::weights::Weight {
 			if !UpgradedToU32RefCount::get() {
 				Account::<T>::translate::<(T::Index, u8, T::AccountData), _>(|_key, (nonce, rc, data)|

substrate/frame/system/src/mock.rs

@@ -117,6 +117,7 @@ impl Config for Test {
 	type OnNewAccount = ();
 	type OnKilledAccount = RecordKilled;
 	type SystemWeightInfo = ();
+	type SS58Prefix = ();
 }
 
 pub type System = Module<Test>;