Metadata V16: Be more dynamic over which hasher is used. (#1974)

* Use DynamicHasher256 to support Blake2 or Keccack depending on chain

* remove Config::Hash associated type, replace with HashFor<Config> alias

* Fix doc links

* fix wasm tests

* Don't strip system pallet associated types. check System.Hashing, not Hash. Rename BlockHash trait to Hash

* Tweak comment

* fmt

* fix merge

* Fix typo

subxt/src/runtime_api/runtime_client.rs

@@ -4,7 +4,12 @@
 
 use super::runtime_types::RuntimeApi;
 
-use crate::{backend::BlockRef, client::OnlineClientT, error::Error, Config};
+use crate::{
+    backend::BlockRef,
+    client::OnlineClientT,
+    config::{Config, HashFor},
+    error::Error,
+};
 use derive_where::derive_where;
 use std::{future::Future, marker::PhantomData};
 
@@ -31,7 +36,7 @@ where
     Client: OnlineClientT<T>,
 {
     /// Obtain a runtime API interface at some block hash.
-    pub fn at(&self, block_ref: impl Into<BlockRef<T::Hash>>) -> RuntimeApi<T, Client> {
+    pub fn at(&self, block_ref: impl Into<BlockRef<HashFor<T>>>) -> RuntimeApi<T, Client> {
         RuntimeApi::new(self.client.clone(), block_ref.into())
     }
 

subxt/src/runtime_api/runtime_types.rs

@@ -6,8 +6,8 @@ use super::Payload;
 use crate::{
     backend::{BackendExt, BlockRef},
     client::OnlineClientT,
+    config::{Config, HashFor},
     error::Error,
-    Config,
 };
 use codec::Decode;
 use derive_where::derive_where;
@@ -17,13 +17,13 @@ use std::{future::Future, marker::PhantomData};
 #[derive_where(Clone; Client)]
 pub struct RuntimeApi<T: Config, Client> {
     client: Client,
-    block_ref: BlockRef<T::Hash>,
+    block_ref: BlockRef<HashFor<T>>,
     _marker: PhantomData<T>,
 }
 
 impl<T: Config, Client> RuntimeApi<T, Client> {
     /// Create a new [`RuntimeApi`]
-    pub(crate) fn new(client: Client, block_ref: BlockRef<T::Hash>) -> Self {
+    pub(crate) fn new(client: Client, block_ref: BlockRef<HashFor<T>>) -> Self {
         Self {
             client,
             block_ref,