Add 'Static' type and improve type substitution codegen to accept it (#886)

* Add Static type which defers to Encode/Decode and impls EncodeAsType/DecodeAsType

* rename to static_type and impl Deref/Mut

* Improve type substitution in codegen so that concrete types can be swapped in

* A couple of comment tweaks and no need for a macro export

* Extend type substitution logic to work recursively on destination type

* cargo fmt

* Fix a couple of comments

* update ui test outpuot

* Add docs and missing_docs lint

* Add test for replacing multiple of Ident

* Update codegen/src/error.rs

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>

* update copyright year and fix ui test

* simplify another error

---------

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>

subxt/src/storage/mod.rs

@@ -1,4 +1,4 @@
-// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
@@ -21,7 +21,8 @@ pub use crate::rpc::types::StorageKey;
 /// entry lives and how to properly decode it.
 pub mod address {
     pub use super::storage_address::{
-        dynamic, dynamic_root, Address, DynamicAddress, StaticStorageMapKey, StorageAddress, Yes,
+        dynamic, dynamic_root, make_static_storage_map_key, Address, DynamicAddress,
+        StaticStorageMapKey, StorageAddress, Yes,
     };
 }
 

subxt/src/storage/storage_address.rs

@@ -1,4 +1,4 @@
-// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
@@ -6,6 +6,7 @@ use crate::{
     dynamic::{DecodedValueThunk, Value},
     error::{Error, StorageAddressError},
     metadata::{DecodeWithMetadata, EncodeWithMetadata, Metadata},
+    utils::{Encoded, Static},
 };
 use frame_metadata::{StorageEntryType, StorageHasher};
 use scale_info::TypeDef;
@@ -211,26 +212,12 @@ where
 
 /// A static storage key; this is some pre-encoded bytes
 /// likely provided by the generated interface.
-pub struct StaticStorageMapKey(pub Vec<u8>);
+pub type StaticStorageMapKey = Static<Encoded>;
 
-impl StaticStorageMapKey {
-    /// Create a new [`StaticStorageMapKey`] by pre-encoding static data.
-    pub fn new<Encodable: codec::Encode>(value: Encodable) -> StaticStorageMapKey {
-        Self(value.encode())
-    }
-}
-
-impl EncodeWithMetadata for StaticStorageMapKey {
-    fn encode_with_metadata(
-        &self,
-        _type_id: u32,
-        _metadata: &Metadata,
-        bytes: &mut Vec<u8>,
-    ) -> Result<(), Error> {
-        // We just use the already-encoded bytes for a static storage key:
-        bytes.extend(&self.0);
-        Ok(())
-    }
+// Used in codegen to construct the above.
+#[doc(hidden)]
+pub fn make_static_storage_map_key<T: codec::Encode>(t: T) -> StaticStorageMapKey {
+    Static(Encoded(t.encode()))
 }
 
 /// Construct a new dynamic storage lookup to the root of some entry.

subxt/src/storage/storage_client.rs

@@ -1,4 +1,4 @@
-// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 

subxt/src/storage/storage_type.rs

@@ -1,4 +1,4 @@
-// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 

subxt/src/storage/utils.rs

@@ -1,4 +1,4 @@
-// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.