XXX: Codegen export decoding type for the result call

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

codegen/src/api/runtime_api.rs

@@ -48,6 +48,9 @@ fn generate_trait_api(
         let params = inputs.iter().map(|(param, _)| param);
         let encoded = inputs.iter().map(|(_, encoded)| encoded);
 
+        let method_target = format_ident!("{}_target", &method.name);
+        let output = type_gen.resolve_type_path(method.output.id());
+
         quote!(
             #( #[doc = #docs ] )*
             pub fn #method_name( #( #params, )* ) -> #crate_path::runtime_api::RuntimeAPIPayload {
@@ -60,6 +63,8 @@ fn generate_trait_api(
                     [0; 32],
                 )
             }
+
+            pub type #method_target = #output;
         )
     }).collect();
 

examples/examples/runtime_calls.rs

@@ -24,7 +24,7 @@ use subxt::{
     OnlineClient,
 };
 
-use codec::Encode;
+use codec::Decode;
 
 #[subxt::subxt(runtime_metadata_url = "http://localhost:9933")]
 pub mod polkadot {}
@@ -40,6 +40,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let bytes = api.runtime_api().at(None).await?.call(api_tx).await?;
 
     println!("Result: {:?}", bytes);
+    let result: polkadot::runtime_api::Core::version_target =
+        Decode::decode(&mut &bytes[..])?;
+
+    println!("Result is: {:?}", result);
 
     Ok(())
 }