[core] Constrain invoke_runtime parameter (#302)

* Constrain invoke_runtime parameter

* Change param to a reference

* Dangling type param

core/src/env2/srml/impls.rs

@@ -349,10 +349,9 @@ where
         ext::deposit_event(topics, data);
     }
 
-    fn invoke_runtime<O, V>(buffer: &mut O, call_data: &V)
+    fn invoke_runtime<O>(buffer: &mut O, call_data: &<Self as EnvTypes>::Call)
     where
         O: scale::Output + AsRef<[u8]> + Reset,
-        V: scale::Encode,
     {
         buffer.reset();
         call_data.encode_to(buffer);

core/src/env2/test/accessor.rs

@@ -65,6 +65,7 @@ use crate::{
     },
     storage::Key,
 };
+use scale::Encode;
 
 thread_local! {
     /// The single thread-local test environment instance.
@@ -420,10 +421,9 @@ where
         })
     }
 
-    fn invoke_runtime<O, V>(_buffer: &mut O, call_data: &V)
+    fn invoke_runtime<O>(_buffer: &mut O, call_data: &<Self as EnvTypes>::Call)
     where
         O: scale::Output + AsRef<[u8]> + Reset,
-        V: scale::Encode,
     {
         // With the off-chain test environment we have no means
         // to emit an event on the chain since there is no chain.

core/src/env2/traits.rs

@@ -147,10 +147,9 @@ pub trait Env:
         Event: Topics<Self> + scale::Encode;
 
     /// Invokes a runtime dispatchable function with the given call data.
-    fn invoke_runtime<O, V>(buffer: &mut O, call_data: &V)
+    fn invoke_runtime<O>(buffer: &mut O, call_data: &<Self as EnvTypes>::Call)
     where
-        O: scale::Output + AsRef<[u8]> + Reset,
-        V: scale::Encode;
+        O: scale::Output + AsRef<[u8]> + Reset;
 
     /// Restores the contract to the given address.
     ///