fix(abigen): ensure correct ABI in `From` impl (#2036)

* fix(abigen): ensure correct ABI in `From` impl

`new` creates a `Contract` with the correct ABI, but the `From` impl
simply wraps the source `Contract`, which could have a completely
different ABI. In effect this was an unsafe cast, and indeed was
observed to trigger a "method not found (this should never happen)"
panic for subsequent method lookups. Implementing `From` in terms of
`new` fixes this, at the cost of an extra `Arc::clone()` (which I can't
see how to eliminate without piercing the `ethers::contract::Contract`
public API).

* Remove unnecessary `async` from test

Co-authored-by: DaniPopes <57450786+DaniPopes@users.noreply.github.com>

Co-authored-by: DaniPopes <57450786+DaniPopes@users.noreply.github.com>

ethers-contract/ethers-contract-abigen/src/contract.rs

@@ -150,7 +150,7 @@ impl Context {
                     /// client at the given `Address`. The contract derefs to a `ethers::Contract`
                     /// object
                     pub fn new<T: Into<#ethers_core::types::Address>>(address: T, client: ::std::sync::Arc<M>) -> Self {
-                        #ethers_contract::Contract::new(address.into(), #abi_name.clone(), client).into()
+                        Self(#ethers_contract::Contract::new(address.into(), #abi_name.clone(), client))
                     }
 
                     #deployment_methods
@@ -163,7 +163,7 @@ impl Context {
 
                 impl<M : #ethers_providers::Middleware> From<#ethers_contract::Contract<M>> for #name<M> {
                     fn from(contract: #ethers_contract::Contract<M>) -> Self {
-                       Self(contract)
+                       Self::new(contract.address(), contract.client())
                     }
                 }
         };

ethers-contract/tests/it/abigen.rs

@@ -750,3 +750,21 @@ fn can_handle_overloaded_function_with_array() {
     ]"#,
     );
 }
+
+#[test]
+fn convert_uses_correct_abi() {
+    abigen!(
+        Foo, r#"[function foo()]"#;
+        Bar, r#"[function bar()]"#;
+    );
+
+    let provider = Arc::new(Provider::new(MockProvider::new()));
+    let foo = Foo::new(Address::default(), Arc::clone(&provider));
+
+    let contract: &ethers_contract::Contract<_> = &foo;
+    let bar: Bar<Provider<MockProvider>> = contract.clone().into();
+
+    // Ensure that `bar` is using the `Bar` ABI internally (this method lookup will panic if `bar`
+    // is incorrectly using the `Foo` ABI internally).
+    bar.bar().call();
+}