fix(contract): rm IntoFuture for CallBuilder

[yash-atreya]

Motivation

Contract calls like contract.balanceOf cannot be directly awaited despite the IntoFuture impl as it requires Self: 'static. Ref: rust-lang/rust#63063.

Awaiting calls results in an ambiguous error for users. See https://t.me/ethers_rs/43016.

let bal = contract.balanceOf(addr).await.unwrap()
// Error: argument requires that borrow lasts for `'static`

The appropriate way to call a contract is:

let bal = contract.balanceOf(addr).call().await.unwrap();

The above error doesn't suggest this.

Solution

Remove the IntoFuture impl for CallBuilder.

Users now have to use .call(). Moreover, using .await results in a slightly better error: CallBuilder is not a future.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

what does this type borrow, do we have an example here?

[DaniPopes]

call() takes &self

[DaniPopes]

let me have one last look to see if i can make this work

[mattsse]

ngl the lifetimes of the ethcall type are a bit confusing

[DaniPopes]

It could be fixable with implementing for &CallBuilder but then .await does not auto borrow so you would have to do (&callbuilder).await

[DaniPopes]

lgtm, let's open an issue to track re-adding this impl