[Suggestion] Improve API around (single) unnamed return values

[zerosnacks]

Component

contract

Describe the feature you would like

Follow up from conversation: alloy-rs/examples#8 (comment)

Consider the following:

 let Counter::numberReturn { _0 } = contract.number().call().await?;

Where Counter is implemented as follows:

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}

It would be preferable to either:

• Be able to assign this return directly to a value (let ret = contract.number().call().await?;)
• Or be able to rename the return value _0 into a user defined value

Additional context

Any changes will be reflected in alloy/examples

[mattsse]

having an unwrapped return type would be more convenient,
I think we can check this when analyzing the abi and check the outputs, if it's just a single type, use that

[prestwich]

we can, but it breaks encoding symmetry for any case where (T,) and T have different abi encodings, which would need to be accounted for

[DaniPopes]

We deemed the current API consistent and good enough. This change would require some specific workarounds and maybe hard to do in the current type system.

If you want return types to have a "nicer name" in functions, you can name them in the returns (...) tuple.

The example in the issue already has a named return value due to it being an elementary type getter:

core/crates/sol-types/tests/macros/sol/mod.rs

Lines 242 to 255 in b4ca4fe

	fn getter_names() {
	sol! {
	contract Getters {
	string public value;
	string[] public array;
	mapping(bytes32 => string) public map;
	mapping(bytes32 k => string v) public mapWithNames;
	mapping(bytes32 k1 => mapping(uint256 k2 => string v2) v1) public nestedMapWithNames;
	}
	}
	let _ = Getters::valueCall {};
	let _ = Getters::valueReturn { value: String::new() };