================================================================================
Async function
================================================================================

async fn abc() {}

async fn main() {
    let x = futures.await?;
}

--------------------------------------------------------------------------------

(source_file
  (function_item
    (function_modifiers)
    (identifier)
    (parameters)
    (block))
  (function_item
    (function_modifiers)
    (identifier)
    (parameters)
    (block
      (let_declaration
        (identifier)
        (try_expression
          (await_expression
            (identifier)))))))

================================================================================
Await expression
================================================================================

futures.await;
futures.await?;
futures.await?.await?;
futures.await?.function().await?;

--------------------------------------------------------------------------------

(source_file
  (expression_statement
    (await_expression
      (identifier)))
  (expression_statement
    (try_expression
      (await_expression
        (identifier))))
  (expression_statement
    (try_expression
      (await_expression
        (try_expression
          (await_expression
            (identifier))))))
  (expression_statement
    (try_expression
      (await_expression
        (call_expression
          (field_expression
            (try_expression
              (await_expression
                (identifier)))
            (field_identifier))
          (arguments))))))

================================================================================
Async Block
================================================================================

async {}
async { let x = 10; }
async move {}

--------------------------------------------------------------------------------

(source_file
  (expression_statement
    (async_block
      (block)))
  (expression_statement
    (async_block
      (block
        (let_declaration
          (identifier)
          (integer_literal)))))
  (expression_statement
    (async_block
      (block))))