Error code E0744

An unsupported expression was used inside a const context.

Erroneous code example:

#![allow(unused)]
fn main() {
const _: i32 = {
    async { 0 }.await
};
}
ⓘ

At the moment, .await is forbidden inside a const, static, or const fn.

This may be allowed at some point in the future, but the implementation is not yet complete. See the tracking issue for async in const fn.