Function declaration requires `sized` lang item

[klutzy]

#![no_std]
fn main() {}

error: requires `sized` lang_item
error: aborting due to previous error

Not sure it's intended or not.

cc #15788

[japaric]

You need to add:

#[lang = "sized"]
trait Sized {}

to your source file. The error message should recommend that.

See #17392 and #17468

[alexcrichton]

I'll note that the intention for #![no_std] users is to almost always include an extern crate core which is intended to take care of problems such as this.

We may not want to invest too much energy into this as lang items are a feature gate as they're pretty unstable. They change pretty regularly and providing a high-quality experience is sadly just not a priority right now.

[alexcrichton]

I believe this is basically working as expected and otherwise I'm going to close this in favor of #27394