"cannot produce proc-macro for crate as the target x86_64-unknown-linux-gnu does not support these crate types" with +crt-static

[youknowone]

This issue looks like the same one but closed #78210. I am creating a new issue because I don't know if it was fixed at that time or won't be fixed or just closed by accident.

Crate code

I created an empty project with this Cargo.toml file.

[package]
name = "broken"
version = "0.1.0"
edition = "2018"

[dependencies]
async-trait = "*"

[lib]
name = "broken"
crate-type = ["staticlib", "rlib"]

And tried to build with

RUSTFLAGS="-C target-feature=+crt-static" cargo build

I expected to see this happen: successful build

Instead, this happened:

error: cannot produce proc-macro for `async-trait v0.1.48` as the target `x86_64-unknown-linux-gnu` does not support these crate types

Version it worked on

It most recently worked on: 1.48

Version with regression

It doesn't work since 1.49 only in Linux.
It still works on macOS with any rust version.

rustc --version --verbose:

rustc 1.51.0 (2fd73fabe 2021-03-23)
binary: rustc
commit-hash: 2fd73fabe469357a12c2c974c140f67e7cdd76d0
commit-date: 2021-03-23
host: x86_64-unknown-linux-gnu
release: 1.51.0
LLVM version: 11.0.1

[jyn514]

I am creating a new issue because I don't know if it was fixed at that time or won't be fixed or just closed by accident.

It says at the end of the issue:

I don't believe we're intending to fix this.

[youknowone]

Thank you to make it clear. I thought it may meant it was unintentionally fixed by the upper PR.