Incorrect link attibute allowed

[bjorn3]

#[link="reiojregioergioregiojrge"]
extern "C" {}

fn main() {}

(Playground)

Output:

   Compiling playground v0.0.1 (file:///playground)
    Finished dev [unoptimized + debuginfo] target(s) in 1.18s
     Running `target/debug/playground`

[varkor]

Nominating for team discussion because it seems bad that this is silently ignored, but we can't make this an error without breaking code that currently compiles on stable (see the discussion in #57139).

The pull request #57139 adds an allow-by-default future incompatibility lint for #[link = "name"]: it would be good to check this is the best solution.

[varkor]

We're going to wait until #57321 lands and then following up on any part of this issue that doesn't fix, separately.

[varkor]

The example in the original post now produces a warning, but more subtle issues covered by #57139, such as duplicate parameters are still not warned, so it's worth keeping this issue open until that's addressed.

[bjorn3]

Fixed:

error: attribute must be of the form `#[link(name = "...", /*opt*/ kind = "dylib|static|...", /*opt*/ cfg = "...")]`
 --> src/main.rs:1:1
  |
1 | #[link="reiojregioergioregiojrge"]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[deny(ill_formed_attribute_input)]` on by default
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #57571 <https://github.com/rust-lang/rust/issues/57571>

error: aborting due to previous error