rustc has stopped emitting unused `repr`/`link`/`panic_handler` attribute lints on macro invocations

[mejrs]

Code

I tried this code:

macro_rules! produce_struct {
    ($name: ident) => {
        pub struct $name {}
    };
}

#[repr(align(64))]
produce_struct!(Foo);

const _: () = assert!(align_of::<Foo>() == 1);

I expected to see this happen: program accepted, with warnings

warning: unused attribute `repr`
 --> <source>:7:1
  |
7 | #[repr(align(64))]
  | ^^^^^^^^^^^^^^^^^^
  |
  = note: -Ztrack-diagnostics: created at /rustc-dev/1159e78c4747b02ef996e55082b704c09b970588/compiler/rustc_lint/src/early.rs:40:26
note: the built-in attribute `repr` will be ignored, since it's applied to the macro invocation `produce_struct`
 --> <source>:8:1
  |
8 | produce_struct!(Foo);
  | ^^^^^^^^^^^^^^
  = note: `#[warn(unused_attributes)]` on by default

Instead, this happened: program accepted, no warnings issued

Version it worked on

It most recently worked on: rust 1.90 and earlier: https://rust.godbolt.org/z/Wzf519Wbv

Version with regression

1.91 and up, including current beta and nightly

The following attributes are also affected, this compiles without warnings (save for incomplete_features).

#![allow(incomplete_features)]
#![feature(dropck_eyepatch)]
#![feature(export_stable)]
#![feature(register_tool)]
#![feature(sanitize)]

macro_rules! produce_struct {
    ($name: ident) => {
        pub struct $name {}
    };
}

#[repr(align(64))]
#[sanitize(address = "off")]
#[register_tool(blah)]
#[link(name = "foo")]
#[export_stable]
#[panic_handler]
#[may_dangle]
produce_struct!(Foo);

[apiraino]

bisection points to these patches, though I am not immediately identifying one that is relevant 🤔

commit[0] 2025-08-24: Auto merge of #137229 - GuillaumeGomez:expand-macro, r=lolbinarycat
commit[1] 2025-08-24: Auto merge of #145262 - compiler-errors:prefer-only-param, r=lcnr
commit[2] 2025-08-25: Auto merge of #145480 - cjgillot:sizeless-chunks, r=Mark-Simulacrum
commit[3] 2025-08-25: Auto merge of #145844 - Zalathar:rollup-4kdll9t, r=Zalathar
commit[4] 2025-08-25: Auto merge of #145472 - Kobzol:bootstrap-dist, r=jieyouxu

[bjorn3]

Maybe #145788?

[mejrs]

As part of the attribute parsing rework we moved many checks that were done at various points during compilation to check_attr, but this pass works on hir, so after macro expansion.

Presumably any attribute that checks their target at https://github.com/rust-lang/rust/blob/main/compiler/rustc_passes/src/check_attr.rs#L172 does not handle macro invocations correctly (this includes repr).

Similarly,

#[diagnostic::on_unimplemented(message = "baz")]
produce_trait!(X);

has always silently done nothing. But I changed diagnostic attributes to do their target checking during attribute parsing and (unknowingly) fixed it to emit a warning.

[apiraino]

Maybe #145788?

Thanks, it was nested in the rollup (sigh)

cc: @jdonszelmann since author of #145788

[rustbot]

Assigning P-high (discussion on Zulip).