non-camel-case-types lint does not flag `repr(C)` types

Code

#![forbid(non_camel_case_types)]

#[repr(C)]
pub struct foo_bar {}

Current output

<no error>

Desired output

Compiling playground v0.0.1 (/playground)
error: type `foo_bar` should have an upper camel case name
 --> src/lib.rs:4:12
  |
4 | pub struct foo_bar {}
  |            ^^^^^^^ help: convert the identifier to upper camel case: `FooBar`
  |
note: the lint level is defined here
 --> src/lib.rs:1:11
  |
1 | #![forbid(non_camel_case_types)]
  |           ^^^^^^^^^^^^^^^^^^^^

error: could not compile `playground` (lib) due to 1 previous error

Rationale and extra context

This was clearly an explicit design choice at one point: https://github.com/rust-lang/rust/blob/81eef2d362a6f03db6f8928f82d94298d31eb81b/compiler/rustc_lint/src/nonstandard_style.rs#L170

Presumably, the idea was that you'd have a bunch of FFI types with their native C names, and that's what repr(C) is for. You wouldn't want this lint firing for such types.

But I don't think it's one that makes sense today. repr(C) is used any time you want a stable layout, not just when you're defining a C type for FFI. The lint should fire in all cases, and crates that define a bunch of C types should silence the lint where appropriate.

Other cases

Rust Version

> rustc --version --verbose
rustc 1.82.0 (f6e511eec 2024-10-15)
binary: rustc
commit-hash: f6e511eec7342f59a25f7c0534f1dbea00d01b14
commit-date: 2024-10-15
host: x86_64-unknown-linux-gnu
release: 1.82.0
LLVM version: 19.1.1

Anything else?

No response

Start with compiler/rustc_lint/src/nonstandard_style.rs, especially the lint handling linked in the issue, and reproduce the provided repr(C) example. Trace why the non_camel_case_types lint skips repr(C) types. Done means the example emits the expected upper-camel-case error while preserving the intended lint behavior elsewhere.