`eq_op` lint in clippy is confusing for floats

Summary

Clippy suggests the eq_op lint in cases where it's not clear how to fix the underlying problem.

I was looking at libm's code (https://github.com/rust-lang/libm/tree/cb2ffdf5435d3302c97a27c8ce7de48e214de037). For this block (https://github.com/rust-lang/libm/blob/cb2ffdf5435d3302c97a27c8ce7de48e214de037/src/math/sinf.rs#L81-L83), clippy shows an error, because this triggers the eq_op lint: https://rust-lang.github.io/rust-clippy/master/index.html#/eq_op.

In my mind, this makes sense, since x - x should always be 0. But, if I swap the line return x - x; to return 0.0;, tests fail immediately in the repo.

thread 'sinf_matches_musl' panicked at /home/takashi/.build/debug/build/libm-33ae80df27fee36a/out/musl-tests.rs:71754:9:
INPUT: [2139095040] EXPECTED: [4290772992] ACTUAL 0.0
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

as far as I can tell, the guard clause of if ix >= 0x7f800000 { means that x's bitwise representation is infinity or NaN, so the return can be return f32::NAN instead of return x - x;. This works because NaN - NaN and inf - inf are NaN: (https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=b060559e29d69eca8c424429b908ad27), and thus the tests pass again.

Is there a way to issue better diagnostics in this case / have the lint explain some common pitfalls with this lint when applied to floats? In the case of libm, return x - x; is intentional because it's basically doing x.is_nan() || x.is_infinite() before doing the operation, so return x - x; looks to be totally fine.

Reproducer

No response

Version

rustc 1.75.0 (82e1608df 2023-12-21)
binary: rustc
commit-hash: 82e1608dfa6e0b5569232559e3d385fea5a93112
commit-date: 2023-12-21
host: x86_64-unknown-linux-gnu
release: 1.75.0
LLVM version: 17.0.6

Additional Labels

No response

Start with Clippy's eq_op lint documentation and the libm example in src/math/sinf.rs at lines 81-83. Compare the lint's behavior with the cited sinf tests and the float cases described in the issue. Done means the diagnostic gives useful guidance or context for intentional float uses without losing the existing lint coverage.