Latest release bugs (v0.3.1506) missing unsafe errors : when using `bit_flags` and derive traits

[hnyls2002]

rust-analyzer version: rust-analyzer version: 0.3.1506-standalone

rustc version: rustc 1.64.0-nightly (f6f9d5e73 2022-08-04)

relevant settings:

This is my cargo

[package]
name = "os"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
riscv = { git = "https://github.com/rcore-os/riscv", features = ["inline-asm"] }
bitflags = "1.2.1"
lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
xmas-elf = "0.7.0"

[features] 
default = ["larger_memory"]

# for larger memory to load app's elf file with debug symbols
larger_memory = []

# for loggers
NoneLog = []
Error = []
Warn = ["Error"]
Debug = ["Warn"]
Info = ["Debug"]
Trace = ["Info"]

[profile.release]
debug = true

Today when I open my vscode to check my repo, I found there are so many rust errors appears. They are all

this operation is unsafe and requires an unsafe function or block

which appear at

bitflags! {
    pub struct PTEFlags : usize{
        const V = 1 << 0; // valid
        const R = 1 << 1; // readable
        const W = 1 << 2; // writable
        const X = 1 << 3; // executable
        const U = 1 << 4; // user
        const G = 1 << 5; // global
        const A = 1 << 6; // accessed
        const D = 1 << 7; // dirty
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]

This is the shoot cut

I don't know why...

[hnyls2002]

The reporting errors are like these

[hnyls2002]

When I rollback my rust-analyzer version from v0.3.1506 to v0.3.1498, this problem solved!

I think this could be a bug for the latest version released yesterday, even #[derive(Debug, Copy, Clone, Eq, PartialEq)] will cause errors...

[lnicola]

Possibly caused by #14725, but it doesn't seem to happen every time.

[HKalbasi]

Which trait(s) causes the error? Can someone post the result of Expand macro recursively on that trait?

[hnyls2002]

Sorry about my previous description about the macro, I just mixed up lazy_static with bit_flags, where the warnings show is actually the macro bit_flags but not lazy_static.

And I have checked the traits, I found when only Debug, Copy, Clone, there is no warning.

It seems that Eq, PartialEq, Ord, PartialOrd four traits causes the warning, and on each block the number of warnings are multiples of four.

Also, in the lazy_static macro, I clicked into it, and I also found that :

Maybe that's where the problems occur...

[HKalbasi]

I can't reproduce this on lazy_static and bit_flags alone, and I'm not sure how to mix them. An standalone reproduction would help.

[Aeledfyr]

I reproduced this just using slotmap's new_key_type, and then simplified it further:

#[derive(PartialOrd, Ord, PartialEq, Eq)]
struct Number(u32);

This fails with "this operation is unsafe and requires an unsafe function or block"

Expanding the Ord implementation results in this:

impl core::cmp::Ord for Number {
    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
        match core::intrinsics::discriminant_value(self)
            .cmp(&core::intrinsics::discriminant_value(other))
        {
            core::cmp::Ordering::Equal => match (self, other) {
                (Number(f0_self), Number(f0_other)) => match f0_self.cmp(&f0_other) {
                    core::cmp::Ordering::Equal => core::cmp::Ordering::Equal,
                    c => return c,
                },
                _unused => core::cmp::Ordering::Equal,
            },
            c => return c,
        }
    }
}

And rust-analyzer is treating core::intrinsics::discriminant_value as unsafe. (Are the reproduction issues with rustc version / standard library source version mismatches?)

(I am using rust-analyzer 0.3.1506-standalone in vscode)

[hnyls2002]

I can't reproduce this on lazy_static and bit_flags alone, and I'm not sure how to mix them. An standalone reproduction would help.

Sorry to bother you, my English is not so good. When I mentioned I mixed lazy_static and bit_flags, I didn't mean that I mixed them in my code, but I just wrote the wrong name in this issue. ( The errors occur at bit_flags, and have nothing to do with lazy_static in my project)

[Veykril]

This is indeed an issue with pre 1.69 rust versions, rust-lang/rust#100719 we rely on the safe intrinsic attribute which was introduced in 1.69 it seems

[Victor-N-Suadicani]

Just stumbled onto this as well. rustup update does indeed fix it, if you're in a position where you can upgrade your Rust version that is.

[Aeledfyr]

What version range of rust does rust-analyzer support? If it's only the latest stable then I guess this can stay closed, but otherwise this issue should be reopened, as the underlying issue is still there.