Deprecated ignored if `since` > rust version and has patch

[ascjones]

When since > version of rustc and patch is in the version then deprecated is ignored:

My expectation is that: since is referring to the version of my crate, not the rustc version.

struct Bar {}
impl Bar {
    #[deprecated(since = "1.32.0")]
    fn patch_works(&self) -> () { () }
    
    #[deprecated(since = "1.33.0")]
    fn patch_ignored1(&self) -> () { () }
    
    #[deprecated(since = "2.1.0")]
    fn patch_ignored2(&self) -> () { () }
    
    #[deprecated(since = "2.0")]
    fn minor_works(&self) -> () { () }
}

fn main() {
    let bar = Bar { };
    bar.patch_works();
    bar.patch_ignored1();
    bar.patch_ignored2();
    bar.minor_works();
}

(Playground)

The docs say:

since expects a version number, as in #[deprecated(since = "1.4.1")]
rustc doesn't know anything about versions, but external tools like clippy may check the validity of this field.

[varkor]

Version numbers are according to semantic versioning, in which there must be three components. 2.0 is not a valid version number and as such as ignored.

[ascjones]

@varkor the deprecated attribute works as expected with 2.0 (see the example). It is when it has all three major.minor.patch (and is greater than 1.32.0) that it is ignored.

[varkor]

If you add #![warn(deprecated_in_future)] to the example (on Beta or Nightly), then it will warn for future versions too.

[jonas-schievink]

I think that part is only supposed to be used by libstd and not by user crates. All of these examples should warn by default. (it doesn't really make sense to deprecate things in a crate based on the Rust version)

[varkor]

it doesn't really make sense to deprecate things in a crate based on the Rust version

Ah, that's true. Maybe it does make more sense to always warn in this case.

[ascjones]

it doesn't really make sense to deprecate things in a crate based on the Rust version

Exactly. My understanding from the docs for the deprecation attribute is that since should refer to the version of my crate - nothing to do with the version of rustc.

Sorry for not being clear enough originally - the problem was I was troubleshooting why a #[deprecated] attribute I had applied was being ignored and I narrowed it down to the cases in the example - and that's when I noticed that it seemed to relate to the rustc version, which looks like a bug, and decided to report it.

I will update the description