rust-lang / rust-lang/rust-analyzer
`mismatched-arg-count` false positive in example with `required-features`
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Description
rust-analyzer version: 0.3.1238-standalone (61504c8d9 2022-10-08)
rustc version: 1.64.0 (a55dd71d5 2022-09-19)
I'm getting an error in the example for the following crate, even though it runs fine:
Cargo.toml
[package]
name = "bevy_test" # Not actually Bevy-related
version = "0.1.0"
edition = "2021"
[features]
feature = []
[[example]]
name = "example"
required-features = [ "feature" ]
src/lib.rs
#[derive(Default)]
pub struct Struct<T>(T);
impl Struct<Type1> {
pub fn do_stuff(&self) {}
}
#[cfg(feature = "feature")]
impl Struct<Type2> {
pub fn do_stuff(&self, _: i32) {}
}
#[derive(Default)]
pub struct Type1;
#[cfg(feature = "feature")]
#[derive(Default)]
pub struct Type2;
examples/example.rs (run with cargo run --example example --features feature)
use bevy_test::{Struct, Type2};
fn main() {
Struct::<Type2>::default().do_stuff(0); // expected 0 arguments, found 1 rust-analyzer(mismatched-arg-count)
}
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Research direction
Reproduce the diagnostic with the provided Cargo.toml, src/lib.rs, and examples/example.rs using cargo run --example example --features feature. Then trace how rust-analyzer handles required-features and conditional implementations; done means the valid call no longer reports mismatched-arg-count under the enabled feature.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100