disallowed-methods not working

[xxchan]

Summary

# in clippy.toml
disallowed-methods = [
     "std::boxed::Box::new"
]

// in main.rs

fn main() {
    let _box = Box::new(3); 
}

no warning

❯ cargo clean; cargo clippy 
    Checking nono v0.1.0 (D:\tmp\nono)
    Finished dev [unoptimized + debuginfo] target(s) in 0.25s

Lint Name

disallowed-methods

Reproducer

No response

Version

rustc 1.58.1 (db9d1b20b 2022-01-20)
binary: rustc
commit-hash: db9d1b20bba1968c1ec1fc49616d4742c1725b4b
commit-date: 2022-01-20
host: x86_64-pc-windows-msvc
release: 1.58.1
LLVM version: 13.0.0

also for 

rustc 1.61.0-nightly (1eb72580d 2022-03-08)
binary: rustc
commit-hash: 1eb72580d076935a3e590deb6e5813a5aef3eca4
commit-date: 2022-03-08
host: x86_64-unknown-linux-gnu
release: 1.61.0-nightly
LLVM version: 14.0.0

[Jarcho]

The proper path for Box is alloc::boxed::Box. std just re-exports it. It would be nice if it worked, but I don't think we have easy access to re-exported names from clippy.

Edit: re-exported paths work fine.

[xxchan]

This is from the example: https://rust-lang.github.io/rust-clippy/master/#disallowed_methods

Btw I also tried std::time::Instant::now, but it also didn't work. I felt it strange, and was not sure whether it's my problem...

[xxchan]

I tried v1.49.0, which is the first version supporting disallowed_methods. But it also didn't work.🤨

[Jarcho]

Just tested on 1.59.0. It works with both std::boxed::Box::new and alloc::boxed::Box::new. I had to explicitly enable the lint though.

[xxchan]

Oh indeed. I misunderstood the clippy config file... Thank you for your hint.

Now it works fine for Box::new.

But the method I actually wanted to disallow is fixedbitset::FixedBitSet::from_iter. It seems that the trait method cannot be disallowed?

[Jarcho]

The lint is /supposed/ to be enabled by default. I don't know what's happening there.

For trait methods it might only work if you name the method on the trait itself, rather than on the type that implements it. Less than useful in this case, unfortunately.

[xxchan]

I found actually it works on v1.61.0-nightly. (Before I just tested the from_iter but not Box on 1.61`) It may because #8261 is quite recent.

Anyway thanks for your help @Jarcho!

[Jarcho]

Just opened #8581 about disallowing methods on trait impls.