`disallowed_methods` false positive `instant::Instant` vs `std::time::Instant`

[emilk]

Summary

I want to forbid std::time::Instant::now, because it doesn't work on web/wasm:

❯ cat clippy.toml 
disallowed-methods = ["std::time::Instant::now"]

Instead I want to use https://crates.io/crates/instant

However, when I use instant::Instant::now I get a false-positive error.

Lint Name

disallowed_methods

Reproducer

I tried this code:

fn main() {
    instant::Instant::now();
}

I saw this happen:

warning: use of a disallowed method `std::time::Instant::now`
 --> src/main.rs:2:15
  |
2 |     let now = instant::Instant::now();
  |               ^^^^^^^^^^^^^^^^^^^^^^^
  |

I expected to see this happen: No warning

Version

rustc 1.67.1 (d5a82bbd2 2023-02-07)
binary: rustc
commit-hash: d5a82bbd26e1ad8b7401f6a718a9c57c96905483
commit-date: 2023-02-07
host: aarch64-apple-darwin
release: 1.67.1
LLVM version: 15.0.6

Additional Labels

No response

[Jarcho]

This may not be fixable. instant::Instant is an alias to std::time::Instant on everything but wasm.

[emilk]

Oh right, of course… that’s interesting. I guess I would need to only disallow std::time::Instant on wasm32, which isn’t possible afaict. Or make a PR to instant to turn instant::Instant into a thin newtype instead. Thanks for the explanation!

[waynexia]

Another lint disallowed_types seems to work. Here is our case for forbidding std::time::Instant apache/datafusion@edb67fa

clippy.toml:

disallowed-types = [
    { path = "std::time::Instant", reason = "" },
]