wrong_self_convention possibly too strict for Copy types

[martin-t]

Lint name: wrong_self_convention

I tried this code:

trait F32Ext {
    fn to_something_else(self) -> f32;
}

I get this:

warning: methods called `to_*` usually take self by reference; consider choosing a less ambiguous name
  --> src/main.rs:66:21
   |
66 |     fn to_some_unit(self) -> f32;
   |                     ^^^^
   |

If this trait is implemented for types such as f32, then i think the to_ prefix makes complete sense - f32 already has methods with that prefix and it makes no sense to take such a small type by reference.

I think this lint should allow to_ on Copy types to take self without reference.

Meta

cargo clippy -V: clippy 0.1.52 (e9920ef 2021-02-11)
rustc -Vv:

rustc 1.52.0-nightly (e9920ef77 2021-02-11)
binary: rustc
commit-hash: e9920ef7749d11fc71cc32ca4ba055bcfeaab945
commit-date: 2021-02-11
host: x86_64-unknown-linux-gnu
release: 1.52.0-nightly
LLVM version: 11.0.1

[baumanj]

I agree this is a false positive per https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv. A owned -> owned conversion for Copy should use to, rather than into as the prefix.

[mgacek8]

@rustbot claim