fix clippy warnings in pyrefly_config

[jorenham]

Summary

I noticed there were some clippy warnings, which I thought was a bit annoying (maybe that's just me though), so I fixed them.

Before:

$ python test.py --no-test --no-conformance --no-jsonschema
Running formatting...
Finished in 1.28 seconds.
Running linting...
warning: module has the same name as its containing module
  --> crates/pyrefly_config/src/environment/mod.rs:10:1
   |
10 | pub mod environment;
   | ^^^^^^^^^^^^^^^^^^^^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#module_inception
   = note: `#[warn(clippy::module_inception)]` on by default

warning: this `if` statement can be collapsed
  --> crates/pyrefly_config/src/error.rs:41:9
   |
41 | /         if let Some(parent) = kind.parent_kind() {
42 | |             if let Some(&severity) = self.0.get(&parent) {
43 | |                 return severity;
44 | |             }
45 | |         }
   | |_________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
   = note: `#[warn(clippy::collapsible_if)]` on by default
help: collapse nested if block
   |
41 ~         if let Some(parent) = kind.parent_kind()
42 ~             && let Some(&severity) = self.0.get(&parent) {
43 |                 return severity;
44 ~             }
   |

warning: this `if` statement can be collapsed
  --> crates/pyrefly_config/src/error.rs:46:9
   |
46 | /         if let Some(alias) = kind.deprecated_alias() {
47 | |             if let Some(&severity) = self.0.get(&alias) {
48 | |                 return severity;
49 | |             }
50 | |         }
   | |_________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
help: collapse nested if block
   |
46 ~         if let Some(alias) = kind.deprecated_alias()
47 ~             && let Some(&severity) = self.0.get(&alias) {
48 |                 return severity;
49 ~             }
   |

warning: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
  --> crates/pyrefly_config/src/migration/mypy/regex_converter.rs:26:19
   |
26 |     fn to_strings(self) -> Vec<String> {
   |                   ^^^^
   |
   = help: consider choosing a less ambiguous name
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wrong_self_convention
   = note: `#[warn(clippy::wrong_self_convention)]` on by default

warning: methods with the following characteristics: (`to_*` and `self` type is not `Copy`) usually take `self` by reference
   --> crates/pyrefly_config/src/migration/pyright.rs:307:22
    |
307 |     pub fn to_config(self) -> Option<ErrorDisplayConfig> {
    |                      ^^^^
    |
    = help: consider choosing a less ambiguous name
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wrong_self_convention

warning: variant name ends with the enum's name
  --> crates/pyrefly_config/src/module_wildcard.rs:35:5
   |
35 |     NoMatch,
   |     ^^^^^^^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#enum_variant_names
   = note: `#[warn(clippy::enum_variant_names)]` on by default

warning: `pyrefly_config` (lib) generated 6 warnings (run `cargo clippy --fix --lib -p pyrefly_config` to apply 2 suggestions)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.11s
Finished in 0.16 seconds.

After:

$ python test.py --no-test --no-conformance --no-jsonschema
Running formatting...
Finished in 1.31 seconds.
Running linting...
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.12s
Finished in 0.17 seconds.

Test Plan

tests still pass

[NathanTempest]

Thanks for cleaning up the clippy warnings, @jorenham! Most of these look good. A couple of notes:

to_strings in regex_converter.rs — consider renaming to into_strings instead

The current fix changes the signature from fn to_strings(self) to fn to_strings(&self), which requires adding .clone() on the Part variant and switching into_iter() to iter() throughout. This introduces unnecessary allocations, the original code intentionally consumed self to move strings without copying.

The Rust convention is:
to_* → borrows &self (may allocate a new value)
into_* → consumes self (zero-copy conversion)

The rest looks great — the collapsible if chains in error.rs are cleaner, and the to_config(&self) change in pyright.rs is a nice improvement since it eliminates the .clone() at the call site in error_codes.rs.

[NathanTempest]

I think this might violate the project convention. We usually do not suppress lints with #[allow()]. If one is necessary, always use #[expect()] instead and provide a justified reason: #[expect(lint_name, reason = "")]

[jorenham]

Ah good to know. Maybe it's an idea to turn on the clippy allow_attributes lint then? https://rust-lang.github.io/rust-clippy/master/index.html?search=allow_attributes

[jorenham]

Hmm, when I enable that in pyrefly_config, three more warnings pop up:

warning: #[allow] attribute found
  --> crates/pyrefly_config/src/migration/mypy/pyproject.rs:31:3
   |
31 | #[allow(dead_code)]
   |   ^^^^^ help: replace it with: `expect`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes
note: the lint level is defined here
  --> crates/pyrefly_config/src/lib.rs:8:9
   |
 8 | #![warn(clippy::allow_attributes)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^

warning: #[allow] attribute found
  --> crates/pyrefly_config/src/util.rs:16:3
   |
16 | #[allow(clippy::trivially_copy_pass_by_ref)]
   |   ^^^^^ help: replace it with: `expect`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes

warning: #[allow] attribute found
  --> crates/pyrefly_config/src/util.rs:22:3
   |
22 | #[allow(clippy::trivially_copy_pass_by_ref)]
   |   ^^^^^ help: replace it with: `expect`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes

warning: `pyrefly_config` (lib) generated 3 warnings (run `cargo clippy --fix --lib -p pyrefly_config` to apply 3 suggestions)

It's probably out-of-scope here, but I figured you might want to know 🤷

[NathanTempest]

Appreciate the prompt response to the fixes, the changes LGTM

[jorenham]

Thanks for reviewing :)

[jorenham]

I see that the "Facebook Internal - Builds & Tests" check failed, but I can't see any of the errors, so I'm not sure what to do with it.

[NathanTempest]

@jorenham The import failed because the branch is out of date with main. Could you rebase on the latest main, so I can try to import again ?

[meta-codesync]

@NathanTempest has imported this pull request. If you are a Meta employee, you can view this in D102193286.

[kinto0]

Review automatically exported from Phabricator review in Meta.