clippy_config/
conf.rs

1use crate::ClippyConfiguration;
2use crate::types::{
3    DisallowedPath, DisallowedPathWithoutReplacement, InherentImplLintScope, MacroMatcher, MatchLintBehaviour,
4    PubUnderscoreFieldsBehaviour, Rename, SourceItemOrdering, SourceItemOrderingCategory,
5    SourceItemOrderingModuleItemGroupings, SourceItemOrderingModuleItemKind, SourceItemOrderingTraitAssocItemKind,
6    SourceItemOrderingTraitAssocItemKinds, SourceItemOrderingWithinModuleItemGroupings,
7};
8use clippy_utils::msrvs::Msrv;
9use itertools::Itertools;
10use rustc_errors::Applicability;
11use rustc_session::Session;
12use rustc_span::edit_distance::edit_distance;
13use rustc_span::{BytePos, Pos, SourceFile, Span, SyntaxContext};
14use serde::de::{IgnoredAny, IntoDeserializer, MapAccess, Visitor};
15use serde::{Deserialize, Deserializer, Serialize};
16use std::collections::HashMap;
17use std::fmt::{Debug, Display, Formatter};
18use std::ops::Range;
19use std::path::PathBuf;
20use std::str::FromStr;
21use std::sync::OnceLock;
22use std::{cmp, env, fmt, fs, io};
23
24#[rustfmt::skip]
25const DEFAULT_DOC_VALID_IDENTS: &[&str] = &[
26    "KiB", "MiB", "GiB", "TiB", "PiB", "EiB",
27    "MHz", "GHz", "THz",
28    "AccessKit",
29    "CoAP", "CoreFoundation", "CoreGraphics", "CoreText",
30    "DevOps",
31    "Direct2D", "Direct3D", "DirectWrite", "DirectX",
32    "ECMAScript",
33    "GPLv2", "GPLv3",
34    "GitHub", "GitLab",
35    "IPv4", "IPv6",
36    "InfiniBand", "RoCE",
37    "ClojureScript", "CoffeeScript", "JavaScript", "PostScript", "PureScript", "TypeScript",
38    "PowerPC", "WebAssembly",
39    "NaN", "NaNs",
40    "OAuth", "GraphQL",
41    "OCaml",
42    "OpenAL", "OpenDNS", "OpenGL", "OpenMP", "OpenSSH", "OpenSSL", "OpenStreetMap", "OpenTelemetry",
43    "OpenType",
44    "WebGL", "WebGL2", "WebGPU", "WebRTC", "WebSocket", "WebTransport",
45    "WebP", "OpenExr", "YCbCr", "sRGB",
46    "TensorFlow",
47    "TrueType",
48    "iOS", "macOS", "FreeBSD", "NetBSD", "OpenBSD", "NixOS",
49    "TeX", "LaTeX", "BibTeX", "BibLaTeX",
50    "MinGW",
51    "CamelCase",
52];
53const DEFAULT_DISALLOWED_NAMES: &[&str] = &["foo", "baz", "quux"];
54const DEFAULT_ALLOWED_IDENTS_BELOW_MIN_CHARS: &[&str] = &["i", "j", "x", "y", "z", "w", "n"];
55const DEFAULT_ALLOWED_PREFIXES: &[&str] = &["to", "as", "into", "from", "try_into", "try_from"];
56const DEFAULT_ALLOWED_TRAITS_WITH_RENAMED_PARAMS: &[&str] =
57    &["core::convert::From", "core::convert::TryFrom", "core::str::FromStr"];
58const DEFAULT_MODULE_ITEM_ORDERING_GROUPS: &[(&str, &[SourceItemOrderingModuleItemKind])] = {
59    #[allow(clippy::enum_glob_use)] // Very local glob use for legibility.
60    use SourceItemOrderingModuleItemKind::*;
61    &[
62        ("modules", &[ExternCrate, Mod, ForeignMod]),
63        ("use", &[Use]),
64        ("macros", &[Macro]),
65        ("global_asm", &[GlobalAsm]),
66        ("UPPER_SNAKE_CASE", &[Static, Const]),
67        ("PascalCase", &[TyAlias, Enum, Struct, Union, Trait, TraitAlias, Impl]),
68        ("lower_snake_case", &[Fn]),
69    ]
70};
71const DEFAULT_TRAIT_ASSOC_ITEM_KINDS_ORDER: &[SourceItemOrderingTraitAssocItemKind] = {
72    #[allow(clippy::enum_glob_use)] // Very local glob use for legibility.
73    use SourceItemOrderingTraitAssocItemKind::*;
74    &[Const, Type, Fn]
75};
76const DEFAULT_SOURCE_ITEM_ORDERING: &[SourceItemOrderingCategory] = {
77    #[allow(clippy::enum_glob_use)] // Very local glob use for legibility.
78    use SourceItemOrderingCategory::*;
79    &[Enum, Impl, Module, Struct, Trait]
80};
81
82/// Conf with parse errors
83#[derive(Default)]
84struct TryConf {
85    conf: Conf,
86    value_spans: HashMap<String, Range<usize>>,
87    errors: Vec<ConfError>,
88    warnings: Vec<ConfError>,
89}
90
91impl TryConf {
92    fn from_toml_error(file: &SourceFile, error: &toml::de::Error) -> Self {
93        Self {
94            conf: Conf::default(),
95            value_spans: HashMap::default(),
96            errors: vec![ConfError::from_toml(file, error)],
97            warnings: vec![],
98        }
99    }
100}
101
102#[derive(Debug)]
103struct ConfError {
104    message: String,
105    suggestion: Option<Suggestion>,
106    span: Span,
107}
108
109impl ConfError {
110    fn from_toml(file: &SourceFile, error: &toml::de::Error) -> Self {
111        let span = error.span().unwrap_or(0..file.normalized_source_len.0 as usize);
112        Self::spanned(file, error.message(), None, span)
113    }
114
115    fn spanned(
116        file: &SourceFile,
117        message: impl Into<String>,
118        suggestion: Option<Suggestion>,
119        span: Range<usize>,
120    ) -> Self {
121        Self {
122            message: message.into(),
123            suggestion,
124            span: span_from_toml_range(file, span),
125        }
126    }
127}
128
129// Remove code tags and code behind '# 's, as they are not needed for the lint docs and --explain
130pub fn sanitize_explanation(raw_docs: &str) -> String {
131    // Remove tags and hidden code:
132    let mut explanation = String::with_capacity(128);
133    let mut in_code = false;
134    for line in raw_docs.lines() {
135        let line = line.strip_prefix(' ').unwrap_or(line);
136
137        if let Some(lang) = line.strip_prefix("```") {
138            let tag = lang.split_once(',').map_or(lang, |(left, _)| left);
139            if !in_code && matches!(tag, "" | "rust" | "ignore" | "should_panic" | "no_run" | "compile_fail") {
140                explanation += "```rust\n";
141            } else {
142                explanation += line;
143                explanation.push('\n');
144            }
145            in_code = !in_code;
146        } else if !(in_code && line.starts_with("# ")) {
147            explanation += line;
148            explanation.push('\n');
149        }
150    }
151
152    explanation
153}
154
155macro_rules! wrap_option {
156    () => {
157        None
158    };
159    ($x:literal) => {
160        Some($x)
161    };
162}
163
164macro_rules! default_text {
165    ($value:expr) => {{
166        let mut text = String::new();
167        $value.serialize(toml::ser::ValueSerializer::new(&mut text)).unwrap();
168        text
169    }};
170    ($value:expr, $override:expr) => {
171        $override.to_string()
172    };
173}
174
175macro_rules! deserialize {
176    ($map:expr, $ty:ty, $errors:expr, $file:expr) => {{
177        let raw_value = $map.next_value::<toml::Spanned<toml::Value>>()?;
178        let value_span = raw_value.span();
179        let value = match <$ty>::deserialize(raw_value.into_inner()) {
180            Err(e) => {
181                $errors.push(ConfError::spanned(
182                    $file,
183                    e.to_string().replace('\n', " ").trim(),
184                    None,
185                    value_span,
186                ));
187                continue;
188            },
189            Ok(value) => value,
190        };
191        (value, value_span)
192    }};
193
194    ($map:expr, $ty:ty, $errors:expr, $file:expr, $replacements_allowed:expr) => {{
195        let array = $map.next_value::<Vec<toml::Spanned<toml::Value>>>()?;
196        let mut disallowed_paths_span = Range {
197            start: usize::MAX,
198            end: usize::MIN,
199        };
200        let mut disallowed_paths = Vec::new();
201        for raw_value in array {
202            let value_span = raw_value.span();
203            let mut disallowed_path = match DisallowedPath::<$replacements_allowed>::deserialize(raw_value.into_inner())
204            {
205                Err(e) => {
206                    $errors.push(ConfError::spanned(
207                        $file,
208                        e.to_string().replace('\n', " ").trim(),
209                        None,
210                        value_span,
211                    ));
212                    continue;
213                },
214                Ok(disallowed_path) => disallowed_path,
215            };
216            disallowed_paths_span = union(&disallowed_paths_span, &value_span);
217            disallowed_path.set_span(span_from_toml_range($file, value_span));
218            disallowed_paths.push(disallowed_path);
219        }
220        (disallowed_paths, disallowed_paths_span)
221    }};
222}
223
224macro_rules! define_Conf {
225    ($(
226        $(#[doc = $doc:literal])+
227        $(#[conf_deprecated($dep:literal, $new_conf:ident)])?
228        $(#[default_text = $default_text:expr])?
229        $(#[disallowed_paths_allow_replacements = $replacements_allowed:expr])?
230        $(#[lints($($for_lints:ident),* $(,)?)])?
231        $name:ident: $ty:ty = $default:expr,
232    )*) => {
233        /// Clippy lint configuration
234        pub struct Conf {
235            $($(#[cfg_attr(doc, doc = $doc)])+ pub $name: $ty,)*
236        }
237
238        mod defaults {
239            use super::*;
240            $(pub fn $name() -> $ty { $default })*
241        }
242
243        impl Default for Conf {
244            fn default() -> Self {
245                Self { $($name: defaults::$name(),)* }
246            }
247        }
248
249        #[derive(Deserialize)]
250        #[serde(field_identifier, rename_all = "kebab-case")]
251        #[expect(non_camel_case_types)]
252        enum Field { $($name,)* third_party, }
253
254        struct ConfVisitor<'a>(&'a SourceFile);
255
256        impl<'de> Visitor<'de> for ConfVisitor<'_> {
257            type Value = TryConf;
258
259            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
260                formatter.write_str("Conf")
261            }
262
263            fn visit_map<V>(self, mut map: V) -> Result<Self::Value, V::Error> where V: MapAccess<'de> {
264                let mut value_spans = HashMap::new();
265                let mut errors = Vec::new();
266                let mut warnings = Vec::new();
267
268                // Declare a local variable for each field available to a configuration file.
269                $(let mut $name = None;)*
270
271                // could get `Field` here directly, but get `String` first for diagnostics
272                while let Some(name) = map.next_key::<toml::Spanned<String>>()? {
273                    let field = match Field::deserialize(name.get_ref().as_str().into_deserializer()) {
274                        Err(e) => {
275                            let e: FieldError = e;
276                            errors.push(ConfError::spanned(self.0, e.error, e.suggestion, name.span()));
277                            continue;
278                        }
279                        Ok(field) => field
280                    };
281
282                    match field {
283                        $(Field::$name => {
284                            // Is this a deprecated field, i.e., is `$dep` set? If so, push a warning.
285                            $(warnings.push(ConfError::spanned(self.0, format!("deprecated field `{}`. {}", name.get_ref(), $dep), None, name.span()));)?
286                            let (value, value_span) =
287                                deserialize!(map, $ty, errors, self.0 $(, $replacements_allowed)?);
288                            // Was this field set previously?
289                            if $name.is_some() {
290                                errors.push(ConfError::spanned(self.0, format!("duplicate field `{}`", name.get_ref()), None, name.span()));
291                                continue;
292                            }
293                            $name = Some(value);
294                            value_spans.insert(name.get_ref().as_str().to_string(), value_span);
295                            // If this is a deprecated field, was the new field (`$new_conf`) set previously?
296                            // Note that `$new_conf` is one of the defined `$name`s.
297                            $(match $new_conf {
298                                Some(_) => errors.push(ConfError::spanned(self.0, concat!(
299                                    "duplicate field `", stringify!($new_conf),
300                                    "` (provided as `", stringify!($name), "`)"
301                                ), None, name.span())),
302                                None => $new_conf = $name.clone(),
303                            })?
304                        })*
305                        // ignore contents of the third_party key
306                        Field::third_party => drop(map.next_value::<IgnoredAny>())
307                    }
308                }
309                let conf = Conf { $($name: $name.unwrap_or_else(defaults::$name),)* };
310                Ok(TryConf { conf, value_spans, errors, warnings })
311            }
312        }
313
314        pub fn get_configuration_metadata() -> Vec<ClippyConfiguration> {
315            vec![$(
316                ClippyConfiguration {
317                    name: stringify!($name).replace('_', "-"),
318                    default: default_text!(defaults::$name() $(, $default_text)?),
319                    lints: &[$($(stringify!($for_lints)),*)?],
320                    doc: concat!($($doc, '\n',)*),
321                    deprecation_reason: wrap_option!($($dep)?)
322                },
323            )*]
324        }
325    };
326}
327
328fn union(x: &Range<usize>, y: &Range<usize>) -> Range<usize> {
329    Range {
330        start: cmp::min(x.start, y.start),
331        end: cmp::max(x.end, y.end),
332    }
333}
334
335fn span_from_toml_range(file: &SourceFile, span: Range<usize>) -> Span {
336    Span::new(
337        file.start_pos + BytePos::from_usize(span.start),
338        file.start_pos + BytePos::from_usize(span.end),
339        SyntaxContext::root(),
340        None,
341    )
342}
343
344define_Conf! {
345    /// Which crates to allow absolute paths from
346    #[lints(absolute_paths)]
347    absolute_paths_allowed_crates: Vec<String> = Vec::new(),
348    /// The maximum number of segments a path can have before being linted, anything above this will
349    /// be linted.
350    #[lints(absolute_paths)]
351    absolute_paths_max_segments: u64 = 2,
352    /// Whether to accept a safety comment to be placed above the attributes for the `unsafe` block
353    #[lints(undocumented_unsafe_blocks)]
354    accept_comment_above_attributes: bool = true,
355    /// Whether to accept a safety comment to be placed above the statement containing the `unsafe` block
356    #[lints(undocumented_unsafe_blocks)]
357    accept_comment_above_statement: bool = true,
358    /// Don't lint when comparing the result of a modulo operation to zero.
359    #[lints(modulo_arithmetic)]
360    allow_comparison_to_zero: bool = true,
361    /// Whether `dbg!` should be allowed in test functions or `#[cfg(test)]`
362    #[lints(dbg_macro)]
363    allow_dbg_in_tests: bool = false,
364    /// Whether an item should be allowed to have the same name as its containing module
365    #[lints(module_name_repetitions)]
366    allow_exact_repetitions: bool = true,
367    /// Whether `expect` should be allowed in code always evaluated at compile time
368    #[lints(expect_used)]
369    allow_expect_in_consts: bool = true,
370    /// Whether `expect` should be allowed in test functions or `#[cfg(test)]`
371    #[lints(expect_used)]
372    allow_expect_in_tests: bool = false,
373    /// Whether `indexing_slicing` should be allowed in test functions or `#[cfg(test)]`
374    #[lints(indexing_slicing)]
375    allow_indexing_slicing_in_tests: bool = false,
376    /// Whether functions inside `#[cfg(test)]` modules or test functions should be checked.
377    #[lints(large_stack_frames)]
378    allow_large_stack_frames_in_tests: bool = true,
379    /// Whether to allow mixed uninlined format args, e.g. `format!("{} {}", a, foo.bar)`
380    #[lints(uninlined_format_args)]
381    allow_mixed_uninlined_format_args: bool = true,
382    /// Whether to allow `r#""#` when `r""` can be used
383    #[lints(needless_raw_string_hashes)]
384    allow_one_hash_in_raw_strings: bool = false,
385    /// Whether `panic` should be allowed in test functions or `#[cfg(test)]`
386    #[lints(panic)]
387    allow_panic_in_tests: bool = false,
388    /// Whether print macros (ex. `println!`) should be allowed in test functions or `#[cfg(test)]`
389    #[lints(print_stderr, print_stdout)]
390    allow_print_in_tests: bool = false,
391    /// Whether to allow module inception if it's not public.
392    #[lints(module_inception)]
393    allow_private_module_inception: bool = false,
394    /// List of trait paths to ignore when checking renamed function parameters.
395    ///
396    /// #### Example
397    ///
398    /// ```toml
399    /// allow-renamed-params-for = [ "std::convert::From" ]
400    /// ```
401    ///
402    /// #### Noteworthy
403    ///
404    /// - By default, the following traits are ignored: `From`, `TryFrom`, `FromStr`
405    /// - `".."` can be used as part of the list to indicate that the configured values should be appended to the
406    /// default configuration of Clippy. By default, any configuration will replace the default value.
407    #[lints(renamed_function_params)]
408    allow_renamed_params_for: Vec<String> =
409        DEFAULT_ALLOWED_TRAITS_WITH_RENAMED_PARAMS.iter().map(ToString::to_string).collect(),
410    /// Whether `unwrap` should be allowed in code always evaluated at compile time
411    #[lints(unwrap_used)]
412    allow_unwrap_in_consts: bool = true,
413    /// Whether `unwrap` should be allowed in test functions or `#[cfg(test)]`
414    #[lints(unwrap_used)]
415    allow_unwrap_in_tests: bool = false,
416    /// Whether `useless_vec` should ignore test functions or `#[cfg(test)]`
417    #[lints(useless_vec)]
418    allow_useless_vec_in_tests: bool = false,
419    /// Additional dotfiles (files or directories starting with a dot) to allow
420    #[lints(path_ends_with_ext)]
421    allowed_dotfiles: Vec<String> = Vec::default(),
422    /// A list of crate names to allow duplicates of
423    #[lints(multiple_crate_versions)]
424    allowed_duplicate_crates: Vec<String> = Vec::new(),
425    /// Allowed names below the minimum allowed characters. The value `".."` can be used as part of
426    /// the list to indicate, that the configured values should be appended to the default
427    /// configuration of Clippy. By default, any configuration will replace the default value.
428    #[lints(min_ident_chars)]
429    allowed_idents_below_min_chars: Vec<String> =
430        DEFAULT_ALLOWED_IDENTS_BELOW_MIN_CHARS.iter().map(ToString::to_string).collect(),
431    /// List of prefixes to allow when determining whether an item's name ends with the module's name.
432    /// If the rest of an item's name is an allowed prefix (e.g. item `ToFoo` or `to_foo` in module `foo`),
433    /// then don't emit a warning.
434    ///
435    /// #### Example
436    ///
437    /// ```toml
438    /// allowed-prefixes = [ "to", "from" ]
439    /// ```
440    ///
441    /// #### Noteworthy
442    ///
443    /// - By default, the following prefixes are allowed: `to`, `as`, `into`, `from`, `try_into` and `try_from`
444    /// - PascalCase variant is included automatically for each snake_case variant (e.g. if `try_into` is included,
445    ///   `TryInto` will also be included)
446    /// - Use `".."` as part of the list to indicate that the configured values should be appended to the
447    /// default configuration of Clippy. By default, any configuration will replace the default value
448    #[lints(module_name_repetitions)]
449    allowed_prefixes: Vec<String> = DEFAULT_ALLOWED_PREFIXES.iter().map(ToString::to_string).collect(),
450    /// The list of unicode scripts allowed to be used in the scope.
451    #[lints(disallowed_script_idents)]
452    allowed_scripts: Vec<String> = vec!["Latin".to_string()],
453    /// List of path segments allowed to have wildcard imports.
454    ///
455    /// #### Example
456    ///
457    /// ```toml
458    /// allowed-wildcard-imports = [ "utils", "common" ]
459    /// ```
460    ///
461    /// #### Noteworthy
462    ///
463    /// 1. This configuration has no effects if used with `warn_on_all_wildcard_imports = true`.
464    /// 2. Paths with any segment that containing the word 'prelude'
465    /// are already allowed by default.
466    #[lints(wildcard_imports)]
467    allowed_wildcard_imports: Vec<String> = Vec::new(),
468    /// Suppress checking of the passed type names in all types of operations.
469    ///
470    /// If a specific operation is desired, consider using `arithmetic_side_effects_allowed_binary` or `arithmetic_side_effects_allowed_unary` instead.
471    ///
472    /// #### Example
473    ///
474    /// ```toml
475    /// arithmetic-side-effects-allowed = ["SomeType", "AnotherType"]
476    /// ```
477    ///
478    /// #### Noteworthy
479    ///
480    /// A type, say `SomeType`, listed in this configuration has the same behavior of
481    /// `["SomeType" , "*"], ["*", "SomeType"]` in `arithmetic_side_effects_allowed_binary`.
482    #[lints(arithmetic_side_effects)]
483    arithmetic_side_effects_allowed: Vec<String> = <_>::default(),
484    /// Suppress checking of the passed type pair names in binary operations like addition or
485    /// multiplication.
486    ///
487    /// Supports the "*" wildcard to indicate that a certain type won't trigger the lint regardless
488    /// of the involved counterpart. For example, `["SomeType", "*"]` or `["*", "AnotherType"]`.
489    ///
490    /// Pairs are asymmetric, which means that `["SomeType", "AnotherType"]` is not the same as
491    /// `["AnotherType", "SomeType"]`.
492    ///
493    /// #### Example
494    ///
495    /// ```toml
496    /// arithmetic-side-effects-allowed-binary = [["SomeType" , "f32"], ["AnotherType", "*"]]
497    /// ```
498    #[lints(arithmetic_side_effects)]
499    arithmetic_side_effects_allowed_binary: Vec<(String, String)> = <_>::default(),
500    /// Suppress checking of the passed type names in unary operations like "negation" (`-`).
501    ///
502    /// #### Example
503    ///
504    /// ```toml
505    /// arithmetic-side-effects-allowed-unary = ["SomeType", "AnotherType"]
506    /// ```
507    #[lints(arithmetic_side_effects)]
508    arithmetic_side_effects_allowed_unary: Vec<String> = <_>::default(),
509    /// The maximum allowed size for arrays on the stack
510    #[lints(large_const_arrays, large_stack_arrays)]
511    array_size_threshold: u64 = 16 * 1024,
512    /// Suppress lints whenever the suggested change would cause breakage for other crates.
513    #[lints(
514        box_collection,
515        enum_variant_names,
516        large_types_passed_by_value,
517        linkedlist,
518        needless_pass_by_ref_mut,
519        option_option,
520        owned_cow,
521        rc_buffer,
522        rc_mutex,
523        redundant_allocation,
524        ref_option,
525        single_call_fn,
526        trivially_copy_pass_by_ref,
527        unnecessary_box_returns,
528        unnecessary_wraps,
529        unused_self,
530        upper_case_acronyms,
531        vec_box,
532        wrong_self_convention,
533    )]
534    avoid_breaking_exported_api: bool = true,
535    /// The list of types which may not be held across an await point.
536    #[disallowed_paths_allow_replacements = false]
537    #[lints(await_holding_invalid_type)]
538    await_holding_invalid_types: Vec<DisallowedPathWithoutReplacement> = Vec::new(),
539    /// DEPRECATED LINT: BLACKLISTED_NAME.
540    ///
541    /// Use the Disallowed Names lint instead
542    #[conf_deprecated("Please use `disallowed-names` instead", disallowed_names)]
543    blacklisted_names: Vec<String> = Vec::new(),
544    /// For internal testing only, ignores the current `publish` settings in the Cargo manifest.
545    #[lints(cargo_common_metadata)]
546    cargo_ignore_publish: bool = false,
547    /// Whether to check MSRV compatibility in `#[test]` and `#[cfg(test)]` code.
548    #[lints(incompatible_msrv)]
549    check_incompatible_msrv_in_tests: bool = false,
550    /// Whether to suggest reordering constructor fields when initializers are present.
551    ///
552    /// Warnings produced by this configuration aren't necessarily fixed by just reordering the fields. Even if the
553    /// suggested code would compile, it can change semantics if the initializer expressions have side effects. The
554    /// following example [from rust-clippy#11846] shows how the suggestion can run into borrow check errors:
555    ///
556    /// ```rust
557    /// struct MyStruct {
558    ///     vector: Vec<u32>,
559    ///     length: usize
560    /// }
561    /// fn main() {
562    ///     let vector = vec![1,2,3];
563    ///     MyStruct { length: vector.len(), vector};
564    /// }
565    /// ```
566    ///
567    /// [from rust-clippy#11846]: https://github.com/rust-lang/rust-clippy/issues/11846#issuecomment-1820747924
568    #[lints(inconsistent_struct_constructor)]
569    check_inconsistent_struct_field_initializers: bool = false,
570    /// Whether to also run the listed lints on private items.
571    #[lints(missing_errors_doc, missing_panics_doc, missing_safety_doc, unnecessary_safety_doc)]
572    check_private_items: bool = false,
573    /// The maximum cognitive complexity a function can have
574    #[lints(cognitive_complexity)]
575    cognitive_complexity_threshold: u64 = 25,
576    /// The minimum digits a const float literal must have to supress the `excessive_precicion` lint
577    #[lints(excessive_precision)]
578    const_literal_digits_threshold: usize = 30,
579    /// DEPRECATED LINT: CYCLOMATIC_COMPLEXITY.
580    ///
581    /// Use the Cognitive Complexity lint instead.
582    #[conf_deprecated("Please use `cognitive-complexity-threshold` instead", cognitive_complexity_threshold)]
583    cyclomatic_complexity_threshold: u64 = 25,
584    /// The list of disallowed macros, written as fully qualified paths.
585    ///
586    /// **Fields:**
587    /// - `path` (required): the fully qualified path to the macro that should be disallowed
588    /// - `reason` (optional): explanation why this macro is disallowed
589    /// - `replacement` (optional): suggested alternative macro
590    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
591    ///   if the path doesn't exist, instead of emitting an error
592    #[disallowed_paths_allow_replacements = true]
593    #[lints(disallowed_macros)]
594    disallowed_macros: Vec<DisallowedPath> = Vec::new(),
595    /// The list of disallowed methods, written as fully qualified paths.
596    ///
597    /// **Fields:**
598    /// - `path` (required): the fully qualified path to the method that should be disallowed
599    /// - `reason` (optional): explanation why this method is disallowed
600    /// - `replacement` (optional): suggested alternative method
601    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
602    ///   if the path doesn't exist, instead of emitting an error
603    #[disallowed_paths_allow_replacements = true]
604    #[lints(disallowed_methods)]
605    disallowed_methods: Vec<DisallowedPath> = Vec::new(),
606    /// The list of disallowed names to lint about. NB: `bar` is not here since it has legitimate uses. The value
607    /// `".."` can be used as part of the list to indicate that the configured values should be appended to the
608    /// default configuration of Clippy. By default, any configuration will replace the default value.
609    #[lints(disallowed_names)]
610    disallowed_names: Vec<String> = DEFAULT_DISALLOWED_NAMES.iter().map(ToString::to_string).collect(),
611    /// The list of disallowed types, written as fully qualified paths.
612    ///
613    /// **Fields:**
614    /// - `path` (required): the fully qualified path to the type that should be disallowed
615    /// - `reason` (optional): explanation why this type is disallowed
616    /// - `replacement` (optional): suggested alternative type
617    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
618    ///   if the path doesn't exist, instead of emitting an error
619    #[disallowed_paths_allow_replacements = true]
620    #[lints(disallowed_types)]
621    disallowed_types: Vec<DisallowedPath> = Vec::new(),
622    /// The list of words this lint should not consider as identifiers needing ticks. The value
623    /// `".."` can be used as part of the list to indicate, that the configured values should be appended to the
624    /// default configuration of Clippy. By default, any configuration will replace the default value. For example:
625    /// * `doc-valid-idents = ["ClipPy"]` would replace the default list with `["ClipPy"]`.
626    /// * `doc-valid-idents = ["ClipPy", ".."]` would append `ClipPy` to the default list.
627    #[lints(doc_markdown)]
628    doc_valid_idents: Vec<String> = DEFAULT_DOC_VALID_IDENTS.iter().map(ToString::to_string).collect(),
629    /// Whether to apply the raw pointer heuristic to determine if a type is `Send`.
630    #[lints(non_send_fields_in_send_ty)]
631    enable_raw_pointer_heuristic_for_send: bool = true,
632    /// Whether to recommend using implicit into iter for reborrowed values.
633    ///
634    /// #### Example
635    /// ```no_run
636    /// let mut vec = vec![1, 2, 3];
637    /// let rmvec = &mut vec;
638    /// for _ in rmvec.iter() {}
639    /// for _ in rmvec.iter_mut() {}
640    /// ```
641    ///
642    /// Use instead:
643    /// ```no_run
644    /// let mut vec = vec![1, 2, 3];
645    /// let rmvec = &mut vec;
646    /// for _ in &*rmvec {}
647    /// for _ in &mut *rmvec {}
648    /// ```
649    #[lints(explicit_iter_loop)]
650    enforce_iter_loop_reborrow: bool = false,
651    /// The list of imports to always rename, a fully qualified path followed by the rename.
652    #[lints(missing_enforced_import_renames)]
653    enforced_import_renames: Vec<Rename> = Vec::new(),
654    /// The minimum number of enum variants for the lints about variant names to trigger
655    #[lints(enum_variant_names)]
656    enum_variant_name_threshold: u64 = 3,
657    /// The maximum size of an enum's variant to avoid box suggestion
658    #[lints(large_enum_variant)]
659    enum_variant_size_threshold: u64 = 200,
660    /// The maximum amount of nesting a block can reside in
661    #[lints(excessive_nesting)]
662    excessive_nesting_threshold: u64 = 0,
663    /// The maximum byte size a `Future` can have, before it triggers the `clippy::large_futures` lint
664    #[lints(large_futures)]
665    future_size_threshold: u64 = 16 * 1024,
666    /// A list of paths to types that should be treated as if they do not contain interior mutability
667    #[lints(borrow_interior_mutable_const, declare_interior_mutable_const, ifs_same_cond, mutable_key_type)]
668    ignore_interior_mutability: Vec<String> = Vec::from(["bytes::Bytes".into()]),
669    /// Sets the scope ("crate", "file", or "module") in which duplicate inherent `impl` blocks for the same type are linted.
670    #[lints(multiple_inherent_impl)]
671    inherent_impl_lint_scope: InherentImplLintScope = InherentImplLintScope::Crate,
672    /// A list of paths to types that should be ignored as overly large `Err`-variants in a
673    /// `Result` returned from a function
674    #[lints(result_large_err)]
675    large_error_ignored: Vec<String> = Vec::default(),
676    /// The maximum size of the `Err`-variant in a `Result` returned from a function
677    #[lints(result_large_err)]
678    large_error_threshold: u64 = 128,
679    /// Whether collapsible `if` and `else if` chains are linted if they contain comments inside the parts
680    /// that would be collapsed.
681    #[lints(collapsible_else_if, collapsible_if)]
682    lint_commented_code: bool = false,
683    /// Whether to suggest reordering constructor fields when initializers are present.
684    /// DEPRECATED CONFIGURATION: lint-inconsistent-struct-field-initializers
685    ///
686    /// Use the `check-inconsistent-struct-field-initializers` configuration instead.
687    #[conf_deprecated("Please use `check-inconsistent-struct-field-initializers` instead", check_inconsistent_struct_field_initializers)]
688    lint_inconsistent_struct_field_initializers: bool = false,
689    /// The lower bound for linting decimal literals
690    #[lints(decimal_literal_representation)]
691    literal_representation_threshold: u64 = 16384,
692    /// Whether the matches should be considered by the lint, and whether there should
693    /// be filtering for common types.
694    #[lints(manual_let_else)]
695    matches_for_let_else: MatchLintBehaviour = MatchLintBehaviour::WellKnownTypes,
696    /// The maximum number of bool parameters a function can have
697    #[lints(fn_params_excessive_bools)]
698    max_fn_params_bools: u64 = 3,
699    /// The maximum size of a file included via `include_bytes!()` or `include_str!()`, in bytes
700    #[lints(large_include_file)]
701    max_include_file_size: u64 = 1_000_000,
702    /// The maximum number of bool fields a struct can have
703    #[lints(struct_excessive_bools)]
704    max_struct_bools: u64 = 3,
705    /// When Clippy suggests using a slice pattern, this is the maximum number of elements allowed in
706    /// the slice pattern that is suggested. If more elements are necessary, the lint is suppressed.
707    /// For example, `[_, _, _, e, ..]` is a slice pattern with 4 elements.
708    #[lints(index_refutable_slice)]
709    max_suggested_slice_pattern_length: u64 = 3,
710    /// The maximum number of bounds a trait can have to be linted
711    #[lints(type_repetition_in_bounds)]
712    max_trait_bounds: u64 = 3,
713    /// Minimum chars an ident can have, anything below or equal to this will be linted.
714    #[lints(min_ident_chars)]
715    min_ident_chars_threshold: u64 = 1,
716    /// Whether to allow fields starting with an underscore to skip documentation requirements
717    #[lints(missing_docs_in_private_items)]
718    missing_docs_allow_unused: bool = false,
719    /// Whether to **only** check for missing documentation in items visible within the current
720    /// crate. For example, `pub(crate)` items.
721    #[lints(missing_docs_in_private_items)]
722    missing_docs_in_crate_items: bool = false,
723    /// The named groupings of different source item kinds within modules.
724    #[lints(arbitrary_source_item_ordering)]
725    module_item_order_groupings: SourceItemOrderingModuleItemGroupings = DEFAULT_MODULE_ITEM_ORDERING_GROUPS.into(),
726    /// Whether the items within module groups should be ordered alphabetically or not.
727    ///
728    /// This option can be configured to "all", "none", or a list of specific grouping names that should be checked
729    /// (e.g. only "enums").
730    #[lints(arbitrary_source_item_ordering)]
731    module_items_ordered_within_groupings: SourceItemOrderingWithinModuleItemGroupings =
732        SourceItemOrderingWithinModuleItemGroupings::None,
733    /// The minimum rust version that the project supports. Defaults to the `rust-version` field in `Cargo.toml`
734    #[default_text = "current version"]
735    #[lints(
736        allow_attributes,
737        allow_attributes_without_reason,
738        almost_complete_range,
739        approx_constant,
740        assigning_clones,
741        borrow_as_ptr,
742        cast_abs_to_unsigned,
743        checked_conversions,
744        cloned_instead_of_copied,
745        collapsible_match,
746        collapsible_str_replace,
747        deprecated_cfg_attr,
748        derivable_impls,
749        err_expect,
750        filter_map_next,
751        from_over_into,
752        if_then_some_else_none,
753        index_refutable_slice,
754        inefficient_to_string,
755        io_other_error,
756        iter_kv_map,
757        legacy_numeric_constants,
758        len_zero,
759        lines_filter_map_ok,
760        manual_abs_diff,
761        manual_bits,
762        manual_c_str_literals,
763        manual_clamp,
764        manual_div_ceil,
765        manual_flatten,
766        manual_hash_one,
767        manual_is_ascii_check,
768        manual_is_power_of_two,
769        manual_let_else,
770        manual_midpoint,
771        manual_non_exhaustive,
772        manual_option_as_slice,
773        manual_pattern_char_comparison,
774        manual_range_contains,
775        manual_rem_euclid,
776        manual_repeat_n,
777        manual_retain,
778        manual_slice_fill,
779        manual_slice_size_calculation,
780        manual_split_once,
781        manual_str_repeat,
782        manual_strip,
783        manual_try_fold,
784        map_clone,
785        map_unwrap_or,
786        map_with_unused_argument_over_ranges,
787        match_like_matches_macro,
788        mem_replace_option_with_some,
789        mem_replace_with_default,
790        missing_const_for_fn,
791        needless_borrow,
792        non_std_lazy_statics,
793        option_as_ref_deref,
794        or_fun_call,
795        ptr_as_ptr,
796        question_mark,
797        redundant_field_names,
798        redundant_static_lifetimes,
799        repeat_vec_with_capacity,
800        same_item_push,
801        seek_from_current,
802        to_digit_is_some,
803        transmute_ptr_to_ref,
804        tuple_array_conversions,
805        type_repetition_in_bounds,
806        unchecked_time_subtraction,
807        uninlined_format_args,
808        unnecessary_lazy_evaluations,
809        unnecessary_unwrap,
810        unnested_or_patterns,
811        unused_trait_names,
812        use_self,
813        zero_ptr,
814    )]
815    msrv: Msrv = Msrv::default(),
816    /// The minimum size (in bytes) to consider a type for passing by reference instead of by value.
817    #[lints(large_types_passed_by_value)]
818    pass_by_value_size_limit: u64 = 256,
819    /// Lint "public" fields in a struct that are prefixed with an underscore based on their
820    /// exported visibility, or whether they are marked as "pub".
821    #[lints(pub_underscore_fields)]
822    pub_underscore_fields_behavior: PubUnderscoreFieldsBehaviour = PubUnderscoreFieldsBehaviour::PubliclyExported,
823    /// Whether the type itself in a struct or enum should be replaced with `Self` when encountering recursive types.
824    #[lints(use_self)]
825    recursive_self_in_type_definitions: bool = true,
826    /// Whether to lint only if it's multiline.
827    #[lints(semicolon_inside_block)]
828    semicolon_inside_block_ignore_singleline: bool = false,
829    /// Whether to lint only if it's singleline.
830    #[lints(semicolon_outside_block)]
831    semicolon_outside_block_ignore_multiline: bool = false,
832    /// The maximum number of single char bindings a scope may have
833    #[lints(many_single_char_names)]
834    single_char_binding_names_threshold: u64 = 4,
835    /// Which kind of elements should be ordered internally, possible values being `enum`, `impl`, `module`, `struct`, `trait`.
836    #[lints(arbitrary_source_item_ordering)]
837    source_item_ordering: SourceItemOrdering = DEFAULT_SOURCE_ITEM_ORDERING.into(),
838    /// The maximum allowed stack size for functions in bytes
839    #[lints(large_stack_frames)]
840    stack_size_threshold: u64 = 512_000,
841    /// Enforce the named macros always use the braces specified.
842    ///
843    /// A `MacroMatcher` can be added like so `{ name = "macro_name", brace = "(" }`. If the macro
844    /// could be used with a full path two `MacroMatcher`s have to be added one with the full path
845    /// `crate_name::macro_name` and one with just the macro name.
846    #[lints(nonstandard_macro_braces)]
847    standard_macro_braces: Vec<MacroMatcher> = Vec::new(),
848    /// The minimum number of struct fields for the lints about field names to trigger
849    #[lints(struct_field_names)]
850    struct_field_name_threshold: u64 = 3,
851    /// Whether to suppress a restriction lint in constant code. In same
852    /// cases the restructured operation might not be unavoidable, as the
853    /// suggested counterparts are unavailable in constant code. This
854    /// configuration will cause restriction lints to trigger even
855    /// if no suggestion can be made.
856    #[lints(indexing_slicing)]
857    suppress_restriction_lint_in_const: bool = false,
858    /// The maximum size of objects (in bytes) that will be linted. Larger objects are ok on the heap
859    #[lints(boxed_local, useless_vec)]
860    too_large_for_stack: u64 = 200,
861    /// The maximum number of argument a function or method can have
862    #[lints(too_many_arguments)]
863    too_many_arguments_threshold: u64 = 7,
864    /// The maximum number of lines a function or method can have
865    #[lints(too_many_lines)]
866    too_many_lines_threshold: u64 = 100,
867    /// The order of associated items in traits.
868    #[lints(arbitrary_source_item_ordering)]
869    trait_assoc_item_kinds_order: SourceItemOrderingTraitAssocItemKinds = DEFAULT_TRAIT_ASSOC_ITEM_KINDS_ORDER.into(),
870    /// The maximum size (in bytes) to consider a `Copy` type for passing by value instead of by
871    /// reference.
872    #[default_text = "target_pointer_width"]
873    #[lints(trivially_copy_pass_by_ref)]
874    trivial_copy_size_limit: Option<u64> = None,
875    /// The maximum complexity a type can have
876    #[lints(type_complexity)]
877    type_complexity_threshold: u64 = 250,
878    /// The byte size a `T` in `Box<T>` can have, below which it triggers the `clippy::unnecessary_box` lint
879    #[lints(unnecessary_box_returns)]
880    unnecessary_box_size: u64 = 128,
881    /// Should the fraction of a decimal be linted to include separators.
882    #[lints(unreadable_literal)]
883    unreadable_literal_lint_fractions: bool = true,
884    /// Enables verbose mode. Triggers if there is more than one uppercase char next to each other
885    #[lints(upper_case_acronyms)]
886    upper_case_acronyms_aggressive: bool = false,
887    /// The size of the boxed type in bytes, where boxing in a `Vec` is allowed
888    #[lints(vec_box)]
889    vec_box_size_threshold: u64 = 4096,
890    /// The maximum allowed size of a bit mask before suggesting to use 'trailing_zeros'
891    #[lints(verbose_bit_mask)]
892    verbose_bit_mask_threshold: u64 = 1,
893    /// Whether to emit warnings on all wildcard imports, including those from `prelude`, from `super` in tests,
894    /// or for `pub use` reexports.
895    #[lints(wildcard_imports)]
896    warn_on_all_wildcard_imports: bool = false,
897    /// Whether to also emit warnings for unsafe blocks with metavariable expansions in **private** macros.
898    #[lints(macro_metavars_in_unsafe)]
899    warn_unsafe_macro_metavars_in_private_macros: bool = false,
900}
901
902/// Search for the configuration file.
903///
904/// # Errors
905///
906/// Returns any unexpected filesystem error encountered when searching for the config file
907pub fn lookup_conf_file() -> io::Result<(Option<PathBuf>, Vec<String>)> {
908    /// Possible filename to search for.
909    const CONFIG_FILE_NAMES: [&str; 2] = [".clippy.toml", "clippy.toml"];
910
911    // Start looking for a config file in CLIPPY_CONF_DIR, or failing that, CARGO_MANIFEST_DIR.
912    // If neither of those exist, use ".". (Update documentation if this priority changes)
913    let mut current = env::var_os("CLIPPY_CONF_DIR")
914        .or_else(|| env::var_os("CARGO_MANIFEST_DIR"))
915        .map_or_else(|| PathBuf::from("."), PathBuf::from)
916        .canonicalize()?;
917
918    let mut found_config: Option<PathBuf> = None;
919    let mut warnings = vec![];
920
921    loop {
922        for config_file_name in &CONFIG_FILE_NAMES {
923            if let Ok(config_file) = current.join(config_file_name).canonicalize() {
924                match fs::metadata(&config_file) {
925                    Err(e) if e.kind() == io::ErrorKind::NotFound => {},
926                    Err(e) => return Err(e),
927                    Ok(md) if md.is_dir() => {},
928                    Ok(_) => {
929                        // warn if we happen to find two config files #8323
930                        if let Some(ref found_config) = found_config {
931                            warnings.push(format!(
932                                "using config file `{}`, `{}` will be ignored",
933                                found_config.display(),
934                                config_file.display()
935                            ));
936                        } else {
937                            found_config = Some(config_file);
938                        }
939                    },
940                }
941            }
942        }
943
944        if found_config.is_some() {
945            return Ok((found_config, warnings));
946        }
947
948        // If the current directory has no parent, we're done searching.
949        if !current.pop() {
950            return Ok((None, warnings));
951        }
952    }
953}
954
955fn deserialize(file: &SourceFile) -> TryConf {
956    match toml::de::Deserializer::new(file.src.as_ref().unwrap()).deserialize_map(ConfVisitor(file)) {
957        Ok(mut conf) => {
958            extend_vec_if_indicator_present(&mut conf.conf.disallowed_names, DEFAULT_DISALLOWED_NAMES);
959            extend_vec_if_indicator_present(&mut conf.conf.allowed_prefixes, DEFAULT_ALLOWED_PREFIXES);
960            extend_vec_if_indicator_present(
961                &mut conf.conf.allow_renamed_params_for,
962                DEFAULT_ALLOWED_TRAITS_WITH_RENAMED_PARAMS,
963            );
964
965            // Confirms that the user has not accidentally configured ordering requirements for groups that
966            // aren't configured.
967            if let SourceItemOrderingWithinModuleItemGroupings::Custom(groupings) =
968                &conf.conf.module_items_ordered_within_groupings
969            {
970                for grouping in groupings {
971                    if !conf.conf.module_item_order_groupings.is_grouping(grouping) {
972                        // Since this isn't fixable by rustfix, don't emit a `Suggestion`. This just adds some useful
973                        // info for the user instead.
974
975                        let names = conf.conf.module_item_order_groupings.grouping_names();
976                        let suggestion = suggest_candidate(grouping, names.iter().map(String::as_str))
977                            .map(|s| format!(" perhaps you meant `{s}`?"))
978                            .unwrap_or_default();
979                        let names = names.iter().map(|s| format!("`{s}`")).join(", ");
980                        let message = format!(
981                            "unknown ordering group: `{grouping}` was not specified in `module-items-ordered-within-groupings`,{suggestion} expected one of: {names}"
982                        );
983
984                        let span = conf
985                            .value_spans
986                            .get("module_item_order_groupings")
987                            .cloned()
988                            .unwrap_or_default();
989                        conf.errors.push(ConfError::spanned(file, message, None, span));
990                    }
991                }
992            }
993
994            // TODO: THIS SHOULD BE TESTED, this comment will be gone soon
995            if conf.conf.allowed_idents_below_min_chars.iter().any(|e| e == "..") {
996                conf.conf
997                    .allowed_idents_below_min_chars
998                    .extend(DEFAULT_ALLOWED_IDENTS_BELOW_MIN_CHARS.iter().map(ToString::to_string));
999            }
1000            if conf.conf.doc_valid_idents.iter().any(|e| e == "..") {
1001                conf.conf
1002                    .doc_valid_idents
1003                    .extend(DEFAULT_DOC_VALID_IDENTS.iter().map(ToString::to_string));
1004            }
1005
1006            conf
1007        },
1008        Err(e) => TryConf::from_toml_error(file, &e),
1009    }
1010}
1011
1012fn extend_vec_if_indicator_present(vec: &mut Vec<String>, default: &[&str]) {
1013    if vec.contains(&"..".to_string()) {
1014        vec.extend(default.iter().map(ToString::to_string));
1015    }
1016}
1017
1018impl Conf {
1019    pub fn read(sess: &Session, path: &io::Result<(Option<PathBuf>, Vec<String>)>) -> &'static Conf {
1020        static CONF: OnceLock<Conf> = OnceLock::new();
1021        CONF.get_or_init(|| Conf::read_inner(sess, path))
1022    }
1023
1024    fn read_inner(sess: &Session, path: &io::Result<(Option<PathBuf>, Vec<String>)>) -> Conf {
1025        match path {
1026            Ok((_, warnings)) => {
1027                for warning in warnings {
1028                    sess.dcx().warn(warning.clone());
1029                }
1030            },
1031            Err(error) => {
1032                sess.dcx()
1033                    .err(format!("error finding Clippy's configuration file: {error}"));
1034            },
1035        }
1036
1037        let TryConf {
1038            mut conf,
1039            value_spans: _,
1040            errors,
1041            warnings,
1042        } = match path {
1043            Ok((Some(path), _)) => match sess.source_map().load_file(path) {
1044                Ok(file) => deserialize(&file),
1045                Err(error) => {
1046                    sess.dcx().err(format!("failed to read `{}`: {error}", path.display()));
1047                    TryConf::default()
1048                },
1049            },
1050            _ => TryConf::default(),
1051        };
1052
1053        conf.msrv.read_cargo(sess);
1054
1055        // all conf errors are non-fatal, we just use the default conf in case of error
1056        for error in errors {
1057            let mut diag = sess.dcx().struct_span_err(
1058                error.span,
1059                format!("error reading Clippy's configuration file: {}", error.message),
1060            );
1061
1062            if let Some(sugg) = error.suggestion {
1063                diag.span_suggestion(error.span, sugg.message, sugg.suggestion, Applicability::MaybeIncorrect);
1064            }
1065
1066            diag.emit();
1067        }
1068
1069        for warning in warnings {
1070            sess.dcx().span_warn(
1071                warning.span,
1072                format!("error reading Clippy's configuration file: {}", warning.message),
1073            );
1074        }
1075
1076        conf
1077    }
1078}
1079
1080const SEPARATOR_WIDTH: usize = 4;
1081
1082#[derive(Debug)]
1083struct FieldError {
1084    error: String,
1085    suggestion: Option<Suggestion>,
1086}
1087
1088#[derive(Debug)]
1089struct Suggestion {
1090    message: &'static str,
1091    suggestion: &'static str,
1092}
1093
1094impl std::error::Error for FieldError {}
1095
1096impl Display for FieldError {
1097    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
1098        f.pad(&self.error)
1099    }
1100}
1101
1102impl serde::de::Error for FieldError {
1103    fn custom<T: Display>(msg: T) -> Self {
1104        Self {
1105            error: msg.to_string(),
1106            suggestion: None,
1107        }
1108    }
1109
1110    fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self {
1111        // List the available fields sorted and at least one per line, more if `CLIPPY_TERMINAL_WIDTH` is
1112        // set and allows it.
1113        use fmt::Write;
1114
1115        let metadata = get_configuration_metadata();
1116        let deprecated = metadata
1117            .iter()
1118            .filter_map(|conf| {
1119                if conf.deprecation_reason.is_some() {
1120                    Some(conf.name.as_str())
1121                } else {
1122                    None
1123                }
1124            })
1125            .collect::<Vec<_>>();
1126
1127        let mut expected = expected
1128            .iter()
1129            .copied()
1130            .filter(|name| !deprecated.contains(name))
1131            .collect::<Vec<_>>();
1132        expected.sort_unstable();
1133
1134        let (rows, column_widths) = calculate_dimensions(&expected);
1135
1136        let mut msg = format!("unknown field `{field}`, expected one of");
1137        for row in 0..rows {
1138            writeln!(msg).unwrap();
1139            for (column, column_width) in column_widths.iter().copied().enumerate() {
1140                let index = column * rows + row;
1141                let field = expected.get(index).copied().unwrap_or_default();
1142                write!(msg, "{:SEPARATOR_WIDTH$}{field:column_width$}", " ").unwrap();
1143            }
1144        }
1145
1146        let suggestion = suggest_candidate(field, expected).map(|suggestion| Suggestion {
1147            message: "perhaps you meant",
1148            suggestion,
1149        });
1150
1151        Self { error: msg, suggestion }
1152    }
1153}
1154
1155fn calculate_dimensions(fields: &[&str]) -> (usize, Vec<usize>) {
1156    let columns = env::var("CLIPPY_TERMINAL_WIDTH")
1157        .ok()
1158        .and_then(|s| <usize as FromStr>::from_str(&s).ok())
1159        .map_or(1, |terminal_width| {
1160            let max_field_width = fields.iter().map(|field| field.len()).max().unwrap();
1161            cmp::max(1, terminal_width / (SEPARATOR_WIDTH + max_field_width))
1162        });
1163
1164    let rows = fields.len().div_ceil(columns);
1165
1166    let column_widths = (0..columns)
1167        .map(|column| {
1168            if column < columns - 1 {
1169                (0..rows)
1170                    .map(|row| {
1171                        let index = column * rows + row;
1172                        let field = fields.get(index).copied().unwrap_or_default();
1173                        field.len()
1174                    })
1175                    .max()
1176                    .unwrap()
1177            } else {
1178                // Avoid adding extra space to the last column.
1179                0
1180            }
1181        })
1182        .collect::<Vec<_>>();
1183
1184    (rows, column_widths)
1185}
1186
1187/// Given a user-provided value that couldn't be matched to a known option, finds the most likely
1188/// candidate among candidates that the user might have meant.
1189fn suggest_candidate<'a, I>(value: &str, candidates: I) -> Option<&'a str>
1190where
1191    I: IntoIterator<Item = &'a str>,
1192{
1193    candidates
1194        .into_iter()
1195        .filter_map(|expected| {
1196            let dist = edit_distance(value, expected, 4)?;
1197            Some((dist, expected))
1198        })
1199        .min_by_key(|&(dist, _)| dist)
1200        .map(|(_, suggestion)| suggestion)
1201}
1202
1203#[cfg(test)]
1204mod tests {
1205    use serde::de::IgnoredAny;
1206    use std::collections::{HashMap, HashSet};
1207    use std::fs;
1208    use walkdir::WalkDir;
1209
1210    #[test]
1211    fn configs_are_tested() {
1212        let mut names: HashSet<String> = crate::get_configuration_metadata()
1213            .into_iter()
1214            .filter_map(|meta| {
1215                if meta.deprecation_reason.is_none() {
1216                    Some(meta.name.replace('_', "-"))
1217                } else {
1218                    None
1219                }
1220            })
1221            .collect();
1222
1223        let toml_files = WalkDir::new("../tests")
1224            .into_iter()
1225            .map(Result::unwrap)
1226            .filter(|entry| entry.file_name() == "clippy.toml");
1227
1228        for entry in toml_files {
1229            let file = fs::read_to_string(entry.path()).unwrap();
1230            #[expect(clippy::zero_sized_map_values)]
1231            if let Ok(map) = toml::from_str::<HashMap<String, IgnoredAny>>(&file) {
1232                for name in map.keys() {
1233                    names.remove(name.as_str());
1234                }
1235            }
1236        }
1237
1238        assert!(
1239            names.is_empty(),
1240            "Configuration variable lacks test: {names:?}\nAdd a test to `tests/ui-toml`"
1241        );
1242    }
1243}