src/librustc_lint/nonstandard_style.rs

   1 use rustc::hir::{self, GenericParamKind, PatKind};
   2 use rustc::hir::def::{Res, DefKind};
   3 use rustc::hir::intravisit::FnKind;
   4 use rustc::lint;
   5 use rustc::ty;
   6 use rustc_target::spec::abi::Abi;
   7 use lint::{EarlyContext, LateContext, LintContext, LintArray};
   8 use lint::{EarlyLintPass, LintPass, LateLintPass};
   9 use syntax::ast;
  10 use syntax::attr;
  11 use syntax::errors::Applicability;
  12 use syntax::symbol::sym;
  13 use syntax_pos::{BytePos, symbol::Ident, Span};
  14
  15 #[derive(PartialEq)]
  16 pub enum MethodLateContext {
  17     TraitAutoImpl,
  18     TraitImpl,
  19     PlainImpl,
  20 }
  21
  22 pub fn method_context(cx: &LateContext<'_, '_>, id: hir::HirId) -> MethodLateContext {
  23     let def_id = cx.tcx.hir().local_def_id(id);
  24     let item = cx.tcx.associated_item(def_id);
  25     match item.container {
  26         ty::TraitContainer(..) => MethodLateContext::TraitAutoImpl,
  27         ty::ImplContainer(cid) => {
  28             match cx.tcx.impl_trait_ref(cid) {
  29                 Some(_) => MethodLateContext::TraitImpl,
  30                 None => MethodLateContext::PlainImpl,
  31             }
  32         }
  33     }
  34 }
  35
  36 declare_lint! {
  37     pub NON_CAMEL_CASE_TYPES,
  38     Warn,
  39     "types, variants, traits and type parameters should have camel case names"
  40 }
  41
  42 declare_lint_pass!(NonCamelCaseTypes => [NON_CAMEL_CASE_TYPES]);
  43
  44 fn char_has_case(c: char) -> bool {
  45     c.is_lowercase() || c.is_uppercase()
  46 }
  47
  48 fn is_camel_case(name: &str) -> bool {
  49     let name = name.trim_matches('_');
  50     if name.is_empty() {
  51         return true;
  52     }
  53
  54     // start with a non-lowercase letter rather than non-uppercase
  55     // ones (some scripts don't have a concept of upper/lowercase)
  56     !name.chars().next().unwrap().is_lowercase()
  57         && !name.contains("__")
  58         && !name.chars().collect::<Vec<_>>().windows(2).any(|pair| {
  59             // contains a capitalisable character followed by, or preceded by, an underscore
  60             char_has_case(pair[0]) && pair[1] == '_' || char_has_case(pair[1]) && pair[0] == '_'
  61         })
  62 }
  63
  64 fn to_camel_case(s: &str) -> String {
  65     s.trim_matches('_')
  66         .split('_')
  67         .filter(|component| !component.is_empty())
  68         .map(|component| {
  69             let mut camel_cased_component = String::new();
  70
  71             let mut new_word = true;
  72             let mut prev_is_lower_case = true;
  73
  74             for c in component.chars() {
  75                 // Preserve the case if an uppercase letter follows a lowercase letter, so that
  76                 // `camelCase` is converted to `CamelCase`.
  77                 if prev_is_lower_case && c.is_uppercase() {
  78                     new_word = true;
  79                 }
  80
  81                 if new_word {
  82                     camel_cased_component.push_str(&c.to_uppercase().to_string());
  83                 } else {
  84                     camel_cased_component.push_str(&c.to_lowercase().to_string());
  85                 }
  86
  87                 prev_is_lower_case = c.is_lowercase();
  88                 new_word = false;
  89             }
  90
  91             camel_cased_component
  92         })
  93         .fold(
  94             (String::new(), None),
  95             |(acc, prev): (String, Option<String>), next| {
  96                 // separate two components with an underscore if their boundary cannot
  97                 // be distinguished using a uppercase/lowercase case distinction
  98                 let join = if let Some(prev) = prev {
  99                     let l = prev.chars().last().unwrap();
 100                     let f = next.chars().next().unwrap();
 101                     !char_has_case(l) && !char_has_case(f)
 102                 } else {
 103                     false
 104                 };
 105                 (acc + if join { "_" } else { "" } + &next, Some(next))
 106             },
 107         )
 108         .0
 109 }
 110
 111 impl NonCamelCaseTypes {
 112     fn check_case(&self, cx: &EarlyContext<'_>, sort: &str, ident: &Ident) {
 113         let name = &ident.name.as_str();
 114
 115         if !is_camel_case(name) {
 116             let msg = format!("{} `{}` should have an upper camel case name", sort, name);
 117             cx.struct_span_lint(NON_CAMEL_CASE_TYPES, ident.span, &msg)
 118                 .span_suggestion(
 119                     ident.span,
 120                     "convert the identifier to upper camel case",
 121                     to_camel_case(name),
 122                     Applicability::MaybeIncorrect,
 123                 )
 124                 .emit();
 125         }
 126     }
 127 }
 128
 129 impl EarlyLintPass for NonCamelCaseTypes {
 130     fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) {
 131         let has_repr_c = it.attrs
 132             .iter()
 133             .any(|attr| attr::find_repr_attrs(&cx.sess.parse_sess, attr).contains(&attr::ReprC));
 134
 135         if has_repr_c {
 136             return;
 137         }
 138
 139         match it.node {
 140             ast::ItemKind::TyAlias(..) |
 141             ast::ItemKind::Enum(..) |
 142             ast::ItemKind::Struct(..) |
 143             ast::ItemKind::Union(..) => self.check_case(cx, "type", &it.ident),
 144             ast::ItemKind::Trait(..) => self.check_case(cx, "trait", &it.ident),
 145             _ => (),
 146         }
 147     }
 148
 149     fn check_variant(&mut self, cx: &EarlyContext<'_>, v: &ast::Variant, _: &ast::Generics) {
 150         self.check_case(cx, "variant", &v.node.ident);
 151     }
 152
 153     fn check_generic_param(&mut self, cx: &EarlyContext<'_>, param: &ast::GenericParam) {
 154         if let ast::GenericParamKind::Type { .. } = param.kind {
 155             self.check_case(cx, "type parameter", &param.ident);
 156         }
 157     }
 158 }
 159
 160 declare_lint! {
 161     pub NON_SNAKE_CASE,
 162     Warn,
 163     "variables, methods, functions, lifetime parameters and modules should have snake case names"
 164 }
 165
 166 declare_lint_pass!(NonSnakeCase => [NON_SNAKE_CASE]);
 167
 168 impl NonSnakeCase {
 169     fn to_snake_case(mut str: &str) -> String {
 170         let mut words = vec![];
 171         // Preserve leading underscores
 172         str = str.trim_start_matches(|c: char| {
 173             if c == '_' {
 174                 words.push(String::new());
 175                 true
 176             } else {
 177                 false
 178             }
 179         });
 180         for s in str.split('_') {
 181             let mut last_upper = false;
 182             let mut buf = String::new();
 183             if s.is_empty() {
 184                 continue;
 185             }
 186             for ch in s.chars() {
 187                 if !buf.is_empty() && buf != "'" && ch.is_uppercase() && !last_upper {
 188                     words.push(buf);
 189                     buf = String::new();
 190                 }
 191                 last_upper = ch.is_uppercase();
 192                 buf.extend(ch.to_lowercase());
 193             }
 194             words.push(buf);
 195         }
 196         words.join("_")
 197     }
 198
 199     /// Checks if a given identifier is snake case, and reports a diagnostic if not.
 200     fn check_snake_case(&self, cx: &LateContext<'_, '_>, sort: &str, ident: &Ident) {
 201         fn is_snake_case(ident: &str) -> bool {
 202             if ident.is_empty() {
 203                 return true;
 204             }
 205             let ident = ident.trim_start_matches('\'');
 206             let ident = ident.trim_matches('_');
 207
 208             let mut allow_underscore = true;
 209             ident.chars().all(|c| {
 210                 allow_underscore = match c {
 211                     '_' if !allow_underscore => return false,
 212                     '_' => false,
 213                     // It would be more obvious to use `c.is_lowercase()`,
 214                     // but some characters do not have a lowercase form
 215                     c if !c.is_uppercase() => true,
 216                     _ => return false,
 217                 };
 218                 true
 219             })
 220         }
 221
 222         let name = &ident.name.as_str();
 223
 224         if !is_snake_case(name) {
 225             let sc = NonSnakeCase::to_snake_case(name);
 226
 227             let msg = format!("{} `{}` should have a snake case name", sort, name);
 228             let mut err = cx.struct_span_lint(NON_SNAKE_CASE, ident.span, &msg);
 229
 230             // We have a valid span in almost all cases, but we don't have one when linting a crate
 231             // name provided via the command line.
 232             if !ident.span.is_dummy() {
 233                 err.span_suggestion(
 234                     ident.span,
 235                     "convert the identifier to snake case",
 236                     sc,
 237                     Applicability::MaybeIncorrect,
 238                 );
 239             } else {
 240                 err.help(&format!("convert the identifier to snake case: `{}`", sc));
 241             }
 242
 243             err.emit();
 244         }
 245     }
 246 }
 247
 248 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
 249     fn check_mod(&mut self, cx: &LateContext<'_, '_>, _: &'tcx hir::Mod, _: Span, id: hir::HirId) {
 250         if id != hir::CRATE_HIR_ID {
 251             return;
 252         }
 253
 254         let crate_ident = if let Some(name) = &cx.tcx.sess.opts.crate_name {
 255             Some(Ident::from_str(name))
 256         } else {
 257             attr::find_by_name(&cx.tcx.hir().attrs(hir::CRATE_HIR_ID), sym::crate_name)
 258                 .and_then(|attr| attr.meta())
 259                 .and_then(|meta| {
 260                     meta.name_value_literal().and_then(|lit| {
 261                         if let ast::LitKind::Str(name, ..) = lit.node {
 262                             // Discard the double quotes surrounding the literal.
 263                             let sp = cx.sess().source_map().span_to_snippet(lit.span)
 264                                 .ok()
 265                                 .and_then(|snippet| {
 266                                     let left = snippet.find('"')?;
 267                                     let right = snippet.rfind('"').map(|pos| snippet.len() - pos)?;
 268
 269                                     Some(
 270                                         lit.span
 271                                             .with_lo(lit.span.lo() + BytePos(left as u32 + 1))
 272                                             .with_hi(lit.span.hi() - BytePos(right as u32)),
 273                                     )
 274                                 })
 275                                 .unwrap_or_else(|| lit.span);
 276
 277                             Some(Ident::new(name, sp))
 278                         } else {
 279                             None
 280                         }
 281                     })
 282                 })
 283         };
 284
 285         if let Some(ident) = &crate_ident {
 286             self.check_snake_case(cx, "crate", ident);
 287         }
 288     }
 289
 290     fn check_generic_param(&mut self, cx: &LateContext<'_, '_>, param: &hir::GenericParam) {
 291         if let GenericParamKind::Lifetime { .. } = param.kind {
 292             self.check_snake_case(cx, "lifetime", &param.name.ident());
 293         }
 294     }
 295
 296     fn check_fn(
 297         &mut self,
 298         cx: &LateContext<'_, '_>,
 299         fk: FnKind<'_>,
 300         _: &hir::FnDecl,
 301         _: &hir::Body,
 302         _: Span,
 303         id: hir::HirId,
 304     ) {
 305         match &fk {
 306             FnKind::Method(ident, ..) => {
 307                 match method_context(cx, id) {
 308                     MethodLateContext::PlainImpl => {
 309                         self.check_snake_case(cx, "method", ident);
 310                     }
 311                     MethodLateContext::TraitAutoImpl => {
 312                         self.check_snake_case(cx, "trait method", ident);
 313                     }
 314                     _ => (),
 315                 }
 316             }
 317             FnKind::ItemFn(ident, _, header, _, attrs) => {
 318                 // Skip foreign-ABI #[no_mangle] functions (Issue #31924)
 319                 if header.abi != Abi::Rust && attr::contains_name(attrs, sym::no_mangle) {
 320                     return;
 321                 }
 322                 self.check_snake_case(cx, "function", ident);
 323             }
 324             FnKind::Closure(_) => (),
 325         }
 326     }
 327
 328     fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
 329         if let hir::ItemKind::Mod(_) = it.node {
 330             self.check_snake_case(cx, "module", &it.ident);
 331         }
 332     }
 333
 334     fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::TraitItem) {
 335         if let hir::TraitItemKind::Method(_, hir::TraitMethod::Required(pnames)) = &item.node {
 336             self.check_snake_case(cx, "trait method", &item.ident);
 337             for param_name in pnames {
 338                 self.check_snake_case(cx, "variable", param_name);
 339             }
 340         }
 341     }
 342
 343     fn check_pat(&mut self, cx: &LateContext<'_, '_>, p: &hir::Pat) {
 344         if let &PatKind::Binding(_, _, ident, _) = &p.node {
 345             self.check_snake_case(cx, "variable", &ident);
 346         }
 347     }
 348
 349     fn check_struct_def(
 350         &mut self,
 351         cx: &LateContext<'_, '_>,
 352         s: &hir::VariantData,
 353         _: ast::Name,
 354         _: &hir::Generics,
 355         _: hir::HirId,
 356     ) {
 357         for sf in s.fields() {
 358             self.check_snake_case(cx, "structure field", &sf.ident);
 359         }
 360     }
 361 }
 362
 363 declare_lint! {
 364     pub NON_UPPER_CASE_GLOBALS,
 365     Warn,
 366     "static constants should have uppercase identifiers"
 367 }
 368
 369 declare_lint_pass!(NonUpperCaseGlobals => [NON_UPPER_CASE_GLOBALS]);
 370
 371 impl NonUpperCaseGlobals {
 372     fn check_upper_case(cx: &LateContext<'_, '_>, sort: &str, ident: &Ident) {
 373         let name = &ident.name.as_str();
 374
 375         if name.chars().any(|c| c.is_lowercase()) {
 376             let uc = NonSnakeCase::to_snake_case(&name).to_uppercase();
 377
 378             let msg = format!("{} `{}` should have an upper case name", sort, name);
 379             cx.struct_span_lint(NON_UPPER_CASE_GLOBALS, ident.span, &msg)
 380                 .span_suggestion(
 381                     ident.span,
 382                     "convert the identifier to upper case",
 383                     uc,
 384                     Applicability::MaybeIncorrect,
 385                 )
 386                 .emit();
 387         }
 388     }
 389 }
 390
 391 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonUpperCaseGlobals {
 392     fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
 393         match it.node {
 394             hir::ItemKind::Static(..) if !attr::contains_name(&it.attrs, sym::no_mangle) => {
 395                 NonUpperCaseGlobals::check_upper_case(cx, "static variable", &it.ident);
 396             }
 397             hir::ItemKind::Const(..) => {
 398                 NonUpperCaseGlobals::check_upper_case(cx, "constant", &it.ident);
 399             }
 400             _ => {}
 401         }
 402     }
 403
 404     fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, ti: &hir::TraitItem) {
 405         if let hir::TraitItemKind::Const(..) = ti.node {
 406             NonUpperCaseGlobals::check_upper_case(cx, "associated constant", &ti.ident);
 407         }
 408     }
 409
 410     fn check_impl_item(&mut self, cx: &LateContext<'_, '_>, ii: &hir::ImplItem) {
 411         if let hir::ImplItemKind::Const(..) = ii.node {
 412             NonUpperCaseGlobals::check_upper_case(cx, "associated constant", &ii.ident);
 413         }
 414     }
 415
 416     fn check_pat(&mut self, cx: &LateContext<'_, '_>, p: &hir::Pat) {
 417         // Lint for constants that look like binding identifiers (#7526)
 418         if let PatKind::Path(hir::QPath::Resolved(None, ref path)) = p.node {
 419             if let Res::Def(DefKind::Const, _) = path.res {
 420                 if path.segments.len() == 1 {
 421                     NonUpperCaseGlobals::check_upper_case(
 422                         cx,
 423                         "constant in pattern",
 424                         &path.segments[0].ident
 425                     );
 426                 }
 427             }
 428         }
 429     }
 430
 431     fn check_generic_param(&mut self, cx: &LateContext<'_, '_>, param: &hir::GenericParam) {
 432         if let GenericParamKind::Const { .. } = param.kind {
 433             NonUpperCaseGlobals::check_upper_case(
 434                 cx,
 435                 "const parameter",
 436                 &param.name.ident(),
 437             );
 438         }
 439     }
 440 }
 441
 442 #[cfg(test)]
 443 mod tests;