src/tools/clippy/clippy_lints/src/utils/author.rs

   1 //! A group of attributes that can be attached to Rust code in order
   2 //! to generate a clippy lint detecting said code automatically.
   3
   4 use clippy_utils::{get_attr, higher};
   5 use rustc_ast::ast::{LitFloatType, LitKind};
   6 use rustc_ast::LitIntType;
   7 use rustc_data_structures::fx::FxHashMap;
   8 use rustc_hir as hir;
   9 use rustc_hir::{
  10     ArrayLen, BindingAnnotation, Closure, ExprKind, FnRetTy, HirId, Lit, PatKind, QPath, StmtKind, TyKind,
  11 };
  12 use rustc_lint::{LateContext, LateLintPass, LintContext};
  13 use rustc_session::{declare_lint_pass, declare_tool_lint};
  14 use rustc_span::symbol::{Ident, Symbol};
  15 use std::fmt::{Display, Formatter, Write as _};
  16
  17 declare_clippy_lint! {
  18     /// ### What it does
  19     /// Generates clippy code that detects the offending pattern
  20     ///
  21     /// ### Example
  22     /// ```rust,ignore
  23     /// // ./tests/ui/my_lint.rs
  24     /// fn foo() {
  25     ///     // detect the following pattern
  26     ///     #[clippy::author]
  27     ///     if x == 42 {
  28     ///         // but ignore everything from here on
  29     ///         #![clippy::author = "ignore"]
  30     ///     }
  31     ///     ()
  32     /// }
  33     /// ```
  34     ///
  35     /// Running `TESTNAME=ui/my_lint cargo uitest` will produce
  36     /// a `./tests/ui/new_lint.stdout` file with the generated code:
  37     ///
  38     /// ```rust,ignore
  39     /// // ./tests/ui/new_lint.stdout
  40     /// if_chain! {
  41     ///     if let ExprKind::If(ref cond, ref then, None) = item.kind,
  42     ///     if let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.kind,
  43     ///     if let ExprKind::Path(ref path) = left.kind,
  44     ///     if let ExprKind::Lit(ref lit) = right.kind,
  45     ///     if let LitKind::Int(42, _) = lit.node,
  46     ///     then {
  47     ///         // report your lint here
  48     ///     }
  49     /// }
  50     /// ```
  51     pub LINT_AUTHOR,
  52     internal_warn,
  53     "helper for writing lints"
  54 }
  55
  56 declare_lint_pass!(Author => [LINT_AUTHOR]);
  57
  58 /// Writes a line of output with indentation added
  59 macro_rules! out {
  60     ($($t:tt)*) => {
  61         println!("    {}", format_args!($($t)*))
  62     };
  63 }
  64
  65 /// The variables passed in are replaced with `&Binding`s where the `value` field is set
  66 /// to the original value of the variable. The `name` field is set to the name of the variable
  67 /// (using `stringify!`) and is adjusted to avoid duplicate names.
  68 /// Note that the `Binding` may be printed directly to output the `name`.
  69 macro_rules! bind {
  70     ($self:ident $(, $name:ident)+) => {
  71         $(let $name = & $self.bind(stringify!($name), $name);)+
  72     };
  73 }
  74
  75 /// Transforms the given `Option<T>` variables into `OptionPat<Binding<T>>`.
  76 /// This displays as `Some($name)` or `None` when printed. The name of the inner binding
  77 /// is set to the name of the variable passed to the macro.
  78 macro_rules! opt_bind {
  79     ($self:ident $(, $name:ident)+) => {
  80         $(let $name = OptionPat::new($name.map(|o| $self.bind(stringify!($name), o)));)+
  81     };
  82 }
  83
  84 /// Creates a `Binding` that accesses the field of an existing `Binding`
  85 macro_rules! field {
  86     ($binding:ident.$field:ident) => {
  87         &Binding {
  88             name: $binding.name.to_string() + stringify!(.$field),
  89             value: $binding.value.$field,
  90         }
  91     };
  92 }
  93
  94 fn prelude() {
  95     println!("if_chain! {{");
  96 }
  97
  98 fn done() {
  99     println!("    then {{");
 100     println!("        // report your lint here");
 101     println!("    }}");
 102     println!("}}");
 103 }
 104
 105 impl<'tcx> LateLintPass<'tcx> for Author {
 106     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
 107         check_item(cx, item.hir_id());
 108     }
 109
 110     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) {
 111         check_item(cx, item.hir_id());
 112     }
 113
 114     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
 115         check_item(cx, item.hir_id());
 116     }
 117
 118     fn check_arm(&mut self, cx: &LateContext<'tcx>, arm: &'tcx hir::Arm<'_>) {
 119         check_node(cx, arm.hir_id, |v| {
 120             v.arm(&v.bind("arm", arm));
 121         });
 122     }
 123
 124     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
 125         check_node(cx, expr.hir_id, |v| {
 126             v.expr(&v.bind("expr", expr));
 127         });
 128     }
 129
 130     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx hir::Stmt<'_>) {
 131         match stmt.kind {
 132             StmtKind::Expr(e) | StmtKind::Semi(e) if has_attr(cx, e.hir_id) => return,
 133             _ => {},
 134         }
 135         check_node(cx, stmt.hir_id, |v| {
 136             v.stmt(&v.bind("stmt", stmt));
 137         });
 138     }
 139 }
 140
 141 fn check_item(cx: &LateContext<'_>, hir_id: HirId) {
 142     let hir = cx.tcx.hir();
 143     if let Some(body_id) = hir.maybe_body_owned_by(hir_id.expect_owner().def_id) {
 144         check_node(cx, hir_id, |v| {
 145             v.expr(&v.bind("expr", hir.body(body_id).value));
 146         });
 147     }
 148 }
 149
 150 fn check_node(cx: &LateContext<'_>, hir_id: HirId, f: impl Fn(&PrintVisitor<'_, '_>)) {
 151     if has_attr(cx, hir_id) {
 152         prelude();
 153         f(&PrintVisitor::new(cx));
 154         done();
 155     }
 156 }
 157
 158 struct Binding<T> {
 159     name: String,
 160     value: T,
 161 }
 162
 163 impl<T> Display for Binding<T> {
 164     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
 165         f.write_str(&self.name)
 166     }
 167 }
 168
 169 struct OptionPat<T> {
 170     pub opt: Option<T>,
 171 }
 172
 173 impl<T> OptionPat<T> {
 174     fn new(opt: Option<T>) -> Self {
 175         Self { opt }
 176     }
 177
 178     fn if_some(&self, f: impl Fn(&T)) {
 179         if let Some(t) = &self.opt {
 180             f(t);
 181         }
 182     }
 183 }
 184
 185 impl<T: Display> Display for OptionPat<T> {
 186     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
 187         match &self.opt {
 188             None => f.write_str("None"),
 189             Some(node) => write!(f, "Some({node})"),
 190         }
 191     }
 192 }
 193
 194 struct PrintVisitor<'a, 'tcx> {
 195     cx: &'a LateContext<'tcx>,
 196     /// Fields are the current index that needs to be appended to pattern
 197     /// binding names
 198     ids: std::cell::Cell<FxHashMap<&'static str, u32>>,
 199 }
 200
 201 #[allow(clippy::unused_self)]
 202 impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 203     fn new(cx: &'a LateContext<'tcx>) -> Self {
 204         Self {
 205             cx,
 206             ids: std::cell::Cell::default(),
 207         }
 208     }
 209
 210     fn next(&self, s: &'static str) -> String {
 211         let mut ids = self.ids.take();
 212         let out = match *ids.entry(s).and_modify(|n| *n += 1).or_default() {
 213             // first usage of the name, use it as is
 214             0 => s.to_string(),
 215             // append a number starting with 1
 216             n => format!("{s}{n}"),
 217         };
 218         self.ids.set(ids);
 219         out
 220     }
 221
 222     fn bind<T>(&self, name: &'static str, value: T) -> Binding<T> {
 223         let name = self.next(name);
 224         Binding { name, value }
 225     }
 226
 227     fn option<T: Copy>(&self, option: &Binding<Option<T>>, name: &'static str, f: impl Fn(&Binding<T>)) {
 228         match option.value {
 229             None => out!("if {option}.is_none();"),
 230             Some(value) => {
 231                 let value = &self.bind(name, value);
 232                 out!("if let Some({value}) = {option};");
 233                 f(value);
 234             },
 235         }
 236     }
 237
 238     fn slice<T>(&self, slice: &Binding<&[T]>, f: impl Fn(&Binding<&T>)) {
 239         if slice.value.is_empty() {
 240             out!("if {slice}.is_empty();");
 241         } else {
 242             out!("if {slice}.len() == {};", slice.value.len());
 243             for (i, value) in slice.value.iter().enumerate() {
 244                 let name = format!("{slice}[{i}]");
 245                 f(&Binding { name, value });
 246             }
 247         }
 248     }
 249
 250     fn destination(&self, destination: &Binding<hir::Destination>) {
 251         self.option(field!(destination.label), "label", |label| {
 252             self.ident(field!(label.ident));
 253         });
 254     }
 255
 256     fn ident(&self, ident: &Binding<Ident>) {
 257         out!("if {ident}.as_str() == {:?};", ident.value.as_str());
 258     }
 259
 260     fn symbol(&self, symbol: &Binding<Symbol>) {
 261         out!("if {symbol}.as_str() == {:?};", symbol.value.as_str());
 262     }
 263
 264     fn qpath(&self, qpath: &Binding<&QPath<'_>>) {
 265         if let QPath::LangItem(lang_item, ..) = *qpath.value {
 266             out!("if matches!({qpath}, QPath::LangItem(LangItem::{lang_item:?}, _));");
 267         } else {
 268             out!("if match_qpath({qpath}, &[{}]);", path_to_string(qpath.value));
 269         }
 270     }
 271
 272     fn lit(&self, lit: &Binding<&Lit>) {
 273         let kind = |kind| out!("if let LitKind::{kind} = {lit}.node;");
 274         macro_rules! kind {
 275             ($($t:tt)*) => (kind(format_args!($($t)*)));
 276         }
 277
 278         match lit.value.node {
 279             LitKind::Bool(val) => kind!("Bool({val:?})"),
 280             LitKind::Char(c) => kind!("Char({c:?})"),
 281             LitKind::Err => kind!("Err"),
 282             LitKind::Byte(b) => kind!("Byte({b})"),
 283             LitKind::Int(i, suffix) => {
 284                 let int_ty = match suffix {
 285                     LitIntType::Signed(int_ty) => format!("LitIntType::Signed(IntTy::{int_ty:?})"),
 286                     LitIntType::Unsigned(uint_ty) => format!("LitIntType::Unsigned(UintTy::{uint_ty:?})"),
 287                     LitIntType::Unsuffixed => String::from("LitIntType::Unsuffixed"),
 288                 };
 289                 kind!("Int({i}, {int_ty})");
 290             },
 291             LitKind::Float(_, suffix) => {
 292                 let float_ty = match suffix {
 293                     LitFloatType::Suffixed(suffix_ty) => format!("LitFloatType::Suffixed(FloatTy::{suffix_ty:?})"),
 294                     LitFloatType::Unsuffixed => String::from("LitFloatType::Unsuffixed"),
 295                 };
 296                 kind!("Float(_, {float_ty})");
 297             },
 298             LitKind::ByteStr(ref vec) => {
 299                 bind!(self, vec);
 300                 kind!("ByteStr(ref {vec})");
 301                 out!("if let [{:?}] = **{vec};", vec.value);
 302             },
 303             LitKind::Str(s, _) => {
 304                 bind!(self, s);
 305                 kind!("Str({s}, _)");
 306                 self.symbol(s);
 307             },
 308         }
 309     }
 310
 311     fn arm(&self, arm: &Binding<&hir::Arm<'_>>) {
 312         self.pat(field!(arm.pat));
 313         match arm.value.guard {
 314             None => out!("if {arm}.guard.is_none();"),
 315             Some(hir::Guard::If(expr)) => {
 316                 bind!(self, expr);
 317                 out!("if let Some(Guard::If({expr})) = {arm}.guard;");
 318                 self.expr(expr);
 319             },
 320             Some(hir::Guard::IfLet(let_expr)) => {
 321                 bind!(self, let_expr);
 322                 out!("if let Some(Guard::IfLet({let_expr}) = {arm}.guard;");
 323                 self.pat(field!(let_expr.pat));
 324                 self.expr(field!(let_expr.init));
 325             },
 326         }
 327         self.expr(field!(arm.body));
 328     }
 329
 330     #[allow(clippy::too_many_lines)]
 331     fn expr(&self, expr: &Binding<&hir::Expr<'_>>) {
 332         if let Some(higher::While { condition, body }) = higher::While::hir(expr.value) {
 333             bind!(self, condition, body);
 334             out!(
 335                 "if let Some(higher::While {{ condition: {condition}, body: {body} }}) \
 336                 = higher::While::hir({expr});"
 337             );
 338             self.expr(condition);
 339             self.expr(body);
 340             return;
 341         }
 342
 343         if let Some(higher::WhileLet {
 344             let_pat,
 345             let_expr,
 346             if_then,
 347         }) = higher::WhileLet::hir(expr.value)
 348         {
 349             bind!(self, let_pat, let_expr, if_then);
 350             out!(
 351                 "if let Some(higher::WhileLet {{ let_pat: {let_pat}, let_expr: {let_expr}, if_then: {if_then} }}) \
 352                 = higher::WhileLet::hir({expr});"
 353             );
 354             self.pat(let_pat);
 355             self.expr(let_expr);
 356             self.expr(if_then);
 357             return;
 358         }
 359
 360         if let Some(higher::ForLoop { pat, arg, body, .. }) = higher::ForLoop::hir(expr.value) {
 361             bind!(self, pat, arg, body);
 362             out!(
 363                 "if let Some(higher::ForLoop {{ pat: {pat}, arg: {arg}, body: {body}, .. }}) \
 364                 = higher::ForLoop::hir({expr});"
 365             );
 366             self.pat(pat);
 367             self.expr(arg);
 368             self.expr(body);
 369             return;
 370         }
 371
 372         let kind = |kind| out!("if let ExprKind::{kind} = {expr}.kind;");
 373         macro_rules! kind {
 374             ($($t:tt)*) => (kind(format_args!($($t)*)));
 375         }
 376
 377         match expr.value.kind {
 378             ExprKind::Let(let_expr) => {
 379                 bind!(self, let_expr);
 380                 kind!("Let({let_expr})");
 381                 self.pat(field!(let_expr.pat));
 382                 // Does what ExprKind::Cast does, only adds a clause for the type
 383                 // if it's a path
 384                 if let Some(TyKind::Path(ref qpath)) = let_expr.value.ty.as_ref().map(|ty| &ty.kind) {
 385                     bind!(self, qpath);
 386                     out!("if let TyKind::Path(ref {qpath}) = {let_expr}.ty.kind;");
 387                     self.qpath(qpath);
 388                 }
 389                 self.expr(field!(let_expr.init));
 390             },
 391             ExprKind::Box(inner) => {
 392                 bind!(self, inner);
 393                 kind!("Box({inner})");
 394                 self.expr(inner);
 395             },
 396             ExprKind::Array(elements) => {
 397                 bind!(self, elements);
 398                 kind!("Array({elements})");
 399                 self.slice(elements, |e| self.expr(e));
 400             },
 401             ExprKind::Call(func, args) => {
 402                 bind!(self, func, args);
 403                 kind!("Call({func}, {args})");
 404                 self.expr(func);
 405                 self.slice(args, |e| self.expr(e));
 406             },
 407             ExprKind::MethodCall(method_name, receiver, args, _) => {
 408                 bind!(self, method_name, receiver, args);
 409                 kind!("MethodCall({method_name}, {receiver}, {args}, _)");
 410                 self.ident(field!(method_name.ident));
 411                 self.expr(receiver);
 412                 self.slice(args, |e| self.expr(e));
 413             },
 414             ExprKind::Tup(elements) => {
 415                 bind!(self, elements);
 416                 kind!("Tup({elements})");
 417                 self.slice(elements, |e| self.expr(e));
 418             },
 419             ExprKind::Binary(op, left, right) => {
 420                 bind!(self, op, left, right);
 421                 kind!("Binary({op}, {left}, {right})");
 422                 out!("if BinOpKind::{:?} == {op}.node;", op.value.node);
 423                 self.expr(left);
 424                 self.expr(right);
 425             },
 426             ExprKind::Unary(op, inner) => {
 427                 bind!(self, inner);
 428                 kind!("Unary(UnOp::{op:?}, {inner})");
 429                 self.expr(inner);
 430             },
 431             ExprKind::Lit(ref lit) => {
 432                 bind!(self, lit);
 433                 kind!("Lit(ref {lit})");
 434                 self.lit(lit);
 435             },
 436             ExprKind::Cast(expr, cast_ty) => {
 437                 bind!(self, expr, cast_ty);
 438                 kind!("Cast({expr}, {cast_ty})");
 439                 if let TyKind::Path(ref qpath) = cast_ty.value.kind {
 440                     bind!(self, qpath);
 441                     out!("if let TyKind::Path(ref {qpath}) = {cast_ty}.kind;");
 442                     self.qpath(qpath);
 443                 }
 444                 self.expr(expr);
 445             },
 446             ExprKind::Type(expr, _ty) => {
 447                 bind!(self, expr);
 448                 kind!("Type({expr}, _)");
 449                 self.expr(expr);
 450             },
 451             ExprKind::Loop(body, label, des, _) => {
 452                 bind!(self, body);
 453                 opt_bind!(self, label);
 454                 kind!("Loop({body}, {label}, LoopSource::{des:?}, _)");
 455                 self.block(body);
 456                 label.if_some(|l| self.ident(field!(l.ident)));
 457             },
 458             ExprKind::If(cond, then, else_expr) => {
 459                 bind!(self, cond, then);
 460                 opt_bind!(self, else_expr);
 461                 kind!("If({cond}, {then}, {else_expr})");
 462                 self.expr(cond);
 463                 self.expr(then);
 464                 else_expr.if_some(|e| self.expr(e));
 465             },
 466             ExprKind::Match(scrutinee, arms, des) => {
 467                 bind!(self, scrutinee, arms);
 468                 kind!("Match({scrutinee}, {arms}, MatchSource::{des:?})");
 469                 self.expr(scrutinee);
 470                 self.slice(arms, |arm| self.arm(arm));
 471             },
 472             ExprKind::Closure(&Closure {
 473                 capture_clause,
 474                 fn_decl,
 475                 body: body_id,
 476                 movability,
 477                 ..
 478             }) => {
 479                 let movability = OptionPat::new(movability.map(|m| format!("Movability::{m:?}")));
 480
 481                 let ret_ty = match fn_decl.output {
 482                     FnRetTy::DefaultReturn(_) => "FnRetTy::DefaultReturn(_)",
 483                     FnRetTy::Return(_) => "FnRetTy::Return(_ty)",
 484                 };
 485
 486                 bind!(self, fn_decl, body_id);
 487                 kind!("Closure(CaptureBy::{capture_clause:?}, {fn_decl}, {body_id}, _, {movability})");
 488                 out!("if let {ret_ty} = {fn_decl}.output;");
 489                 self.body(body_id);
 490             },
 491             ExprKind::Yield(sub, source) => {
 492                 bind!(self, sub);
 493                 kind!("Yield(sub, YieldSource::{source:?})");
 494                 self.expr(sub);
 495             },
 496             ExprKind::Block(block, label) => {
 497                 bind!(self, block);
 498                 opt_bind!(self, label);
 499                 kind!("Block({block}, {label})");
 500                 self.block(block);
 501                 label.if_some(|l| self.ident(field!(l.ident)));
 502             },
 503             ExprKind::Assign(target, value, _) => {
 504                 bind!(self, target, value);
 505                 kind!("Assign({target}, {value}, _span)");
 506                 self.expr(target);
 507                 self.expr(value);
 508             },
 509             ExprKind::AssignOp(op, target, value) => {
 510                 bind!(self, op, target, value);
 511                 kind!("AssignOp({op}, {target}, {value})");
 512                 out!("if BinOpKind::{:?} == {op}.node;", op.value.node);
 513                 self.expr(target);
 514                 self.expr(value);
 515             },
 516             ExprKind::Field(object, field_name) => {
 517                 bind!(self, object, field_name);
 518                 kind!("Field({object}, {field_name})");
 519                 self.ident(field_name);
 520                 self.expr(object);
 521             },
 522             ExprKind::Index(object, index) => {
 523                 bind!(self, object, index);
 524                 kind!("Index({object}, {index})");
 525                 self.expr(object);
 526                 self.expr(index);
 527             },
 528             ExprKind::Path(ref qpath) => {
 529                 bind!(self, qpath);
 530                 kind!("Path(ref {qpath})");
 531                 self.qpath(qpath);
 532             },
 533             ExprKind::AddrOf(kind, mutability, inner) => {
 534                 bind!(self, inner);
 535                 kind!("AddrOf(BorrowKind::{kind:?}, Mutability::{mutability:?}, {inner})");
 536                 self.expr(inner);
 537             },
 538             ExprKind::Break(destination, value) => {
 539                 bind!(self, destination);
 540                 opt_bind!(self, value);
 541                 kind!("Break({destination}, {value})");
 542                 self.destination(destination);
 543                 value.if_some(|e| self.expr(e));
 544             },
 545             ExprKind::Continue(destination) => {
 546                 bind!(self, destination);
 547                 kind!("Continue({destination})");
 548                 self.destination(destination);
 549             },
 550             ExprKind::Ret(value) => {
 551                 opt_bind!(self, value);
 552                 kind!("Ret({value})");
 553                 value.if_some(|e| self.expr(e));
 554             },
 555             ExprKind::InlineAsm(_) => {
 556                 kind!("InlineAsm(_)");
 557                 out!("// unimplemented: `ExprKind::InlineAsm` is not further destructured at the moment");
 558             },
 559             ExprKind::Struct(qpath, fields, base) => {
 560                 bind!(self, qpath, fields);
 561                 opt_bind!(self, base);
 562                 kind!("Struct({qpath}, {fields}, {base})");
 563                 self.qpath(qpath);
 564                 self.slice(fields, |field| {
 565                     self.ident(field!(field.ident));
 566                     self.expr(field!(field.expr));
 567                 });
 568                 base.if_some(|e| self.expr(e));
 569             },
 570             ExprKind::ConstBlock(_) => kind!("ConstBlock(_)"),
 571             ExprKind::Repeat(value, length) => {
 572                 bind!(self, value, length);
 573                 kind!("Repeat({value}, {length})");
 574                 self.expr(value);
 575                 match length.value {
 576                     ArrayLen::Infer(..) => out!("if let ArrayLen::Infer(..) = length;"),
 577                     ArrayLen::Body(anon_const) => {
 578                         bind!(self, anon_const);
 579                         out!("if let ArrayLen::Body({anon_const}) = {length};");
 580                         self.body(field!(anon_const.body));
 581                     },
 582                 }
 583             },
 584             ExprKind::Err => kind!("Err"),
 585             ExprKind::DropTemps(expr) => {
 586                 bind!(self, expr);
 587                 kind!("DropTemps({expr})");
 588                 self.expr(expr);
 589             },
 590         }
 591     }
 592
 593     fn block(&self, block: &Binding<&hir::Block<'_>>) {
 594         self.slice(field!(block.stmts), |stmt| self.stmt(stmt));
 595         self.option(field!(block.expr), "trailing_expr", |expr| {
 596             self.expr(expr);
 597         });
 598     }
 599
 600     fn body(&self, body_id: &Binding<hir::BodyId>) {
 601         let expr = self.cx.tcx.hir().body(body_id.value).value;
 602         bind!(self, expr);
 603         out!("let {expr} = &cx.tcx.hir().body({body_id}).value;");
 604         self.expr(expr);
 605     }
 606
 607     fn pat(&self, pat: &Binding<&hir::Pat<'_>>) {
 608         let kind = |kind| out!("if let PatKind::{kind} = {pat}.kind;");
 609         macro_rules! kind {
 610             ($($t:tt)*) => (kind(format_args!($($t)*)));
 611         }
 612
 613         match pat.value.kind {
 614             PatKind::Wild => kind!("Wild"),
 615             PatKind::Binding(ann, _, name, sub) => {
 616                 bind!(self, name);
 617                 opt_bind!(self, sub);
 618                 let ann = match ann {
 619                     BindingAnnotation::NONE => "NONE",
 620                     BindingAnnotation::REF => "REF",
 621                     BindingAnnotation::MUT => "MUT",
 622                     BindingAnnotation::REF_MUT => "REF_MUT",
 623                 };
 624                 kind!("Binding(BindingAnnotation::{ann}, _, {name}, {sub})");
 625                 self.ident(name);
 626                 sub.if_some(|p| self.pat(p));
 627             },
 628             PatKind::Struct(ref qpath, fields, ignore) => {
 629                 bind!(self, qpath, fields);
 630                 kind!("Struct(ref {qpath}, {fields}, {ignore})");
 631                 self.qpath(qpath);
 632                 self.slice(fields, |field| {
 633                     self.ident(field!(field.ident));
 634                     self.pat(field!(field.pat));
 635                 });
 636             },
 637             PatKind::Or(fields) => {
 638                 bind!(self, fields);
 639                 kind!("Or({fields})");
 640                 self.slice(fields, |pat| self.pat(pat));
 641             },
 642             PatKind::TupleStruct(ref qpath, fields, skip_pos) => {
 643                 bind!(self, qpath, fields);
 644                 kind!("TupleStruct(ref {qpath}, {fields}, {skip_pos:?})");
 645                 self.qpath(qpath);
 646                 self.slice(fields, |pat| self.pat(pat));
 647             },
 648             PatKind::Path(ref qpath) => {
 649                 bind!(self, qpath);
 650                 kind!("Path(ref {qpath})");
 651                 self.qpath(qpath);
 652             },
 653             PatKind::Tuple(fields, skip_pos) => {
 654                 bind!(self, fields);
 655                 kind!("Tuple({fields}, {skip_pos:?})");
 656                 self.slice(fields, |field| self.pat(field));
 657             },
 658             PatKind::Box(pat) => {
 659                 bind!(self, pat);
 660                 kind!("Box({pat})");
 661                 self.pat(pat);
 662             },
 663             PatKind::Ref(pat, muta) => {
 664                 bind!(self, pat);
 665                 kind!("Ref({pat}, Mutability::{muta:?})");
 666                 self.pat(pat);
 667             },
 668             PatKind::Lit(lit_expr) => {
 669                 bind!(self, lit_expr);
 670                 kind!("Lit({lit_expr})");
 671                 self.expr(lit_expr);
 672             },
 673             PatKind::Range(start, end, end_kind) => {
 674                 opt_bind!(self, start, end);
 675                 kind!("Range({start}, {end}, RangeEnd::{end_kind:?})");
 676                 start.if_some(|e| self.expr(e));
 677                 end.if_some(|e| self.expr(e));
 678             },
 679             PatKind::Slice(start, middle, end) => {
 680                 bind!(self, start, end);
 681                 opt_bind!(self, middle);
 682                 kind!("Slice({start}, {middle}, {end})");
 683                 middle.if_some(|p| self.pat(p));
 684                 self.slice(start, |pat| self.pat(pat));
 685                 self.slice(end, |pat| self.pat(pat));
 686             },
 687         }
 688     }
 689
 690     fn stmt(&self, stmt: &Binding<&hir::Stmt<'_>>) {
 691         let kind = |kind| out!("if let StmtKind::{kind} = {stmt}.kind;");
 692         macro_rules! kind {
 693             ($($t:tt)*) => (kind(format_args!($($t)*)));
 694         }
 695
 696         match stmt.value.kind {
 697             StmtKind::Local(local) => {
 698                 bind!(self, local);
 699                 kind!("Local({local})");
 700                 self.option(field!(local.init), "init", |init| {
 701                     self.expr(init);
 702                 });
 703                 self.pat(field!(local.pat));
 704             },
 705             StmtKind::Item(_) => kind!("Item(item_id)"),
 706             StmtKind::Expr(e) => {
 707                 bind!(self, e);
 708                 kind!("Expr({e})");
 709                 self.expr(e);
 710             },
 711             StmtKind::Semi(e) => {
 712                 bind!(self, e);
 713                 kind!("Semi({e})");
 714                 self.expr(e);
 715             },
 716         }
 717     }
 718 }
 719
 720 fn has_attr(cx: &LateContext<'_>, hir_id: hir::HirId) -> bool {
 721     let attrs = cx.tcx.hir().attrs(hir_id);
 722     get_attr(cx.sess(), attrs, "author").count() > 0
 723 }
 724
 725 fn path_to_string(path: &QPath<'_>) -> String {
 726     fn inner(s: &mut String, path: &QPath<'_>) {
 727         match *path {
 728             QPath::Resolved(_, path) => {
 729                 for (i, segment) in path.segments.iter().enumerate() {
 730                     if i > 0 {
 731                         *s += ", ";
 732                     }
 733                     write!(s, "{:?}", segment.ident.as_str()).unwrap();
 734                 }
 735             },
 736             QPath::TypeRelative(ty, segment) => match &ty.kind {
 737                 hir::TyKind::Path(inner_path) => {
 738                     inner(s, inner_path);
 739                     *s += ", ";
 740                     write!(s, "{:?}", segment.ident.as_str()).unwrap();
 741                 },
 742                 other => write!(s, "/* unimplemented: {other:?}*/").unwrap(),
 743             },
 744             QPath::LangItem(..) => panic!("path_to_string: called for lang item qpath"),
 745         }
 746     }
 747     let mut s = String::new();
 748     inner(&mut s, path);
 749     s
 750 }