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;
   5 use rustc_ast::ast::{LitFloatType, LitKind};
   6 use rustc_ast::walk_list;
   7 use rustc_data_structures::fx::FxHashMap;
   8 use rustc_hir as hir;
   9 use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
  10 use rustc_hir::{Block, Expr, ExprKind, Pat, PatKind, QPath, Stmt, StmtKind, TyKind};
  11 use rustc_lint::{LateContext, LateLintPass, LintContext};
  12 use rustc_middle::hir::map::Map;
  13 use rustc_session::{declare_lint_pass, declare_tool_lint};
  14
  15 declare_clippy_lint! {
  16     /// ### What it does
  17     /// Generates clippy code that detects the offending pattern
  18     ///
  19     /// ### Example
  20     /// ```rust,ignore
  21     /// // ./tests/ui/my_lint.rs
  22     /// fn foo() {
  23     ///     // detect the following pattern
  24     ///     #[clippy::author]
  25     ///     if x == 42 {
  26     ///         // but ignore everything from here on
  27     ///         #![clippy::author = "ignore"]
  28     ///     }
  29     ///     ()
  30     /// }
  31     /// ```
  32     ///
  33     /// Running `TESTNAME=ui/my_lint cargo uitest` will produce
  34     /// a `./tests/ui/new_lint.stdout` file with the generated code:
  35     ///
  36     /// ```rust,ignore
  37     /// // ./tests/ui/new_lint.stdout
  38     /// if_chain! {
  39     ///     if let ExprKind::If(ref cond, ref then, None) = item.kind,
  40     ///     if let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.kind,
  41     ///     if let ExprKind::Path(ref path) = left.kind,
  42     ///     if let ExprKind::Lit(ref lit) = right.kind,
  43     ///     if let LitKind::Int(42, _) = lit.node,
  44     ///     then {
  45     ///         // report your lint here
  46     ///     }
  47     /// }
  48     /// ```
  49     pub LINT_AUTHOR,
  50     internal_warn,
  51     "helper for writing lints"
  52 }
  53
  54 declare_lint_pass!(Author => [LINT_AUTHOR]);
  55
  56 fn prelude() {
  57     println!("if_chain! {{");
  58 }
  59
  60 fn done() {
  61     println!("    then {{");
  62     println!("        // report your lint here");
  63     println!("    }}");
  64     println!("}}");
  65 }
  66
  67 impl<'tcx> LateLintPass<'tcx> for Author {
  68     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
  69         if !has_attr(cx, item.hir_id()) {
  70             return;
  71         }
  72         prelude();
  73         PrintVisitor::new("item").visit_item(item);
  74         done();
  75     }
  76
  77     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) {
  78         if !has_attr(cx, item.hir_id()) {
  79             return;
  80         }
  81         prelude();
  82         PrintVisitor::new("item").visit_impl_item(item);
  83         done();
  84     }
  85
  86     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
  87         if !has_attr(cx, item.hir_id()) {
  88             return;
  89         }
  90         prelude();
  91         PrintVisitor::new("item").visit_trait_item(item);
  92         done();
  93     }
  94
  95     fn check_variant(&mut self, cx: &LateContext<'tcx>, var: &'tcx hir::Variant<'_>) {
  96         if !has_attr(cx, var.id) {
  97             return;
  98         }
  99         prelude();
 100         let parent_hir_id = cx.tcx.hir().get_parent_node(var.id);
 101         PrintVisitor::new("var").visit_variant(var, &hir::Generics::empty(), parent_hir_id);
 102         done();
 103     }
 104
 105     fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &'tcx hir::FieldDef<'_>) {
 106         if !has_attr(cx, field.hir_id) {
 107             return;
 108         }
 109         prelude();
 110         PrintVisitor::new("field").visit_field_def(field);
 111         done();
 112     }
 113
 114     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
 115         if !has_attr(cx, expr.hir_id) {
 116             return;
 117         }
 118         prelude();
 119         PrintVisitor::new("expr").visit_expr(expr);
 120         done();
 121     }
 122
 123     fn check_arm(&mut self, cx: &LateContext<'tcx>, arm: &'tcx hir::Arm<'_>) {
 124         if !has_attr(cx, arm.hir_id) {
 125             return;
 126         }
 127         prelude();
 128         PrintVisitor::new("arm").visit_arm(arm);
 129         done();
 130     }
 131
 132     fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx hir::Stmt<'_>) {
 133         if !has_attr(cx, stmt.hir_id) {
 134             return;
 135         }
 136         match stmt.kind {
 137             StmtKind::Expr(e) | StmtKind::Semi(e) if has_attr(cx, e.hir_id) => return,
 138             _ => {},
 139         }
 140         prelude();
 141         PrintVisitor::new("stmt").visit_stmt(stmt);
 142         done();
 143     }
 144
 145     fn check_foreign_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ForeignItem<'_>) {
 146         if !has_attr(cx, item.hir_id()) {
 147             return;
 148         }
 149         prelude();
 150         PrintVisitor::new("item").visit_foreign_item(item);
 151         done();
 152     }
 153 }
 154
 155 impl PrintVisitor {
 156     #[must_use]
 157     fn new(s: &'static str) -> Self {
 158         Self {
 159             ids: FxHashMap::default(),
 160             current: s.to_owned(),
 161         }
 162     }
 163
 164     fn next(&mut self, s: &'static str) -> String {
 165         use std::collections::hash_map::Entry::{Occupied, Vacant};
 166         match self.ids.entry(s) {
 167             // already there: start numbering from `1`
 168             Occupied(mut occ) => {
 169                 let val = occ.get_mut();
 170                 *val += 1;
 171                 format!("{}{}", s, *val)
 172             },
 173             // not there: insert and return name as given
 174             Vacant(vac) => {
 175                 vac.insert(0);
 176                 s.to_owned()
 177             },
 178         }
 179     }
 180
 181     fn print_qpath(&mut self, path: &QPath<'_>) {
 182         if let QPath::LangItem(lang_item, _) = *path {
 183             println!(
 184                 "    if matches!({}, QPath::LangItem(LangItem::{:?}, _));",
 185                 self.current, lang_item,
 186             );
 187         } else {
 188             print!("    if match_qpath({}, &[", self.current);
 189             print_path(path, &mut true);
 190             println!("]);");
 191         }
 192     }
 193 }
 194
 195 struct PrintVisitor {
 196     /// Fields are the current index that needs to be appended to pattern
 197     /// binding names
 198     ids: FxHashMap<&'static str, usize>,
 199     /// the name that needs to be destructured
 200     current: String,
 201 }
 202
 203 impl<'tcx> Visitor<'tcx> for PrintVisitor {
 204     type Map = Map<'tcx>;
 205
 206     #[allow(clippy::too_many_lines)]
 207     fn visit_expr(&mut self, expr: &Expr<'_>) {
 208         print!("    if let ExprKind::");
 209         let current = format!("{}.kind", self.current);
 210         match expr.kind {
 211             ExprKind::Let(pat, expr, _) => {
 212                 let let_pat = self.next("pat");
 213                 let let_expr = self.next("expr");
 214                 println!("    Let(ref {}, ref {}, _) = {};", let_pat, let_expr, current);
 215                 self.current = let_expr;
 216                 self.visit_expr(expr);
 217                 self.current = let_pat;
 218                 self.visit_pat(pat);
 219             },
 220             ExprKind::Box(inner) => {
 221                 let inner_pat = self.next("inner");
 222                 println!("Box(ref {}) = {};", inner_pat, current);
 223                 self.current = inner_pat;
 224                 self.visit_expr(inner);
 225             },
 226             ExprKind::Array(elements) => {
 227                 let elements_pat = self.next("elements");
 228                 println!("Array(ref {}) = {};", elements_pat, current);
 229                 println!("    if {}.len() == {};", elements_pat, elements.len());
 230                 for (i, element) in elements.iter().enumerate() {
 231                     self.current = format!("{}[{}]", elements_pat, i);
 232                     self.visit_expr(element);
 233                 }
 234             },
 235             ExprKind::Call(func, args) => {
 236                 let func_pat = self.next("func");
 237                 let args_pat = self.next("args");
 238                 println!("Call(ref {}, ref {}) = {};", func_pat, args_pat, current);
 239                 self.current = func_pat;
 240                 self.visit_expr(func);
 241                 println!("    if {}.len() == {};", args_pat, args.len());
 242                 for (i, arg) in args.iter().enumerate() {
 243                     self.current = format!("{}[{}]", args_pat, i);
 244                     self.visit_expr(arg);
 245                 }
 246             },
 247             ExprKind::MethodCall(_method_name, ref _generics, _args, ref _fn_span) => {
 248                 println!(
 249                     "MethodCall(ref method_name, ref generics, ref args, ref fn_span) = {};",
 250                     current
 251                 );
 252                 println!("    // unimplemented: `ExprKind::MethodCall` is not further destructured at the moment");
 253             },
 254             ExprKind::Tup(elements) => {
 255                 let elements_pat = self.next("elements");
 256                 println!("Tup(ref {}) = {};", elements_pat, current);
 257                 println!("    if {}.len() == {};", elements_pat, elements.len());
 258                 for (i, element) in elements.iter().enumerate() {
 259                     self.current = format!("{}[{}]", elements_pat, i);
 260                     self.visit_expr(element);
 261                 }
 262             },
 263             ExprKind::Binary(ref op, left, right) => {
 264                 let op_pat = self.next("op");
 265                 let left_pat = self.next("left");
 266                 let right_pat = self.next("right");
 267                 println!(
 268                     "Binary(ref {}, ref {}, ref {}) = {};",
 269                     op_pat, left_pat, right_pat, current
 270                 );
 271                 println!("    if BinOpKind::{:?} == {}.node;", op.node, op_pat);
 272                 self.current = left_pat;
 273                 self.visit_expr(left);
 274                 self.current = right_pat;
 275                 self.visit_expr(right);
 276             },
 277             ExprKind::Unary(ref op, inner) => {
 278                 let inner_pat = self.next("inner");
 279                 println!("Unary(UnOp::{:?}, ref {}) = {};", op, inner_pat, current);
 280                 self.current = inner_pat;
 281                 self.visit_expr(inner);
 282             },
 283             ExprKind::Lit(ref lit) => {
 284                 let lit_pat = self.next("lit");
 285                 println!("Lit(ref {}) = {};", lit_pat, current);
 286                 match lit.node {
 287                     LitKind::Bool(val) => println!("    if let LitKind::Bool({:?}) = {}.node;", val, lit_pat),
 288                     LitKind::Char(c) => println!("    if let LitKind::Char({:?}) = {}.node;", c, lit_pat),
 289                     LitKind::Err(val) => println!("    if let LitKind::Err({}) = {}.node;", val, lit_pat),
 290                     LitKind::Byte(b) => println!("    if let LitKind::Byte({}) = {}.node;", b, lit_pat),
 291                     // FIXME: also check int type
 292                     LitKind::Int(i, _) => println!("    if let LitKind::Int({}, _) = {}.node;", i, lit_pat),
 293                     LitKind::Float(_, LitFloatType::Suffixed(_)) => println!(
 294                         "    if let LitKind::Float(_, LitFloatType::Suffixed(_)) = {}.node;",
 295                         lit_pat
 296                     ),
 297                     LitKind::Float(_, LitFloatType::Unsuffixed) => println!(
 298                         "    if let LitKind::Float(_, LitFloatType::Unsuffixed) = {}.node;",
 299                         lit_pat
 300                     ),
 301                     LitKind::ByteStr(ref vec) => {
 302                         let vec_pat = self.next("vec");
 303                         println!("    if let LitKind::ByteStr(ref {}) = {}.node;", vec_pat, lit_pat);
 304                         println!("    if let [{:?}] = **{};", vec, vec_pat);
 305                     },
 306                     LitKind::Str(ref text, _) => {
 307                         let str_pat = self.next("s");
 308                         println!("    if let LitKind::Str(ref {}, _) = {}.node;", str_pat, lit_pat);
 309                         println!("    if {}.as_str() == {:?}", str_pat, &*text.as_str());
 310                     },
 311                 }
 312             },
 313             ExprKind::Cast(expr, ty) => {
 314                 let cast_pat = self.next("expr");
 315                 let cast_ty = self.next("cast_ty");
 316                 let qp_label = self.next("qp");
 317
 318                 println!("Cast(ref {}, ref {}) = {};", cast_pat, cast_ty, current);
 319                 if let TyKind::Path(ref qp) = ty.kind {
 320                     println!("    if let TyKind::Path(ref {}) = {}.kind;", qp_label, cast_ty);
 321                     self.current = qp_label;
 322                     self.print_qpath(qp);
 323                 }
 324                 self.current = cast_pat;
 325                 self.visit_expr(expr);
 326             },
 327             ExprKind::Type(expr, _ty) => {
 328                 let cast_pat = self.next("expr");
 329                 println!("Type(ref {}, _) = {};", cast_pat, current);
 330                 self.current = cast_pat;
 331                 self.visit_expr(expr);
 332             },
 333             ExprKind::Loop(body, _, des, _) => {
 334                 let body_pat = self.next("body");
 335                 let label_pat = self.next("label");
 336                 println!(
 337                     "Loop(ref {}, ref {}, LoopSource::{:?}) = {};",
 338                     body_pat, label_pat, des, current
 339                 );
 340                 self.current = body_pat;
 341                 self.visit_block(body);
 342             },
 343             ExprKind::If(cond, then, ref opt_else) => {
 344                 let cond_pat = self.next("cond");
 345                 let then_pat = self.next("then");
 346                 if let Some(else_) = *opt_else {
 347                     let else_pat = self.next("else_");
 348                     println!(
 349                         "If(ref {}, ref {}, Some(ref {})) = {};",
 350                         cond_pat, then_pat, else_pat, current
 351                     );
 352                     self.current = else_pat;
 353                     self.visit_expr(else_);
 354                 } else {
 355                     println!("If(ref {}, ref {}, None) = {};", cond_pat, then_pat, current);
 356                 }
 357                 self.current = cond_pat;
 358                 self.visit_expr(cond);
 359                 self.current = then_pat;
 360                 self.visit_expr(then);
 361             },
 362             ExprKind::Match(expr, arms, des) => {
 363                 let expr_pat = self.next("expr");
 364                 let arms_pat = self.next("arms");
 365                 println!(
 366                     "Match(ref {}, ref {}, MatchSource::{:?}) = {};",
 367                     expr_pat, arms_pat, des, current
 368                 );
 369                 self.current = expr_pat;
 370                 self.visit_expr(expr);
 371                 println!("    if {}.len() == {};", arms_pat, arms.len());
 372                 for (i, arm) in arms.iter().enumerate() {
 373                     self.current = format!("{}[{}].body", arms_pat, i);
 374                     self.visit_expr(arm.body);
 375                     if let Some(ref guard) = arm.guard {
 376                         let guard_pat = self.next("guard");
 377                         println!("    if let Some(ref {}) = {}[{}].guard;", guard_pat, arms_pat, i);
 378                         match guard {
 379                             hir::Guard::If(if_expr) => {
 380                                 let if_expr_pat = self.next("expr");
 381                                 println!("    if let Guard::If(ref {}) = {};", if_expr_pat, guard_pat);
 382                                 self.current = if_expr_pat;
 383                                 self.visit_expr(if_expr);
 384                             },
 385                             hir::Guard::IfLet(if_let_pat, if_let_expr) => {
 386                                 let if_let_pat_pat = self.next("pat");
 387                                 let if_let_expr_pat = self.next("expr");
 388                                 println!(
 389                                     "    if let Guard::IfLet(ref {}, ref {}) = {};",
 390                                     if_let_pat_pat, if_let_expr_pat, guard_pat
 391                                 );
 392                                 self.current = if_let_expr_pat;
 393                                 self.visit_expr(if_let_expr);
 394                                 self.current = if_let_pat_pat;
 395                                 self.visit_pat(if_let_pat);
 396                             },
 397                         }
 398                     }
 399                     self.current = format!("{}[{}].pat", arms_pat, i);
 400                     self.visit_pat(arm.pat);
 401                 }
 402             },
 403             ExprKind::Closure(ref _capture_clause, _func, _, _, _) => {
 404                 println!("Closure(ref capture_clause, ref func, _, _, _) = {};", current);
 405                 println!("    // unimplemented: `ExprKind::Closure` is not further destructured at the moment");
 406             },
 407             ExprKind::Yield(sub, _) => {
 408                 let sub_pat = self.next("sub");
 409                 println!("Yield(ref sub) = {};", current);
 410                 self.current = sub_pat;
 411                 self.visit_expr(sub);
 412             },
 413             ExprKind::Block(block, _) => {
 414                 let block_pat = self.next("block");
 415                 println!("Block(ref {}) = {};", block_pat, current);
 416                 self.current = block_pat;
 417                 self.visit_block(block);
 418             },
 419             ExprKind::Assign(target, value, _) => {
 420                 let target_pat = self.next("target");
 421                 let value_pat = self.next("value");
 422                 println!(
 423                     "Assign(ref {}, ref {}, ref _span) = {};",
 424                     target_pat, value_pat, current
 425                 );
 426                 self.current = target_pat;
 427                 self.visit_expr(target);
 428                 self.current = value_pat;
 429                 self.visit_expr(value);
 430             },
 431             ExprKind::AssignOp(ref op, target, value) => {
 432                 let op_pat = self.next("op");
 433                 let target_pat = self.next("target");
 434                 let value_pat = self.next("value");
 435                 println!(
 436                     "AssignOp(ref {}, ref {}, ref {}) = {};",
 437                     op_pat, target_pat, value_pat, current
 438                 );
 439                 println!("    if BinOpKind::{:?} == {}.node;", op.node, op_pat);
 440                 self.current = target_pat;
 441                 self.visit_expr(target);
 442                 self.current = value_pat;
 443                 self.visit_expr(value);
 444             },
 445             ExprKind::Field(object, ref field_ident) => {
 446                 let obj_pat = self.next("object");
 447                 let field_name_pat = self.next("field_name");
 448                 println!("Field(ref {}, ref {}) = {};", obj_pat, field_name_pat, current);
 449                 println!("    if {}.as_str() == {:?}", field_name_pat, field_ident.as_str());
 450                 self.current = obj_pat;
 451                 self.visit_expr(object);
 452             },
 453             ExprKind::Index(object, index) => {
 454                 let object_pat = self.next("object");
 455                 let index_pat = self.next("index");
 456                 println!("Index(ref {}, ref {}) = {};", object_pat, index_pat, current);
 457                 self.current = object_pat;
 458                 self.visit_expr(object);
 459                 self.current = index_pat;
 460                 self.visit_expr(index);
 461             },
 462             ExprKind::Path(ref path) => {
 463                 let path_pat = self.next("path");
 464                 println!("Path(ref {}) = {};", path_pat, current);
 465                 self.current = path_pat;
 466                 self.print_qpath(path);
 467             },
 468             ExprKind::AddrOf(kind, mutability, inner) => {
 469                 let inner_pat = self.next("inner");
 470                 println!(
 471                     "AddrOf(BorrowKind::{:?}, Mutability::{:?}, ref {}) = {};",
 472                     kind, mutability, inner_pat, current
 473                 );
 474                 self.current = inner_pat;
 475                 self.visit_expr(inner);
 476             },
 477             ExprKind::Break(ref _destination, ref opt_value) => {
 478                 let destination_pat = self.next("destination");
 479                 if let Some(value) = *opt_value {
 480                     let value_pat = self.next("value");
 481                     println!("Break(ref {}, Some(ref {})) = {};", destination_pat, value_pat, current);
 482                     self.current = value_pat;
 483                     self.visit_expr(value);
 484                 } else {
 485                     println!("Break(ref {}, None) = {};", destination_pat, current);
 486                 }
 487                 // FIXME: implement label printing
 488             },
 489             ExprKind::Continue(ref _destination) => {
 490                 let destination_pat = self.next("destination");
 491                 println!("Again(ref {}) = {};", destination_pat, current);
 492                 // FIXME: implement label printing
 493             },
 494             ExprKind::Ret(ref opt_value) => {
 495                 if let Some(value) = *opt_value {
 496                     let value_pat = self.next("value");
 497                     println!("Ret(Some(ref {})) = {};", value_pat, current);
 498                     self.current = value_pat;
 499                     self.visit_expr(value);
 500                 } else {
 501                     println!("Ret(None) = {};", current);
 502                 }
 503             },
 504             ExprKind::InlineAsm(_) => {
 505                 println!("InlineAsm(_) = {};", current);
 506                 println!("    // unimplemented: `ExprKind::InlineAsm` is not further destructured at the moment");
 507             },
 508             ExprKind::LlvmInlineAsm(_) => {
 509                 println!("LlvmInlineAsm(_) = {};", current);
 510                 println!("    // unimplemented: `ExprKind::LlvmInlineAsm` is not further destructured at the moment");
 511             },
 512             ExprKind::Struct(path, fields, ref opt_base) => {
 513                 let path_pat = self.next("path");
 514                 let fields_pat = self.next("fields");
 515                 if let Some(base) = *opt_base {
 516                     let base_pat = self.next("base");
 517                     println!(
 518                         "Struct(ref {}, ref {}, Some(ref {})) = {};",
 519                         path_pat, fields_pat, base_pat, current
 520                     );
 521                     self.current = base_pat;
 522                     self.visit_expr(base);
 523                 } else {
 524                     println!("Struct(ref {}, ref {}, None) = {};", path_pat, fields_pat, current);
 525                 }
 526                 self.current = path_pat;
 527                 self.print_qpath(path);
 528                 println!("    if {}.len() == {};", fields_pat, fields.len());
 529                 println!("    // unimplemented: field checks");
 530             },
 531             ExprKind::ConstBlock(_) => {
 532                 let value_pat = self.next("value");
 533                 println!("Const({})", value_pat);
 534                 self.current = value_pat;
 535             },
 536             // FIXME: compute length (needs type info)
 537             ExprKind::Repeat(value, _) => {
 538                 let value_pat = self.next("value");
 539                 println!("Repeat(ref {}, _) = {};", value_pat, current);
 540                 println!("// unimplemented: repeat count check");
 541                 self.current = value_pat;
 542                 self.visit_expr(value);
 543             },
 544             ExprKind::Err => {
 545                 println!("Err = {}", current);
 546             },
 547             ExprKind::DropTemps(expr) => {
 548                 let expr_pat = self.next("expr");
 549                 println!("DropTemps(ref {}) = {};", expr_pat, current);
 550                 self.current = expr_pat;
 551                 self.visit_expr(expr);
 552             },
 553         }
 554     }
 555
 556     fn visit_block(&mut self, block: &Block<'_>) {
 557         println!("    if {}.stmts.len() == {};", self.current, block.stmts.len());
 558         let block_name = self.current.clone();
 559         for (i, stmt) in block.stmts.iter().enumerate() {
 560             self.current = format!("{}.stmts[{}]", block_name, i);
 561             self.visit_stmt(stmt);
 562         }
 563         if let Some(expr) = block.expr {
 564             self.current = self.next("trailing_expr");
 565             println!("    if let Some({}) = &{}.expr;", self.current, block_name);
 566             self.visit_expr(expr);
 567         } else {
 568             println!("    if {}.expr.is_none();", block_name);
 569         }
 570     }
 571
 572     #[allow(clippy::too_many_lines)]
 573     fn visit_pat(&mut self, pat: &Pat<'_>) {
 574         print!("    if let PatKind::");
 575         let current = format!("{}.kind", self.current);
 576         match pat.kind {
 577             PatKind::Wild => println!("Wild = {};", current),
 578             PatKind::Binding(anno, .., ident, ref sub) => {
 579                 let anno_pat = &format!("BindingAnnotation::{:?}", anno);
 580                 let name_pat = self.next("name");
 581                 if let Some(sub) = *sub {
 582                     let sub_pat = self.next("sub");
 583                     println!(
 584                         "Binding({}, _, {}, Some(ref {})) = {};",
 585                         anno_pat, name_pat, sub_pat, current
 586                     );
 587                     self.current = sub_pat;
 588                     self.visit_pat(sub);
 589                 } else {
 590                     println!("Binding({}, _, {}, None) = {};", anno_pat, name_pat, current);
 591                 }
 592                 println!("    if {}.as_str() == \"{}\";", name_pat, ident.as_str());
 593             },
 594             PatKind::Struct(ref path, fields, ignore) => {
 595                 let path_pat = self.next("path");
 596                 let fields_pat = self.next("fields");
 597                 println!(
 598                     "Struct(ref {}, ref {}, {}) = {};",
 599                     path_pat, fields_pat, ignore, current
 600                 );
 601                 self.current = path_pat;
 602                 self.print_qpath(path);
 603                 println!("    if {}.len() == {};", fields_pat, fields.len());
 604                 println!("    // unimplemented: field checks");
 605             },
 606             PatKind::Or(fields) => {
 607                 let fields_pat = self.next("fields");
 608                 println!("Or(ref {}) = {};", fields_pat, current);
 609                 println!("    if {}.len() == {};", fields_pat, fields.len());
 610                 println!("    // unimplemented: field checks");
 611             },
 612             PatKind::TupleStruct(ref path, fields, skip_pos) => {
 613                 let path_pat = self.next("path");
 614                 let fields_pat = self.next("fields");
 615                 println!(
 616                     "TupleStruct(ref {}, ref {}, {:?}) = {};",
 617                     path_pat, fields_pat, skip_pos, current
 618                 );
 619                 self.current = path_pat;
 620                 self.print_qpath(path);
 621                 println!("    if {}.len() == {};", fields_pat, fields.len());
 622                 println!("    // unimplemented: field checks");
 623             },
 624             PatKind::Path(ref path) => {
 625                 let path_pat = self.next("path");
 626                 println!("Path(ref {}) = {};", path_pat, current);
 627                 self.current = path_pat;
 628                 self.print_qpath(path);
 629             },
 630             PatKind::Tuple(fields, skip_pos) => {
 631                 let fields_pat = self.next("fields");
 632                 println!("Tuple(ref {}, {:?}) = {};", fields_pat, skip_pos, current);
 633                 println!("    if {}.len() == {};", fields_pat, fields.len());
 634                 println!("    // unimplemented: field checks");
 635             },
 636             PatKind::Box(pat) => {
 637                 let pat_pat = self.next("pat");
 638                 println!("Box(ref {}) = {};", pat_pat, current);
 639                 self.current = pat_pat;
 640                 self.visit_pat(pat);
 641             },
 642             PatKind::Ref(pat, muta) => {
 643                 let pat_pat = self.next("pat");
 644                 println!("Ref(ref {}, Mutability::{:?}) = {};", pat_pat, muta, current);
 645                 self.current = pat_pat;
 646                 self.visit_pat(pat);
 647             },
 648             PatKind::Lit(lit_expr) => {
 649                 let lit_expr_pat = self.next("lit_expr");
 650                 println!("Lit(ref {}) = {}", lit_expr_pat, current);
 651                 self.current = lit_expr_pat;
 652                 self.visit_expr(lit_expr);
 653             },
 654             PatKind::Range(ref start, ref end, end_kind) => {
 655                 let start_pat = self.next("start");
 656                 let end_pat = self.next("end");
 657                 println!(
 658                     "Range(ref {}, ref {}, RangeEnd::{:?}) = {};",
 659                     start_pat, end_pat, end_kind, current
 660                 );
 661                 self.current = start_pat;
 662                 walk_list!(self, visit_expr, start);
 663                 self.current = end_pat;
 664                 walk_list!(self, visit_expr, end);
 665             },
 666             PatKind::Slice(start, ref middle, end) => {
 667                 let start_pat = self.next("start");
 668                 let end_pat = self.next("end");
 669                 if let Some(middle) = middle {
 670                     let middle_pat = self.next("middle");
 671                     println!(
 672                         "Slice(ref {}, Some(ref {}), ref {}) = {};",
 673                         start_pat, middle_pat, end_pat, current
 674                     );
 675                     self.current = middle_pat;
 676                     self.visit_pat(middle);
 677                 } else {
 678                     println!("Slice(ref {}, None, ref {}) = {};", start_pat, end_pat, current);
 679                 }
 680                 println!("    if {}.len() == {};", start_pat, start.len());
 681                 for (i, pat) in start.iter().enumerate() {
 682                     self.current = format!("{}[{}]", start_pat, i);
 683                     self.visit_pat(pat);
 684                 }
 685                 println!("    if {}.len() == {};", end_pat, end.len());
 686                 for (i, pat) in end.iter().enumerate() {
 687                     self.current = format!("{}[{}]", end_pat, i);
 688                     self.visit_pat(pat);
 689                 }
 690             },
 691         }
 692     }
 693
 694     fn visit_stmt(&mut self, s: &Stmt<'_>) {
 695         print!("    if let StmtKind::");
 696         let current = format!("{}.kind", self.current);
 697         match s.kind {
 698             // A local (let) binding:
 699             StmtKind::Local(local) => {
 700                 let local_pat = self.next("local");
 701                 println!("Local(ref {}) = {};", local_pat, current);
 702                 if let Some(init) = local.init {
 703                     let init_pat = self.next("init");
 704                     println!("    if let Some(ref {}) = {}.init;", init_pat, local_pat);
 705                     self.current = init_pat;
 706                     self.visit_expr(init);
 707                 }
 708                 self.current = format!("{}.pat", local_pat);
 709                 self.visit_pat(local.pat);
 710             },
 711             // An item binding:
 712             StmtKind::Item(_) => {
 713                 println!("Item(item_id) = {};", current);
 714             },
 715
 716             // Expr without trailing semi-colon (must have unit type):
 717             StmtKind::Expr(e) => {
 718                 let e_pat = self.next("e");
 719                 println!("Expr(ref {}, _) = {}", e_pat, current);
 720                 self.current = e_pat;
 721                 self.visit_expr(e);
 722             },
 723
 724             // Expr with trailing semi-colon (may have any type):
 725             StmtKind::Semi(e) => {
 726                 let e_pat = self.next("e");
 727                 println!("Semi(ref {}, _) = {}", e_pat, current);
 728                 self.current = e_pat;
 729                 self.visit_expr(e);
 730             },
 731         }
 732     }
 733
 734     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
 735         NestedVisitorMap::None
 736     }
 737 }
 738
 739 fn has_attr(cx: &LateContext<'_>, hir_id: hir::HirId) -> bool {
 740     let attrs = cx.tcx.hir().attrs(hir_id);
 741     get_attr(cx.sess(), attrs, "author").count() > 0
 742 }
 743
 744 fn print_path(path: &QPath<'_>, first: &mut bool) {
 745     match *path {
 746         QPath::Resolved(_, path) => {
 747             for segment in path.segments {
 748                 if *first {
 749                     *first = false;
 750                 } else {
 751                     print!(", ");
 752                 }
 753                 print!("{:?}", segment.ident.as_str());
 754             }
 755         },
 756         QPath::TypeRelative(ty, segment) => match ty.kind {
 757             hir::TyKind::Path(ref inner_path) => {
 758                 print_path(inner_path, first);
 759                 if *first {
 760                     *first = false;
 761                 } else {
 762                     print!(", ");
 763                 }
 764                 print!("{:?}", segment.ident.as_str());
 765             },
 766             ref other => print!("/* unimplemented: {:?}*/", other),
 767         },
 768         QPath::LangItem(..) => panic!("print_path: called for lang item qpath"),
 769     }
 770 }