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