src/librustc_front/visit.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! HIR walker. Each overridden visit method has full control over what
  12 //! happens with its node, it can do its own traversal of the node's children,
  13 //! call `visit::walk_*` to apply the default traversal algorithm, or prevent
  14 //! deeper traversal by doing nothing.
  15 //!
  16 //! Note: it is an important invariant that the default visitor walks the body
  17 //! of a function in "execution order" (more concretely, reverse post-order
  18 //! with respect to the CFG implied by the AST), meaning that if AST node A may
  19 //! execute before AST node B, then A is visited first.  The borrow checker in
  20 //! particular relies on this property.
  21 //!
  22 //! Note: walking an AST before macro expansion is probably a bad idea. For
  23 //! instance, a walker looking for item names in a module will miss all of
  24 //! those that are created by the expansion of a macro.
  25
  26 use syntax::abi::Abi;
  27 use syntax::ast::{Ident, NodeId, CRATE_NODE_ID, Name, Attribute};
  28 use syntax::codemap::Span;
  29 use hir::*;
  30
  31 #[derive(Copy, Clone, PartialEq, Eq)]
  32 pub enum FnKind<'a> {
  33     /// fn foo() or extern "Abi" fn foo()
  34     ItemFn(Name, &'a Generics, Unsafety, Constness, Abi, Visibility),
  35
  36     /// fn foo(&self)
  37     Method(Name, &'a MethodSig, Option<Visibility>),
  38
  39     /// |x, y| {}
  40     Closure,
  41 }
  42
  43 /// Each method of the Visitor trait is a hook to be potentially
  44 /// overridden.  Each method's default implementation recursively visits
  45 /// the substructure of the input via the corresponding `walk` method;
  46 /// e.g. the `visit_mod` method by default calls `visit::walk_mod`.
  47 ///
  48 /// If you want to ensure that your code handles every variant
  49 /// explicitly, you need to override each method.  (And you also need
  50 /// to monitor future changes to `Visitor` in case a new method with a
  51 /// new default implementation gets introduced.)
  52 pub trait Visitor<'v> : Sized {
  53     fn visit_name(&mut self, _span: Span, _name: Name) {
  54         // Nothing to do.
  55     }
  56     fn visit_ident(&mut self, span: Span, ident: Ident) {
  57         walk_ident(self, span, ident);
  58     }
  59     fn visit_mod(&mut self, m: &'v Mod, _s: Span, _n: NodeId) { walk_mod(self, m) }
  60     fn visit_foreign_item(&mut self, i: &'v ForeignItem) { walk_foreign_item(self, i) }
  61     fn visit_item(&mut self, i: &'v Item) { walk_item(self, i) }
  62     fn visit_local(&mut self, l: &'v Local) { walk_local(self, l) }
  63     fn visit_block(&mut self, b: &'v Block) { walk_block(self, b) }
  64     fn visit_stmt(&mut self, s: &'v Stmt) { walk_stmt(self, s) }
  65     fn visit_arm(&mut self, a: &'v Arm) { walk_arm(self, a) }
  66     fn visit_pat(&mut self, p: &'v Pat) { walk_pat(self, p) }
  67     fn visit_decl(&mut self, d: &'v Decl) { walk_decl(self, d) }
  68     fn visit_expr(&mut self, ex: &'v Expr) { walk_expr(self, ex) }
  69     fn visit_expr_post(&mut self, _ex: &'v Expr) { }
  70     fn visit_ty(&mut self, t: &'v Ty) { walk_ty(self, t) }
  71     fn visit_generics(&mut self, g: &'v Generics) { walk_generics(self, g) }
  72     fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl, b: &'v Block, s: Span, _: NodeId) {
  73         walk_fn(self, fk, fd, b, s)
  74     }
  75     fn visit_trait_item(&mut self, ti: &'v TraitItem) { walk_trait_item(self, ti) }
  76     fn visit_impl_item(&mut self, ii: &'v ImplItem) { walk_impl_item(self, ii) }
  77     fn visit_trait_ref(&mut self, t: &'v TraitRef) { walk_trait_ref(self, t) }
  78     fn visit_ty_param_bound(&mut self, bounds: &'v TyParamBound) {
  79         walk_ty_param_bound(self, bounds)
  80     }
  81     fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef, m: &'v TraitBoundModifier) {
  82         walk_poly_trait_ref(self, t, m)
  83     }
  84     fn visit_struct_def(&mut self, s: &'v StructDef, _: Name, _: &'v Generics, _: NodeId) {
  85         walk_struct_def(self, s)
  86     }
  87     fn visit_struct_field(&mut self, s: &'v StructField) { walk_struct_field(self, s) }
  88     fn visit_enum_def(&mut self, enum_definition: &'v EnumDef,
  89                       generics: &'v Generics) {
  90         walk_enum_def(self, enum_definition, generics)
  91     }
  92
  93     fn visit_variant(&mut self, v: &'v Variant, g: &'v Generics) { walk_variant(self, v, g) }
  94
  95     fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
  96         walk_lifetime(self, lifetime)
  97     }
  98     fn visit_lifetime_def(&mut self, lifetime: &'v LifetimeDef) {
  99         walk_lifetime_def(self, lifetime)
 100     }
 101     fn visit_explicit_self(&mut self, es: &'v ExplicitSelf) {
 102         walk_explicit_self(self, es)
 103     }
 104     fn visit_path(&mut self, path: &'v Path, _id: NodeId) {
 105         walk_path(self, path)
 106     }
 107     fn visit_path_list_item(&mut self, prefix: &'v Path, item: &'v PathListItem) {
 108         walk_path_list_item(self, prefix, item)
 109     }
 110     fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment) {
 111         walk_path_segment(self, path_span, path_segment)
 112     }
 113     fn visit_path_parameters(&mut self, path_span: Span, path_parameters: &'v PathParameters) {
 114         walk_path_parameters(self, path_span, path_parameters)
 115     }
 116     fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding) {
 117         walk_assoc_type_binding(self, type_binding)
 118     }
 119     fn visit_attribute(&mut self, _attr: &'v Attribute) {}
 120     fn visit_macro_def(&mut self, macro_def: &'v MacroDef) {
 121         walk_macro_def(self, macro_def)
 122     }
 123 }
 124
 125 pub fn walk_opt_name<'v, V: Visitor<'v>>(visitor: &mut V, span: Span, opt_name: Option<Name>) {
 126     for name in opt_name {
 127         visitor.visit_name(span, name);
 128     }
 129 }
 130
 131 pub fn walk_opt_ident<'v, V: Visitor<'v>>(visitor: &mut V, span: Span, opt_ident: Option<Ident>) {
 132     for ident in opt_ident {
 133         visitor.visit_ident(span, ident);
 134     }
 135 }
 136
 137 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, span: Span, ident: Ident) {
 138     visitor.visit_name(span, ident.name);
 139 }
 140
 141 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate) {
 142     visitor.visit_mod(&krate.module, krate.span, CRATE_NODE_ID);
 143     walk_list!(visitor, visit_attribute, &krate.attrs);
 144     walk_list!(visitor, visit_macro_def, &krate.exported_macros);
 145 }
 146
 147 pub fn walk_macro_def<'v, V: Visitor<'v>>(visitor: &mut V, macro_def: &'v MacroDef) {
 148     visitor.visit_name(macro_def.span, macro_def.name);
 149     walk_opt_name(visitor, macro_def.span, macro_def.imported_from);
 150     walk_list!(visitor, visit_attribute, &macro_def.attrs);
 151 }
 152
 153 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod) {
 154     walk_list!(visitor, visit_item, &module.items);
 155 }
 156
 157 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local) {
 158     visitor.visit_pat(&local.pat);
 159     walk_list!(visitor, visit_ty, &local.ty);
 160     walk_list!(visitor, visit_expr, &local.init);
 161 }
 162
 163 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
 164     visitor.visit_name(lifetime.span, lifetime.name);
 165 }
 166
 167 pub fn walk_lifetime_def<'v, V: Visitor<'v>>(visitor: &mut V,
 168                                               lifetime_def: &'v LifetimeDef) {
 169     visitor.visit_lifetime(&lifetime_def.lifetime);
 170     walk_list!(visitor, visit_lifetime, &lifetime_def.bounds);
 171 }
 172
 173 pub fn walk_explicit_self<'v, V: Visitor<'v>>(visitor: &mut V,
 174                                               explicit_self: &'v ExplicitSelf) {
 175     match explicit_self.node {
 176         SelfStatic => {},
 177         SelfValue(name) => {
 178             visitor.visit_name(explicit_self.span, name)
 179         }
 180         SelfRegion(ref opt_lifetime, _, name) => {
 181             visitor.visit_name(explicit_self.span, name);
 182             walk_list!(visitor, visit_lifetime, opt_lifetime);
 183         }
 184         SelfExplicit(ref typ, name) => {
 185             visitor.visit_name(explicit_self.span, name);
 186             visitor.visit_ty(typ)
 187         }
 188     }
 189 }
 190
 191 pub fn walk_poly_trait_ref<'v, V>(visitor: &mut V,
 192                                   trait_ref: &'v PolyTraitRef,
 193                                   _modifier: &'v TraitBoundModifier)
 194     where V: Visitor<'v>
 195 {
 196     walk_list!(visitor, visit_lifetime_def, &trait_ref.bound_lifetimes);
 197     visitor.visit_trait_ref(&trait_ref.trait_ref);
 198 }
 199
 200 pub fn walk_trait_ref<'v,V>(visitor: &mut V,
 201                                    trait_ref: &'v TraitRef)
 202     where V: Visitor<'v>
 203 {
 204     visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
 205 }
 206
 207 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
 208     visitor.visit_name(item.span, item.name);
 209     match item.node {
 210         ItemExternCrate(opt_name) => {
 211             walk_opt_name(visitor, item.span, opt_name)
 212         }
 213         ItemUse(ref vp) => {
 214             match vp.node {
 215                 ViewPathSimple(name, ref path) => {
 216                     visitor.visit_name(vp.span, name);
 217                     visitor.visit_path(path, item.id);
 218                 }
 219                 ViewPathGlob(ref path) => {
 220                     visitor.visit_path(path, item.id);
 221                 }
 222                 ViewPathList(ref prefix, ref list) => {
 223                     if !list.is_empty() {
 224                         for item in list {
 225                             visitor.visit_path_list_item(prefix, item)
 226                         }
 227                     } else {
 228                         visitor.visit_path(prefix, item.id);
 229                     }
 230                 }
 231             }
 232         }
 233         ItemStatic(ref typ, _, ref expr) |
 234         ItemConst(ref typ, ref expr) => {
 235             visitor.visit_ty(typ);
 236             visitor.visit_expr(expr);
 237         }
 238         ItemFn(ref declaration, unsafety, constness, abi, ref generics, ref body) => {
 239             visitor.visit_fn(FnKind::ItemFn(item.name, generics, unsafety,
 240                                             constness, abi, item.vis),
 241                              declaration,
 242                              body,
 243                              item.span,
 244                              item.id)
 245         }
 246         ItemMod(ref module) => {
 247             visitor.visit_mod(module, item.span, item.id)
 248         }
 249         ItemForeignMod(ref foreign_module) => {
 250             walk_list!(visitor, visit_foreign_item, &foreign_module.items);
 251         }
 252         ItemTy(ref typ, ref type_parameters) => {
 253             visitor.visit_ty(typ);
 254             visitor.visit_generics(type_parameters)
 255         }
 256         ItemEnum(ref enum_definition, ref type_parameters) => {
 257             visitor.visit_generics(type_parameters);
 258             visitor.visit_enum_def(enum_definition, type_parameters)
 259         }
 260         ItemDefaultImpl(_, ref trait_ref) => {
 261             visitor.visit_trait_ref(trait_ref)
 262         }
 263         ItemImpl(_, _,
 264                  ref type_parameters,
 265                  ref opt_trait_reference,
 266                  ref typ,
 267                  ref impl_items) => {
 268             visitor.visit_generics(type_parameters);
 269             walk_list!(visitor, visit_trait_ref, opt_trait_reference);
 270             visitor.visit_ty(typ);
 271             walk_list!(visitor, visit_impl_item, impl_items);
 272         }
 273         ItemStruct(ref struct_definition, ref generics) => {
 274             visitor.visit_generics(generics);
 275             visitor.visit_struct_def(struct_definition,
 276                                      item.name,
 277                                      generics,
 278                                      item.id)
 279         }
 280         ItemTrait(_, ref generics, ref bounds, ref methods) => {
 281             visitor.visit_generics(generics);
 282             walk_list!(visitor, visit_ty_param_bound, bounds);
 283             walk_list!(visitor, visit_trait_item, methods);
 284         }
 285     }
 286     walk_list!(visitor, visit_attribute, &item.attrs);
 287 }
 288
 289 pub fn walk_enum_def<'v, V: Visitor<'v>>(visitor: &mut V,
 290                                          enum_definition: &'v EnumDef,
 291                                          generics: &'v Generics) {
 292     for variant in &enum_definition.variants {
 293         visitor.visit_variant(variant, generics);
 294     }
 295 }
 296
 297 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V,
 298                                         variant: &'v Variant,
 299                                         generics: &'v Generics) {
 300     visitor.visit_name(variant.span, variant.node.name);
 301
 302     match variant.node.kind {
 303         TupleVariantKind(ref variant_arguments) => {
 304             for variant_argument in variant_arguments {
 305                 visitor.visit_ty(&variant_argument.ty)
 306             }
 307         }
 308         StructVariantKind(ref struct_definition) => {
 309             visitor.visit_struct_def(struct_definition,
 310                                      variant.node.name,
 311                                      generics,
 312                                      variant.node.id)
 313         }
 314     }
 315     walk_list!(visitor, visit_expr, &variant.node.disr_expr);
 316     walk_list!(visitor, visit_attribute, &variant.node.attrs);
 317 }
 318
 319 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
 320     match typ.node {
 321         TyVec(ref ty) | TyParen(ref ty) => {
 322             visitor.visit_ty(ty)
 323         }
 324         TyPtr(ref mutable_type) => {
 325             visitor.visit_ty(&mutable_type.ty)
 326         }
 327         TyRptr(ref opt_lifetime, ref mutable_type) => {
 328             walk_list!(visitor, visit_lifetime, opt_lifetime);
 329             visitor.visit_ty(&mutable_type.ty)
 330         }
 331         TyTup(ref tuple_element_types) => {
 332             walk_list!(visitor, visit_ty, tuple_element_types);
 333         }
 334         TyBareFn(ref function_declaration) => {
 335             walk_fn_decl(visitor, &function_declaration.decl);
 336             walk_list!(visitor, visit_lifetime_def, &function_declaration.lifetimes);
 337         }
 338         TyPath(ref maybe_qself, ref path) => {
 339             for qself in maybe_qself {
 340                 visitor.visit_ty(&qself.ty);
 341             }
 342             visitor.visit_path(path, typ.id);
 343         }
 344         TyObjectSum(ref ty, ref bounds) => {
 345             visitor.visit_ty(ty);
 346             walk_list!(visitor, visit_ty_param_bound, bounds);
 347         }
 348         TyFixedLengthVec(ref ty, ref expression) => {
 349             visitor.visit_ty(ty);
 350             visitor.visit_expr(expression)
 351         }
 352         TyPolyTraitRef(ref bounds) => {
 353             walk_list!(visitor, visit_ty_param_bound, bounds);
 354         }
 355         TyTypeof(ref expression) => {
 356             visitor.visit_expr(expression)
 357         }
 358         TyInfer => {}
 359     }
 360 }
 361
 362 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path) {
 363     for segment in &path.segments {
 364         visitor.visit_path_segment(path.span, segment);
 365     }
 366 }
 367
 368 pub fn walk_path_list_item<'v, V: Visitor<'v>>(visitor: &mut V, prefix: &'v Path,
 369                                                item: &'v PathListItem) {
 370     for segment in &prefix.segments {
 371         visitor.visit_path_segment(prefix.span, segment);
 372     }
 373
 374     walk_opt_name(visitor, item.span, item.node.name());
 375     walk_opt_name(visitor, item.span, item.node.rename());
 376 }
 377
 378 pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V,
 379                                              path_span: Span,
 380                                              segment: &'v PathSegment) {
 381     visitor.visit_ident(path_span, segment.identifier);
 382     visitor.visit_path_parameters(path_span, &segment.parameters);
 383 }
 384
 385 pub fn walk_path_parameters<'v, V: Visitor<'v>>(visitor: &mut V,
 386                                                 _path_span: Span,
 387                                                 path_parameters: &'v PathParameters) {
 388     match *path_parameters {
 389         AngleBracketedParameters(ref data) => {
 390             walk_list!(visitor, visit_ty, &data.types);
 391             walk_list!(visitor, visit_lifetime, &data.lifetimes);
 392             walk_list!(visitor, visit_assoc_type_binding, &data.bindings);
 393         }
 394         ParenthesizedParameters(ref data) => {
 395             walk_list!(visitor, visit_ty, &data.inputs);
 396             walk_list!(visitor, visit_ty, &data.output);
 397         }
 398     }
 399 }
 400
 401 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(visitor: &mut V,
 402                                                    type_binding: &'v TypeBinding) {
 403     visitor.visit_name(type_binding.span, type_binding.name);
 404     visitor.visit_ty(&type_binding.ty);
 405 }
 406
 407 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat) {
 408     match pattern.node {
 409         PatEnum(ref path, ref opt_children) => {
 410             visitor.visit_path(path, pattern.id);
 411             for children in opt_children {
 412                 walk_list!(visitor, visit_pat, children);
 413             }
 414         }
 415         PatQPath(ref qself, ref path) => {
 416             visitor.visit_ty(&qself.ty);
 417             visitor.visit_path(path, pattern.id)
 418         }
 419         PatStruct(ref path, ref fields, _) => {
 420             visitor.visit_path(path, pattern.id);
 421             for field in fields {
 422                 visitor.visit_name(field.span, field.node.name);
 423                 visitor.visit_pat(&field.node.pat)
 424             }
 425         }
 426         PatTup(ref tuple_elements) => {
 427             walk_list!(visitor, visit_pat, tuple_elements);
 428         }
 429         PatBox(ref subpattern) |
 430         PatRegion(ref subpattern, _) => {
 431             visitor.visit_pat(subpattern)
 432         }
 433         PatIdent(_, ref pth1, ref optional_subpattern) => {
 434             visitor.visit_ident(pth1.span, pth1.node);
 435             walk_list!(visitor, visit_pat, optional_subpattern);
 436         }
 437         PatLit(ref expression) => visitor.visit_expr(expression),
 438         PatRange(ref lower_bound, ref upper_bound) => {
 439             visitor.visit_expr(lower_bound);
 440             visitor.visit_expr(upper_bound)
 441         }
 442         PatWild(_) => (),
 443         PatVec(ref prepatterns, ref slice_pattern, ref postpatterns) => {
 444             walk_list!(visitor, visit_pat, prepatterns);
 445             walk_list!(visitor, visit_pat, slice_pattern);
 446             walk_list!(visitor, visit_pat, postpatterns);
 447         }
 448     }
 449 }
 450
 451 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V,
 452                                              foreign_item: &'v ForeignItem) {
 453     visitor.visit_name(foreign_item.span, foreign_item.name);
 454
 455     match foreign_item.node {
 456         ForeignItemFn(ref function_declaration, ref generics) => {
 457             walk_fn_decl(visitor, function_declaration);
 458             visitor.visit_generics(generics)
 459         }
 460         ForeignItemStatic(ref typ, _) => visitor.visit_ty(typ),
 461     }
 462
 463     walk_list!(visitor, visit_attribute, &foreign_item.attrs);
 464 }
 465
 466 pub fn walk_ty_param_bound<'v, V: Visitor<'v>>(visitor: &mut V,
 467                                                bound: &'v TyParamBound) {
 468     match *bound {
 469         TraitTyParamBound(ref typ, ref modifier) => {
 470             visitor.visit_poly_trait_ref(typ, modifier);
 471         }
 472         RegionTyParamBound(ref lifetime) => {
 473             visitor.visit_lifetime(lifetime);
 474         }
 475     }
 476 }
 477
 478 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics) {
 479     for param in &generics.ty_params {
 480         visitor.visit_name(param.span, param.name);
 481         walk_list!(visitor, visit_ty_param_bound, &param.bounds);
 482         walk_list!(visitor, visit_ty, &param.default);
 483     }
 484     walk_list!(visitor, visit_lifetime_def, &generics.lifetimes);
 485     for predicate in &generics.where_clause.predicates {
 486         match predicate {
 487             &WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
 488                                                                           ref bounds,
 489                                                                           ref bound_lifetimes,
 490                                                                           ..}) => {
 491                 visitor.visit_ty(bounded_ty);
 492                 walk_list!(visitor, visit_ty_param_bound, bounds);
 493                 walk_list!(visitor, visit_lifetime_def, bound_lifetimes);
 494             }
 495             &WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
 496                                                                             ref bounds,
 497                                                                             ..}) => {
 498                 visitor.visit_lifetime(lifetime);
 499                 walk_list!(visitor, visit_lifetime, bounds);
 500             }
 501             &WherePredicate::EqPredicate(WhereEqPredicate{id,
 502                                                                     ref path,
 503                                                                     ref ty,
 504                                                                     ..}) => {
 505                 visitor.visit_path(path, id);
 506                 visitor.visit_ty(ty);
 507             }
 508         }
 509     }
 510 }
 511
 512 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FunctionRetTy) {
 513     if let Return(ref output_ty) = *ret_ty {
 514         visitor.visit_ty(output_ty)
 515     }
 516 }
 517
 518 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl) {
 519     for argument in &function_declaration.inputs {
 520         visitor.visit_pat(&argument.pat);
 521         visitor.visit_ty(&argument.ty)
 522     }
 523     walk_fn_ret_ty(visitor, &function_declaration.output)
 524 }
 525
 526 pub fn walk_fn_decl_nopat<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl) {
 527     for argument in &function_declaration.inputs {
 528         visitor.visit_ty(&argument.ty)
 529     }
 530     walk_fn_ret_ty(visitor, &function_declaration.output)
 531 }
 532
 533 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V,
 534                                         function_kind: FnKind<'v>) {
 535     match function_kind {
 536         FnKind::ItemFn(_, generics, _, _, _, _) => {
 537             visitor.visit_generics(generics);
 538         }
 539         FnKind::Method(_, sig, _) => {
 540             visitor.visit_generics(&sig.generics);
 541             visitor.visit_explicit_self(&sig.explicit_self);
 542         }
 543         FnKind::Closure => {}
 544     }
 545 }
 546
 547 pub fn walk_fn<'v, V: Visitor<'v>>(visitor: &mut V,
 548                                    function_kind: FnKind<'v>,
 549                                    function_declaration: &'v FnDecl,
 550                                    function_body: &'v Block,
 551                                    _span: Span) {
 552     walk_fn_decl(visitor, function_declaration);
 553     walk_fn_kind(visitor, function_kind);
 554     visitor.visit_block(function_body)
 555 }
 556
 557 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem) {
 558     visitor.visit_name(trait_item.span, trait_item.name);
 559     walk_list!(visitor, visit_attribute, &trait_item.attrs);
 560     match trait_item.node {
 561         ConstTraitItem(ref ty, ref default) => {
 562             visitor.visit_ty(ty);
 563             walk_list!(visitor, visit_expr, default);
 564         }
 565         MethodTraitItem(ref sig, None) => {
 566             visitor.visit_explicit_self(&sig.explicit_self);
 567             visitor.visit_generics(&sig.generics);
 568             walk_fn_decl(visitor, &sig.decl);
 569         }
 570         MethodTraitItem(ref sig, Some(ref body)) => {
 571             visitor.visit_fn(FnKind::Method(trait_item.name, sig, None), &sig.decl,
 572                              body, trait_item.span, trait_item.id);
 573         }
 574         TypeTraitItem(ref bounds, ref default) => {
 575             walk_list!(visitor, visit_ty_param_bound, bounds);
 576             walk_list!(visitor, visit_ty, default);
 577         }
 578     }
 579 }
 580
 581 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem) {
 582     visitor.visit_name(impl_item.span, impl_item.name);
 583     walk_list!(visitor, visit_attribute, &impl_item.attrs);
 584     match impl_item.node {
 585         ConstImplItem(ref ty, ref expr) => {
 586             visitor.visit_ty(ty);
 587             visitor.visit_expr(expr);
 588         }
 589         MethodImplItem(ref sig, ref body) => {
 590             visitor.visit_fn(FnKind::Method(impl_item.name, sig, Some(impl_item.vis)), &sig.decl,
 591                              body, impl_item.span, impl_item.id);
 592         }
 593         TypeImplItem(ref ty) => {
 594             visitor.visit_ty(ty);
 595         }
 596     }
 597 }
 598
 599 pub fn walk_struct_def<'v, V: Visitor<'v>>(visitor: &mut V,
 600                                            struct_definition: &'v StructDef) {
 601     walk_list!(visitor, visit_struct_field, &struct_definition.fields);
 602 }
 603
 604 pub fn walk_struct_field<'v, V: Visitor<'v>>(visitor: &mut V,
 605                                              struct_field: &'v StructField) {
 606     walk_opt_name(visitor, struct_field.span, struct_field.node.name());
 607     visitor.visit_ty(&struct_field.node.ty);
 608     walk_list!(visitor, visit_attribute, &struct_field.node.attrs);
 609 }
 610
 611 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block) {
 612     walk_list!(visitor, visit_stmt, &block.stmts);
 613     walk_list!(visitor, visit_expr, &block.expr);
 614 }
 615
 616 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
 617     match statement.node {
 618         StmtDecl(ref declaration, _) => visitor.visit_decl(declaration),
 619         StmtExpr(ref expression, _) | StmtSemi(ref expression, _) => {
 620             visitor.visit_expr(expression)
 621         }
 622     }
 623 }
 624
 625 pub fn walk_decl<'v, V: Visitor<'v>>(visitor: &mut V, declaration: &'v Decl) {
 626     match declaration.node {
 627         DeclLocal(ref local) => visitor.visit_local(local),
 628         DeclItem(ref item) => visitor.visit_item(item),
 629     }
 630 }
 631
 632 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
 633     match expression.node {
 634         ExprBox(ref subexpression) => {
 635             visitor.visit_expr(subexpression)
 636         }
 637         ExprVec(ref subexpressions) => {
 638             walk_list!(visitor, visit_expr, subexpressions);
 639         }
 640         ExprRepeat(ref element, ref count) => {
 641             visitor.visit_expr(element);
 642             visitor.visit_expr(count)
 643         }
 644         ExprStruct(ref path, ref fields, ref optional_base) => {
 645             visitor.visit_path(path, expression.id);
 646             for field in fields {
 647                 visitor.visit_name(field.name.span, field.name.node);
 648                 visitor.visit_expr(&field.expr)
 649             }
 650             walk_list!(visitor, visit_expr, optional_base);
 651         }
 652         ExprTup(ref subexpressions) => {
 653             walk_list!(visitor, visit_expr, subexpressions);
 654         }
 655         ExprCall(ref callee_expression, ref arguments) => {
 656             walk_list!(visitor, visit_expr, arguments);
 657             visitor.visit_expr(callee_expression)
 658         }
 659         ExprMethodCall(ref name, ref types, ref arguments) => {
 660             visitor.visit_name(name.span, name.node);
 661             walk_list!(visitor, visit_expr, arguments);
 662             walk_list!(visitor, visit_ty, types);
 663         }
 664         ExprBinary(_, ref left_expression, ref right_expression) => {
 665             visitor.visit_expr(left_expression);
 666             visitor.visit_expr(right_expression)
 667         }
 668         ExprAddrOf(_, ref subexpression) | ExprUnary(_, ref subexpression) => {
 669             visitor.visit_expr(subexpression)
 670         }
 671         ExprLit(_) => {}
 672         ExprCast(ref subexpression, ref typ) => {
 673             visitor.visit_expr(subexpression);
 674             visitor.visit_ty(typ)
 675         }
 676         ExprIf(ref head_expression, ref if_block, ref optional_else) => {
 677             visitor.visit_expr(head_expression);
 678             visitor.visit_block(if_block);
 679             walk_list!(visitor, visit_expr, optional_else);
 680         }
 681         ExprWhile(ref subexpression, ref block, opt_ident) => {
 682             visitor.visit_expr(subexpression);
 683             visitor.visit_block(block);
 684             walk_opt_ident(visitor, expression.span, opt_ident)
 685         }
 686         ExprLoop(ref block, opt_ident) => {
 687             visitor.visit_block(block);
 688             walk_opt_ident(visitor, expression.span, opt_ident)
 689         }
 690         ExprMatch(ref subexpression, ref arms, _) => {
 691             visitor.visit_expr(subexpression);
 692             walk_list!(visitor, visit_arm, arms);
 693         }
 694         ExprClosure(_, ref function_declaration, ref body) => {
 695             visitor.visit_fn(FnKind::Closure,
 696                              function_declaration,
 697                              body,
 698                              expression.span,
 699                              expression.id)
 700         }
 701         ExprBlock(ref block) => visitor.visit_block(block),
 702         ExprAssign(ref left_hand_expression, ref right_hand_expression) => {
 703             visitor.visit_expr(right_hand_expression);
 704             visitor.visit_expr(left_hand_expression)
 705         }
 706         ExprAssignOp(_, ref left_expression, ref right_expression) => {
 707             visitor.visit_expr(right_expression);
 708             visitor.visit_expr(left_expression)
 709         }
 710         ExprField(ref subexpression, ref name) => {
 711             visitor.visit_expr(subexpression);
 712             visitor.visit_name(name.span, name.node);
 713         }
 714         ExprTupField(ref subexpression, _) => {
 715             visitor.visit_expr(subexpression);
 716         }
 717         ExprIndex(ref main_expression, ref index_expression) => {
 718             visitor.visit_expr(main_expression);
 719             visitor.visit_expr(index_expression)
 720         }
 721         ExprRange(ref start, ref end) => {
 722             walk_list!(visitor, visit_expr, start);
 723             walk_list!(visitor, visit_expr, end);
 724         }
 725         ExprPath(ref maybe_qself, ref path) => {
 726             for qself in maybe_qself {
 727                 visitor.visit_ty(&qself.ty);
 728             }
 729             visitor.visit_path(path, expression.id)
 730         }
 731         ExprBreak(ref opt_sp_ident) | ExprAgain(ref opt_sp_ident) => {
 732             for sp_ident in opt_sp_ident {
 733                 visitor.visit_ident(sp_ident.span, sp_ident.node);
 734             }
 735         }
 736         ExprRet(ref optional_expression) => {
 737             walk_list!(visitor, visit_expr, optional_expression);
 738         }
 739         ExprInlineAsm(ref ia) => {
 740             for &(_, ref input) in &ia.inputs {
 741                 visitor.visit_expr(&input)
 742             }
 743             for &(_, ref output, _) in &ia.outputs {
 744                 visitor.visit_expr(&output)
 745             }
 746         }
 747     }
 748
 749     visitor.visit_expr_post(expression)
 750 }
 751
 752 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm) {
 753     walk_list!(visitor, visit_pat, &arm.pats);
 754     walk_list!(visitor, visit_expr, &arm.guard);
 755     visitor.visit_expr(&arm.body);
 756     walk_list!(visitor, visit_attribute, &arm.attrs);
 757 }