1 // Copyright 2012-2014 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.
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.
11 //! AST 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.
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.
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.
31 use owned_slice::OwnedSlice;
33 #[derive(Copy, Clone, PartialEq, Eq)]
35 /// fn foo() or extern "Abi" fn foo()
36 ItemFn(Ident, &'a Generics, Unsafety, Constness, Abi, Visibility),
39 Method(Ident, &'a MethodSig, Option<Visibility>),
45 /// Each method of the Visitor trait is a hook to be potentially
46 /// overridden. Each method's default implementation recursively visits
47 /// the substructure of the input via the corresponding `walk` method;
48 /// e.g. the `visit_mod` method by default calls `visit::walk_mod`.
50 /// If you want to ensure that your code handles every variant
51 /// explicitly, you need to override each method. (And you also need
52 /// to monitor future changes to `Visitor` in case a new method with a
53 /// new default implementation gets introduced.)
54 pub trait Visitor<'v> : Sized {
55 fn visit_name(&mut self, _span: Span, _name: Name) {
58 fn visit_ident(&mut self, span: Span, ident: Ident) {
59 self.visit_name(span, ident.name);
61 fn visit_mod(&mut self, m: &'v Mod, _s: Span, _n: NodeId) { walk_mod(self, m) }
62 fn visit_foreign_item(&mut self, i: &'v ForeignItem) { walk_foreign_item(self, i) }
63 fn visit_item(&mut self, i: &'v Item) { walk_item(self, i) }
64 fn visit_local(&mut self, l: &'v Local) { walk_local(self, l) }
65 fn visit_block(&mut self, b: &'v Block) { walk_block(self, b) }
66 fn visit_stmt(&mut self, s: &'v Stmt) { walk_stmt(self, s) }
67 fn visit_arm(&mut self, a: &'v Arm) { walk_arm(self, a) }
68 fn visit_pat(&mut self, p: &'v Pat) { walk_pat(self, p) }
69 fn visit_decl(&mut self, d: &'v Decl) { walk_decl(self, d) }
70 fn visit_expr(&mut self, ex: &'v Expr) { walk_expr(self, ex) }
71 fn visit_expr_post(&mut self, _ex: &'v Expr) { }
72 fn visit_ty(&mut self, t: &'v Ty) { walk_ty(self, t) }
73 fn visit_generics(&mut self, g: &'v Generics) { walk_generics(self, g) }
74 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl, b: &'v Block, s: Span, _: NodeId) {
75 walk_fn(self, fk, fd, b, s)
77 fn visit_trait_item(&mut self, ti: &'v TraitItem) { walk_trait_item(self, ti) }
78 fn visit_impl_item(&mut self, ii: &'v ImplItem) { walk_impl_item(self, ii) }
79 fn visit_trait_ref(&mut self, t: &'v TraitRef) { walk_trait_ref(self, t) }
80 fn visit_ty_param_bound(&mut self, bounds: &'v TyParamBound) {
81 walk_ty_param_bound(self, bounds)
83 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef, m: &'v TraitBoundModifier) {
84 walk_poly_trait_ref(self, t, m)
86 fn visit_struct_def(&mut self, s: &'v StructDef, _: Ident, _: &'v Generics, _: NodeId) {
87 walk_struct_def(self, s)
89 fn visit_struct_field(&mut self, s: &'v StructField) { walk_struct_field(self, s) }
90 fn visit_enum_def(&mut self, enum_definition: &'v EnumDef,
91 generics: &'v Generics) {
92 walk_enum_def(self, enum_definition, generics)
95 fn visit_variant(&mut self, v: &'v Variant, g: &'v Generics) { walk_variant(self, v, g) }
97 /// Visits an optional reference to a lifetime. The `span` is the span of some surrounding
98 /// reference should opt_lifetime be None.
99 fn visit_opt_lifetime_ref(&mut self,
101 opt_lifetime: &'v Option<Lifetime>) {
102 match *opt_lifetime {
103 Some(ref l) => self.visit_lifetime_ref(l),
107 fn visit_lifetime_bound(&mut self, lifetime: &'v Lifetime) {
108 walk_lifetime_bound(self, lifetime)
110 fn visit_lifetime_ref(&mut self, lifetime: &'v Lifetime) {
111 walk_lifetime_ref(self, lifetime)
113 fn visit_lifetime_def(&mut self, lifetime: &'v LifetimeDef) {
114 walk_lifetime_def(self, lifetime)
116 fn visit_explicit_self(&mut self, es: &'v ExplicitSelf) {
117 walk_explicit_self(self, es)
119 fn visit_mac(&mut self, _mac: &'v Mac) {
120 panic!("visit_mac disabled by default");
121 // NB: see note about macros above.
122 // if you really want a visitor that
123 // works on macros, use this
124 // definition in your trait impl:
125 // visit::walk_mac(self, _mac)
127 fn visit_path(&mut self, path: &'v Path, _id: ast::NodeId) {
128 walk_path(self, path)
130 fn visit_path_list_item(&mut self, prefix: &'v Path, item: &'v PathListItem) {
131 walk_path_list_item(self, prefix, item)
133 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment) {
134 walk_path_segment(self, path_span, path_segment)
136 fn visit_path_parameters(&mut self, path_span: Span, path_parameters: &'v PathParameters) {
137 walk_path_parameters(self, path_span, path_parameters)
139 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding) {
140 walk_assoc_type_binding(self, type_binding)
142 fn visit_attribute(&mut self, _attr: &'v Attribute) {}
145 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate) {
146 visitor.visit_mod(&krate.module, krate.span, CRATE_NODE_ID);
147 for attr in &krate.attrs {
148 visitor.visit_attribute(attr);
152 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod) {
153 for item in &module.items {
154 visitor.visit_item(&**item)
158 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local) {
159 visitor.visit_pat(&*local.pat);
160 walk_ty_opt(visitor, &local.ty);
161 walk_expr_opt(visitor, &local.init);
164 pub fn walk_lifetime_def<'v, V: Visitor<'v>>(visitor: &mut V,
165 lifetime_def: &'v LifetimeDef) {
166 visitor.visit_name(lifetime_def.lifetime.span, lifetime_def.lifetime.name);
167 for bound in &lifetime_def.bounds {
168 visitor.visit_lifetime_bound(bound);
172 pub fn walk_lifetime_bound<'v, V: Visitor<'v>>(visitor: &mut V,
173 lifetime_ref: &'v Lifetime) {
174 visitor.visit_lifetime_ref(lifetime_ref)
177 pub fn walk_lifetime_ref<'v, V: Visitor<'v>>(visitor: &mut V,
178 lifetime_ref: &'v Lifetime) {
179 visitor.visit_name(lifetime_ref.span, lifetime_ref.name)
182 pub fn walk_explicit_self<'v, V: Visitor<'v>>(visitor: &mut V,
183 explicit_self: &'v ExplicitSelf) {
184 match explicit_self.node {
185 SelfStatic | SelfValue(_) => {},
186 SelfRegion(ref lifetime, _, _) => {
187 visitor.visit_opt_lifetime_ref(explicit_self.span, lifetime)
189 SelfExplicit(ref typ, _) => visitor.visit_ty(&**typ),
193 pub fn walk_poly_trait_ref<'v, V>(visitor: &mut V,
194 trait_ref: &'v PolyTraitRef,
195 _modifier: &'v TraitBoundModifier)
198 walk_lifetime_decls_helper(visitor, &trait_ref.bound_lifetimes);
199 visitor.visit_trait_ref(&trait_ref.trait_ref);
202 pub fn walk_trait_ref<'v,V>(visitor: &mut V,
203 trait_ref: &'v TraitRef)
206 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
209 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
210 visitor.visit_ident(item.span, item.ident);
212 ItemExternCrate(..) => {}
215 ViewPathSimple(_ident, ref path) => {
216 visitor.visit_path(path, item.id);
218 ViewPathGlob(ref path) => {
219 visitor.visit_path(path, item.id);
221 ViewPathList(ref prefix, ref list) => {
222 if !list.is_empty() {
224 visitor.visit_path_list_item(prefix, item)
227 // FIXME: uncomment this and fix the resulting ICE
228 // visitor.visit_path(prefix, item.id);
233 ItemStatic(ref typ, _, ref expr) |
234 ItemConst(ref typ, ref expr) => {
235 visitor.visit_ty(&**typ);
236 visitor.visit_expr(&**expr);
238 ItemFn(ref declaration, unsafety, constness, abi, ref generics, ref body) => {
239 visitor.visit_fn(FnKind::ItemFn(item.ident, generics, unsafety,
240 constness, abi, item.vis),
246 ItemMod(ref module) => {
247 visitor.visit_mod(module, item.span, item.id)
249 ItemForeignMod(ref foreign_module) => {
250 for foreign_item in &foreign_module.items {
251 visitor.visit_foreign_item(&**foreign_item)
254 ItemTy(ref typ, ref type_parameters) => {
255 visitor.visit_ty(&**typ);
256 visitor.visit_generics(type_parameters)
258 ItemEnum(ref enum_definition, ref type_parameters) => {
259 visitor.visit_generics(type_parameters);
260 visitor.visit_enum_def(enum_definition, type_parameters)
262 ItemDefaultImpl(_, ref trait_ref) => {
263 visitor.visit_trait_ref(trait_ref)
270 visitor.visit_generics(type_parameters);
271 match *trait_reference {
272 Some(ref trait_reference) => visitor.visit_trait_ref(trait_reference),
275 visitor.visit_ty(&**typ);
276 for impl_item in impl_items {
277 visitor.visit_impl_item(impl_item);
280 ItemStruct(ref struct_definition, ref generics) => {
281 visitor.visit_generics(generics);
282 visitor.visit_struct_def(&**struct_definition,
287 ItemTrait(_, ref generics, ref bounds, ref methods) => {
288 visitor.visit_generics(generics);
289 walk_ty_param_bounds_helper(visitor, bounds);
290 for method in methods {
291 visitor.visit_trait_item(method)
294 ItemMac(ref mac) => visitor.visit_mac(mac),
296 for attr in &item.attrs {
297 visitor.visit_attribute(attr);
301 pub fn walk_enum_def<'v, V: Visitor<'v>>(visitor: &mut V,
302 enum_definition: &'v EnumDef,
303 generics: &'v Generics) {
304 for variant in &enum_definition.variants {
305 visitor.visit_variant(&**variant, generics);
309 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V,
310 variant: &'v Variant,
311 generics: &'v Generics) {
312 visitor.visit_ident(variant.span, variant.node.name);
314 match variant.node.kind {
315 TupleVariantKind(ref variant_arguments) => {
316 for variant_argument in variant_arguments {
317 visitor.visit_ty(&*variant_argument.ty)
320 StructVariantKind(ref struct_definition) => {
321 visitor.visit_struct_def(&**struct_definition,
327 match variant.node.disr_expr {
328 Some(ref expr) => visitor.visit_expr(&**expr),
331 for attr in &variant.node.attrs {
332 visitor.visit_attribute(attr);
336 pub fn skip_ty<'v, V: Visitor<'v>>(_: &mut V, _: &'v Ty) {
340 pub fn walk_ty_opt<'v, V: Visitor<'v>>(visitor: &mut V, optional_type: &'v Option<P<Ty>>) {
341 match *optional_type {
342 Some(ref ty) => visitor.visit_ty(&**ty),
347 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
349 TyVec(ref ty) | TyParen(ref ty) => {
350 visitor.visit_ty(&**ty)
352 TyPtr(ref mutable_type) => {
353 visitor.visit_ty(&*mutable_type.ty)
355 TyRptr(ref lifetime, ref mutable_type) => {
356 visitor.visit_opt_lifetime_ref(typ.span, lifetime);
357 visitor.visit_ty(&*mutable_type.ty)
359 TyTup(ref tuple_element_types) => {
360 for tuple_element_type in tuple_element_types {
361 visitor.visit_ty(&**tuple_element_type)
364 TyBareFn(ref function_declaration) => {
365 for argument in &function_declaration.decl.inputs {
366 visitor.visit_ty(&*argument.ty)
368 walk_fn_ret_ty(visitor, &function_declaration.decl.output);
369 walk_lifetime_decls_helper(visitor, &function_declaration.lifetimes);
371 TyPath(ref maybe_qself, ref path) => {
372 if let Some(ref qself) = *maybe_qself {
373 visitor.visit_ty(&qself.ty);
375 visitor.visit_path(path, typ.id);
377 TyObjectSum(ref ty, ref bounds) => {
378 visitor.visit_ty(&**ty);
379 walk_ty_param_bounds_helper(visitor, bounds);
381 TyFixedLengthVec(ref ty, ref expression) => {
382 visitor.visit_ty(&**ty);
383 visitor.visit_expr(&**expression)
385 TyPolyTraitRef(ref bounds) => {
386 walk_ty_param_bounds_helper(visitor, bounds)
388 TyTypeof(ref expression) => {
389 visitor.visit_expr(&**expression)
393 visitor.visit_mac(mac)
398 pub fn walk_lifetime_decls_helper<'v, V: Visitor<'v>>(visitor: &mut V,
399 lifetimes: &'v Vec<LifetimeDef>) {
401 visitor.visit_lifetime_def(l);
405 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path) {
406 for segment in &path.segments {
407 visitor.visit_path_segment(path.span, segment);
411 pub fn walk_path_list_item<'v, V: Visitor<'v>>(visitor: &mut V, prefix: &'v Path,
412 item: &'v PathListItem) {
413 for segment in &prefix.segments {
414 visitor.visit_path_segment(prefix.span, segment);
417 if let PathListIdent { name, .. } = item.node {
418 visitor.visit_ident(item.span, name);
422 pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V,
424 segment: &'v PathSegment) {
425 visitor.visit_ident(path_span, segment.identifier);
426 visitor.visit_path_parameters(path_span, &segment.parameters);
429 pub fn walk_path_parameters<'v, V: Visitor<'v>>(visitor: &mut V,
431 path_parameters: &'v PathParameters) {
432 match *path_parameters {
433 ast::AngleBracketedParameters(ref data) => {
434 for typ in data.types.iter() {
435 visitor.visit_ty(&**typ);
437 for lifetime in &data.lifetimes {
438 visitor.visit_lifetime_ref(lifetime);
440 for binding in data.bindings.iter() {
441 visitor.visit_assoc_type_binding(&**binding);
444 ast::ParenthesizedParameters(ref data) => {
445 for typ in &data.inputs {
446 visitor.visit_ty(&**typ);
448 if let Some(ref typ) = data.output {
449 visitor.visit_ty(&**typ);
455 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(visitor: &mut V,
456 type_binding: &'v TypeBinding) {
457 visitor.visit_ident(type_binding.span, type_binding.ident);
458 visitor.visit_ty(&*type_binding.ty);
461 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat) {
463 PatEnum(ref path, ref children) => {
464 visitor.visit_path(path, pattern.id);
465 if let Some(ref children) = *children {
466 for child in children {
467 visitor.visit_pat(&*child)
471 PatQPath(ref qself, ref path) => {
472 visitor.visit_ty(&qself.ty);
473 visitor.visit_path(path, pattern.id)
475 PatStruct(ref path, ref fields, _) => {
476 visitor.visit_path(path, pattern.id);
477 for field in fields {
478 visitor.visit_pat(&*field.node.pat)
481 PatTup(ref tuple_elements) => {
482 for tuple_element in tuple_elements {
483 visitor.visit_pat(&**tuple_element)
486 PatBox(ref subpattern) |
487 PatRegion(ref subpattern, _) => {
488 visitor.visit_pat(&**subpattern)
490 PatIdent(_, ref pth1, ref optional_subpattern) => {
491 visitor.visit_ident(pth1.span, pth1.node);
492 match *optional_subpattern {
494 Some(ref subpattern) => visitor.visit_pat(&**subpattern),
497 PatLit(ref expression) => visitor.visit_expr(&**expression),
498 PatRange(ref lower_bound, ref upper_bound) => {
499 visitor.visit_expr(&**lower_bound);
500 visitor.visit_expr(&**upper_bound)
503 PatVec(ref prepattern, ref slice_pattern, ref postpatterns) => {
504 for prepattern in prepattern {
505 visitor.visit_pat(&**prepattern)
507 if let Some(ref slice_pattern) = *slice_pattern {
508 visitor.visit_pat(&**slice_pattern)
510 for postpattern in postpatterns {
511 visitor.visit_pat(&**postpattern)
514 PatMac(ref mac) => visitor.visit_mac(mac),
518 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V,
519 foreign_item: &'v ForeignItem) {
520 visitor.visit_ident(foreign_item.span, foreign_item.ident);
522 match foreign_item.node {
523 ForeignItemFn(ref function_declaration, ref generics) => {
524 walk_fn_decl(visitor, &**function_declaration);
525 visitor.visit_generics(generics)
527 ForeignItemStatic(ref typ, _) => visitor.visit_ty(&**typ),
530 for attr in &foreign_item.attrs {
531 visitor.visit_attribute(attr);
535 pub fn walk_ty_param_bounds_helper<'v, V: Visitor<'v>>(visitor: &mut V,
536 bounds: &'v OwnedSlice<TyParamBound>) {
537 for bound in bounds.iter() {
538 visitor.visit_ty_param_bound(bound)
542 pub fn walk_ty_param_bound<'v, V: Visitor<'v>>(visitor: &mut V,
543 bound: &'v TyParamBound) {
545 TraitTyParamBound(ref typ, ref modifier) => {
546 visitor.visit_poly_trait_ref(typ, modifier);
548 RegionTyParamBound(ref lifetime) => {
549 visitor.visit_lifetime_bound(lifetime);
554 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics) {
555 for param in generics.ty_params.iter() {
556 visitor.visit_ident(param.span, param.ident);
557 walk_ty_param_bounds_helper(visitor, ¶m.bounds);
558 walk_ty_opt(visitor, ¶m.default);
560 walk_lifetime_decls_helper(visitor, &generics.lifetimes);
561 for predicate in &generics.where_clause.predicates {
563 &ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate{ref bounded_ty,
566 visitor.visit_ty(&**bounded_ty);
567 walk_ty_param_bounds_helper(visitor, bounds);
569 &ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate{ref lifetime,
572 visitor.visit_lifetime_ref(lifetime);
574 for bound in bounds {
575 visitor.visit_lifetime_ref(bound);
578 &ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{id,
582 visitor.visit_path(path, id);
583 visitor.visit_ty(&**ty);
589 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FunctionRetTy) {
590 if let Return(ref output_ty) = *ret_ty {
591 visitor.visit_ty(&**output_ty)
595 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl) {
596 for argument in &function_declaration.inputs {
597 visitor.visit_pat(&*argument.pat);
598 visitor.visit_ty(&*argument.ty)
600 walk_fn_ret_ty(visitor, &function_declaration.output)
603 pub fn walk_fn<'v, V: Visitor<'v>>(visitor: &mut V,
604 function_kind: FnKind<'v>,
605 function_declaration: &'v FnDecl,
606 function_body: &'v Block,
608 walk_fn_decl(visitor, function_declaration);
610 match function_kind {
611 FnKind::ItemFn(_, generics, _, _, _, _) => {
612 visitor.visit_generics(generics);
614 FnKind::Method(_, sig, _) => {
615 visitor.visit_generics(&sig.generics);
616 visitor.visit_explicit_self(&sig.explicit_self);
618 FnKind::Closure(..) => {}
621 visitor.visit_block(function_body)
624 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem) {
625 visitor.visit_ident(trait_item.span, trait_item.ident);
626 for attr in &trait_item.attrs {
627 visitor.visit_attribute(attr);
629 match trait_item.node {
630 ConstTraitItem(ref ty, ref default) => {
631 visitor.visit_ty(ty);
632 if let Some(ref expr) = *default {
633 visitor.visit_expr(expr);
636 MethodTraitItem(ref sig, None) => {
637 visitor.visit_explicit_self(&sig.explicit_self);
638 visitor.visit_generics(&sig.generics);
639 walk_fn_decl(visitor, &sig.decl);
641 MethodTraitItem(ref sig, Some(ref body)) => {
642 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None), &sig.decl,
643 body, trait_item.span, trait_item.id);
645 TypeTraitItem(ref bounds, ref default) => {
646 walk_ty_param_bounds_helper(visitor, bounds);
647 walk_ty_opt(visitor, default);
652 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem) {
653 visitor.visit_ident(impl_item.span, impl_item.ident);
654 for attr in &impl_item.attrs {
655 visitor.visit_attribute(attr);
657 match impl_item.node {
658 ConstImplItem(ref ty, ref expr) => {
659 visitor.visit_ty(ty);
660 visitor.visit_expr(expr);
662 MethodImplItem(ref sig, ref body) => {
663 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(impl_item.vis)), &sig.decl,
664 body, impl_item.span, impl_item.id);
666 TypeImplItem(ref ty) => {
667 visitor.visit_ty(ty);
669 MacImplItem(ref mac) => {
670 visitor.visit_mac(mac);
675 pub fn walk_struct_def<'v, V: Visitor<'v>>(visitor: &mut V,
676 struct_definition: &'v StructDef) {
677 for field in &struct_definition.fields {
678 visitor.visit_struct_field(field)
682 pub fn walk_struct_field<'v, V: Visitor<'v>>(visitor: &mut V,
683 struct_field: &'v StructField) {
684 if let NamedField(name, _) = struct_field.node.kind {
685 visitor.visit_ident(struct_field.span, name);
688 visitor.visit_ty(&*struct_field.node.ty);
690 for attr in &struct_field.node.attrs {
691 visitor.visit_attribute(attr);
695 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block) {
696 for statement in &block.stmts {
697 visitor.visit_stmt(&**statement)
699 walk_expr_opt(visitor, &block.expr)
702 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
703 match statement.node {
704 StmtDecl(ref declaration, _) => visitor.visit_decl(&**declaration),
705 StmtExpr(ref expression, _) | StmtSemi(ref expression, _) => {
706 visitor.visit_expr(&**expression)
708 StmtMac(ref mac, _) => visitor.visit_mac(&**mac),
712 pub fn walk_decl<'v, V: Visitor<'v>>(visitor: &mut V, declaration: &'v Decl) {
713 match declaration.node {
714 DeclLocal(ref local) => visitor.visit_local(&**local),
715 DeclItem(ref item) => visitor.visit_item(&**item),
719 pub fn walk_expr_opt<'v, V: Visitor<'v>>(visitor: &mut V,
720 optional_expression: &'v Option<P<Expr>>) {
721 match *optional_expression {
723 Some(ref expression) => visitor.visit_expr(&**expression),
727 pub fn walk_exprs<'v, V: Visitor<'v>>(visitor: &mut V, expressions: &'v [P<Expr>]) {
728 for expression in expressions {
729 visitor.visit_expr(&**expression)
733 pub fn walk_mac<'v, V: Visitor<'v>>(_: &mut V, _: &'v Mac) {
737 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
738 match expression.node {
739 ExprBox(ref place, ref subexpression) => {
740 place.as_ref().map(|e|visitor.visit_expr(&**e));
741 visitor.visit_expr(&**subexpression)
743 ExprVec(ref subexpressions) => {
744 walk_exprs(visitor, subexpressions)
746 ExprRepeat(ref element, ref count) => {
747 visitor.visit_expr(&**element);
748 visitor.visit_expr(&**count)
750 ExprStruct(ref path, ref fields, ref optional_base) => {
751 visitor.visit_path(path, expression.id);
752 for field in fields {
753 visitor.visit_expr(&*field.expr)
755 walk_expr_opt(visitor, optional_base)
757 ExprTup(ref subexpressions) => {
758 for subexpression in subexpressions {
759 visitor.visit_expr(&**subexpression)
762 ExprCall(ref callee_expression, ref arguments) => {
763 for argument in arguments {
764 visitor.visit_expr(&**argument)
766 visitor.visit_expr(&**callee_expression)
768 ExprMethodCall(_, ref types, ref arguments) => {
769 walk_exprs(visitor, arguments);
771 visitor.visit_ty(&**typ)
774 ExprBinary(_, ref left_expression, ref right_expression) => {
775 visitor.visit_expr(&**left_expression);
776 visitor.visit_expr(&**right_expression)
778 ExprAddrOf(_, ref subexpression) | ExprUnary(_, ref subexpression) => {
779 visitor.visit_expr(&**subexpression)
782 ExprCast(ref subexpression, ref typ) => {
783 visitor.visit_expr(&**subexpression);
784 visitor.visit_ty(&**typ)
786 ExprIf(ref head_expression, ref if_block, ref optional_else) => {
787 visitor.visit_expr(&**head_expression);
788 visitor.visit_block(&**if_block);
789 walk_expr_opt(visitor, optional_else)
791 ExprWhile(ref subexpression, ref block, _) => {
792 visitor.visit_expr(&**subexpression);
793 visitor.visit_block(&**block)
795 ExprIfLet(ref pattern, ref subexpression, ref if_block, ref optional_else) => {
796 visitor.visit_pat(&**pattern);
797 visitor.visit_expr(&**subexpression);
798 visitor.visit_block(&**if_block);
799 walk_expr_opt(visitor, optional_else);
801 ExprWhileLet(ref pattern, ref subexpression, ref block, _) => {
802 visitor.visit_pat(&**pattern);
803 visitor.visit_expr(&**subexpression);
804 visitor.visit_block(&**block);
806 ExprForLoop(ref pattern, ref subexpression, ref block, _) => {
807 visitor.visit_pat(&**pattern);
808 visitor.visit_expr(&**subexpression);
809 visitor.visit_block(&**block)
811 ExprLoop(ref block, _) => visitor.visit_block(&**block),
812 ExprMatch(ref subexpression, ref arms, _) => {
813 visitor.visit_expr(&**subexpression);
815 visitor.visit_arm(arm)
818 ExprClosure(_, ref function_declaration, ref body) => {
819 visitor.visit_fn(FnKind::Closure,
820 &**function_declaration,
825 ExprBlock(ref block) => visitor.visit_block(&**block),
826 ExprAssign(ref left_hand_expression, ref right_hand_expression) => {
827 visitor.visit_expr(&**right_hand_expression);
828 visitor.visit_expr(&**left_hand_expression)
830 ExprAssignOp(_, ref left_expression, ref right_expression) => {
831 visitor.visit_expr(&**right_expression);
832 visitor.visit_expr(&**left_expression)
834 ExprField(ref subexpression, _) => {
835 visitor.visit_expr(&**subexpression);
837 ExprTupField(ref subexpression, _) => {
838 visitor.visit_expr(&**subexpression);
840 ExprIndex(ref main_expression, ref index_expression) => {
841 visitor.visit_expr(&**main_expression);
842 visitor.visit_expr(&**index_expression)
844 ExprRange(ref start, ref end) => {
845 walk_expr_opt(visitor, start);
846 walk_expr_opt(visitor, end)
848 ExprPath(ref maybe_qself, ref path) => {
849 if let Some(ref qself) = *maybe_qself {
850 visitor.visit_ty(&qself.ty);
852 visitor.visit_path(path, expression.id)
854 ExprBreak(_) | ExprAgain(_) => {}
855 ExprRet(ref optional_expression) => {
856 walk_expr_opt(visitor, optional_expression)
858 ExprMac(ref mac) => visitor.visit_mac(mac),
859 ExprParen(ref subexpression) => {
860 visitor.visit_expr(&**subexpression)
862 ExprInlineAsm(ref ia) => {
863 for input in &ia.inputs {
864 let (_, ref input) = *input;
865 visitor.visit_expr(&**input)
867 for output in &ia.outputs {
868 let (_, ref output, _) = *output;
869 visitor.visit_expr(&**output)
874 visitor.visit_expr_post(expression)
877 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm) {
878 for pattern in &arm.pats {
879 visitor.visit_pat(&**pattern)
881 walk_expr_opt(visitor, &arm.guard);
882 visitor.visit_expr(&*arm.body);
883 for attr in &arm.attrs {
884 visitor.visit_attribute(attr);