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.
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.
28 use parse::token::Token;
29 use tokenstream::{TokenTree, TokenStream};
31 #[derive(Copy, Clone)]
33 /// fn foo() or extern "Abi" fn foo()
34 ItemFn(Ident, FnHeader, &'a Visibility, &'a Block),
37 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a Block),
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`.
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<'ast>: Sized {
53 fn visit_name(&mut self, _span: Span, _name: Name) {
56 fn visit_ident(&mut self, ident: Ident) {
57 walk_ident(self, ident);
59 fn visit_mod(&mut self, m: &'ast Mod, _s: Span, _attrs: &[Attribute], _n: NodeId) {
62 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) { walk_foreign_item(self, i) }
63 fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) { walk_global_asm(self, ga) }
64 fn visit_item(&mut self, i: &'ast Item) { walk_item(self, i) }
65 fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
66 fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
67 fn visit_stmt(&mut self, s: &'ast Stmt) { walk_stmt(self, s) }
68 fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
69 fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
70 fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
71 fn visit_expr(&mut self, ex: &'ast Expr) { walk_expr(self, ex) }
72 fn visit_expr_post(&mut self, _ex: &'ast Expr) { }
73 fn visit_ty(&mut self, t: &'ast Ty) { walk_ty(self, t) }
74 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
75 walk_generic_param(self, param)
77 fn visit_generics(&mut self, g: &'ast Generics) { walk_generics(self, g) }
78 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
79 walk_where_predicate(self, p)
81 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
82 walk_fn(self, fk, fd, s)
84 fn visit_trait_item(&mut self, ti: &'ast TraitItem) { walk_trait_item(self, ti) }
85 fn visit_impl_item(&mut self, ii: &'ast ImplItem) { walk_impl_item(self, ii) }
86 fn visit_trait_ref(&mut self, t: &'ast TraitRef) { walk_trait_ref(self, t) }
87 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
88 walk_param_bound(self, bounds)
90 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
91 walk_poly_trait_ref(self, t, m)
93 fn visit_variant_data(&mut self, s: &'ast VariantData, _: Ident,
94 _: &'ast Generics, _: NodeId, _: Span) {
95 walk_struct_def(self, s)
97 fn visit_struct_field(&mut self, s: &'ast StructField) { walk_struct_field(self, s) }
98 fn visit_enum_def(&mut self, enum_definition: &'ast EnumDef,
99 generics: &'ast Generics, item_id: NodeId, _: Span) {
100 walk_enum_def(self, enum_definition, generics, item_id)
102 fn visit_variant(&mut self, v: &'ast Variant, g: &'ast Generics, item_id: NodeId) {
103 walk_variant(self, v, g, item_id)
105 fn visit_label(&mut self, label: &'ast Label) {
106 walk_label(self, label)
108 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
109 walk_lifetime(self, lifetime)
111 fn visit_mac(&mut self, _mac: &'ast Mac) {
112 panic!("visit_mac disabled by default");
113 // NB: see note about macros above.
114 // if you really want a visitor that
115 // works on macros, use this
116 // definition in your trait impl:
117 // visit::walk_mac(self, _mac)
119 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
122 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
123 walk_path(self, path)
125 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
126 walk_use_tree(self, use_tree, id)
128 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
129 walk_path_segment(self, path_span, path_segment)
131 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
132 walk_generic_args(self, path_span, generic_args)
134 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
136 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
137 GenericArg::Type(ty) => self.visit_ty(ty),
140 fn visit_assoc_type_binding(&mut self, type_binding: &'ast TypeBinding) {
141 walk_assoc_type_binding(self, type_binding)
143 fn visit_attribute(&mut self, attr: &'ast Attribute) {
144 walk_attribute(self, attr)
146 fn visit_tt(&mut self, tt: TokenTree) {
149 fn visit_tts(&mut self, tts: TokenStream) {
152 fn visit_token(&mut self, _t: Token) {}
153 // FIXME: add `visit_interpolated` and `walk_interpolated`
154 fn visit_vis(&mut self, vis: &'ast Visibility) {
157 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
158 walk_fn_ret_ty(self, ret_ty)
163 macro_rules! walk_list {
164 ($visitor: expr, $method: ident, $list: expr) => {
166 $visitor.$method(elem)
169 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
171 $visitor.$method(elem, $($extra_args,)*)
176 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
177 visitor.visit_name(ident.span, ident.name);
180 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
181 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
182 walk_list!(visitor, visit_attribute, &krate.attrs);
185 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
186 walk_list!(visitor, visit_item, &module.items);
189 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
190 for attr in local.attrs.iter() {
191 visitor.visit_attribute(attr);
193 visitor.visit_pat(&local.pat);
194 walk_list!(visitor, visit_ty, &local.ty);
195 walk_list!(visitor, visit_expr, &local.init);
198 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
199 visitor.visit_ident(label.ident);
202 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
203 visitor.visit_ident(lifetime.ident);
206 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
207 trait_ref: &'a PolyTraitRef,
208 _: &TraitBoundModifier)
209 where V: Visitor<'a>,
211 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
212 visitor.visit_trait_ref(&trait_ref.trait_ref);
215 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
216 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
219 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
220 visitor.visit_vis(&item.vis);
221 visitor.visit_ident(item.ident);
223 ItemKind::ExternCrate(orig_name) => {
224 if let Some(orig_name) = orig_name {
225 visitor.visit_name(item.span, orig_name);
228 ItemKind::Use(ref use_tree) => {
229 visitor.visit_use_tree(use_tree, item.id, false)
231 ItemKind::Static(ref typ, _, ref expr) |
232 ItemKind::Const(ref typ, ref expr) => {
233 visitor.visit_ty(typ);
234 visitor.visit_expr(expr);
236 ItemKind::Fn(ref declaration, header, ref generics, ref body) => {
237 visitor.visit_generics(generics);
238 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
244 ItemKind::Mod(ref module) => {
245 visitor.visit_mod(module, item.span, &item.attrs, item.id)
247 ItemKind::ForeignMod(ref foreign_module) => {
248 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
250 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
251 ItemKind::Ty(ref typ, ref type_parameters) => {
252 visitor.visit_ty(typ);
253 visitor.visit_generics(type_parameters)
255 ItemKind::Enum(ref enum_definition, ref type_parameters) => {
256 visitor.visit_generics(type_parameters);
257 visitor.visit_enum_def(enum_definition, type_parameters, item.id, item.span)
259 ItemKind::Impl(_, _, _,
261 ref opt_trait_reference,
264 visitor.visit_generics(type_parameters);
265 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
266 visitor.visit_ty(typ);
267 walk_list!(visitor, visit_impl_item, impl_items);
269 ItemKind::Struct(ref struct_definition, ref generics) |
270 ItemKind::Union(ref struct_definition, ref generics) => {
271 visitor.visit_generics(generics);
272 visitor.visit_variant_data(struct_definition, item.ident,
273 generics, item.id, item.span);
275 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
276 visitor.visit_generics(generics);
277 walk_list!(visitor, visit_param_bound, bounds);
278 walk_list!(visitor, visit_trait_item, methods);
280 ItemKind::TraitAlias(ref generics, ref bounds) => {
281 visitor.visit_generics(generics);
282 walk_list!(visitor, visit_param_bound, bounds);
284 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
285 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
287 walk_list!(visitor, visit_attribute, &item.attrs);
290 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
291 enum_definition: &'a EnumDef,
292 generics: &'a Generics,
294 walk_list!(visitor, visit_variant, &enum_definition.variants, generics, item_id);
297 pub fn walk_variant<'a, V>(visitor: &mut V,
298 variant: &'a Variant,
299 generics: &'a Generics,
301 where V: Visitor<'a>,
303 visitor.visit_ident(variant.node.ident);
304 visitor.visit_variant_data(&variant.node.data, variant.node.ident,
305 generics, item_id, variant.span);
306 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
307 walk_list!(visitor, visit_attribute, &variant.node.attrs);
310 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
312 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
315 TyKind::Ptr(ref mutable_type) => {
316 visitor.visit_ty(&mutable_type.ty)
318 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
319 walk_list!(visitor, visit_lifetime, opt_lifetime);
320 visitor.visit_ty(&mutable_type.ty)
323 TyKind::Tup(ref tuple_element_types) => {
324 walk_list!(visitor, visit_ty, tuple_element_types);
326 TyKind::BareFn(ref function_declaration) => {
327 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
328 walk_fn_decl(visitor, &function_declaration.decl);
330 TyKind::Path(ref maybe_qself, ref path) => {
331 if let Some(ref qself) = *maybe_qself {
332 visitor.visit_ty(&qself.ty);
334 visitor.visit_path(path, typ.id);
336 TyKind::Array(ref ty, ref length) => {
337 visitor.visit_ty(ty);
338 visitor.visit_anon_const(length)
340 TyKind::TraitObject(ref bounds, ..) |
341 TyKind::ImplTrait(_, ref bounds) => {
342 walk_list!(visitor, visit_param_bound, bounds);
344 TyKind::Typeof(ref expression) => {
345 visitor.visit_anon_const(expression)
347 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
348 TyKind::Mac(ref mac) => {
349 visitor.visit_mac(mac)
354 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
355 for segment in &path.segments {
356 visitor.visit_path_segment(path.span, segment);
360 pub fn walk_use_tree<'a, V: Visitor<'a>>(
361 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
363 visitor.visit_path(&use_tree.prefix, id);
364 match use_tree.kind {
365 UseTreeKind::Simple(rename, ..) => {
366 // the extra IDs are handled during HIR lowering
367 if let Some(rename) = rename {
368 visitor.visit_ident(rename);
371 UseTreeKind::Glob => {},
372 UseTreeKind::Nested(ref use_trees) => {
373 for &(ref nested_tree, nested_id) in use_trees {
374 visitor.visit_use_tree(nested_tree, nested_id, true);
380 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
382 segment: &'a PathSegment) {
383 visitor.visit_ident(segment.ident);
384 if let Some(ref args) = segment.args {
385 visitor.visit_generic_args(path_span, args);
389 pub fn walk_generic_args<'a, V>(visitor: &mut V,
391 generic_args: &'a GenericArgs)
392 where V: Visitor<'a>,
394 match *generic_args {
395 GenericArgs::AngleBracketed(ref data) => {
396 walk_list!(visitor, visit_generic_arg, &data.args);
397 walk_list!(visitor, visit_assoc_type_binding, &data.bindings);
399 GenericArgs::Parenthesized(ref data) => {
400 walk_list!(visitor, visit_ty, &data.inputs);
401 walk_list!(visitor, visit_ty, &data.output);
406 pub fn walk_assoc_type_binding<'a, V: Visitor<'a>>(visitor: &mut V,
407 type_binding: &'a TypeBinding) {
408 visitor.visit_ident(type_binding.ident);
409 visitor.visit_ty(&type_binding.ty);
412 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
414 PatKind::TupleStruct(ref path, ref children, _) => {
415 visitor.visit_path(path, pattern.id);
416 walk_list!(visitor, visit_pat, children);
418 PatKind::Path(ref opt_qself, ref path) => {
419 if let Some(ref qself) = *opt_qself {
420 visitor.visit_ty(&qself.ty);
422 visitor.visit_path(path, pattern.id)
424 PatKind::Struct(ref path, ref fields, _) => {
425 visitor.visit_path(path, pattern.id);
426 for field in fields {
427 walk_list!(visitor, visit_attribute, field.node.attrs.iter());
428 visitor.visit_ident(field.node.ident);
429 visitor.visit_pat(&field.node.pat)
432 PatKind::Tuple(ref tuple_elements, _) => {
433 walk_list!(visitor, visit_pat, tuple_elements);
435 PatKind::Box(ref subpattern) |
436 PatKind::Ref(ref subpattern, _) |
437 PatKind::Paren(ref subpattern) => {
438 visitor.visit_pat(subpattern)
440 PatKind::Ident(_, ident, ref optional_subpattern) => {
441 visitor.visit_ident(ident);
442 walk_list!(visitor, visit_pat, optional_subpattern);
444 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
445 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
446 visitor.visit_expr(lower_bound);
447 visitor.visit_expr(upper_bound);
450 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
451 walk_list!(visitor, visit_pat, prepatterns);
452 walk_list!(visitor, visit_pat, slice_pattern);
453 walk_list!(visitor, visit_pat, postpatterns);
455 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
459 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
460 visitor.visit_vis(&foreign_item.vis);
461 visitor.visit_ident(foreign_item.ident);
463 match foreign_item.node {
464 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
465 walk_fn_decl(visitor, function_declaration);
466 visitor.visit_generics(generics)
468 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
469 ForeignItemKind::Ty => (),
470 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
473 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
476 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
480 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
482 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
483 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
487 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
488 visitor.visit_ident(param.ident);
489 walk_list!(visitor, visit_attribute, param.attrs.iter());
490 walk_list!(visitor, visit_param_bound, ¶m.bounds);
492 GenericParamKind::Lifetime => {}
493 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
497 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
498 walk_list!(visitor, visit_generic_param, &generics.params);
499 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
502 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
504 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
506 ref bound_generic_params,
508 visitor.visit_ty(bounded_ty);
509 walk_list!(visitor, visit_param_bound, bounds);
510 walk_list!(visitor, visit_generic_param, bound_generic_params);
512 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
515 visitor.visit_lifetime(lifetime);
516 walk_list!(visitor, visit_param_bound, bounds);
518 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
521 visitor.visit_ty(lhs_ty);
522 visitor.visit_ty(rhs_ty);
527 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
528 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
529 visitor.visit_ty(output_ty)
533 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
534 for argument in &function_declaration.inputs {
535 visitor.visit_pat(&argument.pat);
536 visitor.visit_ty(&argument.ty)
538 visitor.visit_fn_ret_ty(&function_declaration.output)
541 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
542 where V: Visitor<'a>,
545 FnKind::ItemFn(_, _, _, body) => {
546 walk_fn_decl(visitor, declaration);
547 visitor.visit_block(body);
549 FnKind::Method(_, _, _, body) => {
550 walk_fn_decl(visitor, declaration);
551 visitor.visit_block(body);
553 FnKind::Closure(body) => {
554 walk_fn_decl(visitor, declaration);
555 visitor.visit_expr(body);
560 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
561 visitor.visit_ident(trait_item.ident);
562 walk_list!(visitor, visit_attribute, &trait_item.attrs);
563 visitor.visit_generics(&trait_item.generics);
564 match trait_item.node {
565 TraitItemKind::Const(ref ty, ref default) => {
566 visitor.visit_ty(ty);
567 walk_list!(visitor, visit_expr, default);
569 TraitItemKind::Method(ref sig, None) => {
570 walk_fn_decl(visitor, &sig.decl);
572 TraitItemKind::Method(ref sig, Some(ref body)) => {
573 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
574 &sig.decl, trait_item.span, trait_item.id);
576 TraitItemKind::Type(ref bounds, ref default) => {
577 walk_list!(visitor, visit_param_bound, bounds);
578 walk_list!(visitor, visit_ty, default);
580 TraitItemKind::Macro(ref mac) => {
581 visitor.visit_mac(mac);
586 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
587 visitor.visit_vis(&impl_item.vis);
588 visitor.visit_ident(impl_item.ident);
589 walk_list!(visitor, visit_attribute, &impl_item.attrs);
590 visitor.visit_generics(&impl_item.generics);
591 match impl_item.node {
592 ImplItemKind::Const(ref ty, ref expr) => {
593 visitor.visit_ty(ty);
594 visitor.visit_expr(expr);
596 ImplItemKind::Method(ref sig, ref body) => {
597 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
598 &sig.decl, impl_item.span, impl_item.id);
600 ImplItemKind::Type(ref ty) => {
601 visitor.visit_ty(ty);
603 ImplItemKind::Macro(ref mac) => {
604 visitor.visit_mac(mac);
609 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
610 walk_list!(visitor, visit_struct_field, struct_definition.fields());
613 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
614 visitor.visit_vis(&struct_field.vis);
615 if let Some(ident) = struct_field.ident {
616 visitor.visit_ident(ident);
618 visitor.visit_ty(&struct_field.ty);
619 walk_list!(visitor, visit_attribute, &struct_field.attrs);
622 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
623 walk_list!(visitor, visit_stmt, &block.stmts);
626 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
627 match statement.node {
628 StmtKind::Local(ref local) => visitor.visit_local(local),
629 StmtKind::Item(ref item) => visitor.visit_item(item),
630 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
631 visitor.visit_expr(expression)
633 StmtKind::Mac(ref mac) => {
634 let (ref mac, _, ref attrs) = **mac;
635 visitor.visit_mac(mac);
636 for attr in attrs.iter() {
637 visitor.visit_attribute(attr);
643 pub fn walk_mac<'a, V: Visitor<'a>>(_: &mut V, _: &Mac) {
647 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
648 visitor.visit_expr(&constant.value);
651 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
652 for attr in expression.attrs.iter() {
653 visitor.visit_attribute(attr);
655 match expression.node {
656 ExprKind::Box(ref subexpression) => {
657 visitor.visit_expr(subexpression)
659 ExprKind::ObsoleteInPlace(ref place, ref subexpression) => {
660 visitor.visit_expr(place);
661 visitor.visit_expr(subexpression)
663 ExprKind::Array(ref subexpressions) => {
664 walk_list!(visitor, visit_expr, subexpressions);
666 ExprKind::Repeat(ref element, ref count) => {
667 visitor.visit_expr(element);
668 visitor.visit_anon_const(count)
670 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
671 visitor.visit_path(path, expression.id);
672 for field in fields {
673 walk_list!(visitor, visit_attribute, field.attrs.iter());
674 visitor.visit_ident(field.ident);
675 visitor.visit_expr(&field.expr)
677 walk_list!(visitor, visit_expr, optional_base);
679 ExprKind::Tup(ref subexpressions) => {
680 walk_list!(visitor, visit_expr, subexpressions);
682 ExprKind::Call(ref callee_expression, ref arguments) => {
683 visitor.visit_expr(callee_expression);
684 walk_list!(visitor, visit_expr, arguments);
686 ExprKind::MethodCall(ref segment, ref arguments) => {
687 visitor.visit_path_segment(expression.span, segment);
688 walk_list!(visitor, visit_expr, arguments);
690 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
691 visitor.visit_expr(left_expression);
692 visitor.visit_expr(right_expression)
694 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
695 visitor.visit_expr(subexpression)
697 ExprKind::Lit(_) => {}
698 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
699 visitor.visit_expr(subexpression);
700 visitor.visit_ty(typ)
702 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
703 visitor.visit_expr(head_expression);
704 visitor.visit_block(if_block);
705 walk_list!(visitor, visit_expr, optional_else);
707 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
708 walk_list!(visitor, visit_label, opt_label);
709 visitor.visit_expr(subexpression);
710 visitor.visit_block(block);
712 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
713 walk_list!(visitor, visit_pat, pats);
714 visitor.visit_expr(subexpression);
715 visitor.visit_block(if_block);
716 walk_list!(visitor, visit_expr, optional_else);
718 ExprKind::WhileLet(ref pats, ref subexpression, ref block, ref opt_label) => {
719 walk_list!(visitor, visit_label, opt_label);
720 walk_list!(visitor, visit_pat, pats);
721 visitor.visit_expr(subexpression);
722 visitor.visit_block(block);
724 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
725 walk_list!(visitor, visit_label, opt_label);
726 visitor.visit_pat(pattern);
727 visitor.visit_expr(subexpression);
728 visitor.visit_block(block);
730 ExprKind::Loop(ref block, ref opt_label) => {
731 walk_list!(visitor, visit_label, opt_label);
732 visitor.visit_block(block);
734 ExprKind::Match(ref subexpression, ref arms) => {
735 visitor.visit_expr(subexpression);
736 walk_list!(visitor, visit_arm, arms);
738 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => {
739 visitor.visit_fn(FnKind::Closure(body),
740 function_declaration,
744 ExprKind::Block(ref block, ref opt_label) => {
745 walk_list!(visitor, visit_label, opt_label);
746 visitor.visit_block(block);
748 ExprKind::Async(_, _, ref body) => {
749 visitor.visit_block(body);
751 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
752 visitor.visit_expr(left_hand_expression);
753 visitor.visit_expr(right_hand_expression);
755 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
756 visitor.visit_expr(left_expression);
757 visitor.visit_expr(right_expression);
759 ExprKind::Field(ref subexpression, ident) => {
760 visitor.visit_expr(subexpression);
761 visitor.visit_ident(ident);
763 ExprKind::Index(ref main_expression, ref index_expression) => {
764 visitor.visit_expr(main_expression);
765 visitor.visit_expr(index_expression)
767 ExprKind::Range(ref start, ref end, _) => {
768 walk_list!(visitor, visit_expr, start);
769 walk_list!(visitor, visit_expr, end);
771 ExprKind::Path(ref maybe_qself, ref path) => {
772 if let Some(ref qself) = *maybe_qself {
773 visitor.visit_ty(&qself.ty);
775 visitor.visit_path(path, expression.id)
777 ExprKind::Break(ref opt_label, ref opt_expr) => {
778 walk_list!(visitor, visit_label, opt_label);
779 walk_list!(visitor, visit_expr, opt_expr);
781 ExprKind::Continue(ref opt_label) => {
782 walk_list!(visitor, visit_label, opt_label);
784 ExprKind::Ret(ref optional_expression) => {
785 walk_list!(visitor, visit_expr, optional_expression);
787 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
788 ExprKind::Paren(ref subexpression) => {
789 visitor.visit_expr(subexpression)
791 ExprKind::InlineAsm(ref ia) => {
792 for &(_, ref input) in &ia.inputs {
793 visitor.visit_expr(input)
795 for output in &ia.outputs {
796 visitor.visit_expr(&output.expr)
799 ExprKind::Yield(ref optional_expression) => {
800 walk_list!(visitor, visit_expr, optional_expression);
802 ExprKind::Try(ref subexpression) => {
803 visitor.visit_expr(subexpression)
805 ExprKind::Catch(ref body) => {
806 visitor.visit_block(body)
810 visitor.visit_expr_post(expression)
813 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
814 walk_list!(visitor, visit_pat, &arm.pats);
815 walk_list!(visitor, visit_expr, &arm.guard);
816 visitor.visit_expr(&arm.body);
817 walk_list!(visitor, visit_attribute, &arm.attrs);
820 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
821 if let VisibilityKind::Restricted { ref path, id } = vis.node {
822 visitor.visit_path(path, id);
826 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
827 visitor.visit_tts(attr.tokens.clone());
830 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
832 TokenTree::Token(_, tok) => visitor.visit_token(tok),
833 TokenTree::Delimited(_, delimed) => visitor.visit_tts(delimed.stream()),
837 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
838 for tt in tts.trees() {
839 visitor.visit_tt(tt);