1 //! AST walker. Each overridden visit method has full control over what
2 //! happens with its node, it can do its own traversal of the node's children,
3 //! call `visit::walk_*` to apply the default traversal algorithm, or prevent
4 //! deeper traversal by doing nothing.
6 //! Note: it is an important invariant that the default visitor walks the body
7 //! of a function in "execution order" (more concretely, reverse post-order
8 //! with respect to the CFG implied by the AST), meaning that if AST node A may
9 //! execute before AST node B, then A is visited first. The borrow checker in
10 //! particular relies on this property.
12 //! Note: walking an AST before macro expansion is probably a bad idea. For
13 //! instance, a walker looking for item names in a module will miss all of
14 //! those that are created by the expansion of a macro.
17 use crate::parse::token::Token;
18 use crate::tokenstream::{TokenTree, TokenStream};
22 #[derive(Copy, Clone)]
24 /// fn foo() or extern "Abi" fn foo()
25 ItemFn(Ident, FnHeader, &'a Visibility, &'a Block),
28 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a Block),
34 /// Each method of the Visitor trait is a hook to be potentially
35 /// overridden. Each method's default implementation recursively visits
36 /// the substructure of the input via the corresponding `walk` method;
37 /// e.g., the `visit_mod` method by default calls `visit::walk_mod`.
39 /// If you want to ensure that your code handles every variant
40 /// explicitly, you need to override each method. (And you also need
41 /// to monitor future changes to `Visitor` in case a new method with a
42 /// new default implementation gets introduced.)
43 pub trait Visitor<'ast>: Sized {
44 fn visit_name(&mut self, _span: Span, _name: Name) {
47 fn visit_ident(&mut self, ident: Ident) {
48 walk_ident(self, ident);
50 fn visit_mod(&mut self, m: &'ast Mod, _s: Span, _attrs: &[Attribute], _n: NodeId) {
53 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) { walk_foreign_item(self, i) }
54 fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) { walk_global_asm(self, ga) }
55 fn visit_item(&mut self, i: &'ast Item) { walk_item(self, i) }
56 fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
57 fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
58 fn visit_stmt(&mut self, s: &'ast Stmt) { walk_stmt(self, s) }
59 fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
60 fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
61 fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
62 fn visit_expr(&mut self, ex: &'ast Expr) { walk_expr(self, ex) }
63 fn visit_expr_post(&mut self, _ex: &'ast Expr) { }
64 fn visit_ty(&mut self, t: &'ast Ty) { walk_ty(self, t) }
65 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
66 walk_generic_param(self, param)
68 fn visit_generics(&mut self, g: &'ast Generics) { walk_generics(self, g) }
69 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
70 walk_where_predicate(self, p)
72 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
73 walk_fn(self, fk, fd, s)
75 fn visit_trait_item(&mut self, ti: &'ast TraitItem) { walk_trait_item(self, ti) }
76 fn visit_impl_item(&mut self, ii: &'ast ImplItem) { walk_impl_item(self, ii) }
77 fn visit_trait_ref(&mut self, t: &'ast TraitRef) { walk_trait_ref(self, t) }
78 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
79 walk_param_bound(self, bounds)
81 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
82 walk_poly_trait_ref(self, t, m)
84 fn visit_variant_data(&mut self, s: &'ast VariantData, _: Ident,
85 _: &'ast Generics, _: NodeId, _: Span) {
86 walk_struct_def(self, s)
88 fn visit_struct_field(&mut self, s: &'ast StructField) { walk_struct_field(self, s) }
89 fn visit_enum_def(&mut self, enum_definition: &'ast EnumDef,
90 generics: &'ast Generics, item_id: NodeId, _: Span) {
91 walk_enum_def(self, enum_definition, generics, item_id)
93 fn visit_variant(&mut self, v: &'ast Variant, g: &'ast Generics, item_id: NodeId) {
94 walk_variant(self, v, g, item_id)
96 fn visit_label(&mut self, label: &'ast Label) {
97 walk_label(self, label)
99 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
100 walk_lifetime(self, lifetime)
102 fn visit_mac(&mut self, _mac: &'ast Mac) {
103 panic!("visit_mac disabled by default");
104 // N.B., see note about macros above.
105 // if you really want a visitor that
106 // works on macros, use this
107 // definition in your trait impl:
108 // visit::walk_mac(self, _mac)
110 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
113 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
114 walk_path(self, path)
116 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
117 walk_use_tree(self, use_tree, id)
119 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
120 walk_path_segment(self, path_span, path_segment)
122 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
123 walk_generic_args(self, path_span, generic_args)
125 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
127 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
128 GenericArg::Type(ty) => self.visit_ty(ty),
129 GenericArg::Const(ct) => self.visit_anon_const(ct),
132 fn visit_assoc_type_binding(&mut self, type_binding: &'ast TypeBinding) {
133 walk_assoc_type_binding(self, type_binding)
135 fn visit_attribute(&mut self, attr: &'ast Attribute) {
136 walk_attribute(self, attr)
138 fn visit_tt(&mut self, tt: TokenTree) {
141 fn visit_tts(&mut self, tts: TokenStream) {
144 fn visit_token(&mut self, _t: Token) {}
145 // FIXME: add `visit_interpolated` and `walk_interpolated`
146 fn visit_vis(&mut self, vis: &'ast Visibility) {
149 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
150 walk_fn_ret_ty(self, ret_ty)
155 macro_rules! walk_list {
156 ($visitor: expr, $method: ident, $list: expr) => {
158 $visitor.$method(elem)
161 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
163 $visitor.$method(elem, $($extra_args,)*)
168 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
169 visitor.visit_name(ident.span, ident.name);
172 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
173 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
174 walk_list!(visitor, visit_attribute, &krate.attrs);
177 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
178 walk_list!(visitor, visit_item, &module.items);
181 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
182 for attr in local.attrs.iter() {
183 visitor.visit_attribute(attr);
185 visitor.visit_pat(&local.pat);
186 walk_list!(visitor, visit_ty, &local.ty);
187 walk_list!(visitor, visit_expr, &local.init);
190 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
191 visitor.visit_ident(label.ident);
194 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
195 visitor.visit_ident(lifetime.ident);
198 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
199 trait_ref: &'a PolyTraitRef,
200 _: &TraitBoundModifier)
201 where V: Visitor<'a>,
203 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
204 visitor.visit_trait_ref(&trait_ref.trait_ref);
207 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
208 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
211 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
212 visitor.visit_vis(&item.vis);
213 visitor.visit_ident(item.ident);
215 ItemKind::ExternCrate(orig_name) => {
216 if let Some(orig_name) = orig_name {
217 visitor.visit_name(item.span, orig_name);
220 ItemKind::Use(ref use_tree) => {
221 visitor.visit_use_tree(use_tree, item.id, false)
223 ItemKind::Static(ref typ, _, ref expr) |
224 ItemKind::Const(ref typ, ref expr) => {
225 visitor.visit_ty(typ);
226 visitor.visit_expr(expr);
228 ItemKind::Fn(ref declaration, header, ref generics, ref body) => {
229 visitor.visit_generics(generics);
230 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
236 ItemKind::Mod(ref module) => {
237 visitor.visit_mod(module, item.span, &item.attrs, item.id)
239 ItemKind::ForeignMod(ref foreign_module) => {
240 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
242 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
243 ItemKind::Ty(ref typ, ref type_parameters) => {
244 visitor.visit_ty(typ);
245 visitor.visit_generics(type_parameters)
247 ItemKind::Existential(ref bounds, ref type_parameters) => {
248 walk_list!(visitor, visit_param_bound, bounds);
249 visitor.visit_generics(type_parameters)
251 ItemKind::Enum(ref enum_definition, ref type_parameters) => {
252 visitor.visit_generics(type_parameters);
253 visitor.visit_enum_def(enum_definition, type_parameters, item.id, item.span)
255 ItemKind::Impl(_, _, _,
257 ref opt_trait_reference,
260 visitor.visit_generics(type_parameters);
261 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
262 visitor.visit_ty(typ);
263 walk_list!(visitor, visit_impl_item, impl_items);
265 ItemKind::Struct(ref struct_definition, ref generics) |
266 ItemKind::Union(ref struct_definition, ref generics) => {
267 visitor.visit_generics(generics);
268 visitor.visit_variant_data(struct_definition, item.ident,
269 generics, item.id, item.span);
271 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
272 visitor.visit_generics(generics);
273 walk_list!(visitor, visit_param_bound, bounds);
274 walk_list!(visitor, visit_trait_item, methods);
276 ItemKind::TraitAlias(ref generics, ref bounds) => {
277 visitor.visit_generics(generics);
278 walk_list!(visitor, visit_param_bound, bounds);
280 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
281 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
283 walk_list!(visitor, visit_attribute, &item.attrs);
286 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
287 enum_definition: &'a EnumDef,
288 generics: &'a Generics,
290 walk_list!(visitor, visit_variant, &enum_definition.variants, generics, item_id);
293 pub fn walk_variant<'a, V>(visitor: &mut V,
294 variant: &'a Variant,
295 generics: &'a Generics,
297 where V: Visitor<'a>,
299 visitor.visit_ident(variant.node.ident);
300 visitor.visit_variant_data(&variant.node.data, variant.node.ident,
301 generics, item_id, variant.span);
302 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
303 walk_list!(visitor, visit_attribute, &variant.node.attrs);
306 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
308 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
311 TyKind::Ptr(ref mutable_type) => {
312 visitor.visit_ty(&mutable_type.ty)
314 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
315 walk_list!(visitor, visit_lifetime, opt_lifetime);
316 visitor.visit_ty(&mutable_type.ty)
319 TyKind::Tup(ref tuple_element_types) => {
320 walk_list!(visitor, visit_ty, tuple_element_types);
322 TyKind::BareFn(ref function_declaration) => {
323 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
324 walk_fn_decl(visitor, &function_declaration.decl);
326 TyKind::Path(ref maybe_qself, ref path) => {
327 if let Some(ref qself) = *maybe_qself {
328 visitor.visit_ty(&qself.ty);
330 visitor.visit_path(path, typ.id);
332 TyKind::Array(ref ty, ref length) => {
333 visitor.visit_ty(ty);
334 visitor.visit_anon_const(length)
336 TyKind::TraitObject(ref bounds, ..) |
337 TyKind::ImplTrait(_, ref bounds) => {
338 walk_list!(visitor, visit_param_bound, bounds);
340 TyKind::Typeof(ref expression) => {
341 visitor.visit_anon_const(expression)
343 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
344 TyKind::Mac(ref mac) => {
345 visitor.visit_mac(mac)
350 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
351 for segment in &path.segments {
352 visitor.visit_path_segment(path.span, segment);
356 pub fn walk_use_tree<'a, V: Visitor<'a>>(
357 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
359 visitor.visit_path(&use_tree.prefix, id);
360 match use_tree.kind {
361 UseTreeKind::Simple(rename, ..) => {
362 // the extra IDs are handled during HIR lowering
363 if let Some(rename) = rename {
364 visitor.visit_ident(rename);
367 UseTreeKind::Glob => {},
368 UseTreeKind::Nested(ref use_trees) => {
369 for &(ref nested_tree, nested_id) in use_trees {
370 visitor.visit_use_tree(nested_tree, nested_id, true);
376 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
378 segment: &'a PathSegment) {
379 visitor.visit_ident(segment.ident);
380 if let Some(ref args) = segment.args {
381 visitor.visit_generic_args(path_span, args);
385 pub fn walk_generic_args<'a, V>(visitor: &mut V,
387 generic_args: &'a GenericArgs)
388 where V: Visitor<'a>,
390 match *generic_args {
391 GenericArgs::AngleBracketed(ref data) => {
392 walk_list!(visitor, visit_generic_arg, &data.args);
393 walk_list!(visitor, visit_assoc_type_binding, &data.bindings);
395 GenericArgs::Parenthesized(ref data) => {
396 walk_list!(visitor, visit_ty, &data.inputs);
397 walk_list!(visitor, visit_ty, &data.output);
402 pub fn walk_assoc_type_binding<'a, V: Visitor<'a>>(visitor: &mut V,
403 type_binding: &'a TypeBinding) {
404 visitor.visit_ident(type_binding.ident);
405 visitor.visit_ty(&type_binding.ty);
408 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
410 PatKind::TupleStruct(ref path, ref children, _) => {
411 visitor.visit_path(path, pattern.id);
412 walk_list!(visitor, visit_pat, children);
414 PatKind::Path(ref opt_qself, ref path) => {
415 if let Some(ref qself) = *opt_qself {
416 visitor.visit_ty(&qself.ty);
418 visitor.visit_path(path, pattern.id)
420 PatKind::Struct(ref path, ref fields, _) => {
421 visitor.visit_path(path, pattern.id);
422 for field in fields {
423 walk_list!(visitor, visit_attribute, field.node.attrs.iter());
424 visitor.visit_ident(field.node.ident);
425 visitor.visit_pat(&field.node.pat)
428 PatKind::Tuple(ref tuple_elements, _) => {
429 walk_list!(visitor, visit_pat, tuple_elements);
431 PatKind::Box(ref subpattern) |
432 PatKind::Ref(ref subpattern, _) |
433 PatKind::Paren(ref subpattern) => {
434 visitor.visit_pat(subpattern)
436 PatKind::Ident(_, ident, ref optional_subpattern) => {
437 visitor.visit_ident(ident);
438 walk_list!(visitor, visit_pat, optional_subpattern);
440 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
441 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
442 visitor.visit_expr(lower_bound);
443 visitor.visit_expr(upper_bound);
446 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
447 walk_list!(visitor, visit_pat, prepatterns);
448 walk_list!(visitor, visit_pat, slice_pattern);
449 walk_list!(visitor, visit_pat, postpatterns);
451 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
455 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
456 visitor.visit_vis(&foreign_item.vis);
457 visitor.visit_ident(foreign_item.ident);
459 match foreign_item.node {
460 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
461 walk_fn_decl(visitor, function_declaration);
462 visitor.visit_generics(generics)
464 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
465 ForeignItemKind::Ty => (),
466 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
469 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
472 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
476 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
478 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
479 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
483 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
484 visitor.visit_ident(param.ident);
485 walk_list!(visitor, visit_attribute, param.attrs.iter());
486 walk_list!(visitor, visit_param_bound, ¶m.bounds);
488 GenericParamKind::Lifetime => {}
489 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
490 GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
494 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
495 walk_list!(visitor, visit_generic_param, &generics.params);
496 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
499 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
501 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
503 ref bound_generic_params,
505 visitor.visit_ty(bounded_ty);
506 walk_list!(visitor, visit_param_bound, bounds);
507 walk_list!(visitor, visit_generic_param, bound_generic_params);
509 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
512 visitor.visit_lifetime(lifetime);
513 walk_list!(visitor, visit_param_bound, bounds);
515 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
518 visitor.visit_ty(lhs_ty);
519 visitor.visit_ty(rhs_ty);
524 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
525 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
526 visitor.visit_ty(output_ty)
530 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
531 for argument in &function_declaration.inputs {
532 visitor.visit_pat(&argument.pat);
533 visitor.visit_ty(&argument.ty)
535 visitor.visit_fn_ret_ty(&function_declaration.output)
538 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
539 where V: Visitor<'a>,
542 FnKind::ItemFn(_, _, _, body) => {
543 walk_fn_decl(visitor, declaration);
544 visitor.visit_block(body);
546 FnKind::Method(_, _, _, body) => {
547 walk_fn_decl(visitor, declaration);
548 visitor.visit_block(body);
550 FnKind::Closure(body) => {
551 walk_fn_decl(visitor, declaration);
552 visitor.visit_expr(body);
557 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
558 visitor.visit_ident(trait_item.ident);
559 walk_list!(visitor, visit_attribute, &trait_item.attrs);
560 visitor.visit_generics(&trait_item.generics);
561 match trait_item.node {
562 TraitItemKind::Const(ref ty, ref default) => {
563 visitor.visit_ty(ty);
564 walk_list!(visitor, visit_expr, default);
566 TraitItemKind::Method(ref sig, None) => {
567 walk_fn_decl(visitor, &sig.decl);
569 TraitItemKind::Method(ref sig, Some(ref body)) => {
570 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
571 &sig.decl, trait_item.span, trait_item.id);
573 TraitItemKind::Type(ref bounds, ref default) => {
574 walk_list!(visitor, visit_param_bound, bounds);
575 walk_list!(visitor, visit_ty, default);
577 TraitItemKind::Macro(ref mac) => {
578 visitor.visit_mac(mac);
583 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
584 visitor.visit_vis(&impl_item.vis);
585 visitor.visit_ident(impl_item.ident);
586 walk_list!(visitor, visit_attribute, &impl_item.attrs);
587 visitor.visit_generics(&impl_item.generics);
588 match impl_item.node {
589 ImplItemKind::Const(ref ty, ref expr) => {
590 visitor.visit_ty(ty);
591 visitor.visit_expr(expr);
593 ImplItemKind::Method(ref sig, ref body) => {
594 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
595 &sig.decl, impl_item.span, impl_item.id);
597 ImplItemKind::Type(ref ty) => {
598 visitor.visit_ty(ty);
600 ImplItemKind::Existential(ref bounds) => {
601 walk_list!(visitor, visit_param_bound, bounds);
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::TryBlock(ref body) => {
806 visitor.visit_block(body)
811 visitor.visit_expr_post(expression)
814 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
815 walk_list!(visitor, visit_pat, &arm.pats);
816 if let Some(ref g) = &arm.guard {
818 Guard::If(ref e) => visitor.visit_expr(e),
821 visitor.visit_expr(&arm.body);
822 walk_list!(visitor, visit_attribute, &arm.attrs);
825 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
826 if let VisibilityKind::Restricted { ref path, id } = vis.node {
827 visitor.visit_path(path, id);
831 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
832 visitor.visit_tts(attr.tokens.clone());
835 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
837 TokenTree::Token(_, tok) => visitor.visit_token(tok),
838 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
842 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
843 for tt in tts.trees() {
844 visitor.visit_tt(tt);