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.
18 use parse::token::Token;
19 use tokenstream::{TokenTree, TokenStream};
21 #[derive(Copy, Clone)]
23 /// fn foo() or extern "Abi" fn foo()
24 ItemFn(Ident, FnHeader, &'a Visibility, &'a Block),
27 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a Block),
33 /// Each method of the Visitor trait is a hook to be potentially
34 /// overridden. Each method's default implementation recursively visits
35 /// the substructure of the input via the corresponding `walk` method;
36 /// e.g., the `visit_mod` method by default calls `visit::walk_mod`.
38 /// If you want to ensure that your code handles every variant
39 /// explicitly, you need to override each method. (And you also need
40 /// to monitor future changes to `Visitor` in case a new method with a
41 /// new default implementation gets introduced.)
42 pub trait Visitor<'ast>: Sized {
43 fn visit_name(&mut self, _span: Span, _name: Name) {
46 fn visit_ident(&mut self, ident: Ident) {
47 walk_ident(self, ident);
49 fn visit_mod(&mut self, m: &'ast Mod, _s: Span, _attrs: &[Attribute], _n: NodeId) {
52 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) { walk_foreign_item(self, i) }
53 fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) { walk_global_asm(self, ga) }
54 fn visit_item(&mut self, i: &'ast Item) { walk_item(self, i) }
55 fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
56 fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
57 fn visit_stmt(&mut self, s: &'ast Stmt) { walk_stmt(self, s) }
58 fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
59 fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
60 fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
61 fn visit_expr(&mut self, ex: &'ast Expr) { walk_expr(self, ex) }
62 fn visit_expr_post(&mut self, _ex: &'ast Expr) { }
63 fn visit_ty(&mut self, t: &'ast Ty) { walk_ty(self, t) }
64 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
65 walk_generic_param(self, param)
67 fn visit_generics(&mut self, g: &'ast Generics) { walk_generics(self, g) }
68 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
69 walk_where_predicate(self, p)
71 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
72 walk_fn(self, fk, fd, s)
74 fn visit_trait_item(&mut self, ti: &'ast TraitItem) { walk_trait_item(self, ti) }
75 fn visit_impl_item(&mut self, ii: &'ast ImplItem) { walk_impl_item(self, ii) }
76 fn visit_trait_ref(&mut self, t: &'ast TraitRef) { walk_trait_ref(self, t) }
77 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
78 walk_param_bound(self, bounds)
80 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
81 walk_poly_trait_ref(self, t, m)
83 fn visit_variant_data(&mut self, s: &'ast VariantData, _: Ident,
84 _: &'ast Generics, _: NodeId, _: Span) {
85 walk_struct_def(self, s)
87 fn visit_struct_field(&mut self, s: &'ast StructField) { walk_struct_field(self, s) }
88 fn visit_enum_def(&mut self, enum_definition: &'ast EnumDef,
89 generics: &'ast Generics, item_id: NodeId, _: Span) {
90 walk_enum_def(self, enum_definition, generics, item_id)
92 fn visit_variant(&mut self, v: &'ast Variant, g: &'ast Generics, item_id: NodeId) {
93 walk_variant(self, v, g, item_id)
95 fn visit_label(&mut self, label: &'ast Label) {
96 walk_label(self, label)
98 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
99 walk_lifetime(self, lifetime)
101 fn visit_mac(&mut self, _mac: &'ast Mac) {
102 panic!("visit_mac disabled by default");
103 // N.B., see note about macros above.
104 // if you really want a visitor that
105 // works on macros, use this
106 // definition in your trait impl:
107 // visit::walk_mac(self, _mac)
109 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
112 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
113 walk_path(self, path)
115 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
116 walk_use_tree(self, use_tree, id)
118 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
119 walk_path_segment(self, path_span, path_segment)
121 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
122 walk_generic_args(self, path_span, generic_args)
124 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
126 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
127 GenericArg::Type(ty) => self.visit_ty(ty),
130 fn visit_assoc_type_binding(&mut self, type_binding: &'ast TypeBinding) {
131 walk_assoc_type_binding(self, type_binding)
133 fn visit_attribute(&mut self, attr: &'ast Attribute) {
134 walk_attribute(self, attr)
136 fn visit_tt(&mut self, tt: TokenTree) {
139 fn visit_tts(&mut self, tts: TokenStream) {
142 fn visit_token(&mut self, _t: Token) {}
143 // FIXME: add `visit_interpolated` and `walk_interpolated`
144 fn visit_vis(&mut self, vis: &'ast Visibility) {
147 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
148 walk_fn_ret_ty(self, ret_ty)
153 macro_rules! walk_list {
154 ($visitor: expr, $method: ident, $list: expr) => {
156 $visitor.$method(elem)
159 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
161 $visitor.$method(elem, $($extra_args,)*)
166 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
167 visitor.visit_name(ident.span, ident.name);
170 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
171 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
172 walk_list!(visitor, visit_attribute, &krate.attrs);
175 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
176 walk_list!(visitor, visit_item, &module.items);
179 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
180 for attr in local.attrs.iter() {
181 visitor.visit_attribute(attr);
183 visitor.visit_pat(&local.pat);
184 walk_list!(visitor, visit_ty, &local.ty);
185 walk_list!(visitor, visit_expr, &local.init);
188 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
189 visitor.visit_ident(label.ident);
192 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
193 visitor.visit_ident(lifetime.ident);
196 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
197 trait_ref: &'a PolyTraitRef,
198 _: &TraitBoundModifier)
199 where V: Visitor<'a>,
201 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
202 visitor.visit_trait_ref(&trait_ref.trait_ref);
205 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
206 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
209 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
210 visitor.visit_vis(&item.vis);
211 visitor.visit_ident(item.ident);
213 ItemKind::ExternCrate(orig_name) => {
214 if let Some(orig_name) = orig_name {
215 visitor.visit_name(item.span, orig_name);
218 ItemKind::Use(ref use_tree) => {
219 visitor.visit_use_tree(use_tree, item.id, false)
221 ItemKind::Static(ref typ, _, ref expr) |
222 ItemKind::Const(ref typ, ref expr) => {
223 visitor.visit_ty(typ);
224 visitor.visit_expr(expr);
226 ItemKind::Fn(ref declaration, header, ref generics, ref body) => {
227 visitor.visit_generics(generics);
228 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
234 ItemKind::Mod(ref module) => {
235 visitor.visit_mod(module, item.span, &item.attrs, item.id)
237 ItemKind::ForeignMod(ref foreign_module) => {
238 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
240 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
241 ItemKind::Ty(ref typ, ref type_parameters) => {
242 visitor.visit_ty(typ);
243 visitor.visit_generics(type_parameters)
245 ItemKind::Existential(ref bounds, ref type_parameters) => {
246 walk_list!(visitor, visit_param_bound, bounds);
247 visitor.visit_generics(type_parameters)
249 ItemKind::Enum(ref enum_definition, ref type_parameters) => {
250 visitor.visit_generics(type_parameters);
251 visitor.visit_enum_def(enum_definition, type_parameters, item.id, item.span)
253 ItemKind::Impl(_, _, _,
255 ref opt_trait_reference,
258 visitor.visit_generics(type_parameters);
259 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
260 visitor.visit_ty(typ);
261 walk_list!(visitor, visit_impl_item, impl_items);
263 ItemKind::Struct(ref struct_definition, ref generics) |
264 ItemKind::Union(ref struct_definition, ref generics) => {
265 visitor.visit_generics(generics);
266 visitor.visit_variant_data(struct_definition, item.ident,
267 generics, item.id, item.span);
269 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
270 visitor.visit_generics(generics);
271 walk_list!(visitor, visit_param_bound, bounds);
272 walk_list!(visitor, visit_trait_item, methods);
274 ItemKind::TraitAlias(ref generics, ref bounds) => {
275 visitor.visit_generics(generics);
276 walk_list!(visitor, visit_param_bound, bounds);
278 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
279 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
281 walk_list!(visitor, visit_attribute, &item.attrs);
284 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
285 enum_definition: &'a EnumDef,
286 generics: &'a Generics,
288 walk_list!(visitor, visit_variant, &enum_definition.variants, generics, item_id);
291 pub fn walk_variant<'a, V>(visitor: &mut V,
292 variant: &'a Variant,
293 generics: &'a Generics,
295 where V: Visitor<'a>,
297 visitor.visit_ident(variant.node.ident);
298 visitor.visit_variant_data(&variant.node.data, variant.node.ident,
299 generics, item_id, variant.span);
300 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
301 walk_list!(visitor, visit_attribute, &variant.node.attrs);
304 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
306 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
309 TyKind::Ptr(ref mutable_type) => {
310 visitor.visit_ty(&mutable_type.ty)
312 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
313 walk_list!(visitor, visit_lifetime, opt_lifetime);
314 visitor.visit_ty(&mutable_type.ty)
317 TyKind::Tup(ref tuple_element_types) => {
318 walk_list!(visitor, visit_ty, tuple_element_types);
320 TyKind::BareFn(ref function_declaration) => {
321 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
322 walk_fn_decl(visitor, &function_declaration.decl);
324 TyKind::Path(ref maybe_qself, ref path) => {
325 if let Some(ref qself) = *maybe_qself {
326 visitor.visit_ty(&qself.ty);
328 visitor.visit_path(path, typ.id);
330 TyKind::Array(ref ty, ref length) => {
331 visitor.visit_ty(ty);
332 visitor.visit_anon_const(length)
334 TyKind::TraitObject(ref bounds, ..) |
335 TyKind::ImplTrait(_, ref bounds) => {
336 walk_list!(visitor, visit_param_bound, bounds);
338 TyKind::Typeof(ref expression) => {
339 visitor.visit_anon_const(expression)
341 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
342 TyKind::Mac(ref mac) => {
343 visitor.visit_mac(mac)
348 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
349 for segment in &path.segments {
350 visitor.visit_path_segment(path.span, segment);
354 pub fn walk_use_tree<'a, V: Visitor<'a>>(
355 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
357 visitor.visit_path(&use_tree.prefix, id);
358 match use_tree.kind {
359 UseTreeKind::Simple(rename, ..) => {
360 // the extra IDs are handled during HIR lowering
361 if let Some(rename) = rename {
362 visitor.visit_ident(rename);
365 UseTreeKind::Glob => {},
366 UseTreeKind::Nested(ref use_trees) => {
367 for &(ref nested_tree, nested_id) in use_trees {
368 visitor.visit_use_tree(nested_tree, nested_id, true);
374 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
376 segment: &'a PathSegment) {
377 visitor.visit_ident(segment.ident);
378 if let Some(ref args) = segment.args {
379 visitor.visit_generic_args(path_span, args);
383 pub fn walk_generic_args<'a, V>(visitor: &mut V,
385 generic_args: &'a GenericArgs)
386 where V: Visitor<'a>,
388 match *generic_args {
389 GenericArgs::AngleBracketed(ref data) => {
390 walk_list!(visitor, visit_generic_arg, &data.args);
391 walk_list!(visitor, visit_assoc_type_binding, &data.bindings);
393 GenericArgs::Parenthesized(ref data) => {
394 walk_list!(visitor, visit_ty, &data.inputs);
395 walk_list!(visitor, visit_ty, &data.output);
400 pub fn walk_assoc_type_binding<'a, V: Visitor<'a>>(visitor: &mut V,
401 type_binding: &'a TypeBinding) {
402 visitor.visit_ident(type_binding.ident);
403 visitor.visit_ty(&type_binding.ty);
406 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
408 PatKind::TupleStruct(ref path, ref children, _) => {
409 visitor.visit_path(path, pattern.id);
410 walk_list!(visitor, visit_pat, children);
412 PatKind::Path(ref opt_qself, ref path) => {
413 if let Some(ref qself) = *opt_qself {
414 visitor.visit_ty(&qself.ty);
416 visitor.visit_path(path, pattern.id)
418 PatKind::Struct(ref path, ref fields, _) => {
419 visitor.visit_path(path, pattern.id);
420 for field in fields {
421 walk_list!(visitor, visit_attribute, field.node.attrs.iter());
422 visitor.visit_ident(field.node.ident);
423 visitor.visit_pat(&field.node.pat)
426 PatKind::Tuple(ref tuple_elements, _) => {
427 walk_list!(visitor, visit_pat, tuple_elements);
429 PatKind::Box(ref subpattern) |
430 PatKind::Ref(ref subpattern, _) |
431 PatKind::Paren(ref subpattern) => {
432 visitor.visit_pat(subpattern)
434 PatKind::Ident(_, ident, ref optional_subpattern) => {
435 visitor.visit_ident(ident);
436 walk_list!(visitor, visit_pat, optional_subpattern);
438 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
439 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
440 visitor.visit_expr(lower_bound);
441 visitor.visit_expr(upper_bound);
444 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
445 walk_list!(visitor, visit_pat, prepatterns);
446 walk_list!(visitor, visit_pat, slice_pattern);
447 walk_list!(visitor, visit_pat, postpatterns);
449 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
453 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
454 visitor.visit_vis(&foreign_item.vis);
455 visitor.visit_ident(foreign_item.ident);
457 match foreign_item.node {
458 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
459 walk_fn_decl(visitor, function_declaration);
460 visitor.visit_generics(generics)
462 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
463 ForeignItemKind::Ty => (),
464 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
467 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
470 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
474 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
476 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
477 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
481 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
482 visitor.visit_ident(param.ident);
483 walk_list!(visitor, visit_attribute, param.attrs.iter());
484 walk_list!(visitor, visit_param_bound, ¶m.bounds);
486 GenericParamKind::Lifetime => {}
487 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
491 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
492 walk_list!(visitor, visit_generic_param, &generics.params);
493 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
496 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
498 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
500 ref bound_generic_params,
502 visitor.visit_ty(bounded_ty);
503 walk_list!(visitor, visit_param_bound, bounds);
504 walk_list!(visitor, visit_generic_param, bound_generic_params);
506 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
509 visitor.visit_lifetime(lifetime);
510 walk_list!(visitor, visit_param_bound, bounds);
512 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
515 visitor.visit_ty(lhs_ty);
516 visitor.visit_ty(rhs_ty);
521 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
522 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
523 visitor.visit_ty(output_ty)
527 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
528 for argument in &function_declaration.inputs {
529 visitor.visit_pat(&argument.pat);
530 visitor.visit_ty(&argument.ty)
532 visitor.visit_fn_ret_ty(&function_declaration.output)
535 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
536 where V: Visitor<'a>,
539 FnKind::ItemFn(_, _, _, body) => {
540 walk_fn_decl(visitor, declaration);
541 visitor.visit_block(body);
543 FnKind::Method(_, _, _, body) => {
544 walk_fn_decl(visitor, declaration);
545 visitor.visit_block(body);
547 FnKind::Closure(body) => {
548 walk_fn_decl(visitor, declaration);
549 visitor.visit_expr(body);
554 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
555 visitor.visit_ident(trait_item.ident);
556 walk_list!(visitor, visit_attribute, &trait_item.attrs);
557 visitor.visit_generics(&trait_item.generics);
558 match trait_item.node {
559 TraitItemKind::Const(ref ty, ref default) => {
560 visitor.visit_ty(ty);
561 walk_list!(visitor, visit_expr, default);
563 TraitItemKind::Method(ref sig, None) => {
564 walk_fn_decl(visitor, &sig.decl);
566 TraitItemKind::Method(ref sig, Some(ref body)) => {
567 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
568 &sig.decl, trait_item.span, trait_item.id);
570 TraitItemKind::Type(ref bounds, ref default) => {
571 walk_list!(visitor, visit_param_bound, bounds);
572 walk_list!(visitor, visit_ty, default);
574 TraitItemKind::Macro(ref mac) => {
575 visitor.visit_mac(mac);
580 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
581 visitor.visit_vis(&impl_item.vis);
582 visitor.visit_ident(impl_item.ident);
583 walk_list!(visitor, visit_attribute, &impl_item.attrs);
584 visitor.visit_generics(&impl_item.generics);
585 match impl_item.node {
586 ImplItemKind::Const(ref ty, ref expr) => {
587 visitor.visit_ty(ty);
588 visitor.visit_expr(expr);
590 ImplItemKind::Method(ref sig, ref body) => {
591 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
592 &sig.decl, impl_item.span, impl_item.id);
594 ImplItemKind::Type(ref ty) => {
595 visitor.visit_ty(ty);
597 ImplItemKind::Existential(ref bounds) => {
598 walk_list!(visitor, visit_param_bound, bounds);
600 ImplItemKind::Macro(ref mac) => {
601 visitor.visit_mac(mac);
606 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
607 walk_list!(visitor, visit_struct_field, struct_definition.fields());
610 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
611 visitor.visit_vis(&struct_field.vis);
612 if let Some(ident) = struct_field.ident {
613 visitor.visit_ident(ident);
615 visitor.visit_ty(&struct_field.ty);
616 walk_list!(visitor, visit_attribute, &struct_field.attrs);
619 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
620 walk_list!(visitor, visit_stmt, &block.stmts);
623 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
624 match statement.node {
625 StmtKind::Local(ref local) => visitor.visit_local(local),
626 StmtKind::Item(ref item) => visitor.visit_item(item),
627 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
628 visitor.visit_expr(expression)
630 StmtKind::Mac(ref mac) => {
631 let (ref mac, _, ref attrs) = **mac;
632 visitor.visit_mac(mac);
633 for attr in attrs.iter() {
634 visitor.visit_attribute(attr);
640 pub fn walk_mac<'a, V: Visitor<'a>>(_: &mut V, _: &Mac) {
644 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
645 visitor.visit_expr(&constant.value);
648 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
649 for attr in expression.attrs.iter() {
650 visitor.visit_attribute(attr);
652 match expression.node {
653 ExprKind::Box(ref subexpression) => {
654 visitor.visit_expr(subexpression)
656 ExprKind::ObsoleteInPlace(ref place, ref subexpression) => {
657 visitor.visit_expr(place);
658 visitor.visit_expr(subexpression)
660 ExprKind::Array(ref subexpressions) => {
661 walk_list!(visitor, visit_expr, subexpressions);
663 ExprKind::Repeat(ref element, ref count) => {
664 visitor.visit_expr(element);
665 visitor.visit_anon_const(count)
667 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
668 visitor.visit_path(path, expression.id);
669 for field in fields {
670 walk_list!(visitor, visit_attribute, field.attrs.iter());
671 visitor.visit_ident(field.ident);
672 visitor.visit_expr(&field.expr)
674 walk_list!(visitor, visit_expr, optional_base);
676 ExprKind::Tup(ref subexpressions) => {
677 walk_list!(visitor, visit_expr, subexpressions);
679 ExprKind::Call(ref callee_expression, ref arguments) => {
680 visitor.visit_expr(callee_expression);
681 walk_list!(visitor, visit_expr, arguments);
683 ExprKind::MethodCall(ref segment, ref arguments) => {
684 visitor.visit_path_segment(expression.span, segment);
685 walk_list!(visitor, visit_expr, arguments);
687 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
688 visitor.visit_expr(left_expression);
689 visitor.visit_expr(right_expression)
691 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
692 visitor.visit_expr(subexpression)
694 ExprKind::Lit(_) => {}
695 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
696 visitor.visit_expr(subexpression);
697 visitor.visit_ty(typ)
699 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
700 visitor.visit_expr(head_expression);
701 visitor.visit_block(if_block);
702 walk_list!(visitor, visit_expr, optional_else);
704 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
705 walk_list!(visitor, visit_label, opt_label);
706 visitor.visit_expr(subexpression);
707 visitor.visit_block(block);
709 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
710 walk_list!(visitor, visit_pat, pats);
711 visitor.visit_expr(subexpression);
712 visitor.visit_block(if_block);
713 walk_list!(visitor, visit_expr, optional_else);
715 ExprKind::WhileLet(ref pats, ref subexpression, ref block, ref opt_label) => {
716 walk_list!(visitor, visit_label, opt_label);
717 walk_list!(visitor, visit_pat, pats);
718 visitor.visit_expr(subexpression);
719 visitor.visit_block(block);
721 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
722 walk_list!(visitor, visit_label, opt_label);
723 visitor.visit_pat(pattern);
724 visitor.visit_expr(subexpression);
725 visitor.visit_block(block);
727 ExprKind::Loop(ref block, ref opt_label) => {
728 walk_list!(visitor, visit_label, opt_label);
729 visitor.visit_block(block);
731 ExprKind::Match(ref subexpression, ref arms) => {
732 visitor.visit_expr(subexpression);
733 walk_list!(visitor, visit_arm, arms);
735 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => {
736 visitor.visit_fn(FnKind::Closure(body),
737 function_declaration,
741 ExprKind::Block(ref block, ref opt_label) => {
742 walk_list!(visitor, visit_label, opt_label);
743 visitor.visit_block(block);
745 ExprKind::Async(_, _, ref body) => {
746 visitor.visit_block(body);
748 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
749 visitor.visit_expr(left_hand_expression);
750 visitor.visit_expr(right_hand_expression);
752 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
753 visitor.visit_expr(left_expression);
754 visitor.visit_expr(right_expression);
756 ExprKind::Field(ref subexpression, ident) => {
757 visitor.visit_expr(subexpression);
758 visitor.visit_ident(ident);
760 ExprKind::Index(ref main_expression, ref index_expression) => {
761 visitor.visit_expr(main_expression);
762 visitor.visit_expr(index_expression)
764 ExprKind::Range(ref start, ref end, _) => {
765 walk_list!(visitor, visit_expr, start);
766 walk_list!(visitor, visit_expr, end);
768 ExprKind::Path(ref maybe_qself, ref path) => {
769 if let Some(ref qself) = *maybe_qself {
770 visitor.visit_ty(&qself.ty);
772 visitor.visit_path(path, expression.id)
774 ExprKind::Break(ref opt_label, ref opt_expr) => {
775 walk_list!(visitor, visit_label, opt_label);
776 walk_list!(visitor, visit_expr, opt_expr);
778 ExprKind::Continue(ref opt_label) => {
779 walk_list!(visitor, visit_label, opt_label);
781 ExprKind::Ret(ref optional_expression) => {
782 walk_list!(visitor, visit_expr, optional_expression);
784 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
785 ExprKind::Paren(ref subexpression) => {
786 visitor.visit_expr(subexpression)
788 ExprKind::InlineAsm(ref ia) => {
789 for &(_, ref input) in &ia.inputs {
790 visitor.visit_expr(input)
792 for output in &ia.outputs {
793 visitor.visit_expr(&output.expr)
796 ExprKind::Yield(ref optional_expression) => {
797 walk_list!(visitor, visit_expr, optional_expression);
799 ExprKind::Try(ref subexpression) => {
800 visitor.visit_expr(subexpression)
802 ExprKind::TryBlock(ref body) => {
803 visitor.visit_block(body)
808 visitor.visit_expr_post(expression)
811 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
812 walk_list!(visitor, visit_pat, &arm.pats);
813 if let Some(ref g) = &arm.guard {
815 Guard::If(ref e) => visitor.visit_expr(e),
818 visitor.visit_expr(&arm.body);
819 walk_list!(visitor, visit_attribute, &arm.attrs);
822 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
823 if let VisibilityKind::Restricted { ref path, id } = vis.node {
824 visitor.visit_path(path, id);
828 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
829 visitor.visit_tts(attr.tokens.clone());
832 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
834 TokenTree::Token(_, tok) => visitor.visit_token(tok),
835 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts.stream()),
839 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
840 for tt in tts.trees() {
841 visitor.visit_tt(tt);