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, &'a FnHeader, &'a Visibility, &'a Block),
28 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a Block),
35 pub fn header(&self) -> Option<&'a FnHeader> {
37 FnKind::ItemFn(_, header, _, _) => Some(header),
38 FnKind::Method(_, sig, _, _) => Some(&sig.header),
39 FnKind::Closure(_) => None,
44 /// Each method of the Visitor trait is a hook to be potentially
45 /// overridden. Each method's default implementation recursively visits
46 /// the substructure of the input via the corresponding `walk` method;
47 /// e.g., the `visit_mod` method by default calls `visit::walk_mod`.
49 /// If you want to ensure that your code handles every variant
50 /// explicitly, you need to override each method. (And you also need
51 /// to monitor future changes to `Visitor` in case a new method with a
52 /// new default implementation gets introduced.)
53 pub trait Visitor<'ast>: Sized {
54 fn visit_name(&mut self, _span: Span, _name: Name) {
57 fn visit_ident(&mut self, ident: Ident) {
58 walk_ident(self, ident);
60 fn visit_mod(&mut self, m: &'ast Mod, _s: Span, _attrs: &[Attribute], _n: NodeId) {
63 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) { walk_foreign_item(self, i) }
64 fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) { walk_global_asm(self, ga) }
65 fn visit_item(&mut self, i: &'ast Item) { walk_item(self, i) }
66 fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
67 fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
68 fn visit_stmt(&mut self, s: &'ast Stmt) { walk_stmt(self, s) }
69 fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
70 fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
71 fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
72 fn visit_expr(&mut self, ex: &'ast Expr) { walk_expr(self, ex) }
73 fn visit_expr_post(&mut self, _ex: &'ast Expr) { }
74 fn visit_ty(&mut self, t: &'ast Ty) { walk_ty(self, t) }
75 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
76 walk_generic_param(self, param)
78 fn visit_generics(&mut self, g: &'ast Generics) { walk_generics(self, g) }
79 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
80 walk_where_predicate(self, p)
82 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
83 walk_fn(self, fk, fd, s)
85 fn visit_trait_item(&mut self, ti: &'ast TraitItem) { walk_trait_item(self, ti) }
86 fn visit_impl_item(&mut self, ii: &'ast ImplItem) { walk_impl_item(self, ii) }
87 fn visit_trait_ref(&mut self, t: &'ast TraitRef) { walk_trait_ref(self, t) }
88 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
89 walk_param_bound(self, bounds)
91 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
92 walk_poly_trait_ref(self, t, m)
94 fn visit_variant_data(&mut self, s: &'ast VariantData, _: Ident,
95 _: &'ast Generics, _: NodeId, _: Span) {
96 walk_struct_def(self, s)
98 fn visit_struct_field(&mut self, s: &'ast StructField) { walk_struct_field(self, s) }
99 fn visit_enum_def(&mut self, enum_definition: &'ast EnumDef,
100 generics: &'ast Generics, item_id: NodeId, _: Span) {
101 walk_enum_def(self, enum_definition, generics, item_id)
103 fn visit_variant(&mut self, v: &'ast Variant, g: &'ast Generics, item_id: NodeId) {
104 walk_variant(self, v, g, item_id)
106 fn visit_label(&mut self, label: &'ast Label) {
107 walk_label(self, label)
109 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
110 walk_lifetime(self, lifetime)
112 fn visit_mac(&mut self, _mac: &'ast Mac) {
113 panic!("visit_mac disabled by default");
114 // N.B., see note about macros above.
115 // if you really want a visitor that
116 // works on macros, use this
117 // definition in your trait impl:
118 // visit::walk_mac(self, _mac)
120 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
123 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
124 walk_path(self, path)
126 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
127 walk_use_tree(self, use_tree, id)
129 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
130 walk_path_segment(self, path_span, path_segment)
132 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
133 walk_generic_args(self, path_span, generic_args)
135 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
137 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
138 GenericArg::Type(ty) => self.visit_ty(ty),
139 GenericArg::Const(ct) => self.visit_anon_const(ct),
142 fn visit_assoc_ty_constraint(&mut self, constraint: &'ast AssocTyConstraint) {
143 walk_assoc_ty_constraint(self, constraint)
145 fn visit_attribute(&mut self, attr: &'ast Attribute) {
146 walk_attribute(self, attr)
148 fn visit_tt(&mut self, tt: TokenTree) {
151 fn visit_tts(&mut self, tts: TokenStream) {
154 fn visit_token(&mut self, _t: Token) {}
155 // FIXME: add `visit_interpolated` and `walk_interpolated`
156 fn visit_vis(&mut self, vis: &'ast Visibility) {
159 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
160 walk_fn_ret_ty(self, ret_ty)
162 fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
168 macro_rules! walk_list {
169 ($visitor: expr, $method: ident, $list: expr) => {
171 $visitor.$method(elem)
174 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
176 $visitor.$method(elem, $($extra_args,)*)
181 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
182 visitor.visit_name(ident.span, ident.name);
185 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
186 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
187 walk_list!(visitor, visit_attribute, &krate.attrs);
190 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
191 walk_list!(visitor, visit_item, &module.items);
194 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
195 for attr in local.attrs.iter() {
196 visitor.visit_attribute(attr);
198 visitor.visit_pat(&local.pat);
199 walk_list!(visitor, visit_ty, &local.ty);
200 walk_list!(visitor, visit_expr, &local.init);
203 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
204 visitor.visit_ident(label.ident);
207 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
208 visitor.visit_ident(lifetime.ident);
211 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
212 trait_ref: &'a PolyTraitRef,
213 _: &TraitBoundModifier)
214 where V: Visitor<'a>,
216 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
217 visitor.visit_trait_ref(&trait_ref.trait_ref);
220 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
221 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
224 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
225 visitor.visit_vis(&item.vis);
226 visitor.visit_ident(item.ident);
228 ItemKind::ExternCrate(orig_name) => {
229 if let Some(orig_name) = orig_name {
230 visitor.visit_name(item.span, orig_name);
233 ItemKind::Use(ref use_tree) => {
234 visitor.visit_use_tree(use_tree, item.id, false)
236 ItemKind::Static(ref typ, _, ref expr) |
237 ItemKind::Const(ref typ, ref expr) => {
238 visitor.visit_ty(typ);
239 visitor.visit_expr(expr);
241 ItemKind::Fn(ref declaration, ref header, ref generics, ref body) => {
242 visitor.visit_generics(generics);
243 visitor.visit_fn_header(header);
244 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
250 ItemKind::Mod(ref module) => {
251 visitor.visit_mod(module, item.span, &item.attrs, item.id)
253 ItemKind::ForeignMod(ref foreign_module) => {
254 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
256 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
257 ItemKind::Ty(ref typ, ref generics) => {
258 visitor.visit_ty(typ);
259 visitor.visit_generics(generics)
261 ItemKind::Existential(ref bounds, ref generics) => {
262 walk_list!(visitor, visit_param_bound, bounds);
263 visitor.visit_generics(generics)
265 ItemKind::Enum(ref enum_definition, ref generics) => {
266 visitor.visit_generics(generics);
267 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
269 ItemKind::Impl(_, _, _,
271 ref opt_trait_reference,
274 visitor.visit_generics(generics);
275 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
276 visitor.visit_ty(typ);
277 walk_list!(visitor, visit_impl_item, impl_items);
279 ItemKind::Struct(ref struct_definition, ref generics) |
280 ItemKind::Union(ref struct_definition, ref generics) => {
281 visitor.visit_generics(generics);
282 visitor.visit_variant_data(struct_definition, item.ident,
283 generics, item.id, item.span);
285 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
286 visitor.visit_generics(generics);
287 walk_list!(visitor, visit_param_bound, bounds);
288 walk_list!(visitor, visit_trait_item, methods);
290 ItemKind::TraitAlias(ref generics, ref bounds) => {
291 visitor.visit_generics(generics);
292 walk_list!(visitor, visit_param_bound, bounds);
294 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
295 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
297 walk_list!(visitor, visit_attribute, &item.attrs);
300 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
301 enum_definition: &'a EnumDef,
302 generics: &'a Generics,
304 walk_list!(visitor, visit_variant, &enum_definition.variants, generics, item_id);
307 pub fn walk_variant<'a, V>(visitor: &mut V,
308 variant: &'a Variant,
309 generics: &'a Generics,
311 where V: Visitor<'a>,
313 visitor.visit_ident(variant.node.ident);
314 visitor.visit_variant_data(&variant.node.data, variant.node.ident,
315 generics, item_id, variant.span);
316 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
317 walk_list!(visitor, visit_attribute, &variant.node.attrs);
320 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
322 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
325 TyKind::Ptr(ref mutable_type) => {
326 visitor.visit_ty(&mutable_type.ty)
328 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
329 walk_list!(visitor, visit_lifetime, opt_lifetime);
330 visitor.visit_ty(&mutable_type.ty)
332 TyKind::Never | TyKind::CVarArgs => {}
333 TyKind::Tup(ref tuple_element_types) => {
334 walk_list!(visitor, visit_ty, tuple_element_types);
336 TyKind::BareFn(ref function_declaration) => {
337 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
338 walk_fn_decl(visitor, &function_declaration.decl);
340 TyKind::Path(ref maybe_qself, ref path) => {
341 if let Some(ref qself) = *maybe_qself {
342 visitor.visit_ty(&qself.ty);
344 visitor.visit_path(path, typ.id);
346 TyKind::Array(ref ty, ref length) => {
347 visitor.visit_ty(ty);
348 visitor.visit_anon_const(length)
350 TyKind::TraitObject(ref bounds, ..) |
351 TyKind::ImplTrait(_, ref bounds) => {
352 walk_list!(visitor, visit_param_bound, bounds);
354 TyKind::Typeof(ref expression) => {
355 visitor.visit_anon_const(expression)
357 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
358 TyKind::Mac(ref mac) => {
359 visitor.visit_mac(mac)
364 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
365 for segment in &path.segments {
366 visitor.visit_path_segment(path.span, segment);
370 pub fn walk_use_tree<'a, V: Visitor<'a>>(
371 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
373 visitor.visit_path(&use_tree.prefix, id);
374 match use_tree.kind {
375 UseTreeKind::Simple(rename, ..) => {
376 // the extra IDs are handled during HIR lowering
377 if let Some(rename) = rename {
378 visitor.visit_ident(rename);
381 UseTreeKind::Glob => {},
382 UseTreeKind::Nested(ref use_trees) => {
383 for &(ref nested_tree, nested_id) in use_trees {
384 visitor.visit_use_tree(nested_tree, nested_id, true);
390 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
392 segment: &'a PathSegment) {
393 visitor.visit_ident(segment.ident);
394 if let Some(ref args) = segment.args {
395 visitor.visit_generic_args(path_span, args);
399 pub fn walk_generic_args<'a, V>(visitor: &mut V,
401 generic_args: &'a GenericArgs)
402 where V: Visitor<'a>,
404 match *generic_args {
405 GenericArgs::AngleBracketed(ref data) => {
406 walk_list!(visitor, visit_generic_arg, &data.args);
407 walk_list!(visitor, visit_assoc_ty_constraint, &data.constraints);
409 GenericArgs::Parenthesized(ref data) => {
410 walk_list!(visitor, visit_ty, &data.inputs);
411 walk_list!(visitor, visit_ty, &data.output);
416 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(visitor: &mut V,
417 constraint: &'a AssocTyConstraint) {
418 visitor.visit_ident(constraint.ident);
419 match constraint.kind {
420 AssocTyConstraintKind::Equality { ref ty } => {
421 visitor.visit_ty(ty);
423 AssocTyConstraintKind::Bound { ref bounds } => {
424 walk_list!(visitor, visit_param_bound, bounds);
429 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
431 PatKind::TupleStruct(ref path, ref children, _) => {
432 visitor.visit_path(path, pattern.id);
433 walk_list!(visitor, visit_pat, children);
435 PatKind::Path(ref opt_qself, ref path) => {
436 if let Some(ref qself) = *opt_qself {
437 visitor.visit_ty(&qself.ty);
439 visitor.visit_path(path, pattern.id)
441 PatKind::Struct(ref path, ref fields, _) => {
442 visitor.visit_path(path, pattern.id);
443 for field in fields {
444 walk_list!(visitor, visit_attribute, field.node.attrs.iter());
445 visitor.visit_ident(field.node.ident);
446 visitor.visit_pat(&field.node.pat)
449 PatKind::Tuple(ref tuple_elements, _) => {
450 walk_list!(visitor, visit_pat, tuple_elements);
452 PatKind::Box(ref subpattern) |
453 PatKind::Ref(ref subpattern, _) |
454 PatKind::Paren(ref subpattern) => {
455 visitor.visit_pat(subpattern)
457 PatKind::Ident(_, ident, ref optional_subpattern) => {
458 visitor.visit_ident(ident);
459 walk_list!(visitor, visit_pat, optional_subpattern);
461 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
462 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
463 visitor.visit_expr(lower_bound);
464 visitor.visit_expr(upper_bound);
467 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
468 walk_list!(visitor, visit_pat, prepatterns);
469 walk_list!(visitor, visit_pat, slice_pattern);
470 walk_list!(visitor, visit_pat, postpatterns);
472 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
476 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
477 visitor.visit_vis(&foreign_item.vis);
478 visitor.visit_ident(foreign_item.ident);
480 match foreign_item.node {
481 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
482 walk_fn_decl(visitor, function_declaration);
483 visitor.visit_generics(generics)
485 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
486 ForeignItemKind::Ty => (),
487 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
490 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
493 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
497 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
499 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
500 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
504 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
505 visitor.visit_ident(param.ident);
506 walk_list!(visitor, visit_attribute, param.attrs.iter());
507 walk_list!(visitor, visit_param_bound, ¶m.bounds);
509 GenericParamKind::Lifetime => (),
510 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
511 GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
515 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
516 walk_list!(visitor, visit_generic_param, &generics.params);
517 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
520 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
522 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
524 ref bound_generic_params,
526 visitor.visit_ty(bounded_ty);
527 walk_list!(visitor, visit_param_bound, bounds);
528 walk_list!(visitor, visit_generic_param, bound_generic_params);
530 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
533 visitor.visit_lifetime(lifetime);
534 walk_list!(visitor, visit_param_bound, bounds);
536 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
539 visitor.visit_ty(lhs_ty);
540 visitor.visit_ty(rhs_ty);
545 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
546 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
547 visitor.visit_ty(output_ty)
551 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
552 for argument in &function_declaration.inputs {
553 walk_list!(visitor, visit_attribute, argument.attrs.iter());
554 visitor.visit_pat(&argument.pat);
555 visitor.visit_ty(&argument.ty);
557 visitor.visit_fn_ret_ty(&function_declaration.output)
560 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
561 where V: Visitor<'a>,
564 FnKind::ItemFn(_, header, _, body) => {
565 visitor.visit_fn_header(header);
566 walk_fn_decl(visitor, declaration);
567 visitor.visit_block(body);
569 FnKind::Method(_, sig, _, body) => {
570 visitor.visit_fn_header(&sig.header);
571 walk_fn_decl(visitor, declaration);
572 visitor.visit_block(body);
574 FnKind::Closure(body) => {
575 walk_fn_decl(visitor, declaration);
576 visitor.visit_expr(body);
581 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
582 visitor.visit_ident(trait_item.ident);
583 walk_list!(visitor, visit_attribute, &trait_item.attrs);
584 visitor.visit_generics(&trait_item.generics);
585 match trait_item.node {
586 TraitItemKind::Const(ref ty, ref default) => {
587 visitor.visit_ty(ty);
588 walk_list!(visitor, visit_expr, default);
590 TraitItemKind::Method(ref sig, None) => {
591 visitor.visit_fn_header(&sig.header);
592 walk_fn_decl(visitor, &sig.decl);
594 TraitItemKind::Method(ref sig, Some(ref body)) => {
595 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
596 &sig.decl, trait_item.span, trait_item.id);
598 TraitItemKind::Type(ref bounds, ref default) => {
599 walk_list!(visitor, visit_param_bound, bounds);
600 walk_list!(visitor, visit_ty, default);
602 TraitItemKind::Macro(ref mac) => {
603 visitor.visit_mac(mac);
608 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
609 visitor.visit_vis(&impl_item.vis);
610 visitor.visit_ident(impl_item.ident);
611 walk_list!(visitor, visit_attribute, &impl_item.attrs);
612 visitor.visit_generics(&impl_item.generics);
613 match impl_item.node {
614 ImplItemKind::Const(ref ty, ref expr) => {
615 visitor.visit_ty(ty);
616 visitor.visit_expr(expr);
618 ImplItemKind::Method(ref sig, ref body) => {
619 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
620 &sig.decl, impl_item.span, impl_item.id);
622 ImplItemKind::Type(ref ty) => {
623 visitor.visit_ty(ty);
625 ImplItemKind::Existential(ref bounds) => {
626 walk_list!(visitor, visit_param_bound, bounds);
628 ImplItemKind::Macro(ref mac) => {
629 visitor.visit_mac(mac);
634 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
635 walk_list!(visitor, visit_struct_field, struct_definition.fields());
638 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
639 visitor.visit_vis(&struct_field.vis);
640 if let Some(ident) = struct_field.ident {
641 visitor.visit_ident(ident);
643 visitor.visit_ty(&struct_field.ty);
644 walk_list!(visitor, visit_attribute, &struct_field.attrs);
647 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
648 walk_list!(visitor, visit_stmt, &block.stmts);
651 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
652 match statement.node {
653 StmtKind::Local(ref local) => visitor.visit_local(local),
654 StmtKind::Item(ref item) => visitor.visit_item(item),
655 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
656 visitor.visit_expr(expression)
658 StmtKind::Mac(ref mac) => {
659 let (ref mac, _, ref attrs) = **mac;
660 visitor.visit_mac(mac);
661 for attr in attrs.iter() {
662 visitor.visit_attribute(attr);
668 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a Mac) {
669 visitor.visit_path(&mac.node.path, DUMMY_NODE_ID);
672 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
673 visitor.visit_expr(&constant.value);
676 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
677 for attr in expression.attrs.iter() {
678 visitor.visit_attribute(attr);
680 match expression.node {
681 ExprKind::Box(ref subexpression) => {
682 visitor.visit_expr(subexpression)
684 ExprKind::Array(ref subexpressions) => {
685 walk_list!(visitor, visit_expr, subexpressions);
687 ExprKind::Repeat(ref element, ref count) => {
688 visitor.visit_expr(element);
689 visitor.visit_anon_const(count)
691 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
692 visitor.visit_path(path, expression.id);
693 for field in fields {
694 walk_list!(visitor, visit_attribute, field.attrs.iter());
695 visitor.visit_ident(field.ident);
696 visitor.visit_expr(&field.expr)
698 walk_list!(visitor, visit_expr, optional_base);
700 ExprKind::Tup(ref subexpressions) => {
701 walk_list!(visitor, visit_expr, subexpressions);
703 ExprKind::Call(ref callee_expression, ref arguments) => {
704 visitor.visit_expr(callee_expression);
705 walk_list!(visitor, visit_expr, arguments);
707 ExprKind::MethodCall(ref segment, ref arguments) => {
708 visitor.visit_path_segment(expression.span, segment);
709 walk_list!(visitor, visit_expr, arguments);
711 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
712 visitor.visit_expr(left_expression);
713 visitor.visit_expr(right_expression)
715 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
716 visitor.visit_expr(subexpression)
718 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
719 visitor.visit_expr(subexpression);
720 visitor.visit_ty(typ)
722 ExprKind::Let(ref pats, ref scrutinee) => {
723 walk_list!(visitor, visit_pat, pats);
724 visitor.visit_expr(scrutinee);
726 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
727 visitor.visit_expr(head_expression);
728 visitor.visit_block(if_block);
729 walk_list!(visitor, visit_expr, optional_else);
731 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
732 walk_list!(visitor, visit_label, opt_label);
733 visitor.visit_expr(subexpression);
734 visitor.visit_block(block);
736 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
737 walk_list!(visitor, visit_label, opt_label);
738 visitor.visit_pat(pattern);
739 visitor.visit_expr(subexpression);
740 visitor.visit_block(block);
742 ExprKind::Loop(ref block, ref opt_label) => {
743 walk_list!(visitor, visit_label, opt_label);
744 visitor.visit_block(block);
746 ExprKind::Match(ref subexpression, ref arms) => {
747 visitor.visit_expr(subexpression);
748 walk_list!(visitor, visit_arm, arms);
750 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => {
751 visitor.visit_fn(FnKind::Closure(body),
752 function_declaration,
756 ExprKind::Block(ref block, ref opt_label) => {
757 walk_list!(visitor, visit_label, opt_label);
758 visitor.visit_block(block);
760 ExprKind::Async(_, _, ref body) => {
761 visitor.visit_block(body);
763 ExprKind::Await(_, ref expr) => visitor.visit_expr(expr),
764 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
765 visitor.visit_expr(left_hand_expression);
766 visitor.visit_expr(right_hand_expression);
768 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
769 visitor.visit_expr(left_expression);
770 visitor.visit_expr(right_expression);
772 ExprKind::Field(ref subexpression, ident) => {
773 visitor.visit_expr(subexpression);
774 visitor.visit_ident(ident);
776 ExprKind::Index(ref main_expression, ref index_expression) => {
777 visitor.visit_expr(main_expression);
778 visitor.visit_expr(index_expression)
780 ExprKind::Range(ref start, ref end, _) => {
781 walk_list!(visitor, visit_expr, start);
782 walk_list!(visitor, visit_expr, end);
784 ExprKind::Path(ref maybe_qself, ref path) => {
785 if let Some(ref qself) = *maybe_qself {
786 visitor.visit_ty(&qself.ty);
788 visitor.visit_path(path, expression.id)
790 ExprKind::Break(ref opt_label, ref opt_expr) => {
791 walk_list!(visitor, visit_label, opt_label);
792 walk_list!(visitor, visit_expr, opt_expr);
794 ExprKind::Continue(ref opt_label) => {
795 walk_list!(visitor, visit_label, opt_label);
797 ExprKind::Ret(ref optional_expression) => {
798 walk_list!(visitor, visit_expr, optional_expression);
800 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
801 ExprKind::Paren(ref subexpression) => {
802 visitor.visit_expr(subexpression)
804 ExprKind::InlineAsm(ref ia) => {
805 for &(_, ref input) in &ia.inputs {
806 visitor.visit_expr(input)
808 for output in &ia.outputs {
809 visitor.visit_expr(&output.expr)
812 ExprKind::Yield(ref optional_expression) => {
813 walk_list!(visitor, visit_expr, optional_expression);
815 ExprKind::Try(ref subexpression) => {
816 visitor.visit_expr(subexpression)
818 ExprKind::TryBlock(ref body) => {
819 visitor.visit_block(body)
821 ExprKind::Lit(_) | ExprKind::Err => {}
824 visitor.visit_expr_post(expression)
827 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
828 walk_list!(visitor, visit_pat, &arm.pats);
829 if let Some(ref e) = &arm.guard {
830 visitor.visit_expr(e);
832 visitor.visit_expr(&arm.body);
833 walk_list!(visitor, visit_attribute, &arm.attrs);
836 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
837 if let VisibilityKind::Restricted { ref path, id } = vis.node {
838 visitor.visit_path(path, id);
842 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
843 visitor.visit_tts(attr.tokens.clone());
846 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
848 TokenTree::Token(token) => visitor.visit_token(token),
849 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
853 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
854 for tt in tts.trees() {
855 visitor.visit_tt(tt);