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_arg(&mut self, arg: &'ast Arg) { walk_arg(self, arg) }
70 fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
71 fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
72 fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
73 fn visit_expr(&mut self, ex: &'ast Expr) { walk_expr(self, ex) }
74 fn visit_expr_post(&mut self, _ex: &'ast Expr) { }
75 fn visit_ty(&mut self, t: &'ast Ty) { walk_ty(self, t) }
76 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
77 walk_generic_param(self, param)
79 fn visit_generics(&mut self, g: &'ast Generics) { walk_generics(self, g) }
80 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
81 walk_where_predicate(self, p)
83 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
84 walk_fn(self, fk, fd, s)
86 fn visit_trait_item(&mut self, ti: &'ast TraitItem) { walk_trait_item(self, ti) }
87 fn visit_impl_item(&mut self, ii: &'ast ImplItem) { walk_impl_item(self, ii) }
88 fn visit_trait_ref(&mut self, t: &'ast TraitRef) { walk_trait_ref(self, t) }
89 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
90 walk_param_bound(self, bounds)
92 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
93 walk_poly_trait_ref(self, t, m)
95 fn visit_variant_data(&mut self, s: &'ast VariantData, _: Ident,
96 _: &'ast Generics, _: NodeId, _: Span) {
97 walk_struct_def(self, s)
99 fn visit_struct_field(&mut self, s: &'ast StructField) { walk_struct_field(self, s) }
100 fn visit_enum_def(&mut self, enum_definition: &'ast EnumDef,
101 generics: &'ast Generics, item_id: NodeId, _: Span) {
102 walk_enum_def(self, enum_definition, generics, item_id)
104 fn visit_variant(&mut self, v: &'ast Variant, g: &'ast Generics, item_id: NodeId) {
105 walk_variant(self, v, g, item_id)
107 fn visit_label(&mut self, label: &'ast Label) {
108 walk_label(self, label)
110 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
111 walk_lifetime(self, lifetime)
113 fn visit_mac(&mut self, _mac: &'ast Mac) {
114 panic!("visit_mac disabled by default");
115 // N.B., see note about macros above.
116 // if you really want a visitor that
117 // works on macros, use this
118 // definition in your trait impl:
119 // visit::walk_mac(self, _mac)
121 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
124 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
125 walk_path(self, path)
127 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
128 walk_use_tree(self, use_tree, id)
130 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
131 walk_path_segment(self, path_span, path_segment)
133 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
134 walk_generic_args(self, path_span, generic_args)
136 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
138 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
139 GenericArg::Type(ty) => self.visit_ty(ty),
140 GenericArg::Const(ct) => self.visit_anon_const(ct),
143 fn visit_assoc_ty_constraint(&mut self, constraint: &'ast AssocTyConstraint) {
144 walk_assoc_ty_constraint(self, constraint)
146 fn visit_attribute(&mut self, attr: &'ast Attribute) {
147 walk_attribute(self, attr)
149 fn visit_tt(&mut self, tt: TokenTree) {
152 fn visit_tts(&mut self, tts: TokenStream) {
155 fn visit_token(&mut self, _t: Token) {}
156 // FIXME: add `visit_interpolated` and `walk_interpolated`
157 fn visit_vis(&mut self, vis: &'ast Visibility) {
160 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
161 walk_fn_ret_ty(self, ret_ty)
163 fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
169 macro_rules! walk_list {
170 ($visitor: expr, $method: ident, $list: expr) => {
172 $visitor.$method(elem)
175 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
177 $visitor.$method(elem, $($extra_args,)*)
182 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
183 visitor.visit_name(ident.span, ident.name);
186 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
187 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
188 walk_list!(visitor, visit_attribute, &krate.attrs);
191 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
192 walk_list!(visitor, visit_item, &module.items);
195 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
196 for attr in local.attrs.iter() {
197 visitor.visit_attribute(attr);
199 visitor.visit_pat(&local.pat);
200 walk_list!(visitor, visit_ty, &local.ty);
201 walk_list!(visitor, visit_expr, &local.init);
204 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
205 visitor.visit_ident(label.ident);
208 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
209 visitor.visit_ident(lifetime.ident);
212 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
213 trait_ref: &'a PolyTraitRef,
214 _: &TraitBoundModifier)
215 where V: Visitor<'a>,
217 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
218 visitor.visit_trait_ref(&trait_ref.trait_ref);
221 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
222 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
225 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
226 visitor.visit_vis(&item.vis);
227 visitor.visit_ident(item.ident);
229 ItemKind::ExternCrate(orig_name) => {
230 if let Some(orig_name) = orig_name {
231 visitor.visit_name(item.span, orig_name);
234 ItemKind::Use(ref use_tree) => {
235 visitor.visit_use_tree(use_tree, item.id, false)
237 ItemKind::Static(ref typ, _, ref expr) |
238 ItemKind::Const(ref typ, ref expr) => {
239 visitor.visit_ty(typ);
240 visitor.visit_expr(expr);
242 ItemKind::Fn(ref declaration, ref header, ref generics, ref body) => {
243 visitor.visit_generics(generics);
244 visitor.visit_fn_header(header);
245 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
251 ItemKind::Mod(ref module) => {
252 visitor.visit_mod(module, item.span, &item.attrs, item.id)
254 ItemKind::ForeignMod(ref foreign_module) => {
255 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
257 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
258 ItemKind::Ty(ref typ, ref generics) => {
259 visitor.visit_ty(typ);
260 visitor.visit_generics(generics)
262 ItemKind::Existential(ref bounds, ref generics) => {
263 walk_list!(visitor, visit_param_bound, bounds);
264 visitor.visit_generics(generics)
266 ItemKind::Enum(ref enum_definition, ref generics) => {
267 visitor.visit_generics(generics);
268 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
270 ItemKind::Impl(_, _, _,
272 ref opt_trait_reference,
275 visitor.visit_generics(generics);
276 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
277 visitor.visit_ty(typ);
278 walk_list!(visitor, visit_impl_item, impl_items);
280 ItemKind::Struct(ref struct_definition, ref generics) |
281 ItemKind::Union(ref struct_definition, ref generics) => {
282 visitor.visit_generics(generics);
283 visitor.visit_variant_data(struct_definition, item.ident,
284 generics, item.id, item.span);
286 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
287 visitor.visit_generics(generics);
288 walk_list!(visitor, visit_param_bound, bounds);
289 walk_list!(visitor, visit_trait_item, methods);
291 ItemKind::TraitAlias(ref generics, ref bounds) => {
292 visitor.visit_generics(generics);
293 walk_list!(visitor, visit_param_bound, bounds);
295 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
296 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
298 walk_list!(visitor, visit_attribute, &item.attrs);
301 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
302 enum_definition: &'a EnumDef,
303 generics: &'a Generics,
305 walk_list!(visitor, visit_variant, &enum_definition.variants, generics, item_id);
308 pub fn walk_variant<'a, V>(visitor: &mut V,
309 variant: &'a Variant,
310 generics: &'a Generics,
312 where V: Visitor<'a>,
314 visitor.visit_ident(variant.node.ident);
315 visitor.visit_variant_data(&variant.node.data, variant.node.ident,
316 generics, item_id, variant.span);
317 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
318 walk_list!(visitor, visit_attribute, &variant.node.attrs);
321 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
323 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
326 TyKind::Ptr(ref mutable_type) => {
327 visitor.visit_ty(&mutable_type.ty)
329 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
330 walk_list!(visitor, visit_lifetime, opt_lifetime);
331 visitor.visit_ty(&mutable_type.ty)
333 TyKind::Never | TyKind::CVarArgs => {}
334 TyKind::Tup(ref tuple_element_types) => {
335 walk_list!(visitor, visit_ty, tuple_element_types);
337 TyKind::BareFn(ref function_declaration) => {
338 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
339 walk_fn_decl(visitor, &function_declaration.decl);
341 TyKind::Path(ref maybe_qself, ref path) => {
342 if let Some(ref qself) = *maybe_qself {
343 visitor.visit_ty(&qself.ty);
345 visitor.visit_path(path, typ.id);
347 TyKind::Array(ref ty, ref length) => {
348 visitor.visit_ty(ty);
349 visitor.visit_anon_const(length)
351 TyKind::TraitObject(ref bounds, ..) |
352 TyKind::ImplTrait(_, ref bounds) => {
353 walk_list!(visitor, visit_param_bound, bounds);
355 TyKind::Typeof(ref expression) => {
356 visitor.visit_anon_const(expression)
358 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
359 TyKind::Mac(ref mac) => {
360 visitor.visit_mac(mac)
365 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
366 for segment in &path.segments {
367 visitor.visit_path_segment(path.span, segment);
371 pub fn walk_use_tree<'a, V: Visitor<'a>>(
372 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
374 visitor.visit_path(&use_tree.prefix, id);
375 match use_tree.kind {
376 UseTreeKind::Simple(rename, ..) => {
377 // the extra IDs are handled during HIR lowering
378 if let Some(rename) = rename {
379 visitor.visit_ident(rename);
382 UseTreeKind::Glob => {},
383 UseTreeKind::Nested(ref use_trees) => {
384 for &(ref nested_tree, nested_id) in use_trees {
385 visitor.visit_use_tree(nested_tree, nested_id, true);
391 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
393 segment: &'a PathSegment) {
394 visitor.visit_ident(segment.ident);
395 if let Some(ref args) = segment.args {
396 visitor.visit_generic_args(path_span, args);
400 pub fn walk_generic_args<'a, V>(visitor: &mut V,
402 generic_args: &'a GenericArgs)
403 where V: Visitor<'a>,
405 match *generic_args {
406 GenericArgs::AngleBracketed(ref data) => {
407 walk_list!(visitor, visit_generic_arg, &data.args);
408 walk_list!(visitor, visit_assoc_ty_constraint, &data.constraints);
410 GenericArgs::Parenthesized(ref data) => {
411 walk_list!(visitor, visit_ty, &data.inputs);
412 walk_list!(visitor, visit_ty, &data.output);
417 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(visitor: &mut V,
418 constraint: &'a AssocTyConstraint) {
419 visitor.visit_ident(constraint.ident);
420 match constraint.kind {
421 AssocTyConstraintKind::Equality { ref ty } => {
422 visitor.visit_ty(ty);
424 AssocTyConstraintKind::Bound { ref bounds } => {
425 walk_list!(visitor, visit_param_bound, bounds);
430 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
432 PatKind::TupleStruct(ref path, ref elems) => {
433 visitor.visit_path(path, pattern.id);
434 walk_list!(visitor, visit_pat, elems);
436 PatKind::Path(ref opt_qself, ref path) => {
437 if let Some(ref qself) = *opt_qself {
438 visitor.visit_ty(&qself.ty);
440 visitor.visit_path(path, pattern.id)
442 PatKind::Struct(ref path, ref fields, _) => {
443 visitor.visit_path(path, pattern.id);
444 for field in fields {
445 walk_list!(visitor, visit_attribute, field.node.attrs.iter());
446 visitor.visit_ident(field.node.ident);
447 visitor.visit_pat(&field.node.pat)
450 PatKind::Tuple(ref elems) => {
451 walk_list!(visitor, visit_pat, elems);
453 PatKind::Box(ref subpattern) |
454 PatKind::Ref(ref subpattern, _) |
455 PatKind::Paren(ref subpattern) => {
456 visitor.visit_pat(subpattern)
458 PatKind::Ident(_, ident, ref optional_subpattern) => {
459 visitor.visit_ident(ident);
460 walk_list!(visitor, visit_pat, optional_subpattern);
462 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
463 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
464 visitor.visit_expr(lower_bound);
465 visitor.visit_expr(upper_bound);
467 PatKind::Wild | PatKind::Rest => {},
468 PatKind::Slice(ref elems) => {
469 walk_list!(visitor, visit_pat, elems);
471 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
475 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
476 visitor.visit_vis(&foreign_item.vis);
477 visitor.visit_ident(foreign_item.ident);
479 match foreign_item.node {
480 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
481 walk_fn_decl(visitor, function_declaration);
482 visitor.visit_generics(generics)
484 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
485 ForeignItemKind::Ty => (),
486 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
489 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
492 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
496 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
498 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
499 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
503 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
504 visitor.visit_ident(param.ident);
505 walk_list!(visitor, visit_attribute, param.attrs.iter());
506 walk_list!(visitor, visit_param_bound, ¶m.bounds);
508 GenericParamKind::Lifetime => (),
509 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
510 GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
514 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
515 walk_list!(visitor, visit_generic_param, &generics.params);
516 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
519 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
521 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
523 ref bound_generic_params,
525 visitor.visit_ty(bounded_ty);
526 walk_list!(visitor, visit_param_bound, bounds);
527 walk_list!(visitor, visit_generic_param, bound_generic_params);
529 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
532 visitor.visit_lifetime(lifetime);
533 walk_list!(visitor, visit_param_bound, bounds);
535 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
538 visitor.visit_ty(lhs_ty);
539 visitor.visit_ty(rhs_ty);
544 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
545 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
546 visitor.visit_ty(output_ty)
550 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
551 for arg in &function_declaration.inputs {
552 visitor.visit_arg(arg);
554 visitor.visit_fn_ret_ty(&function_declaration.output);
557 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
558 where V: Visitor<'a>,
561 FnKind::ItemFn(_, header, _, body) => {
562 visitor.visit_fn_header(header);
563 walk_fn_decl(visitor, declaration);
564 visitor.visit_block(body);
566 FnKind::Method(_, sig, _, body) => {
567 visitor.visit_fn_header(&sig.header);
568 walk_fn_decl(visitor, declaration);
569 visitor.visit_block(body);
571 FnKind::Closure(body) => {
572 walk_fn_decl(visitor, declaration);
573 visitor.visit_expr(body);
578 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
579 visitor.visit_ident(trait_item.ident);
580 walk_list!(visitor, visit_attribute, &trait_item.attrs);
581 visitor.visit_generics(&trait_item.generics);
582 match trait_item.node {
583 TraitItemKind::Const(ref ty, ref default) => {
584 visitor.visit_ty(ty);
585 walk_list!(visitor, visit_expr, default);
587 TraitItemKind::Method(ref sig, None) => {
588 visitor.visit_fn_header(&sig.header);
589 walk_fn_decl(visitor, &sig.decl);
591 TraitItemKind::Method(ref sig, Some(ref body)) => {
592 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
593 &sig.decl, trait_item.span, trait_item.id);
595 TraitItemKind::Type(ref bounds, ref default) => {
596 walk_list!(visitor, visit_param_bound, bounds);
597 walk_list!(visitor, visit_ty, default);
599 TraitItemKind::Macro(ref mac) => {
600 visitor.visit_mac(mac);
605 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
606 visitor.visit_vis(&impl_item.vis);
607 visitor.visit_ident(impl_item.ident);
608 walk_list!(visitor, visit_attribute, &impl_item.attrs);
609 visitor.visit_generics(&impl_item.generics);
610 match impl_item.node {
611 ImplItemKind::Const(ref ty, ref expr) => {
612 visitor.visit_ty(ty);
613 visitor.visit_expr(expr);
615 ImplItemKind::Method(ref sig, ref body) => {
616 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
617 &sig.decl, impl_item.span, impl_item.id);
619 ImplItemKind::Type(ref ty) => {
620 visitor.visit_ty(ty);
622 ImplItemKind::Existential(ref bounds) => {
623 walk_list!(visitor, visit_param_bound, bounds);
625 ImplItemKind::Macro(ref mac) => {
626 visitor.visit_mac(mac);
631 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
632 walk_list!(visitor, visit_struct_field, struct_definition.fields());
635 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
636 visitor.visit_vis(&struct_field.vis);
637 if let Some(ident) = struct_field.ident {
638 visitor.visit_ident(ident);
640 visitor.visit_ty(&struct_field.ty);
641 walk_list!(visitor, visit_attribute, &struct_field.attrs);
644 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
645 walk_list!(visitor, visit_stmt, &block.stmts);
648 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
649 match statement.node {
650 StmtKind::Local(ref local) => visitor.visit_local(local),
651 StmtKind::Item(ref item) => visitor.visit_item(item),
652 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
653 visitor.visit_expr(expression)
655 StmtKind::Mac(ref mac) => {
656 let (ref mac, _, ref attrs) = **mac;
657 visitor.visit_mac(mac);
658 for attr in attrs.iter() {
659 visitor.visit_attribute(attr);
665 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a Mac) {
666 visitor.visit_path(&mac.node.path, DUMMY_NODE_ID);
669 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
670 visitor.visit_expr(&constant.value);
673 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
674 for attr in expression.attrs.iter() {
675 visitor.visit_attribute(attr);
677 match expression.node {
678 ExprKind::Box(ref subexpression) => {
679 visitor.visit_expr(subexpression)
681 ExprKind::Array(ref subexpressions) => {
682 walk_list!(visitor, visit_expr, subexpressions);
684 ExprKind::Repeat(ref element, ref count) => {
685 visitor.visit_expr(element);
686 visitor.visit_anon_const(count)
688 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
689 visitor.visit_path(path, expression.id);
690 for field in fields {
691 walk_list!(visitor, visit_attribute, field.attrs.iter());
692 visitor.visit_ident(field.ident);
693 visitor.visit_expr(&field.expr)
695 walk_list!(visitor, visit_expr, optional_base);
697 ExprKind::Tup(ref subexpressions) => {
698 walk_list!(visitor, visit_expr, subexpressions);
700 ExprKind::Call(ref callee_expression, ref arguments) => {
701 visitor.visit_expr(callee_expression);
702 walk_list!(visitor, visit_expr, arguments);
704 ExprKind::MethodCall(ref segment, ref arguments) => {
705 visitor.visit_path_segment(expression.span, segment);
706 walk_list!(visitor, visit_expr, arguments);
708 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
709 visitor.visit_expr(left_expression);
710 visitor.visit_expr(right_expression)
712 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
713 visitor.visit_expr(subexpression)
715 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
716 visitor.visit_expr(subexpression);
717 visitor.visit_ty(typ)
719 ExprKind::Let(ref pats, ref scrutinee) => {
720 walk_list!(visitor, visit_pat, pats);
721 visitor.visit_expr(scrutinee);
723 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
724 visitor.visit_expr(head_expression);
725 visitor.visit_block(if_block);
726 walk_list!(visitor, visit_expr, optional_else);
728 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
729 walk_list!(visitor, visit_label, opt_label);
730 visitor.visit_expr(subexpression);
731 visitor.visit_block(block);
733 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
734 walk_list!(visitor, visit_label, opt_label);
735 visitor.visit_pat(pattern);
736 visitor.visit_expr(subexpression);
737 visitor.visit_block(block);
739 ExprKind::Loop(ref block, ref opt_label) => {
740 walk_list!(visitor, visit_label, opt_label);
741 visitor.visit_block(block);
743 ExprKind::Match(ref subexpression, ref arms) => {
744 visitor.visit_expr(subexpression);
745 walk_list!(visitor, visit_arm, arms);
747 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => {
748 visitor.visit_fn(FnKind::Closure(body),
749 function_declaration,
753 ExprKind::Block(ref block, ref opt_label) => {
754 walk_list!(visitor, visit_label, opt_label);
755 visitor.visit_block(block);
757 ExprKind::Async(_, _, ref body) => {
758 visitor.visit_block(body);
760 ExprKind::Await(_, ref expr) => visitor.visit_expr(expr),
761 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
762 visitor.visit_expr(left_hand_expression);
763 visitor.visit_expr(right_hand_expression);
765 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
766 visitor.visit_expr(left_expression);
767 visitor.visit_expr(right_expression);
769 ExprKind::Field(ref subexpression, ident) => {
770 visitor.visit_expr(subexpression);
771 visitor.visit_ident(ident);
773 ExprKind::Index(ref main_expression, ref index_expression) => {
774 visitor.visit_expr(main_expression);
775 visitor.visit_expr(index_expression)
777 ExprKind::Range(ref start, ref end, _) => {
778 walk_list!(visitor, visit_expr, start);
779 walk_list!(visitor, visit_expr, end);
781 ExprKind::Path(ref maybe_qself, ref path) => {
782 if let Some(ref qself) = *maybe_qself {
783 visitor.visit_ty(&qself.ty);
785 visitor.visit_path(path, expression.id)
787 ExprKind::Break(ref opt_label, ref opt_expr) => {
788 walk_list!(visitor, visit_label, opt_label);
789 walk_list!(visitor, visit_expr, opt_expr);
791 ExprKind::Continue(ref opt_label) => {
792 walk_list!(visitor, visit_label, opt_label);
794 ExprKind::Ret(ref optional_expression) => {
795 walk_list!(visitor, visit_expr, optional_expression);
797 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
798 ExprKind::Paren(ref subexpression) => {
799 visitor.visit_expr(subexpression)
801 ExprKind::InlineAsm(ref ia) => {
802 for &(_, ref input) in &ia.inputs {
803 visitor.visit_expr(input)
805 for output in &ia.outputs {
806 visitor.visit_expr(&output.expr)
809 ExprKind::Yield(ref optional_expression) => {
810 walk_list!(visitor, visit_expr, optional_expression);
812 ExprKind::Try(ref subexpression) => {
813 visitor.visit_expr(subexpression)
815 ExprKind::TryBlock(ref body) => {
816 visitor.visit_block(body)
818 ExprKind::Lit(_) | ExprKind::Err => {}
821 visitor.visit_expr_post(expression)
824 pub fn walk_arg<'a, V: Visitor<'a>>(visitor: &mut V, arg: &'a Arg) {
825 walk_list!(visitor, visit_attribute, arg.attrs.iter());
826 visitor.visit_pat(&arg.pat);
827 visitor.visit_ty(&arg.ty);
830 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
831 walk_list!(visitor, visit_pat, &arm.pats);
832 if let Some(ref e) = &arm.guard {
833 visitor.visit_expr(e);
835 visitor.visit_expr(&arm.body);
836 walk_list!(visitor, visit_attribute, &arm.attrs);
839 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
840 if let VisibilityKind::Restricted { ref path, id } = vis.node {
841 visitor.visit_path(path, id);
845 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
846 visitor.visit_tts(attr.tokens.clone());
849 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
851 TokenTree::Token(token) => visitor.visit_token(token),
852 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
856 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
857 for tt in tts.trees() {
858 visitor.visit_tt(tt);