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_param(&mut self, param: &'ast Param) { walk_param(self, param) }
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) {
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) {
104 walk_variant(self, v)
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) {
165 fn visit_field(&mut self, f: &'ast Field) {
168 fn visit_field_pattern(&mut self, fp: &'ast FieldPat) {
169 walk_field_pattern(self, fp)
174 macro_rules! walk_list {
175 ($visitor: expr, $method: ident, $list: expr) => {
177 $visitor.$method(elem)
180 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
182 $visitor.$method(elem, $($extra_args,)*)
187 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
188 visitor.visit_name(ident.span, ident.name);
191 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
192 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
193 walk_list!(visitor, visit_attribute, &krate.attrs);
196 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
197 walk_list!(visitor, visit_item, &module.items);
200 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
201 for attr in local.attrs.iter() {
202 visitor.visit_attribute(attr);
204 visitor.visit_pat(&local.pat);
205 walk_list!(visitor, visit_ty, &local.ty);
206 walk_list!(visitor, visit_expr, &local.init);
209 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
210 visitor.visit_ident(label.ident);
213 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
214 visitor.visit_ident(lifetime.ident);
217 pub fn walk_poly_trait_ref<'a, V>(visitor: &mut V,
218 trait_ref: &'a PolyTraitRef,
219 _: &TraitBoundModifier)
220 where V: Visitor<'a>,
222 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
223 visitor.visit_trait_ref(&trait_ref.trait_ref);
226 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
227 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
230 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
231 visitor.visit_vis(&item.vis);
232 visitor.visit_ident(item.ident);
234 ItemKind::ExternCrate(orig_name) => {
235 if let Some(orig_name) = orig_name {
236 visitor.visit_name(item.span, orig_name);
239 ItemKind::Use(ref use_tree) => {
240 visitor.visit_use_tree(use_tree, item.id, false)
242 ItemKind::Static(ref typ, _, ref expr) |
243 ItemKind::Const(ref typ, ref expr) => {
244 visitor.visit_ty(typ);
245 visitor.visit_expr(expr);
247 ItemKind::Fn(ref declaration, ref header, ref generics, ref body) => {
248 visitor.visit_generics(generics);
249 visitor.visit_fn_header(header);
250 visitor.visit_fn(FnKind::ItemFn(item.ident, header,
256 ItemKind::Mod(ref module) => {
257 visitor.visit_mod(module, item.span, &item.attrs, item.id)
259 ItemKind::ForeignMod(ref foreign_module) => {
260 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
262 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
263 ItemKind::TyAlias(ref typ, ref generics) => {
264 visitor.visit_ty(typ);
265 visitor.visit_generics(generics)
267 ItemKind::OpaqueTy(ref bounds, ref generics) => {
268 walk_list!(visitor, visit_param_bound, bounds);
269 visitor.visit_generics(generics)
271 ItemKind::Enum(ref enum_definition, ref generics) => {
272 visitor.visit_generics(generics);
273 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
275 ItemKind::Impl(_, _, _,
277 ref opt_trait_reference,
280 visitor.visit_generics(generics);
281 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
282 visitor.visit_ty(typ);
283 walk_list!(visitor, visit_impl_item, impl_items);
285 ItemKind::Struct(ref struct_definition, ref generics) |
286 ItemKind::Union(ref struct_definition, ref generics) => {
287 visitor.visit_generics(generics);
288 visitor.visit_variant_data(struct_definition);
290 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
291 visitor.visit_generics(generics);
292 walk_list!(visitor, visit_param_bound, bounds);
293 walk_list!(visitor, visit_trait_item, methods);
295 ItemKind::TraitAlias(ref generics, ref bounds) => {
296 visitor.visit_generics(generics);
297 walk_list!(visitor, visit_param_bound, bounds);
299 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
300 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
302 walk_list!(visitor, visit_attribute, &item.attrs);
305 pub fn walk_enum_def<'a, V: Visitor<'a>>(visitor: &mut V,
306 enum_definition: &'a EnumDef,
309 walk_list!(visitor, visit_variant, &enum_definition.variants);
312 pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
313 where V: Visitor<'a>,
315 visitor.visit_ident(variant.ident);
316 visitor.visit_variant_data(&variant.data);
317 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
318 walk_list!(visitor, visit_attribute, &variant.attrs);
321 pub fn walk_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a Field) {
322 visitor.visit_expr(&f.expr);
323 visitor.visit_ident(f.ident);
324 walk_list!(visitor, visit_attribute, f.attrs.iter());
327 pub fn walk_field_pattern<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a FieldPat) {
328 visitor.visit_ident(fp.ident);
329 visitor.visit_pat(&fp.pat);
330 walk_list!(visitor, visit_attribute, fp.attrs.iter());
333 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
335 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => {
338 TyKind::Ptr(ref mutable_type) => {
339 visitor.visit_ty(&mutable_type.ty)
341 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
342 walk_list!(visitor, visit_lifetime, opt_lifetime);
343 visitor.visit_ty(&mutable_type.ty)
345 TyKind::Never | TyKind::CVarArgs => {}
346 TyKind::Tup(ref tuple_element_types) => {
347 walk_list!(visitor, visit_ty, tuple_element_types);
349 TyKind::BareFn(ref function_declaration) => {
350 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
351 walk_fn_decl(visitor, &function_declaration.decl);
353 TyKind::Path(ref maybe_qself, ref path) => {
354 if let Some(ref qself) = *maybe_qself {
355 visitor.visit_ty(&qself.ty);
357 visitor.visit_path(path, typ.id);
359 TyKind::Array(ref ty, ref length) => {
360 visitor.visit_ty(ty);
361 visitor.visit_anon_const(length)
363 TyKind::TraitObject(ref bounds, ..) |
364 TyKind::ImplTrait(_, ref bounds) => {
365 walk_list!(visitor, visit_param_bound, bounds);
367 TyKind::Typeof(ref expression) => {
368 visitor.visit_anon_const(expression)
370 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
371 TyKind::Mac(ref mac) => {
372 visitor.visit_mac(mac)
377 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
378 for segment in &path.segments {
379 visitor.visit_path_segment(path.span, segment);
383 pub fn walk_use_tree<'a, V: Visitor<'a>>(
384 visitor: &mut V, use_tree: &'a UseTree, id: NodeId,
386 visitor.visit_path(&use_tree.prefix, id);
387 match use_tree.kind {
388 UseTreeKind::Simple(rename, ..) => {
389 // the extra IDs are handled during HIR lowering
390 if let Some(rename) = rename {
391 visitor.visit_ident(rename);
394 UseTreeKind::Glob => {},
395 UseTreeKind::Nested(ref use_trees) => {
396 for &(ref nested_tree, nested_id) in use_trees {
397 visitor.visit_use_tree(nested_tree, nested_id, true);
403 pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V,
405 segment: &'a PathSegment) {
406 visitor.visit_ident(segment.ident);
407 if let Some(ref args) = segment.args {
408 visitor.visit_generic_args(path_span, args);
412 pub fn walk_generic_args<'a, V>(visitor: &mut V,
414 generic_args: &'a GenericArgs)
415 where V: Visitor<'a>,
417 match *generic_args {
418 GenericArgs::AngleBracketed(ref data) => {
419 walk_list!(visitor, visit_generic_arg, &data.args);
420 walk_list!(visitor, visit_assoc_ty_constraint, &data.constraints);
422 GenericArgs::Parenthesized(ref data) => {
423 walk_list!(visitor, visit_ty, &data.inputs);
424 walk_list!(visitor, visit_ty, &data.output);
429 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(visitor: &mut V,
430 constraint: &'a AssocTyConstraint) {
431 visitor.visit_ident(constraint.ident);
432 match constraint.kind {
433 AssocTyConstraintKind::Equality { ref ty } => {
434 visitor.visit_ty(ty);
436 AssocTyConstraintKind::Bound { ref bounds } => {
437 walk_list!(visitor, visit_param_bound, bounds);
442 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
444 PatKind::TupleStruct(ref path, ref elems) => {
445 visitor.visit_path(path, pattern.id);
446 walk_list!(visitor, visit_pat, elems);
448 PatKind::Path(ref opt_qself, ref path) => {
449 if let Some(ref qself) = *opt_qself {
450 visitor.visit_ty(&qself.ty);
452 visitor.visit_path(path, pattern.id)
454 PatKind::Struct(ref path, ref fields, _) => {
455 visitor.visit_path(path, pattern.id);
456 walk_list!(visitor, visit_field_pattern, fields);
458 PatKind::Box(ref subpattern) |
459 PatKind::Ref(ref subpattern, _) |
460 PatKind::Paren(ref subpattern) => {
461 visitor.visit_pat(subpattern)
463 PatKind::Ident(_, ident, ref optional_subpattern) => {
464 visitor.visit_ident(ident);
465 walk_list!(visitor, visit_pat, optional_subpattern);
467 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
468 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
469 visitor.visit_expr(lower_bound);
470 visitor.visit_expr(upper_bound);
472 PatKind::Wild | PatKind::Rest => {},
473 PatKind::Tuple(ref elems)
474 | PatKind::Slice(ref elems)
475 | PatKind::Or(ref elems) => {
476 walk_list!(visitor, visit_pat, elems);
478 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
482 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
483 visitor.visit_vis(&foreign_item.vis);
484 visitor.visit_ident(foreign_item.ident);
486 match foreign_item.node {
487 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
488 walk_fn_decl(visitor, function_declaration);
489 visitor.visit_generics(generics)
491 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
492 ForeignItemKind::Ty => (),
493 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
496 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
499 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
503 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
505 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
506 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
510 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
511 visitor.visit_ident(param.ident);
512 walk_list!(visitor, visit_attribute, param.attrs.iter());
513 walk_list!(visitor, visit_param_bound, ¶m.bounds);
515 GenericParamKind::Lifetime => (),
516 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
517 GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
521 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
522 walk_list!(visitor, visit_generic_param, &generics.params);
523 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
526 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
528 WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
530 ref bound_generic_params,
532 visitor.visit_ty(bounded_ty);
533 walk_list!(visitor, visit_param_bound, bounds);
534 walk_list!(visitor, visit_generic_param, bound_generic_params);
536 WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
539 visitor.visit_lifetime(lifetime);
540 walk_list!(visitor, visit_param_bound, bounds);
542 WherePredicate::EqPredicate(WhereEqPredicate{ref lhs_ty,
545 visitor.visit_ty(lhs_ty);
546 visitor.visit_ty(rhs_ty);
551 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
552 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
553 visitor.visit_ty(output_ty)
557 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
558 for param in &function_declaration.inputs {
559 visitor.visit_param(param);
561 visitor.visit_fn_ret_ty(&function_declaration.output);
564 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
565 where V: Visitor<'a>,
568 FnKind::ItemFn(_, header, _, body) => {
569 visitor.visit_fn_header(header);
570 walk_fn_decl(visitor, declaration);
571 visitor.visit_block(body);
573 FnKind::Method(_, sig, _, body) => {
574 visitor.visit_fn_header(&sig.header);
575 walk_fn_decl(visitor, declaration);
576 visitor.visit_block(body);
578 FnKind::Closure(body) => {
579 walk_fn_decl(visitor, declaration);
580 visitor.visit_expr(body);
585 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, trait_item: &'a TraitItem) {
586 visitor.visit_ident(trait_item.ident);
587 walk_list!(visitor, visit_attribute, &trait_item.attrs);
588 visitor.visit_generics(&trait_item.generics);
589 match trait_item.node {
590 TraitItemKind::Const(ref ty, ref default) => {
591 visitor.visit_ty(ty);
592 walk_list!(visitor, visit_expr, default);
594 TraitItemKind::Method(ref sig, None) => {
595 visitor.visit_fn_header(&sig.header);
596 walk_fn_decl(visitor, &sig.decl);
598 TraitItemKind::Method(ref sig, Some(ref body)) => {
599 visitor.visit_fn(FnKind::Method(trait_item.ident, sig, None, body),
600 &sig.decl, trait_item.span, trait_item.id);
602 TraitItemKind::Type(ref bounds, ref default) => {
603 walk_list!(visitor, visit_param_bound, bounds);
604 walk_list!(visitor, visit_ty, default);
606 TraitItemKind::Macro(ref mac) => {
607 visitor.visit_mac(mac);
612 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, impl_item: &'a ImplItem) {
613 visitor.visit_vis(&impl_item.vis);
614 visitor.visit_ident(impl_item.ident);
615 walk_list!(visitor, visit_attribute, &impl_item.attrs);
616 visitor.visit_generics(&impl_item.generics);
617 match impl_item.node {
618 ImplItemKind::Const(ref ty, ref expr) => {
619 visitor.visit_ty(ty);
620 visitor.visit_expr(expr);
622 ImplItemKind::Method(ref sig, ref body) => {
623 visitor.visit_fn(FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), body),
624 &sig.decl, impl_item.span, impl_item.id);
626 ImplItemKind::TyAlias(ref ty) => {
627 visitor.visit_ty(ty);
629 ImplItemKind::OpaqueTy(ref bounds) => {
630 walk_list!(visitor, visit_param_bound, bounds);
632 ImplItemKind::Macro(ref mac) => {
633 visitor.visit_mac(mac);
638 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
639 walk_list!(visitor, visit_struct_field, struct_definition.fields());
642 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
643 visitor.visit_vis(&struct_field.vis);
644 if let Some(ident) = struct_field.ident {
645 visitor.visit_ident(ident);
647 visitor.visit_ty(&struct_field.ty);
648 walk_list!(visitor, visit_attribute, &struct_field.attrs);
651 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
652 walk_list!(visitor, visit_stmt, &block.stmts);
655 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
656 match statement.node {
657 StmtKind::Local(ref local) => visitor.visit_local(local),
658 StmtKind::Item(ref item) => visitor.visit_item(item),
659 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
660 visitor.visit_expr(expression)
662 StmtKind::Mac(ref mac) => {
663 let (ref mac, _, ref attrs) = **mac;
664 visitor.visit_mac(mac);
665 for attr in attrs.iter() {
666 visitor.visit_attribute(attr);
672 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a Mac) {
673 visitor.visit_path(&mac.path, DUMMY_NODE_ID);
676 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
677 visitor.visit_expr(&constant.value);
680 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
681 walk_list!(visitor, visit_attribute, expression.attrs.iter());
683 match expression.node {
684 ExprKind::Box(ref subexpression) => {
685 visitor.visit_expr(subexpression)
687 ExprKind::Array(ref subexpressions) => {
688 walk_list!(visitor, visit_expr, subexpressions);
690 ExprKind::Repeat(ref element, ref count) => {
691 visitor.visit_expr(element);
692 visitor.visit_anon_const(count)
694 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
695 visitor.visit_path(path, expression.id);
696 walk_list!(visitor, visit_field, fields);
697 walk_list!(visitor, visit_expr, optional_base);
699 ExprKind::Tup(ref subexpressions) => {
700 walk_list!(visitor, visit_expr, subexpressions);
702 ExprKind::Call(ref callee_expression, ref arguments) => {
703 visitor.visit_expr(callee_expression);
704 walk_list!(visitor, visit_expr, arguments);
706 ExprKind::MethodCall(ref segment, ref arguments) => {
707 visitor.visit_path_segment(expression.span, segment);
708 walk_list!(visitor, visit_expr, arguments);
710 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
711 visitor.visit_expr(left_expression);
712 visitor.visit_expr(right_expression)
714 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
715 visitor.visit_expr(subexpression)
717 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
718 visitor.visit_expr(subexpression);
719 visitor.visit_ty(typ)
721 ExprKind::Let(ref pat, ref scrutinee) => {
722 visitor.visit_pat(pat);
723 visitor.visit_expr(scrutinee);
725 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
726 visitor.visit_expr(head_expression);
727 visitor.visit_block(if_block);
728 walk_list!(visitor, visit_expr, optional_else);
730 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
731 walk_list!(visitor, visit_label, opt_label);
732 visitor.visit_expr(subexpression);
733 visitor.visit_block(block);
735 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
736 walk_list!(visitor, visit_label, opt_label);
737 visitor.visit_pat(pattern);
738 visitor.visit_expr(subexpression);
739 visitor.visit_block(block);
741 ExprKind::Loop(ref block, ref opt_label) => {
742 walk_list!(visitor, visit_label, opt_label);
743 visitor.visit_block(block);
745 ExprKind::Match(ref subexpression, ref arms) => {
746 visitor.visit_expr(subexpression);
747 walk_list!(visitor, visit_arm, arms);
749 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => {
750 visitor.visit_fn(FnKind::Closure(body),
751 function_declaration,
755 ExprKind::Block(ref block, ref opt_label) => {
756 walk_list!(visitor, visit_label, opt_label);
757 visitor.visit_block(block);
759 ExprKind::Async(_, _, ref body) => {
760 visitor.visit_block(body);
762 ExprKind::Await(ref expr) => visitor.visit_expr(expr),
763 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
764 visitor.visit_expr(left_hand_expression);
765 visitor.visit_expr(right_hand_expression);
767 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
768 visitor.visit_expr(left_expression);
769 visitor.visit_expr(right_expression);
771 ExprKind::Field(ref subexpression, ident) => {
772 visitor.visit_expr(subexpression);
773 visitor.visit_ident(ident);
775 ExprKind::Index(ref main_expression, ref index_expression) => {
776 visitor.visit_expr(main_expression);
777 visitor.visit_expr(index_expression)
779 ExprKind::Range(ref start, ref end, _) => {
780 walk_list!(visitor, visit_expr, start);
781 walk_list!(visitor, visit_expr, end);
783 ExprKind::Path(ref maybe_qself, ref path) => {
784 if let Some(ref qself) = *maybe_qself {
785 visitor.visit_ty(&qself.ty);
787 visitor.visit_path(path, expression.id)
789 ExprKind::Break(ref opt_label, ref opt_expr) => {
790 walk_list!(visitor, visit_label, opt_label);
791 walk_list!(visitor, visit_expr, opt_expr);
793 ExprKind::Continue(ref opt_label) => {
794 walk_list!(visitor, visit_label, opt_label);
796 ExprKind::Ret(ref optional_expression) => {
797 walk_list!(visitor, visit_expr, optional_expression);
799 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
800 ExprKind::Paren(ref subexpression) => {
801 visitor.visit_expr(subexpression)
803 ExprKind::InlineAsm(ref ia) => {
804 for &(_, ref input) in &ia.inputs {
805 visitor.visit_expr(input)
807 for output in &ia.outputs {
808 visitor.visit_expr(&output.expr)
811 ExprKind::Yield(ref optional_expression) => {
812 walk_list!(visitor, visit_expr, optional_expression);
814 ExprKind::Try(ref subexpression) => {
815 visitor.visit_expr(subexpression)
817 ExprKind::TryBlock(ref body) => {
818 visitor.visit_block(body)
820 ExprKind::Lit(_) | ExprKind::Err => {}
823 visitor.visit_expr_post(expression)
826 pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
827 walk_list!(visitor, visit_attribute, param.attrs.iter());
828 visitor.visit_pat(¶m.pat);
829 visitor.visit_ty(¶m.ty);
832 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
833 visitor.visit_pat(&arm.pat);
834 // NOTE(or_patterns; Centril | dlrobertson):
835 // If you change this, also change the hack in `lowering.rs`.
836 walk_list!(visitor, visit_expr, &arm.guard);
837 visitor.visit_expr(&arm.body);
838 walk_list!(visitor, visit_attribute, &arm.attrs);
841 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
842 if let VisibilityKind::Restricted { ref path, id } = vis.node {
843 visitor.visit_path(path, id);
847 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
848 visitor.visit_tts(attr.tokens.clone());
851 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
853 TokenTree::Token(token) => visitor.visit_token(token),
854 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
858 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
859 for tt in tts.trees() {
860 visitor.visit_tt(tt);