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.
19 use rustc_span::symbol::{Ident, Symbol};
22 #[derive(Copy, Clone, Debug, PartialEq)]
28 #[derive(Copy, Clone, Debug, PartialEq)]
35 #[derive(Copy, Clone, Debug)]
37 /// Trait bounds in generics bounds and type/trait alias.
38 /// E.g., `<T: Bound>`, `type A: Bound`, or `where T: Bound`.
41 /// Trait bounds in `impl` type.
42 /// E.g., `type Foo = impl Bound1 + Bound2 + Bound3`.
45 /// Trait bounds in trait object type.
46 /// E.g., `dyn Bound1 + Bound2 + Bound3`.
49 /// Super traits of a trait.
50 /// E.g., `trait A: B`
54 #[derive(Copy, Clone, Debug)]
56 /// E.g., `fn foo()`, `fn foo(&self)`, or `extern "Abi" fn foo()`.
57 Fn(FnCtxt, Ident, &'a FnSig, &'a Visibility, &'a Generics, Option<&'a Block>),
59 /// E.g., `|x, y| body`.
60 Closure(&'a FnDecl, &'a Expr),
64 pub fn header(&self) -> Option<&'a FnHeader> {
66 FnKind::Fn(_, _, sig, _, _, _) => Some(&sig.header),
67 FnKind::Closure(_, _) => None,
71 pub fn ident(&self) -> Option<&Ident> {
73 FnKind::Fn(_, ident, ..) => Some(ident),
78 pub fn decl(&self) -> &'a FnDecl {
80 FnKind::Fn(_, _, sig, _, _, _) => &sig.decl,
81 FnKind::Closure(decl, _) => decl,
85 pub fn ctxt(&self) -> Option<FnCtxt> {
87 FnKind::Fn(ctxt, ..) => Some(*ctxt),
88 FnKind::Closure(..) => None,
93 /// Each method of the `Visitor` trait is a hook to be potentially
94 /// overridden. Each method's default implementation recursively visits
95 /// the substructure of the input via the corresponding `walk` method;
96 /// e.g., the `visit_item` method by default calls `visit::walk_item`.
98 /// If you want to ensure that your code handles every variant
99 /// explicitly, you need to override each method. (And you also need
100 /// to monitor future changes to `Visitor` in case a new method with a
101 /// new default implementation gets introduced.)
102 pub trait Visitor<'ast>: Sized {
103 fn visit_name(&mut self, _span: Span, _name: Symbol) {
106 fn visit_ident(&mut self, ident: Ident) {
107 walk_ident(self, ident);
109 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) {
110 walk_foreign_item(self, i)
112 fn visit_item(&mut self, i: &'ast Item) {
115 fn visit_local(&mut self, l: &'ast Local) {
118 fn visit_block(&mut self, b: &'ast Block) {
121 fn visit_stmt(&mut self, s: &'ast Stmt) {
124 fn visit_param(&mut self, param: &'ast Param) {
125 walk_param(self, param)
127 fn visit_arm(&mut self, a: &'ast Arm) {
130 fn visit_pat(&mut self, p: &'ast Pat) {
133 fn visit_anon_const(&mut self, c: &'ast AnonConst) {
134 walk_anon_const(self, c)
136 fn visit_expr(&mut self, ex: &'ast Expr) {
139 fn visit_expr_post(&mut self, _ex: &'ast Expr) {}
140 fn visit_ty(&mut self, t: &'ast Ty) {
143 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
144 walk_generic_param(self, param)
146 fn visit_generics(&mut self, g: &'ast Generics) {
147 walk_generics(self, g)
149 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
150 walk_where_predicate(self, p)
152 fn visit_fn(&mut self, fk: FnKind<'ast>, s: Span, _: NodeId) {
155 fn visit_assoc_item(&mut self, i: &'ast AssocItem, ctxt: AssocCtxt) {
156 walk_assoc_item(self, i, ctxt)
158 fn visit_trait_ref(&mut self, t: &'ast TraitRef) {
159 walk_trait_ref(self, t)
161 fn visit_param_bound(&mut self, bounds: &'ast GenericBound, _ctxt: BoundKind) {
162 walk_param_bound(self, bounds)
164 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
165 walk_poly_trait_ref(self, t, m)
167 fn visit_variant_data(&mut self, s: &'ast VariantData) {
168 walk_struct_def(self, s)
170 fn visit_field_def(&mut self, s: &'ast FieldDef) {
171 walk_field_def(self, s)
175 enum_definition: &'ast EnumDef,
176 generics: &'ast Generics,
180 walk_enum_def(self, enum_definition, generics, item_id)
182 fn visit_variant(&mut self, v: &'ast Variant) {
183 walk_variant(self, v)
185 fn visit_label(&mut self, label: &'ast Label) {
186 walk_label(self, label)
188 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
189 walk_lifetime(self, lifetime)
191 fn visit_mac_call(&mut self, mac: &'ast MacCall) {
194 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
197 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
198 walk_path(self, path)
200 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
201 walk_use_tree(self, use_tree, id)
203 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
204 walk_path_segment(self, path_span, path_segment)
206 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
207 walk_generic_args(self, path_span, generic_args)
209 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
210 walk_generic_arg(self, generic_arg)
212 fn visit_assoc_constraint(&mut self, constraint: &'ast AssocConstraint) {
213 walk_assoc_constraint(self, constraint)
215 fn visit_attribute(&mut self, attr: &'ast Attribute) {
216 walk_attribute(self, attr)
218 fn visit_vis(&mut self, vis: &'ast Visibility) {
221 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FnRetTy) {
222 walk_fn_ret_ty(self, ret_ty)
224 fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
227 fn visit_expr_field(&mut self, f: &'ast ExprField) {
228 walk_expr_field(self, f)
230 fn visit_pat_field(&mut self, fp: &'ast PatField) {
231 walk_pat_field(self, fp)
233 fn visit_crate(&mut self, krate: &'ast Crate) {
234 walk_crate(self, krate)
236 fn visit_inline_asm(&mut self, asm: &'ast InlineAsm) {
237 walk_inline_asm(self, asm)
239 fn visit_inline_asm_sym(&mut self, sym: &'ast InlineAsmSym) {
240 walk_inline_asm_sym(self, sym)
245 macro_rules! walk_list {
246 ($visitor: expr, $method: ident, $list: expr) => {
248 $visitor.$method(elem)
251 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
253 $visitor.$method(elem, $($extra_args,)*)
258 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
259 visitor.visit_name(ident.span, ident.name);
262 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
263 walk_list!(visitor, visit_item, &krate.items);
264 walk_list!(visitor, visit_attribute, &krate.attrs);
267 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
268 for attr in local.attrs.iter() {
269 visitor.visit_attribute(attr);
271 visitor.visit_pat(&local.pat);
272 walk_list!(visitor, visit_ty, &local.ty);
273 if let Some((init, els)) = local.kind.init_else_opt() {
274 visitor.visit_expr(init);
275 walk_list!(visitor, visit_block, els);
279 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
280 visitor.visit_ident(label.ident);
283 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
284 visitor.visit_ident(lifetime.ident);
287 pub fn walk_poly_trait_ref<'a, V>(
289 trait_ref: &'a PolyTraitRef,
290 _: &TraitBoundModifier,
294 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
295 visitor.visit_trait_ref(&trait_ref.trait_ref);
298 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
299 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
302 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
303 visitor.visit_vis(&item.vis);
304 visitor.visit_ident(item.ident);
306 ItemKind::ExternCrate(orig_name) => {
307 if let Some(orig_name) = orig_name {
308 visitor.visit_name(item.span, orig_name);
311 ItemKind::Use(ref use_tree) => visitor.visit_use_tree(use_tree, item.id, false),
312 ItemKind::Static(ref typ, _, ref expr) | ItemKind::Const(_, ref typ, ref expr) => {
313 visitor.visit_ty(typ);
314 walk_list!(visitor, visit_expr, expr);
316 ItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
318 FnKind::Fn(FnCtxt::Free, item.ident, sig, &item.vis, generics, body.as_deref());
319 visitor.visit_fn(kind, item.span, item.id)
321 ItemKind::Mod(_unsafety, ref mod_kind) => match mod_kind {
322 ModKind::Loaded(items, _inline, _inner_span) => {
323 walk_list!(visitor, visit_item, items)
325 ModKind::Unloaded => {}
327 ItemKind::ForeignMod(ref foreign_module) => {
328 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
330 ItemKind::GlobalAsm(ref asm) => walk_inline_asm(visitor, asm),
331 ItemKind::TyAlias(box TyAlias { ref generics, ref bounds, ref ty, .. }) => {
332 visitor.visit_generics(generics);
333 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
334 walk_list!(visitor, visit_ty, ty);
336 ItemKind::Enum(ref enum_definition, ref generics) => {
337 visitor.visit_generics(generics);
338 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
340 ItemKind::Impl(box Impl {
350 visitor.visit_generics(generics);
351 walk_list!(visitor, visit_trait_ref, of_trait);
352 visitor.visit_ty(self_ty);
353 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Impl);
355 ItemKind::Struct(ref struct_definition, ref generics)
356 | ItemKind::Union(ref struct_definition, ref generics) => {
357 visitor.visit_generics(generics);
358 visitor.visit_variant_data(struct_definition);
360 ItemKind::Trait(box Trait {
367 visitor.visit_generics(generics);
368 walk_list!(visitor, visit_param_bound, bounds, BoundKind::SuperTraits);
369 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Trait);
371 ItemKind::TraitAlias(ref generics, ref bounds) => {
372 visitor.visit_generics(generics);
373 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
375 ItemKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
376 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
378 walk_list!(visitor, visit_attribute, &item.attrs);
381 pub fn walk_enum_def<'a, V: Visitor<'a>>(
383 enum_definition: &'a EnumDef,
387 walk_list!(visitor, visit_variant, &enum_definition.variants);
390 pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
394 visitor.visit_ident(variant.ident);
395 visitor.visit_vis(&variant.vis);
396 visitor.visit_variant_data(&variant.data);
397 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
398 walk_list!(visitor, visit_attribute, &variant.attrs);
401 pub fn walk_expr_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a ExprField) {
402 visitor.visit_expr(&f.expr);
403 visitor.visit_ident(f.ident);
404 walk_list!(visitor, visit_attribute, f.attrs.iter());
407 pub fn walk_pat_field<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a PatField) {
408 visitor.visit_ident(fp.ident);
409 visitor.visit_pat(&fp.pat);
410 walk_list!(visitor, visit_attribute, fp.attrs.iter());
413 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
415 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => visitor.visit_ty(ty),
416 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
417 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
418 walk_list!(visitor, visit_lifetime, opt_lifetime);
419 visitor.visit_ty(&mutable_type.ty)
421 TyKind::Tup(ref tuple_element_types) => {
422 walk_list!(visitor, visit_ty, tuple_element_types);
424 TyKind::BareFn(ref function_declaration) => {
425 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
426 walk_fn_decl(visitor, &function_declaration.decl);
428 TyKind::Path(ref maybe_qself, ref path) => {
429 if let Some(ref qself) = *maybe_qself {
430 visitor.visit_ty(&qself.ty);
432 visitor.visit_path(path, typ.id);
434 TyKind::Array(ref ty, ref length) => {
435 visitor.visit_ty(ty);
436 visitor.visit_anon_const(length)
438 TyKind::TraitObject(ref bounds, ..) => {
439 walk_list!(visitor, visit_param_bound, bounds, BoundKind::TraitObject);
441 TyKind::ImplTrait(_, ref bounds) => {
442 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Impl);
444 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
445 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
446 TyKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
447 TyKind::Never | TyKind::CVarArgs => {}
451 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
452 for segment in &path.segments {
453 visitor.visit_path_segment(path.span, segment);
457 pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree, id: NodeId) {
458 visitor.visit_path(&use_tree.prefix, id);
459 match use_tree.kind {
460 UseTreeKind::Simple(rename, ..) => {
461 // The extra IDs are handled during HIR lowering.
462 if let Some(rename) = rename {
463 visitor.visit_ident(rename);
466 UseTreeKind::Glob => {}
467 UseTreeKind::Nested(ref use_trees) => {
468 for &(ref nested_tree, nested_id) in use_trees {
469 visitor.visit_use_tree(nested_tree, nested_id, true);
475 pub fn walk_path_segment<'a, V: Visitor<'a>>(
478 segment: &'a PathSegment,
480 visitor.visit_ident(segment.ident);
481 if let Some(ref args) = segment.args {
482 visitor.visit_generic_args(path_span, args);
486 pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
490 match *generic_args {
491 GenericArgs::AngleBracketed(ref data) => {
492 for arg in &data.args {
494 AngleBracketedArg::Arg(a) => visitor.visit_generic_arg(a),
495 AngleBracketedArg::Constraint(c) => visitor.visit_assoc_constraint(c),
499 GenericArgs::Parenthesized(ref data) => {
500 walk_list!(visitor, visit_ty, &data.inputs);
501 walk_fn_ret_ty(visitor, &data.output);
506 pub fn walk_generic_arg<'a, V>(visitor: &mut V, generic_arg: &'a GenericArg)
511 GenericArg::Lifetime(lt) => visitor.visit_lifetime(lt),
512 GenericArg::Type(ty) => visitor.visit_ty(ty),
513 GenericArg::Const(ct) => visitor.visit_anon_const(ct),
517 pub fn walk_assoc_constraint<'a, V: Visitor<'a>>(visitor: &mut V, constraint: &'a AssocConstraint) {
518 visitor.visit_ident(constraint.ident);
519 if let Some(ref gen_args) = constraint.gen_args {
520 visitor.visit_generic_args(gen_args.span(), gen_args);
522 match constraint.kind {
523 AssocConstraintKind::Equality { ref term } => match term {
524 Term::Ty(ty) => visitor.visit_ty(ty),
525 Term::Const(c) => visitor.visit_anon_const(c),
527 AssocConstraintKind::Bound { ref bounds } => {
528 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
533 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
535 PatKind::TupleStruct(ref opt_qself, ref path, ref elems) => {
536 if let Some(ref qself) = *opt_qself {
537 visitor.visit_ty(&qself.ty);
539 visitor.visit_path(path, pattern.id);
540 walk_list!(visitor, visit_pat, elems);
542 PatKind::Path(ref opt_qself, ref path) => {
543 if let Some(ref qself) = *opt_qself {
544 visitor.visit_ty(&qself.ty);
546 visitor.visit_path(path, pattern.id)
548 PatKind::Struct(ref opt_qself, ref path, ref fields, _) => {
549 if let Some(ref qself) = *opt_qself {
550 visitor.visit_ty(&qself.ty);
552 visitor.visit_path(path, pattern.id);
553 walk_list!(visitor, visit_pat_field, fields);
555 PatKind::Box(ref subpattern)
556 | PatKind::Ref(ref subpattern, _)
557 | PatKind::Paren(ref subpattern) => visitor.visit_pat(subpattern),
558 PatKind::Ident(_, ident, ref optional_subpattern) => {
559 visitor.visit_ident(ident);
560 walk_list!(visitor, visit_pat, optional_subpattern);
562 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
563 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
564 walk_list!(visitor, visit_expr, lower_bound);
565 walk_list!(visitor, visit_expr, upper_bound);
567 PatKind::Wild | PatKind::Rest => {}
568 PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
569 walk_list!(visitor, visit_pat, elems);
571 PatKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
575 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a ForeignItem) {
576 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
577 visitor.visit_vis(vis);
578 visitor.visit_ident(ident);
579 walk_list!(visitor, visit_attribute, attrs);
581 ForeignItemKind::Static(ty, _, expr) => {
582 visitor.visit_ty(ty);
583 walk_list!(visitor, visit_expr, expr);
585 ForeignItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
586 let kind = FnKind::Fn(FnCtxt::Foreign, ident, sig, vis, generics, body.as_deref());
587 visitor.visit_fn(kind, span, id);
589 ForeignItemKind::TyAlias(box TyAlias { generics, bounds, ty, .. }) => {
590 visitor.visit_generics(generics);
591 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
592 walk_list!(visitor, visit_ty, ty);
594 ForeignItemKind::MacCall(mac) => {
595 visitor.visit_mac_call(mac);
600 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
602 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
603 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
607 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
608 visitor.visit_ident(param.ident);
609 walk_list!(visitor, visit_attribute, param.attrs.iter());
610 walk_list!(visitor, visit_param_bound, ¶m.bounds, BoundKind::Bound);
612 GenericParamKind::Lifetime => (),
613 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
614 GenericParamKind::Const { ref ty, ref default, .. } => {
615 visitor.visit_ty(ty);
616 if let Some(default) = default {
617 visitor.visit_anon_const(default);
623 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
624 walk_list!(visitor, visit_generic_param, &generics.params);
625 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
628 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
630 WherePredicate::BoundPredicate(WhereBoundPredicate {
633 ref bound_generic_params,
636 visitor.visit_ty(bounded_ty);
637 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
638 walk_list!(visitor, visit_generic_param, bound_generic_params);
640 WherePredicate::RegionPredicate(WhereRegionPredicate {
641 ref lifetime, ref bounds, ..
643 visitor.visit_lifetime(lifetime);
644 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
646 WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
647 visitor.visit_ty(lhs_ty);
648 visitor.visit_ty(rhs_ty);
653 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FnRetTy) {
654 if let FnRetTy::Ty(ref output_ty) = *ret_ty {
655 visitor.visit_ty(output_ty)
659 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
660 for param in &function_declaration.inputs {
661 visitor.visit_param(param);
663 visitor.visit_fn_ret_ty(&function_declaration.output);
666 pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Span) {
668 FnKind::Fn(_, _, sig, _, generics, body) => {
669 visitor.visit_generics(generics);
670 visitor.visit_fn_header(&sig.header);
671 walk_fn_decl(visitor, &sig.decl);
672 walk_list!(visitor, visit_block, body);
674 FnKind::Closure(decl, body) => {
675 walk_fn_decl(visitor, decl);
676 visitor.visit_expr(body);
681 pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem, ctxt: AssocCtxt) {
682 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
683 visitor.visit_vis(vis);
684 visitor.visit_ident(ident);
685 walk_list!(visitor, visit_attribute, attrs);
687 AssocItemKind::Const(_, ty, expr) => {
688 visitor.visit_ty(ty);
689 walk_list!(visitor, visit_expr, expr);
691 AssocItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
692 let kind = FnKind::Fn(FnCtxt::Assoc(ctxt), ident, sig, vis, generics, body.as_deref());
693 visitor.visit_fn(kind, span, id);
695 AssocItemKind::TyAlias(box TyAlias { generics, bounds, ty, .. }) => {
696 visitor.visit_generics(generics);
697 walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
698 walk_list!(visitor, visit_ty, ty);
700 AssocItemKind::MacCall(mac) => {
701 visitor.visit_mac_call(mac);
706 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
707 walk_list!(visitor, visit_field_def, struct_definition.fields());
710 pub fn walk_field_def<'a, V: Visitor<'a>>(visitor: &mut V, field: &'a FieldDef) {
711 visitor.visit_vis(&field.vis);
712 if let Some(ident) = field.ident {
713 visitor.visit_ident(ident);
715 visitor.visit_ty(&field.ty);
716 walk_list!(visitor, visit_attribute, &field.attrs);
719 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
720 walk_list!(visitor, visit_stmt, &block.stmts);
723 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
724 match statement.kind {
725 StmtKind::Local(ref local) => visitor.visit_local(local),
726 StmtKind::Item(ref item) => visitor.visit_item(item),
727 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => visitor.visit_expr(expr),
728 StmtKind::Empty => {}
729 StmtKind::MacCall(ref mac) => {
730 let MacCallStmt { ref mac, style: _, ref attrs, tokens: _ } = **mac;
731 visitor.visit_mac_call(mac);
732 for attr in attrs.iter() {
733 visitor.visit_attribute(attr);
739 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a MacCall) {
740 visitor.visit_path(&mac.path, DUMMY_NODE_ID);
743 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
744 visitor.visit_expr(&constant.value);
747 pub fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm) {
748 for (op, _) in &asm.operands {
750 InlineAsmOperand::In { expr, .. }
751 | InlineAsmOperand::Out { expr: Some(expr), .. }
752 | InlineAsmOperand::InOut { expr, .. } => visitor.visit_expr(expr),
753 InlineAsmOperand::Out { expr: None, .. } => {}
754 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
755 visitor.visit_expr(in_expr);
756 if let Some(out_expr) = out_expr {
757 visitor.visit_expr(out_expr);
760 InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),
761 InlineAsmOperand::Sym { sym } => visitor.visit_inline_asm_sym(sym),
766 pub fn walk_inline_asm_sym<'a, V: Visitor<'a>>(visitor: &mut V, sym: &'a InlineAsmSym) {
767 if let Some(ref qself) = sym.qself {
768 visitor.visit_ty(&qself.ty);
770 visitor.visit_path(&sym.path, sym.id);
773 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
774 walk_list!(visitor, visit_attribute, expression.attrs.iter());
776 match expression.kind {
777 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
778 ExprKind::Array(ref subexpressions) => {
779 walk_list!(visitor, visit_expr, subexpressions);
781 ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
782 ExprKind::Repeat(ref element, ref count) => {
783 visitor.visit_expr(element);
784 visitor.visit_anon_const(count)
786 ExprKind::Struct(ref se) => {
787 if let Some(ref qself) = se.qself {
788 visitor.visit_ty(&qself.ty);
790 visitor.visit_path(&se.path, expression.id);
791 walk_list!(visitor, visit_expr_field, &se.fields);
793 StructRest::Base(expr) => visitor.visit_expr(expr),
794 StructRest::Rest(_span) => {}
795 StructRest::None => {}
798 ExprKind::Tup(ref subexpressions) => {
799 walk_list!(visitor, visit_expr, subexpressions);
801 ExprKind::Call(ref callee_expression, ref arguments) => {
802 visitor.visit_expr(callee_expression);
803 walk_list!(visitor, visit_expr, arguments);
805 ExprKind::MethodCall(ref segment, ref arguments, _span) => {
806 visitor.visit_path_segment(expression.span, segment);
807 walk_list!(visitor, visit_expr, arguments);
809 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
810 visitor.visit_expr(left_expression);
811 visitor.visit_expr(right_expression)
813 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
814 visitor.visit_expr(subexpression)
816 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
817 visitor.visit_expr(subexpression);
818 visitor.visit_ty(typ)
820 ExprKind::Let(ref pat, ref expr, _) => {
821 visitor.visit_pat(pat);
822 visitor.visit_expr(expr);
824 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
825 visitor.visit_expr(head_expression);
826 visitor.visit_block(if_block);
827 walk_list!(visitor, visit_expr, optional_else);
829 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
830 walk_list!(visitor, visit_label, opt_label);
831 visitor.visit_expr(subexpression);
832 visitor.visit_block(block);
834 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
835 walk_list!(visitor, visit_label, opt_label);
836 visitor.visit_pat(pattern);
837 visitor.visit_expr(subexpression);
838 visitor.visit_block(block);
840 ExprKind::Loop(ref block, ref opt_label) => {
841 walk_list!(visitor, visit_label, opt_label);
842 visitor.visit_block(block);
844 ExprKind::Match(ref subexpression, ref arms) => {
845 visitor.visit_expr(subexpression);
846 walk_list!(visitor, visit_arm, arms);
848 ExprKind::Closure(_, _, _, ref decl, ref body, _decl_span) => {
849 visitor.visit_fn(FnKind::Closure(decl, body), expression.span, expression.id)
851 ExprKind::Block(ref block, ref opt_label) => {
852 walk_list!(visitor, visit_label, opt_label);
853 visitor.visit_block(block);
855 ExprKind::Async(_, _, ref body) => {
856 visitor.visit_block(body);
858 ExprKind::Await(ref expr) => visitor.visit_expr(expr),
859 ExprKind::Assign(ref lhs, ref rhs, _) => {
860 visitor.visit_expr(lhs);
861 visitor.visit_expr(rhs);
863 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
864 visitor.visit_expr(left_expression);
865 visitor.visit_expr(right_expression);
867 ExprKind::Field(ref subexpression, ident) => {
868 visitor.visit_expr(subexpression);
869 visitor.visit_ident(ident);
871 ExprKind::Index(ref main_expression, ref index_expression) => {
872 visitor.visit_expr(main_expression);
873 visitor.visit_expr(index_expression)
875 ExprKind::Range(ref start, ref end, _) => {
876 walk_list!(visitor, visit_expr, start);
877 walk_list!(visitor, visit_expr, end);
879 ExprKind::Underscore => {}
880 ExprKind::Path(ref maybe_qself, ref path) => {
881 if let Some(ref qself) = *maybe_qself {
882 visitor.visit_ty(&qself.ty);
884 visitor.visit_path(path, expression.id)
886 ExprKind::Break(ref opt_label, ref opt_expr) => {
887 walk_list!(visitor, visit_label, opt_label);
888 walk_list!(visitor, visit_expr, opt_expr);
890 ExprKind::Continue(ref opt_label) => {
891 walk_list!(visitor, visit_label, opt_label);
893 ExprKind::Ret(ref optional_expression) => {
894 walk_list!(visitor, visit_expr, optional_expression);
896 ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
897 ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
898 ExprKind::InlineAsm(ref asm) => walk_inline_asm(visitor, asm),
899 ExprKind::Yield(ref optional_expression) => {
900 walk_list!(visitor, visit_expr, optional_expression);
902 ExprKind::Try(ref subexpression) => visitor.visit_expr(subexpression),
903 ExprKind::TryBlock(ref body) => visitor.visit_block(body),
904 ExprKind::Lit(_) | ExprKind::Err => {}
907 visitor.visit_expr_post(expression)
910 pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
911 walk_list!(visitor, visit_attribute, param.attrs.iter());
912 visitor.visit_pat(¶m.pat);
913 visitor.visit_ty(¶m.ty);
916 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
917 visitor.visit_pat(&arm.pat);
918 walk_list!(visitor, visit_expr, &arm.guard);
919 visitor.visit_expr(&arm.body);
920 walk_list!(visitor, visit_attribute, &arm.attrs);
923 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
924 if let VisibilityKind::Restricted { ref path, id } = vis.kind {
925 visitor.visit_path(path, id);
929 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
931 AttrKind::Normal(ref item, ref _tokens) => walk_mac_args(visitor, &item.args),
932 AttrKind::DocComment(..) => {}
936 pub fn walk_mac_args<'a, V: Visitor<'a>>(visitor: &mut V, args: &'a MacArgs) {
939 MacArgs::Delimited(_dspan, _delim, _tokens) => {}
940 // The value in `#[key = VALUE]` must be visited as an expression for backward
941 // compatibility, so that macros can be expanded in that position.
942 MacArgs::Eq(_eq_span, token) => match &token.kind {
943 token::Interpolated(nt) => match &**nt {
944 token::NtExpr(expr) => visitor.visit_expr(expr),
945 t => panic!("unexpected token in key-value attribute: {:?}", t),
947 t => panic!("unexpected token in key-value attribute: {:?}", t),