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 /// E.g., `fn foo()`, `fn foo(&self)`, or `extern "Abi" fn foo()`.
38 Fn(FnCtxt, Ident, &'a FnSig, &'a Visibility, Option<&'a Block>),
40 /// E.g., `|x, y| body`.
41 Closure(&'a FnDecl, &'a Expr),
45 pub fn header(&self) -> Option<&'a FnHeader> {
47 FnKind::Fn(_, _, sig, _, _) => Some(&sig.header),
48 FnKind::Closure(_, _) => None,
52 pub fn ident(&self) -> Option<&Ident> {
54 FnKind::Fn(_, ident, ..) => Some(ident),
59 pub fn decl(&self) -> &'a FnDecl {
61 FnKind::Fn(_, _, sig, _, _) => &sig.decl,
62 FnKind::Closure(decl, _) => decl,
66 pub fn ctxt(&self) -> Option<FnCtxt> {
68 FnKind::Fn(ctxt, ..) => Some(*ctxt),
69 FnKind::Closure(..) => None,
74 /// Each method of the `Visitor` trait is a hook to be potentially
75 /// overridden. Each method's default implementation recursively visits
76 /// the substructure of the input via the corresponding `walk` method;
77 /// e.g., the `visit_item` method by default calls `visit::walk_item`.
79 /// If you want to ensure that your code handles every variant
80 /// explicitly, you need to override each method. (And you also need
81 /// to monitor future changes to `Visitor` in case a new method with a
82 /// new default implementation gets introduced.)
83 pub trait Visitor<'ast>: Sized {
84 fn visit_name(&mut self, _span: Span, _name: Symbol) {
87 fn visit_ident(&mut self, ident: Ident) {
88 walk_ident(self, ident);
90 fn visit_foreign_item(&mut self, i: &'ast ForeignItem) {
91 walk_foreign_item(self, i)
93 fn visit_item(&mut self, i: &'ast Item) {
96 fn visit_local(&mut self, l: &'ast Local) {
99 fn visit_block(&mut self, b: &'ast Block) {
102 fn visit_stmt(&mut self, s: &'ast Stmt) {
105 fn visit_param(&mut self, param: &'ast Param) {
106 walk_param(self, param)
108 fn visit_arm(&mut self, a: &'ast Arm) {
111 fn visit_pat(&mut self, p: &'ast Pat) {
114 fn visit_anon_const(&mut self, c: &'ast AnonConst) {
115 walk_anon_const(self, c)
117 fn visit_expr(&mut self, ex: &'ast Expr) {
120 fn visit_expr_post(&mut self, _ex: &'ast Expr) {}
121 fn visit_ty(&mut self, t: &'ast Ty) {
124 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
125 walk_generic_param(self, param)
127 fn visit_generics(&mut self, g: &'ast Generics) {
128 walk_generics(self, g)
130 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
131 walk_where_predicate(self, p)
133 fn visit_fn(&mut self, fk: FnKind<'ast>, s: Span, _: NodeId) {
136 fn visit_assoc_item(&mut self, i: &'ast AssocItem, ctxt: AssocCtxt) {
137 walk_assoc_item(self, i, ctxt)
139 fn visit_trait_ref(&mut self, t: &'ast TraitRef) {
140 walk_trait_ref(self, t)
142 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
143 walk_param_bound(self, bounds)
145 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
146 walk_poly_trait_ref(self, t, m)
148 fn visit_variant_data(&mut self, s: &'ast VariantData) {
149 walk_struct_def(self, s)
151 fn visit_field_def(&mut self, s: &'ast FieldDef) {
152 walk_field_def(self, s)
156 enum_definition: &'ast EnumDef,
157 generics: &'ast Generics,
161 walk_enum_def(self, enum_definition, generics, item_id)
163 fn visit_variant(&mut self, v: &'ast Variant) {
164 walk_variant(self, v)
166 fn visit_label(&mut self, label: &'ast Label) {
167 walk_label(self, label)
169 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
170 walk_lifetime(self, lifetime)
172 fn visit_mac_call(&mut self, mac: &'ast MacCall) {
175 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
178 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
179 walk_path(self, path)
181 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
182 walk_use_tree(self, use_tree, id)
184 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
185 walk_path_segment(self, path_span, path_segment)
187 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
188 walk_generic_args(self, path_span, generic_args)
190 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
191 walk_generic_arg(self, generic_arg)
193 fn visit_assoc_ty_constraint(&mut self, constraint: &'ast AssocTyConstraint) {
194 walk_assoc_ty_constraint(self, constraint)
196 fn visit_attribute(&mut self, attr: &'ast Attribute) {
197 walk_attribute(self, attr)
199 fn visit_vis(&mut self, vis: &'ast Visibility) {
202 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FnRetTy) {
203 walk_fn_ret_ty(self, ret_ty)
205 fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
208 fn visit_expr_field(&mut self, f: &'ast ExprField) {
209 walk_expr_field(self, f)
211 fn visit_pat_field(&mut self, fp: &'ast PatField) {
212 walk_pat_field(self, fp)
217 macro_rules! walk_list {
218 ($visitor: expr, $method: ident, $list: expr) => {
220 $visitor.$method(elem)
223 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
225 $visitor.$method(elem, $($extra_args,)*)
230 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
231 visitor.visit_name(ident.span, ident.name);
234 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
235 walk_list!(visitor, visit_item, &krate.items);
236 walk_list!(visitor, visit_attribute, &krate.attrs);
239 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
240 for attr in local.attrs.iter() {
241 visitor.visit_attribute(attr);
243 visitor.visit_pat(&local.pat);
244 walk_list!(visitor, visit_ty, &local.ty);
245 if let Some((init, els)) = local.kind.init_else_opt() {
246 visitor.visit_expr(init);
247 walk_list!(visitor, visit_block, els);
251 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
252 visitor.visit_ident(label.ident);
255 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
256 visitor.visit_ident(lifetime.ident);
259 pub fn walk_poly_trait_ref<'a, V>(
261 trait_ref: &'a PolyTraitRef,
262 _: &TraitBoundModifier,
266 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
267 visitor.visit_trait_ref(&trait_ref.trait_ref);
270 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
271 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
274 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
275 visitor.visit_vis(&item.vis);
276 visitor.visit_ident(item.ident);
278 ItemKind::ExternCrate(orig_name) => {
279 if let Some(orig_name) = orig_name {
280 visitor.visit_name(item.span, orig_name);
283 ItemKind::Use(ref use_tree) => visitor.visit_use_tree(use_tree, item.id, false),
284 ItemKind::Static(ref typ, _, ref expr) | ItemKind::Const(_, ref typ, ref expr) => {
285 visitor.visit_ty(typ);
286 walk_list!(visitor, visit_expr, expr);
288 ItemKind::Fn(box FnKind(_, ref sig, ref generics, ref body)) => {
289 visitor.visit_generics(generics);
290 let kind = FnKind::Fn(FnCtxt::Free, item.ident, sig, &item.vis, body.as_deref());
291 visitor.visit_fn(kind, item.span, item.id)
293 ItemKind::Mod(_unsafety, ref mod_kind) => match mod_kind {
294 ModKind::Loaded(items, _inline, _inner_span) => {
295 walk_list!(visitor, visit_item, items)
297 ModKind::Unloaded => {}
299 ItemKind::ForeignMod(ref foreign_module) => {
300 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
302 ItemKind::GlobalAsm(ref asm) => walk_inline_asm(visitor, asm),
303 ItemKind::TyAlias(box TyAliasKind(_, ref generics, ref bounds, ref ty)) => {
304 visitor.visit_generics(generics);
305 walk_list!(visitor, visit_param_bound, bounds);
306 walk_list!(visitor, visit_ty, ty);
308 ItemKind::Enum(ref enum_definition, ref generics) => {
309 visitor.visit_generics(generics);
310 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
312 ItemKind::Impl(box ImplKind {
322 visitor.visit_generics(generics);
323 walk_list!(visitor, visit_trait_ref, of_trait);
324 visitor.visit_ty(self_ty);
325 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Impl);
327 ItemKind::Struct(ref struct_definition, ref generics)
328 | ItemKind::Union(ref struct_definition, ref generics) => {
329 visitor.visit_generics(generics);
330 visitor.visit_variant_data(struct_definition);
332 ItemKind::Trait(box TraitKind(.., ref generics, ref bounds, ref items)) => {
333 visitor.visit_generics(generics);
334 walk_list!(visitor, visit_param_bound, bounds);
335 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Trait);
337 ItemKind::TraitAlias(ref generics, ref bounds) => {
338 visitor.visit_generics(generics);
339 walk_list!(visitor, visit_param_bound, bounds);
341 ItemKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
342 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
344 walk_list!(visitor, visit_attribute, &item.attrs);
347 pub fn walk_enum_def<'a, V: Visitor<'a>>(
349 enum_definition: &'a EnumDef,
353 walk_list!(visitor, visit_variant, &enum_definition.variants);
356 pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
360 visitor.visit_ident(variant.ident);
361 visitor.visit_vis(&variant.vis);
362 visitor.visit_variant_data(&variant.data);
363 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
364 walk_list!(visitor, visit_attribute, &variant.attrs);
367 pub fn walk_expr_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a ExprField) {
368 visitor.visit_expr(&f.expr);
369 visitor.visit_ident(f.ident);
370 walk_list!(visitor, visit_attribute, f.attrs.iter());
373 pub fn walk_pat_field<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a PatField) {
374 visitor.visit_ident(fp.ident);
375 visitor.visit_pat(&fp.pat);
376 walk_list!(visitor, visit_attribute, fp.attrs.iter());
379 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
381 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => visitor.visit_ty(ty),
382 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
383 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
384 walk_list!(visitor, visit_lifetime, opt_lifetime);
385 visitor.visit_ty(&mutable_type.ty)
387 TyKind::Tup(ref tuple_element_types) => {
388 walk_list!(visitor, visit_ty, tuple_element_types);
390 TyKind::BareFn(ref function_declaration) => {
391 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
392 walk_fn_decl(visitor, &function_declaration.decl);
394 TyKind::Path(ref maybe_qself, ref path) => {
395 if let Some(ref qself) = *maybe_qself {
396 visitor.visit_ty(&qself.ty);
398 visitor.visit_path(path, typ.id);
400 TyKind::Array(ref ty, ref length) => {
401 visitor.visit_ty(ty);
402 visitor.visit_anon_const(length)
404 TyKind::TraitObject(ref bounds, ..) | TyKind::ImplTrait(_, ref bounds) => {
405 walk_list!(visitor, visit_param_bound, bounds);
407 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
408 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
409 TyKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
410 TyKind::Never | TyKind::CVarArgs => {}
414 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
415 for segment in &path.segments {
416 visitor.visit_path_segment(path.span, segment);
420 pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree, id: NodeId) {
421 visitor.visit_path(&use_tree.prefix, id);
422 match use_tree.kind {
423 UseTreeKind::Simple(rename, ..) => {
424 // The extra IDs are handled during HIR lowering.
425 if let Some(rename) = rename {
426 visitor.visit_ident(rename);
429 UseTreeKind::Glob => {}
430 UseTreeKind::Nested(ref use_trees) => {
431 for &(ref nested_tree, nested_id) in use_trees {
432 visitor.visit_use_tree(nested_tree, nested_id, true);
438 pub fn walk_path_segment<'a, V: Visitor<'a>>(
441 segment: &'a PathSegment,
443 visitor.visit_ident(segment.ident);
444 if let Some(ref args) = segment.args {
445 visitor.visit_generic_args(path_span, args);
449 pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
453 match *generic_args {
454 GenericArgs::AngleBracketed(ref data) => {
455 for arg in &data.args {
457 AngleBracketedArg::Arg(a) => visitor.visit_generic_arg(a),
458 AngleBracketedArg::Constraint(c) => visitor.visit_assoc_ty_constraint(c),
462 GenericArgs::Parenthesized(ref data) => {
463 walk_list!(visitor, visit_ty, &data.inputs);
464 walk_fn_ret_ty(visitor, &data.output);
469 pub fn walk_generic_arg<'a, V>(visitor: &mut V, generic_arg: &'a GenericArg)
474 GenericArg::Lifetime(lt) => visitor.visit_lifetime(lt),
475 GenericArg::Type(ty) => visitor.visit_ty(ty),
476 GenericArg::Const(ct) => visitor.visit_anon_const(ct),
480 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(
482 constraint: &'a AssocTyConstraint,
484 visitor.visit_ident(constraint.ident);
485 if let Some(ref gen_args) = constraint.gen_args {
486 visitor.visit_generic_args(gen_args.span(), gen_args);
488 match constraint.kind {
489 AssocTyConstraintKind::Equality { ref ty } => {
490 visitor.visit_ty(ty);
492 AssocTyConstraintKind::Bound { ref bounds } => {
493 walk_list!(visitor, visit_param_bound, bounds);
498 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
500 PatKind::TupleStruct(ref opt_qself, ref path, ref elems) => {
501 if let Some(ref qself) = *opt_qself {
502 visitor.visit_ty(&qself.ty);
504 visitor.visit_path(path, pattern.id);
505 walk_list!(visitor, visit_pat, elems);
507 PatKind::Path(ref opt_qself, ref path) => {
508 if let Some(ref qself) = *opt_qself {
509 visitor.visit_ty(&qself.ty);
511 visitor.visit_path(path, pattern.id)
513 PatKind::Struct(ref opt_qself, ref path, ref fields, _) => {
514 if let Some(ref qself) = *opt_qself {
515 visitor.visit_ty(&qself.ty);
517 visitor.visit_path(path, pattern.id);
518 walk_list!(visitor, visit_pat_field, fields);
520 PatKind::Box(ref subpattern)
521 | PatKind::Ref(ref subpattern, _)
522 | PatKind::Paren(ref subpattern) => visitor.visit_pat(subpattern),
523 PatKind::Ident(_, ident, ref optional_subpattern) => {
524 visitor.visit_ident(ident);
525 walk_list!(visitor, visit_pat, optional_subpattern);
527 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
528 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
529 walk_list!(visitor, visit_expr, lower_bound);
530 walk_list!(visitor, visit_expr, upper_bound);
532 PatKind::Wild | PatKind::Rest => {}
533 PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
534 walk_list!(visitor, visit_pat, elems);
536 PatKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
540 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a ForeignItem) {
541 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
542 visitor.visit_vis(vis);
543 visitor.visit_ident(ident);
544 walk_list!(visitor, visit_attribute, attrs);
546 ForeignItemKind::Static(ty, _, expr) => {
547 visitor.visit_ty(ty);
548 walk_list!(visitor, visit_expr, expr);
550 ForeignItemKind::Fn(box FnKind(_, sig, generics, body)) => {
551 visitor.visit_generics(generics);
552 let kind = FnKind::Fn(FnCtxt::Foreign, ident, sig, vis, body.as_deref());
553 visitor.visit_fn(kind, span, id);
555 ForeignItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
556 visitor.visit_generics(generics);
557 walk_list!(visitor, visit_param_bound, bounds);
558 walk_list!(visitor, visit_ty, ty);
560 ForeignItemKind::MacCall(mac) => {
561 visitor.visit_mac_call(mac);
566 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
568 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
569 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
573 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
574 visitor.visit_ident(param.ident);
575 walk_list!(visitor, visit_attribute, param.attrs.iter());
576 walk_list!(visitor, visit_param_bound, ¶m.bounds);
578 GenericParamKind::Lifetime => (),
579 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
580 GenericParamKind::Const { ref ty, ref default, .. } => {
581 visitor.visit_ty(ty);
582 if let Some(default) = default {
583 visitor.visit_anon_const(default);
589 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
590 walk_list!(visitor, visit_generic_param, &generics.params);
591 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
594 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
596 WherePredicate::BoundPredicate(WhereBoundPredicate {
599 ref bound_generic_params,
602 visitor.visit_ty(bounded_ty);
603 walk_list!(visitor, visit_param_bound, bounds);
604 walk_list!(visitor, visit_generic_param, bound_generic_params);
606 WherePredicate::RegionPredicate(WhereRegionPredicate {
607 ref lifetime, ref bounds, ..
609 visitor.visit_lifetime(lifetime);
610 walk_list!(visitor, visit_param_bound, bounds);
612 WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
613 visitor.visit_ty(lhs_ty);
614 visitor.visit_ty(rhs_ty);
619 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FnRetTy) {
620 if let FnRetTy::Ty(ref output_ty) = *ret_ty {
621 visitor.visit_ty(output_ty)
625 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
626 for param in &function_declaration.inputs {
627 visitor.visit_param(param);
629 visitor.visit_fn_ret_ty(&function_declaration.output);
632 pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Span) {
634 FnKind::Fn(_, _, sig, _, body) => {
635 visitor.visit_fn_header(&sig.header);
636 walk_fn_decl(visitor, &sig.decl);
637 walk_list!(visitor, visit_block, body);
639 FnKind::Closure(decl, body) => {
640 walk_fn_decl(visitor, decl);
641 visitor.visit_expr(body);
646 pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem, ctxt: AssocCtxt) {
647 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
648 visitor.visit_vis(vis);
649 visitor.visit_ident(ident);
650 walk_list!(visitor, visit_attribute, attrs);
652 AssocItemKind::Const(_, ty, expr) => {
653 visitor.visit_ty(ty);
654 walk_list!(visitor, visit_expr, expr);
656 AssocItemKind::Fn(box FnKind(_, sig, generics, body)) => {
657 visitor.visit_generics(generics);
658 let kind = FnKind::Fn(FnCtxt::Assoc(ctxt), ident, sig, vis, body.as_deref());
659 visitor.visit_fn(kind, span, id);
661 AssocItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
662 visitor.visit_generics(generics);
663 walk_list!(visitor, visit_param_bound, bounds);
664 walk_list!(visitor, visit_ty, ty);
666 AssocItemKind::MacCall(mac) => {
667 visitor.visit_mac_call(mac);
672 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
673 walk_list!(visitor, visit_field_def, struct_definition.fields());
676 pub fn walk_field_def<'a, V: Visitor<'a>>(visitor: &mut V, field: &'a FieldDef) {
677 visitor.visit_vis(&field.vis);
678 if let Some(ident) = field.ident {
679 visitor.visit_ident(ident);
681 visitor.visit_ty(&field.ty);
682 walk_list!(visitor, visit_attribute, &field.attrs);
685 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
686 walk_list!(visitor, visit_stmt, &block.stmts);
689 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
690 match statement.kind {
691 StmtKind::Local(ref local) => visitor.visit_local(local),
692 StmtKind::Item(ref item) => visitor.visit_item(item),
693 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => visitor.visit_expr(expr),
694 StmtKind::Empty => {}
695 StmtKind::MacCall(ref mac) => {
696 let MacCallStmt { ref mac, style: _, ref attrs, tokens: _ } = **mac;
697 visitor.visit_mac_call(mac);
698 for attr in attrs.iter() {
699 visitor.visit_attribute(attr);
705 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a MacCall) {
706 visitor.visit_path(&mac.path, DUMMY_NODE_ID);
709 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
710 visitor.visit_expr(&constant.value);
713 fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm) {
714 for (op, _) in &asm.operands {
716 InlineAsmOperand::In { expr, .. }
717 | InlineAsmOperand::Out { expr: Some(expr), .. }
718 | InlineAsmOperand::InOut { expr, .. }
719 | InlineAsmOperand::Sym { expr, .. } => visitor.visit_expr(expr),
720 InlineAsmOperand::Out { expr: None, .. } => {}
721 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
722 visitor.visit_expr(in_expr);
723 if let Some(out_expr) = out_expr {
724 visitor.visit_expr(out_expr);
727 InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),
732 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
733 walk_list!(visitor, visit_attribute, expression.attrs.iter());
735 match expression.kind {
736 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
737 ExprKind::Array(ref subexpressions) => {
738 walk_list!(visitor, visit_expr, subexpressions);
740 ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
741 ExprKind::Repeat(ref element, ref count) => {
742 visitor.visit_expr(element);
743 visitor.visit_anon_const(count)
745 ExprKind::Struct(ref se) => {
746 if let Some(ref qself) = se.qself {
747 visitor.visit_ty(&qself.ty);
749 visitor.visit_path(&se.path, expression.id);
750 walk_list!(visitor, visit_expr_field, &se.fields);
752 StructRest::Base(expr) => visitor.visit_expr(expr),
753 StructRest::Rest(_span) => {}
754 StructRest::None => {}
757 ExprKind::Tup(ref subexpressions) => {
758 walk_list!(visitor, visit_expr, subexpressions);
760 ExprKind::Call(ref callee_expression, ref arguments) => {
761 visitor.visit_expr(callee_expression);
762 walk_list!(visitor, visit_expr, arguments);
764 ExprKind::MethodCall(ref segment, ref arguments, _span) => {
765 visitor.visit_path_segment(expression.span, segment);
766 walk_list!(visitor, visit_expr, arguments);
768 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
769 visitor.visit_expr(left_expression);
770 visitor.visit_expr(right_expression)
772 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
773 visitor.visit_expr(subexpression)
775 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
776 visitor.visit_expr(subexpression);
777 visitor.visit_ty(typ)
779 ExprKind::Let(ref pat, ref expr, _) => {
780 visitor.visit_pat(pat);
781 visitor.visit_expr(expr);
783 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
784 visitor.visit_expr(head_expression);
785 visitor.visit_block(if_block);
786 walk_list!(visitor, visit_expr, optional_else);
788 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
789 walk_list!(visitor, visit_label, opt_label);
790 visitor.visit_expr(subexpression);
791 visitor.visit_block(block);
793 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
794 walk_list!(visitor, visit_label, opt_label);
795 visitor.visit_pat(pattern);
796 visitor.visit_expr(subexpression);
797 visitor.visit_block(block);
799 ExprKind::Loop(ref block, ref opt_label) => {
800 walk_list!(visitor, visit_label, opt_label);
801 visitor.visit_block(block);
803 ExprKind::Match(ref subexpression, ref arms) => {
804 visitor.visit_expr(subexpression);
805 walk_list!(visitor, visit_arm, arms);
807 ExprKind::Closure(_, _, _, ref decl, ref body, _decl_span) => {
808 visitor.visit_fn(FnKind::Closure(decl, body), expression.span, expression.id)
810 ExprKind::Block(ref block, ref opt_label) => {
811 walk_list!(visitor, visit_label, opt_label);
812 visitor.visit_block(block);
814 ExprKind::Async(_, _, ref body) => {
815 visitor.visit_block(body);
817 ExprKind::Await(ref expr) => visitor.visit_expr(expr),
818 ExprKind::Assign(ref lhs, ref rhs, _) => {
819 visitor.visit_expr(lhs);
820 visitor.visit_expr(rhs);
822 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
823 visitor.visit_expr(left_expression);
824 visitor.visit_expr(right_expression);
826 ExprKind::Field(ref subexpression, ident) => {
827 visitor.visit_expr(subexpression);
828 visitor.visit_ident(ident);
830 ExprKind::Index(ref main_expression, ref index_expression) => {
831 visitor.visit_expr(main_expression);
832 visitor.visit_expr(index_expression)
834 ExprKind::Range(ref start, ref end, _) => {
835 walk_list!(visitor, visit_expr, start);
836 walk_list!(visitor, visit_expr, end);
838 ExprKind::Underscore => {}
839 ExprKind::Path(ref maybe_qself, ref path) => {
840 if let Some(ref qself) = *maybe_qself {
841 visitor.visit_ty(&qself.ty);
843 visitor.visit_path(path, expression.id)
845 ExprKind::Break(ref opt_label, ref opt_expr) => {
846 walk_list!(visitor, visit_label, opt_label);
847 walk_list!(visitor, visit_expr, opt_expr);
849 ExprKind::Continue(ref opt_label) => {
850 walk_list!(visitor, visit_label, opt_label);
852 ExprKind::Ret(ref optional_expression) => {
853 walk_list!(visitor, visit_expr, optional_expression);
855 ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
856 ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
857 ExprKind::InlineAsm(ref asm) => walk_inline_asm(visitor, asm),
858 ExprKind::LlvmInlineAsm(ref ia) => {
859 for &(_, ref input) in &ia.inputs {
860 visitor.visit_expr(input)
862 for output in &ia.outputs {
863 visitor.visit_expr(&output.expr)
866 ExprKind::Yield(ref optional_expression) => {
867 walk_list!(visitor, visit_expr, optional_expression);
869 ExprKind::Try(ref subexpression) => visitor.visit_expr(subexpression),
870 ExprKind::TryBlock(ref body) => visitor.visit_block(body),
871 ExprKind::Lit(_) | ExprKind::Err => {}
874 visitor.visit_expr_post(expression)
877 pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
878 walk_list!(visitor, visit_attribute, param.attrs.iter());
879 visitor.visit_pat(¶m.pat);
880 visitor.visit_ty(¶m.ty);
883 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
884 visitor.visit_pat(&arm.pat);
885 walk_list!(visitor, visit_expr, &arm.guard);
886 visitor.visit_expr(&arm.body);
887 walk_list!(visitor, visit_attribute, &arm.attrs);
890 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
891 if let VisibilityKind::Restricted { ref path, id } = vis.kind {
892 visitor.visit_path(path, id);
896 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
898 AttrKind::Normal(ref item, ref _tokens) => walk_mac_args(visitor, &item.args),
899 AttrKind::DocComment(..) => {}
903 pub fn walk_mac_args<'a, V: Visitor<'a>>(visitor: &mut V, args: &'a MacArgs) {
906 MacArgs::Delimited(_dspan, _delim, _tokens) => {}
907 // The value in `#[key = VALUE]` must be visited as an expression for backward
908 // compatibility, so that macros can be expanded in that position.
909 MacArgs::Eq(_eq_span, token) => match &token.kind {
910 token::Interpolated(nt) => match &**nt {
911 token::NtExpr(expr) => visitor.visit_expr(expr),
912 t => panic!("unexpected token in key-value attribute: {:?}", t),
914 t => panic!("unexpected token in key-value attribute: {:?}", t),