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)
214 fn visit_crate(&mut self, krate: &'ast Crate) {
215 walk_crate(self, krate)
220 macro_rules! walk_list {
221 ($visitor: expr, $method: ident, $list: expr) => {
223 $visitor.$method(elem)
226 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
228 $visitor.$method(elem, $($extra_args,)*)
233 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
234 visitor.visit_name(ident.span, ident.name);
237 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
238 walk_list!(visitor, visit_item, &krate.items);
239 walk_list!(visitor, visit_attribute, &krate.attrs);
242 pub fn walk_local<'a, V: Visitor<'a>>(visitor: &mut V, local: &'a Local) {
243 for attr in local.attrs.iter() {
244 visitor.visit_attribute(attr);
246 visitor.visit_pat(&local.pat);
247 walk_list!(visitor, visit_ty, &local.ty);
248 if let Some((init, els)) = local.kind.init_else_opt() {
249 visitor.visit_expr(init);
250 walk_list!(visitor, visit_block, els);
254 pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
255 visitor.visit_ident(label.ident);
258 pub fn walk_lifetime<'a, V: Visitor<'a>>(visitor: &mut V, lifetime: &'a Lifetime) {
259 visitor.visit_ident(lifetime.ident);
262 pub fn walk_poly_trait_ref<'a, V>(
264 trait_ref: &'a PolyTraitRef,
265 _: &TraitBoundModifier,
269 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
270 visitor.visit_trait_ref(&trait_ref.trait_ref);
273 pub fn walk_trait_ref<'a, V: Visitor<'a>>(visitor: &mut V, trait_ref: &'a TraitRef) {
274 visitor.visit_path(&trait_ref.path, trait_ref.ref_id)
277 pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
278 visitor.visit_vis(&item.vis);
279 visitor.visit_ident(item.ident);
281 ItemKind::ExternCrate(orig_name) => {
282 if let Some(orig_name) = orig_name {
283 visitor.visit_name(item.span, orig_name);
286 ItemKind::Use(ref use_tree) => visitor.visit_use_tree(use_tree, item.id, false),
287 ItemKind::Static(ref typ, _, ref expr) | ItemKind::Const(_, ref typ, ref expr) => {
288 visitor.visit_ty(typ);
289 walk_list!(visitor, visit_expr, expr);
291 ItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
292 visitor.visit_generics(generics);
293 let kind = FnKind::Fn(FnCtxt::Free, item.ident, sig, &item.vis, body.as_deref());
294 visitor.visit_fn(kind, item.span, item.id)
296 ItemKind::Mod(_unsafety, ref mod_kind) => match mod_kind {
297 ModKind::Loaded(items, _inline, _inner_span) => {
298 walk_list!(visitor, visit_item, items)
300 ModKind::Unloaded => {}
302 ItemKind::ForeignMod(ref foreign_module) => {
303 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
305 ItemKind::GlobalAsm(ref asm) => walk_inline_asm(visitor, asm),
306 ItemKind::TyAlias(box TyAlias { defaultness: _, ref generics, ref bounds, ref ty }) => {
307 visitor.visit_generics(generics);
308 walk_list!(visitor, visit_param_bound, bounds);
309 walk_list!(visitor, visit_ty, ty);
311 ItemKind::Enum(ref enum_definition, ref generics) => {
312 visitor.visit_generics(generics);
313 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
315 ItemKind::Impl(box Impl {
325 visitor.visit_generics(generics);
326 walk_list!(visitor, visit_trait_ref, of_trait);
327 visitor.visit_ty(self_ty);
328 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Impl);
330 ItemKind::Struct(ref struct_definition, ref generics)
331 | ItemKind::Union(ref struct_definition, ref generics) => {
332 visitor.visit_generics(generics);
333 visitor.visit_variant_data(struct_definition);
335 ItemKind::Trait(box Trait {
342 visitor.visit_generics(generics);
343 walk_list!(visitor, visit_param_bound, bounds);
344 walk_list!(visitor, visit_assoc_item, items, AssocCtxt::Trait);
346 ItemKind::TraitAlias(ref generics, ref bounds) => {
347 visitor.visit_generics(generics);
348 walk_list!(visitor, visit_param_bound, bounds);
350 ItemKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
351 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
353 walk_list!(visitor, visit_attribute, &item.attrs);
356 pub fn walk_enum_def<'a, V: Visitor<'a>>(
358 enum_definition: &'a EnumDef,
362 walk_list!(visitor, visit_variant, &enum_definition.variants);
365 pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
369 visitor.visit_ident(variant.ident);
370 visitor.visit_vis(&variant.vis);
371 visitor.visit_variant_data(&variant.data);
372 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
373 walk_list!(visitor, visit_attribute, &variant.attrs);
376 pub fn walk_expr_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a ExprField) {
377 visitor.visit_expr(&f.expr);
378 visitor.visit_ident(f.ident);
379 walk_list!(visitor, visit_attribute, f.attrs.iter());
382 pub fn walk_pat_field<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a PatField) {
383 visitor.visit_ident(fp.ident);
384 visitor.visit_pat(&fp.pat);
385 walk_list!(visitor, visit_attribute, fp.attrs.iter());
388 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
390 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => visitor.visit_ty(ty),
391 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
392 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
393 walk_list!(visitor, visit_lifetime, opt_lifetime);
394 visitor.visit_ty(&mutable_type.ty)
396 TyKind::Tup(ref tuple_element_types) => {
397 walk_list!(visitor, visit_ty, tuple_element_types);
399 TyKind::BareFn(ref function_declaration) => {
400 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
401 walk_fn_decl(visitor, &function_declaration.decl);
403 TyKind::Path(ref maybe_qself, ref path) => {
404 if let Some(ref qself) = *maybe_qself {
405 visitor.visit_ty(&qself.ty);
407 visitor.visit_path(path, typ.id);
409 TyKind::Array(ref ty, ref length) => {
410 visitor.visit_ty(ty);
411 visitor.visit_anon_const(length)
413 TyKind::TraitObject(ref bounds, ..) | TyKind::ImplTrait(_, ref bounds) => {
414 walk_list!(visitor, visit_param_bound, bounds);
416 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
417 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
418 TyKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
419 TyKind::Never | TyKind::CVarArgs => {}
423 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
424 for segment in &path.segments {
425 visitor.visit_path_segment(path.span, segment);
429 pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree, id: NodeId) {
430 visitor.visit_path(&use_tree.prefix, id);
431 match use_tree.kind {
432 UseTreeKind::Simple(rename, ..) => {
433 // The extra IDs are handled during HIR lowering.
434 if let Some(rename) = rename {
435 visitor.visit_ident(rename);
438 UseTreeKind::Glob => {}
439 UseTreeKind::Nested(ref use_trees) => {
440 for &(ref nested_tree, nested_id) in use_trees {
441 visitor.visit_use_tree(nested_tree, nested_id, true);
447 pub fn walk_path_segment<'a, V: Visitor<'a>>(
450 segment: &'a PathSegment,
452 visitor.visit_ident(segment.ident);
453 if let Some(ref args) = segment.args {
454 visitor.visit_generic_args(path_span, args);
458 pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
462 match *generic_args {
463 GenericArgs::AngleBracketed(ref data) => {
464 for arg in &data.args {
466 AngleBracketedArg::Arg(a) => visitor.visit_generic_arg(a),
467 AngleBracketedArg::Constraint(c) => visitor.visit_assoc_ty_constraint(c),
471 GenericArgs::Parenthesized(ref data) => {
472 walk_list!(visitor, visit_ty, &data.inputs);
473 walk_fn_ret_ty(visitor, &data.output);
478 pub fn walk_generic_arg<'a, V>(visitor: &mut V, generic_arg: &'a GenericArg)
483 GenericArg::Lifetime(lt) => visitor.visit_lifetime(lt),
484 GenericArg::Type(ty) => visitor.visit_ty(ty),
485 GenericArg::Const(ct) => visitor.visit_anon_const(ct),
489 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(
491 constraint: &'a AssocTyConstraint,
493 visitor.visit_ident(constraint.ident);
494 if let Some(ref gen_args) = constraint.gen_args {
495 visitor.visit_generic_args(gen_args.span(), gen_args);
497 match constraint.kind {
498 AssocTyConstraintKind::Equality { ref ty } => {
499 visitor.visit_ty(ty);
501 AssocTyConstraintKind::Bound { ref bounds } => {
502 walk_list!(visitor, visit_param_bound, bounds);
507 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
509 PatKind::TupleStruct(ref opt_qself, ref path, ref elems) => {
510 if let Some(ref qself) = *opt_qself {
511 visitor.visit_ty(&qself.ty);
513 visitor.visit_path(path, pattern.id);
514 walk_list!(visitor, visit_pat, elems);
516 PatKind::Path(ref opt_qself, ref path) => {
517 if let Some(ref qself) = *opt_qself {
518 visitor.visit_ty(&qself.ty);
520 visitor.visit_path(path, pattern.id)
522 PatKind::Struct(ref opt_qself, ref path, ref fields, _) => {
523 if let Some(ref qself) = *opt_qself {
524 visitor.visit_ty(&qself.ty);
526 visitor.visit_path(path, pattern.id);
527 walk_list!(visitor, visit_pat_field, fields);
529 PatKind::Box(ref subpattern)
530 | PatKind::Ref(ref subpattern, _)
531 | PatKind::Paren(ref subpattern) => visitor.visit_pat(subpattern),
532 PatKind::Ident(_, ident, ref optional_subpattern) => {
533 visitor.visit_ident(ident);
534 walk_list!(visitor, visit_pat, optional_subpattern);
536 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
537 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
538 walk_list!(visitor, visit_expr, lower_bound);
539 walk_list!(visitor, visit_expr, upper_bound);
541 PatKind::Wild | PatKind::Rest => {}
542 PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
543 walk_list!(visitor, visit_pat, elems);
545 PatKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
549 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a ForeignItem) {
550 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
551 visitor.visit_vis(vis);
552 visitor.visit_ident(ident);
553 walk_list!(visitor, visit_attribute, attrs);
555 ForeignItemKind::Static(ty, _, expr) => {
556 visitor.visit_ty(ty);
557 walk_list!(visitor, visit_expr, expr);
559 ForeignItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
560 visitor.visit_generics(generics);
561 let kind = FnKind::Fn(FnCtxt::Foreign, ident, sig, vis, body.as_deref());
562 visitor.visit_fn(kind, span, id);
564 ForeignItemKind::TyAlias(box TyAlias { defaultness: _, generics, bounds, ty }) => {
565 visitor.visit_generics(generics);
566 walk_list!(visitor, visit_param_bound, bounds);
567 walk_list!(visitor, visit_ty, ty);
569 ForeignItemKind::MacCall(mac) => {
570 visitor.visit_mac_call(mac);
575 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
577 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
578 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
582 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
583 visitor.visit_ident(param.ident);
584 walk_list!(visitor, visit_attribute, param.attrs.iter());
585 walk_list!(visitor, visit_param_bound, ¶m.bounds);
587 GenericParamKind::Lifetime => (),
588 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
589 GenericParamKind::Const { ref ty, ref default, .. } => {
590 visitor.visit_ty(ty);
591 if let Some(default) = default {
592 visitor.visit_anon_const(default);
598 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
599 walk_list!(visitor, visit_generic_param, &generics.params);
600 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
603 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
605 WherePredicate::BoundPredicate(WhereBoundPredicate {
608 ref bound_generic_params,
611 visitor.visit_ty(bounded_ty);
612 walk_list!(visitor, visit_param_bound, bounds);
613 walk_list!(visitor, visit_generic_param, bound_generic_params);
615 WherePredicate::RegionPredicate(WhereRegionPredicate {
616 ref lifetime, ref bounds, ..
618 visitor.visit_lifetime(lifetime);
619 walk_list!(visitor, visit_param_bound, bounds);
621 WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
622 visitor.visit_ty(lhs_ty);
623 visitor.visit_ty(rhs_ty);
628 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FnRetTy) {
629 if let FnRetTy::Ty(ref output_ty) = *ret_ty {
630 visitor.visit_ty(output_ty)
634 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
635 for param in &function_declaration.inputs {
636 visitor.visit_param(param);
638 visitor.visit_fn_ret_ty(&function_declaration.output);
641 pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>, _span: Span) {
643 FnKind::Fn(_, _, sig, _, body) => {
644 visitor.visit_fn_header(&sig.header);
645 walk_fn_decl(visitor, &sig.decl);
646 walk_list!(visitor, visit_block, body);
648 FnKind::Closure(decl, body) => {
649 walk_fn_decl(visitor, decl);
650 visitor.visit_expr(body);
655 pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem, ctxt: AssocCtxt) {
656 let Item { id, span, ident, ref vis, ref attrs, ref kind, tokens: _ } = *item;
657 visitor.visit_vis(vis);
658 visitor.visit_ident(ident);
659 walk_list!(visitor, visit_attribute, attrs);
661 AssocItemKind::Const(_, ty, expr) => {
662 visitor.visit_ty(ty);
663 walk_list!(visitor, visit_expr, expr);
665 AssocItemKind::Fn(box Fn { defaultness: _, ref generics, ref sig, ref body }) => {
666 visitor.visit_generics(generics);
667 let kind = FnKind::Fn(FnCtxt::Assoc(ctxt), ident, sig, vis, body.as_deref());
668 visitor.visit_fn(kind, span, id);
670 AssocItemKind::TyAlias(box TyAlias { defaultness: _, generics, bounds, ty }) => {
671 visitor.visit_generics(generics);
672 walk_list!(visitor, visit_param_bound, bounds);
673 walk_list!(visitor, visit_ty, ty);
675 AssocItemKind::MacCall(mac) => {
676 visitor.visit_mac_call(mac);
681 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
682 walk_list!(visitor, visit_field_def, struct_definition.fields());
685 pub fn walk_field_def<'a, V: Visitor<'a>>(visitor: &mut V, field: &'a FieldDef) {
686 visitor.visit_vis(&field.vis);
687 if let Some(ident) = field.ident {
688 visitor.visit_ident(ident);
690 visitor.visit_ty(&field.ty);
691 walk_list!(visitor, visit_attribute, &field.attrs);
694 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
695 walk_list!(visitor, visit_stmt, &block.stmts);
698 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
699 match statement.kind {
700 StmtKind::Local(ref local) => visitor.visit_local(local),
701 StmtKind::Item(ref item) => visitor.visit_item(item),
702 StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => visitor.visit_expr(expr),
703 StmtKind::Empty => {}
704 StmtKind::MacCall(ref mac) => {
705 let MacCallStmt { ref mac, style: _, ref attrs, tokens: _ } = **mac;
706 visitor.visit_mac_call(mac);
707 for attr in attrs.iter() {
708 visitor.visit_attribute(attr);
714 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a MacCall) {
715 visitor.visit_path(&mac.path, DUMMY_NODE_ID);
718 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
719 visitor.visit_expr(&constant.value);
722 fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm) {
723 for (op, _) in &asm.operands {
725 InlineAsmOperand::In { expr, .. }
726 | InlineAsmOperand::Out { expr: Some(expr), .. }
727 | InlineAsmOperand::InOut { expr, .. }
728 | InlineAsmOperand::Sym { expr, .. } => visitor.visit_expr(expr),
729 InlineAsmOperand::Out { expr: None, .. } => {}
730 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
731 visitor.visit_expr(in_expr);
732 if let Some(out_expr) = out_expr {
733 visitor.visit_expr(out_expr);
736 InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),
741 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
742 walk_list!(visitor, visit_attribute, expression.attrs.iter());
744 match expression.kind {
745 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
746 ExprKind::Array(ref subexpressions) => {
747 walk_list!(visitor, visit_expr, subexpressions);
749 ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
750 ExprKind::Repeat(ref element, ref count) => {
751 visitor.visit_expr(element);
752 visitor.visit_anon_const(count)
754 ExprKind::Struct(ref se) => {
755 if let Some(ref qself) = se.qself {
756 visitor.visit_ty(&qself.ty);
758 visitor.visit_path(&se.path, expression.id);
759 walk_list!(visitor, visit_expr_field, &se.fields);
761 StructRest::Base(expr) => visitor.visit_expr(expr),
762 StructRest::Rest(_span) => {}
763 StructRest::None => {}
766 ExprKind::Tup(ref subexpressions) => {
767 walk_list!(visitor, visit_expr, subexpressions);
769 ExprKind::Call(ref callee_expression, ref arguments) => {
770 visitor.visit_expr(callee_expression);
771 walk_list!(visitor, visit_expr, arguments);
773 ExprKind::MethodCall(ref segment, ref arguments, _span) => {
774 visitor.visit_path_segment(expression.span, segment);
775 walk_list!(visitor, visit_expr, arguments);
777 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
778 visitor.visit_expr(left_expression);
779 visitor.visit_expr(right_expression)
781 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
782 visitor.visit_expr(subexpression)
784 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
785 visitor.visit_expr(subexpression);
786 visitor.visit_ty(typ)
788 ExprKind::Let(ref pat, ref expr, _) => {
789 visitor.visit_pat(pat);
790 visitor.visit_expr(expr);
792 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
793 visitor.visit_expr(head_expression);
794 visitor.visit_block(if_block);
795 walk_list!(visitor, visit_expr, optional_else);
797 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
798 walk_list!(visitor, visit_label, opt_label);
799 visitor.visit_expr(subexpression);
800 visitor.visit_block(block);
802 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
803 walk_list!(visitor, visit_label, opt_label);
804 visitor.visit_pat(pattern);
805 visitor.visit_expr(subexpression);
806 visitor.visit_block(block);
808 ExprKind::Loop(ref block, ref opt_label) => {
809 walk_list!(visitor, visit_label, opt_label);
810 visitor.visit_block(block);
812 ExprKind::Match(ref subexpression, ref arms) => {
813 visitor.visit_expr(subexpression);
814 walk_list!(visitor, visit_arm, arms);
816 ExprKind::Closure(_, _, _, ref decl, ref body, _decl_span) => {
817 visitor.visit_fn(FnKind::Closure(decl, body), expression.span, expression.id)
819 ExprKind::Block(ref block, ref opt_label) => {
820 walk_list!(visitor, visit_label, opt_label);
821 visitor.visit_block(block);
823 ExprKind::Async(_, _, ref body) => {
824 visitor.visit_block(body);
826 ExprKind::Await(ref expr) => visitor.visit_expr(expr),
827 ExprKind::Assign(ref lhs, ref rhs, _) => {
828 visitor.visit_expr(lhs);
829 visitor.visit_expr(rhs);
831 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
832 visitor.visit_expr(left_expression);
833 visitor.visit_expr(right_expression);
835 ExprKind::Field(ref subexpression, ident) => {
836 visitor.visit_expr(subexpression);
837 visitor.visit_ident(ident);
839 ExprKind::Index(ref main_expression, ref index_expression) => {
840 visitor.visit_expr(main_expression);
841 visitor.visit_expr(index_expression)
843 ExprKind::Range(ref start, ref end, _) => {
844 walk_list!(visitor, visit_expr, start);
845 walk_list!(visitor, visit_expr, end);
847 ExprKind::Underscore => {}
848 ExprKind::Path(ref maybe_qself, ref path) => {
849 if let Some(ref qself) = *maybe_qself {
850 visitor.visit_ty(&qself.ty);
852 visitor.visit_path(path, expression.id)
854 ExprKind::Break(ref opt_label, ref opt_expr) => {
855 walk_list!(visitor, visit_label, opt_label);
856 walk_list!(visitor, visit_expr, opt_expr);
858 ExprKind::Continue(ref opt_label) => {
859 walk_list!(visitor, visit_label, opt_label);
861 ExprKind::Ret(ref optional_expression) => {
862 walk_list!(visitor, visit_expr, optional_expression);
864 ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
865 ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
866 ExprKind::InlineAsm(ref asm) => walk_inline_asm(visitor, asm),
867 ExprKind::LlvmInlineAsm(ref ia) => {
868 for &(_, ref input) in &ia.inputs {
869 visitor.visit_expr(input)
871 for output in &ia.outputs {
872 visitor.visit_expr(&output.expr)
875 ExprKind::Yield(ref optional_expression) => {
876 walk_list!(visitor, visit_expr, optional_expression);
878 ExprKind::Try(ref subexpression) => visitor.visit_expr(subexpression),
879 ExprKind::TryBlock(ref body) => visitor.visit_block(body),
880 ExprKind::Lit(_) | ExprKind::Err => {}
883 visitor.visit_expr_post(expression)
886 pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
887 walk_list!(visitor, visit_attribute, param.attrs.iter());
888 visitor.visit_pat(¶m.pat);
889 visitor.visit_ty(¶m.ty);
892 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
893 visitor.visit_pat(&arm.pat);
894 walk_list!(visitor, visit_expr, &arm.guard);
895 visitor.visit_expr(&arm.body);
896 walk_list!(visitor, visit_attribute, &arm.attrs);
899 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
900 if let VisibilityKind::Restricted { ref path, id } = vis.kind {
901 visitor.visit_path(path, id);
905 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
907 AttrKind::Normal(ref item, ref _tokens) => walk_mac_args(visitor, &item.args),
908 AttrKind::DocComment(..) => {}
912 pub fn walk_mac_args<'a, V: Visitor<'a>>(visitor: &mut V, args: &'a MacArgs) {
915 MacArgs::Delimited(_dspan, _delim, _tokens) => {}
916 // The value in `#[key = VALUE]` must be visited as an expression for backward
917 // compatibility, so that macros can be expanded in that position.
918 MacArgs::Eq(_eq_span, token) => match &token.kind {
919 token::Interpolated(nt) => match &**nt {
920 token::NtExpr(expr) => visitor.visit_expr(expr),
921 t => panic!("unexpected token in key-value attribute: {:?}", t),
923 t => panic!("unexpected token in key-value attribute: {:?}", t),