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::token::Token;
18 use crate::tokenstream::{TokenStream, TokenTree};
22 #[derive(Copy, Clone)]
24 /// E.g., `fn foo()` or `extern "Abi" fn foo()`.
25 ItemFn(Ident, &'a FnHeader, &'a Visibility, &'a Block),
27 /// E.g., `fn foo(&self)`.
28 Method(Ident, &'a FnSig, &'a Visibility, &'a Block),
30 /// E.g., `|x, y| body`.
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) {
64 walk_foreign_item(self, i)
66 fn visit_global_asm(&mut self, ga: &'ast GlobalAsm) {
67 walk_global_asm(self, ga)
69 fn visit_item(&mut self, i: &'ast Item) {
72 fn visit_local(&mut self, l: &'ast Local) {
75 fn visit_block(&mut self, b: &'ast Block) {
78 fn visit_stmt(&mut self, s: &'ast Stmt) {
81 fn visit_param(&mut self, param: &'ast Param) {
82 walk_param(self, param)
84 fn visit_arm(&mut self, a: &'ast Arm) {
87 fn visit_pat(&mut self, p: &'ast Pat) {
90 fn visit_anon_const(&mut self, c: &'ast AnonConst) {
91 walk_anon_const(self, c)
93 fn visit_expr(&mut self, ex: &'ast Expr) {
96 fn visit_expr_post(&mut self, _ex: &'ast Expr) {}
97 fn visit_ty(&mut self, t: &'ast Ty) {
100 fn visit_generic_param(&mut self, param: &'ast GenericParam) {
101 walk_generic_param(self, param)
103 fn visit_generics(&mut self, g: &'ast Generics) {
104 walk_generics(self, g)
106 fn visit_where_predicate(&mut self, p: &'ast WherePredicate) {
107 walk_where_predicate(self, p)
109 fn visit_fn(&mut self, fk: FnKind<'ast>, fd: &'ast FnDecl, s: Span, _: NodeId) {
110 walk_fn(self, fk, fd, s)
112 fn visit_trait_item(&mut self, i: &'ast AssocItem) {
113 walk_trait_item(self, i)
115 fn visit_impl_item(&mut self, i: &'ast AssocItem) {
116 walk_impl_item(self, i)
118 fn visit_assoc_item(&mut self, i: &'ast AssocItem) {
119 walk_assoc_item(self, i)
121 fn visit_trait_ref(&mut self, t: &'ast TraitRef) {
122 walk_trait_ref(self, t)
124 fn visit_param_bound(&mut self, bounds: &'ast GenericBound) {
125 walk_param_bound(self, bounds)
127 fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef, m: &'ast TraitBoundModifier) {
128 walk_poly_trait_ref(self, t, m)
130 fn visit_variant_data(&mut self, s: &'ast VariantData) {
131 walk_struct_def(self, s)
133 fn visit_struct_field(&mut self, s: &'ast StructField) {
134 walk_struct_field(self, s)
138 enum_definition: &'ast EnumDef,
139 generics: &'ast Generics,
143 walk_enum_def(self, enum_definition, generics, item_id)
145 fn visit_variant(&mut self, v: &'ast Variant) {
146 walk_variant(self, v)
148 fn visit_label(&mut self, label: &'ast Label) {
149 walk_label(self, label)
151 fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
152 walk_lifetime(self, lifetime)
154 fn visit_mac(&mut self, _mac: &'ast Mac) {
155 panic!("visit_mac disabled by default");
156 // N.B., see note about macros above.
157 // if you really want a visitor that
158 // works on macros, use this
159 // definition in your trait impl:
160 // visit::walk_mac(self, _mac)
162 fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
165 fn visit_path(&mut self, path: &'ast Path, _id: NodeId) {
166 walk_path(self, path)
168 fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
169 walk_use_tree(self, use_tree, id)
171 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
172 walk_path_segment(self, path_span, path_segment)
174 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
175 walk_generic_args(self, path_span, generic_args)
177 fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
179 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
180 GenericArg::Type(ty) => self.visit_ty(ty),
181 GenericArg::Const(ct) => self.visit_anon_const(ct),
184 fn visit_assoc_ty_constraint(&mut self, constraint: &'ast AssocTyConstraint) {
185 walk_assoc_ty_constraint(self, constraint)
187 fn visit_attribute(&mut self, attr: &'ast Attribute) {
188 walk_attribute(self, attr)
190 fn visit_tt(&mut self, tt: TokenTree) {
193 fn visit_tts(&mut self, tts: TokenStream) {
196 fn visit_token(&mut self, _t: Token) {}
197 // FIXME: add `visit_interpolated` and `walk_interpolated`
198 fn visit_vis(&mut self, vis: &'ast Visibility) {
201 fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FunctionRetTy) {
202 walk_fn_ret_ty(self, ret_ty)
204 fn visit_fn_header(&mut self, _header: &'ast FnHeader) {
207 fn visit_field(&mut self, f: &'ast Field) {
210 fn visit_field_pattern(&mut self, fp: &'ast FieldPat) {
211 walk_field_pattern(self, fp)
216 macro_rules! walk_list {
217 ($visitor: expr, $method: ident, $list: expr) => {
219 $visitor.$method(elem)
222 ($visitor: expr, $method: ident, $list: expr, $($extra_args: expr),*) => {
224 $visitor.$method(elem, $($extra_args,)*)
229 pub fn walk_ident<'a, V: Visitor<'a>>(visitor: &mut V, ident: Ident) {
230 visitor.visit_name(ident.span, ident.name);
233 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) {
234 visitor.visit_mod(&krate.module, krate.span, &krate.attrs, CRATE_NODE_ID);
235 walk_list!(visitor, visit_attribute, &krate.attrs);
238 pub fn walk_mod<'a, V: Visitor<'a>>(visitor: &mut V, module: &'a Mod) {
239 walk_list!(visitor, visit_item, &module.items);
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 walk_list!(visitor, visit_expr, &local.init);
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 visitor.visit_expr(expr);
288 ItemKind::Fn(ref sig, ref generics, ref body) => {
289 visitor.visit_generics(generics);
290 visitor.visit_fn_header(&sig.header);
292 FnKind::ItemFn(item.ident, &sig.header, &item.vis, body),
298 ItemKind::Mod(ref module) => visitor.visit_mod(module, item.span, &item.attrs, item.id),
299 ItemKind::ForeignMod(ref foreign_module) => {
300 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
302 ItemKind::GlobalAsm(ref ga) => visitor.visit_global_asm(ga),
303 ItemKind::TyAlias(ref typ, ref generics) => {
304 visitor.visit_ty(typ);
305 visitor.visit_generics(generics)
307 ItemKind::Enum(ref enum_definition, ref generics) => {
308 visitor.visit_generics(generics);
309 visitor.visit_enum_def(enum_definition, generics, item.id, item.span)
321 visitor.visit_generics(generics);
322 walk_list!(visitor, visit_trait_ref, of_trait);
323 visitor.visit_ty(self_ty);
324 walk_list!(visitor, visit_impl_item, items);
326 ItemKind::Struct(ref struct_definition, ref generics)
327 | ItemKind::Union(ref struct_definition, ref generics) => {
328 visitor.visit_generics(generics);
329 visitor.visit_variant_data(struct_definition);
331 ItemKind::Trait(.., ref generics, ref bounds, ref methods) => {
332 visitor.visit_generics(generics);
333 walk_list!(visitor, visit_param_bound, bounds);
334 walk_list!(visitor, visit_trait_item, methods);
336 ItemKind::TraitAlias(ref generics, ref bounds) => {
337 visitor.visit_generics(generics);
338 walk_list!(visitor, visit_param_bound, bounds);
340 ItemKind::Mac(ref mac) => visitor.visit_mac(mac),
341 ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
343 walk_list!(visitor, visit_attribute, &item.attrs);
346 pub fn walk_enum_def<'a, V: Visitor<'a>>(
348 enum_definition: &'a EnumDef,
352 walk_list!(visitor, visit_variant, &enum_definition.variants);
355 pub fn walk_variant<'a, V: Visitor<'a>>(visitor: &mut V, variant: &'a Variant)
359 visitor.visit_ident(variant.ident);
360 visitor.visit_vis(&variant.vis);
361 visitor.visit_variant_data(&variant.data);
362 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
363 walk_list!(visitor, visit_attribute, &variant.attrs);
366 pub fn walk_field<'a, V: Visitor<'a>>(visitor: &mut V, f: &'a Field) {
367 visitor.visit_expr(&f.expr);
368 visitor.visit_ident(f.ident);
369 walk_list!(visitor, visit_attribute, f.attrs.iter());
372 pub fn walk_field_pattern<'a, V: Visitor<'a>>(visitor: &mut V, fp: &'a FieldPat) {
373 visitor.visit_ident(fp.ident);
374 visitor.visit_pat(&fp.pat);
375 walk_list!(visitor, visit_attribute, fp.attrs.iter());
378 pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
380 TyKind::Slice(ref ty) | TyKind::Paren(ref ty) => visitor.visit_ty(ty),
381 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
382 TyKind::Rptr(ref opt_lifetime, ref mutable_type) => {
383 walk_list!(visitor, visit_lifetime, opt_lifetime);
384 visitor.visit_ty(&mutable_type.ty)
386 TyKind::Tup(ref tuple_element_types) => {
387 walk_list!(visitor, visit_ty, tuple_element_types);
389 TyKind::BareFn(ref function_declaration) => {
390 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
391 walk_fn_decl(visitor, &function_declaration.decl);
393 TyKind::Path(ref maybe_qself, ref path) => {
394 if let Some(ref qself) = *maybe_qself {
395 visitor.visit_ty(&qself.ty);
397 visitor.visit_path(path, typ.id);
399 TyKind::Array(ref ty, ref length) => {
400 visitor.visit_ty(ty);
401 visitor.visit_anon_const(length)
403 TyKind::TraitObject(ref bounds, ..) | TyKind::ImplTrait(_, ref bounds) => {
404 walk_list!(visitor, visit_param_bound, bounds);
406 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
407 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
408 TyKind::Mac(ref mac) => visitor.visit_mac(mac),
409 TyKind::Never | TyKind::CVarArgs => {}
413 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
414 for segment in &path.segments {
415 visitor.visit_path_segment(path.span, segment);
419 pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree, id: NodeId) {
420 visitor.visit_path(&use_tree.prefix, id);
421 match use_tree.kind {
422 UseTreeKind::Simple(rename, ..) => {
423 // The extra IDs are handled during HIR lowering.
424 if let Some(rename) = rename {
425 visitor.visit_ident(rename);
428 UseTreeKind::Glob => {}
429 UseTreeKind::Nested(ref use_trees) => {
430 for &(ref nested_tree, nested_id) in use_trees {
431 visitor.visit_use_tree(nested_tree, nested_id, true);
437 pub fn walk_path_segment<'a, V: Visitor<'a>>(
440 segment: &'a PathSegment,
442 visitor.visit_ident(segment.ident);
443 if let Some(ref args) = segment.args {
444 visitor.visit_generic_args(path_span, args);
448 pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
452 match *generic_args {
453 GenericArgs::AngleBracketed(ref data) => {
454 walk_list!(visitor, visit_generic_arg, &data.args);
455 walk_list!(visitor, visit_assoc_ty_constraint, &data.constraints);
457 GenericArgs::Parenthesized(ref data) => {
458 walk_list!(visitor, visit_ty, &data.inputs);
459 walk_fn_ret_ty(visitor, &data.output);
464 pub fn walk_assoc_ty_constraint<'a, V: Visitor<'a>>(
466 constraint: &'a AssocTyConstraint,
468 visitor.visit_ident(constraint.ident);
469 match constraint.kind {
470 AssocTyConstraintKind::Equality { ref ty } => {
471 visitor.visit_ty(ty);
473 AssocTyConstraintKind::Bound { ref bounds } => {
474 walk_list!(visitor, visit_param_bound, bounds);
479 pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
481 PatKind::TupleStruct(ref path, ref elems) => {
482 visitor.visit_path(path, pattern.id);
483 walk_list!(visitor, visit_pat, elems);
485 PatKind::Path(ref opt_qself, ref path) => {
486 if let Some(ref qself) = *opt_qself {
487 visitor.visit_ty(&qself.ty);
489 visitor.visit_path(path, pattern.id)
491 PatKind::Struct(ref path, ref fields, _) => {
492 visitor.visit_path(path, pattern.id);
493 walk_list!(visitor, visit_field_pattern, fields);
495 PatKind::Box(ref subpattern)
496 | PatKind::Ref(ref subpattern, _)
497 | PatKind::Paren(ref subpattern) => visitor.visit_pat(subpattern),
498 PatKind::Ident(_, ident, ref optional_subpattern) => {
499 visitor.visit_ident(ident);
500 walk_list!(visitor, visit_pat, optional_subpattern);
502 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
503 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
504 walk_list!(visitor, visit_expr, lower_bound);
505 walk_list!(visitor, visit_expr, upper_bound);
507 PatKind::Wild | PatKind::Rest => {}
508 PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
509 walk_list!(visitor, visit_pat, elems);
511 PatKind::Mac(ref mac) => visitor.visit_mac(mac),
515 pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, foreign_item: &'a ForeignItem) {
516 visitor.visit_vis(&foreign_item.vis);
517 visitor.visit_ident(foreign_item.ident);
519 match foreign_item.kind {
520 ForeignItemKind::Fn(ref function_declaration, ref generics) => {
521 walk_fn_decl(visitor, function_declaration);
522 visitor.visit_generics(generics)
524 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
525 ForeignItemKind::Ty => (),
526 ForeignItemKind::Macro(ref mac) => visitor.visit_mac(mac),
529 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
532 pub fn walk_global_asm<'a, V: Visitor<'a>>(_: &mut V, _: &'a GlobalAsm) {
536 pub fn walk_param_bound<'a, V: Visitor<'a>>(visitor: &mut V, bound: &'a GenericBound) {
538 GenericBound::Trait(ref typ, ref modifier) => visitor.visit_poly_trait_ref(typ, modifier),
539 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
543 pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a GenericParam) {
544 visitor.visit_ident(param.ident);
545 walk_list!(visitor, visit_attribute, param.attrs.iter());
546 walk_list!(visitor, visit_param_bound, ¶m.bounds);
548 GenericParamKind::Lifetime => (),
549 GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
550 GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
554 pub fn walk_generics<'a, V: Visitor<'a>>(visitor: &mut V, generics: &'a Generics) {
555 walk_list!(visitor, visit_generic_param, &generics.params);
556 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
559 pub fn walk_where_predicate<'a, V: Visitor<'a>>(visitor: &mut V, predicate: &'a WherePredicate) {
561 WherePredicate::BoundPredicate(WhereBoundPredicate {
564 ref bound_generic_params,
567 visitor.visit_ty(bounded_ty);
568 walk_list!(visitor, visit_param_bound, bounds);
569 walk_list!(visitor, visit_generic_param, bound_generic_params);
571 WherePredicate::RegionPredicate(WhereRegionPredicate {
572 ref lifetime, ref bounds, ..
574 visitor.visit_lifetime(lifetime);
575 walk_list!(visitor, visit_param_bound, bounds);
577 WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
578 visitor.visit_ty(lhs_ty);
579 visitor.visit_ty(rhs_ty);
584 pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionRetTy) {
585 if let FunctionRetTy::Ty(ref output_ty) = *ret_ty {
586 visitor.visit_ty(output_ty)
590 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
591 for param in &function_declaration.inputs {
592 visitor.visit_param(param);
594 visitor.visit_fn_ret_ty(&function_declaration.output);
597 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
602 FnKind::ItemFn(_, header, _, body) => {
603 visitor.visit_fn_header(header);
604 walk_fn_decl(visitor, declaration);
605 visitor.visit_block(body);
607 FnKind::Method(_, sig, _, body) => {
608 visitor.visit_fn_header(&sig.header);
609 walk_fn_decl(visitor, declaration);
610 visitor.visit_block(body);
612 FnKind::Closure(body) => {
613 walk_fn_decl(visitor, declaration);
614 visitor.visit_expr(body);
619 pub fn walk_impl_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem) {
620 visitor.visit_assoc_item(item);
623 pub fn walk_trait_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem) {
624 visitor.visit_assoc_item(item);
627 pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem) {
628 visitor.visit_vis(&item.vis);
629 visitor.visit_ident(item.ident);
630 walk_list!(visitor, visit_attribute, &item.attrs);
631 visitor.visit_generics(&item.generics);
633 AssocItemKind::Const(ref ty, ref expr) => {
634 visitor.visit_ty(ty);
635 walk_list!(visitor, visit_expr, expr);
637 AssocItemKind::Fn(ref sig, None) => {
638 visitor.visit_fn_header(&sig.header);
639 walk_fn_decl(visitor, &sig.decl);
641 AssocItemKind::Fn(ref sig, Some(ref body)) => {
643 FnKind::Method(item.ident, sig, &item.vis, body),
649 AssocItemKind::TyAlias(ref bounds, ref ty) => {
650 walk_list!(visitor, visit_param_bound, bounds);
651 walk_list!(visitor, visit_ty, ty);
653 AssocItemKind::Macro(ref mac) => {
654 visitor.visit_mac(mac);
659 pub fn walk_struct_def<'a, V: Visitor<'a>>(visitor: &mut V, struct_definition: &'a VariantData) {
660 walk_list!(visitor, visit_struct_field, struct_definition.fields());
663 pub fn walk_struct_field<'a, V: Visitor<'a>>(visitor: &mut V, struct_field: &'a StructField) {
664 visitor.visit_vis(&struct_field.vis);
665 if let Some(ident) = struct_field.ident {
666 visitor.visit_ident(ident);
668 visitor.visit_ty(&struct_field.ty);
669 walk_list!(visitor, visit_attribute, &struct_field.attrs);
672 pub fn walk_block<'a, V: Visitor<'a>>(visitor: &mut V, block: &'a Block) {
673 walk_list!(visitor, visit_stmt, &block.stmts);
676 pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
677 match statement.kind {
678 StmtKind::Local(ref local) => visitor.visit_local(local),
679 StmtKind::Item(ref item) => visitor.visit_item(item),
680 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
681 visitor.visit_expr(expression)
683 StmtKind::Mac(ref mac) => {
684 let (ref mac, _, ref attrs) = **mac;
685 visitor.visit_mac(mac);
686 for attr in attrs.iter() {
687 visitor.visit_attribute(attr);
693 pub fn walk_mac<'a, V: Visitor<'a>>(visitor: &mut V, mac: &'a Mac) {
694 visitor.visit_path(&mac.path, DUMMY_NODE_ID);
697 pub fn walk_anon_const<'a, V: Visitor<'a>>(visitor: &mut V, constant: &'a AnonConst) {
698 visitor.visit_expr(&constant.value);
701 pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
702 walk_list!(visitor, visit_attribute, expression.attrs.iter());
704 match expression.kind {
705 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
706 ExprKind::Array(ref subexpressions) => {
707 walk_list!(visitor, visit_expr, subexpressions);
709 ExprKind::Repeat(ref element, ref count) => {
710 visitor.visit_expr(element);
711 visitor.visit_anon_const(count)
713 ExprKind::Struct(ref path, ref fields, ref optional_base) => {
714 visitor.visit_path(path, expression.id);
715 walk_list!(visitor, visit_field, fields);
716 walk_list!(visitor, visit_expr, optional_base);
718 ExprKind::Tup(ref subexpressions) => {
719 walk_list!(visitor, visit_expr, subexpressions);
721 ExprKind::Call(ref callee_expression, ref arguments) => {
722 visitor.visit_expr(callee_expression);
723 walk_list!(visitor, visit_expr, arguments);
725 ExprKind::MethodCall(ref segment, ref arguments) => {
726 visitor.visit_path_segment(expression.span, segment);
727 walk_list!(visitor, visit_expr, arguments);
729 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
730 visitor.visit_expr(left_expression);
731 visitor.visit_expr(right_expression)
733 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
734 visitor.visit_expr(subexpression)
736 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
737 visitor.visit_expr(subexpression);
738 visitor.visit_ty(typ)
740 ExprKind::Let(ref pat, ref scrutinee) => {
741 visitor.visit_pat(pat);
742 visitor.visit_expr(scrutinee);
744 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
745 visitor.visit_expr(head_expression);
746 visitor.visit_block(if_block);
747 walk_list!(visitor, visit_expr, optional_else);
749 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
750 walk_list!(visitor, visit_label, opt_label);
751 visitor.visit_expr(subexpression);
752 visitor.visit_block(block);
754 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, ref opt_label) => {
755 walk_list!(visitor, visit_label, opt_label);
756 visitor.visit_pat(pattern);
757 visitor.visit_expr(subexpression);
758 visitor.visit_block(block);
760 ExprKind::Loop(ref block, ref opt_label) => {
761 walk_list!(visitor, visit_label, opt_label);
762 visitor.visit_block(block);
764 ExprKind::Match(ref subexpression, ref arms) => {
765 visitor.visit_expr(subexpression);
766 walk_list!(visitor, visit_arm, arms);
768 ExprKind::Closure(_, _, _, ref function_declaration, ref body, _decl_span) => visitor
769 .visit_fn(FnKind::Closure(body), function_declaration, expression.span, expression.id),
770 ExprKind::Block(ref block, ref opt_label) => {
771 walk_list!(visitor, visit_label, opt_label);
772 visitor.visit_block(block);
774 ExprKind::Async(_, _, ref body) => {
775 visitor.visit_block(body);
777 ExprKind::Await(ref expr) => visitor.visit_expr(expr),
778 ExprKind::Assign(ref lhs, ref rhs, _) => {
779 visitor.visit_expr(lhs);
780 visitor.visit_expr(rhs);
782 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
783 visitor.visit_expr(left_expression);
784 visitor.visit_expr(right_expression);
786 ExprKind::Field(ref subexpression, ident) => {
787 visitor.visit_expr(subexpression);
788 visitor.visit_ident(ident);
790 ExprKind::Index(ref main_expression, ref index_expression) => {
791 visitor.visit_expr(main_expression);
792 visitor.visit_expr(index_expression)
794 ExprKind::Range(ref start, ref end, _) => {
795 walk_list!(visitor, visit_expr, start);
796 walk_list!(visitor, visit_expr, end);
798 ExprKind::Path(ref maybe_qself, ref path) => {
799 if let Some(ref qself) = *maybe_qself {
800 visitor.visit_ty(&qself.ty);
802 visitor.visit_path(path, expression.id)
804 ExprKind::Break(ref opt_label, ref opt_expr) => {
805 walk_list!(visitor, visit_label, opt_label);
806 walk_list!(visitor, visit_expr, opt_expr);
808 ExprKind::Continue(ref opt_label) => {
809 walk_list!(visitor, visit_label, opt_label);
811 ExprKind::Ret(ref optional_expression) => {
812 walk_list!(visitor, visit_expr, optional_expression);
814 ExprKind::Mac(ref mac) => visitor.visit_mac(mac),
815 ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
816 ExprKind::InlineAsm(ref ia) => {
817 for &(_, ref input) in &ia.inputs {
818 visitor.visit_expr(input)
820 for output in &ia.outputs {
821 visitor.visit_expr(&output.expr)
824 ExprKind::Yield(ref optional_expression) => {
825 walk_list!(visitor, visit_expr, optional_expression);
827 ExprKind::Try(ref subexpression) => visitor.visit_expr(subexpression),
828 ExprKind::TryBlock(ref body) => visitor.visit_block(body),
829 ExprKind::Lit(_) | ExprKind::Err => {}
832 visitor.visit_expr_post(expression)
835 pub fn walk_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Param) {
836 walk_list!(visitor, visit_attribute, param.attrs.iter());
837 visitor.visit_pat(¶m.pat);
838 visitor.visit_ty(¶m.ty);
841 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
842 visitor.visit_pat(&arm.pat);
843 walk_list!(visitor, visit_expr, &arm.guard);
844 visitor.visit_expr(&arm.body);
845 walk_list!(visitor, visit_attribute, &arm.attrs);
848 pub fn walk_vis<'a, V: Visitor<'a>>(visitor: &mut V, vis: &'a Visibility) {
849 if let VisibilityKind::Restricted { ref path, id } = vis.node {
850 visitor.visit_path(path, id);
854 pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute) {
856 AttrKind::Normal(ref item) => walk_mac_args(visitor, &item.args),
857 AttrKind::DocComment(_) => {}
861 pub fn walk_mac_args<'a, V: Visitor<'a>>(visitor: &mut V, args: &'a MacArgs) {
864 MacArgs::Delimited(_dspan, _delim, tokens) => visitor.visit_tts(tokens.clone()),
865 MacArgs::Eq(_eq_span, tokens) => visitor.visit_tts(tokens.clone()),
869 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
871 TokenTree::Token(token) => visitor.visit_token(token),
872 TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
876 pub fn walk_tts<'a, V: Visitor<'a>>(visitor: &mut V, tts: TokenStream) {
877 for tt in tts.trees() {
878 visitor.visit_tt(tt);