1 //! HIR walker for walking the contents of nodes.
3 //! **For an overview of the visitor strategy, see the docs on the
4 //! `super::itemlikevisit::ItemLikeVisitor` trait.**
6 //! If you have decided to use this visitor, here are some general
7 //! notes on how to do so:
9 //! Each overridden visit method has full control over what
10 //! happens with its node, it can do its own traversal of the node's children,
11 //! call `intravisit::walk_*` to apply the default traversal algorithm, or prevent
12 //! deeper traversal by doing nothing.
14 //! When visiting the HIR, the contents of nested items are NOT visited
15 //! by default. This is different from the AST visitor, which does a deep walk.
16 //! Hence this module is called `intravisit`; see the method `visit_nested_item`
19 //! Note: it is an important invariant that the default visitor walks
20 //! the body of a function in "execution order" - more concretely, if
21 //! we consider the reverse post-order (RPO) of the CFG implied by the HIR,
22 //! then a pre-order traversal of the HIR is consistent with the CFG RPO
23 //! on the *initial CFG point* of each HIR node, while a post-order traversal
24 //! of the HIR is consistent with the CFG RPO on each *final CFG point* of
27 //! One thing that follows is that if HIR node A always starts/ends executing
28 //! before HIR node B, then A appears in traversal pre/postorder before B,
29 //! respectively. (This follows from RPO respecting CFG domination).
31 //! This order consistency is required in a few places in rustc, for
32 //! example generator inference, and possibly also HIR borrowck.
34 use syntax::ast::{Ident, Name, Attribute};
37 use crate::hir::map::Map;
38 use super::itemlikevisit::DeepVisitor;
40 #[derive(Copy, Clone)]
42 /// `#[xxx] pub async/const/extern "Abi" fn foo()`
43 ItemFn(Ident, &'a Generics, FnHeader, &'a Visibility, &'a [Attribute]),
46 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a [Attribute]),
49 Closure(&'a [Attribute]),
53 pub fn attrs(&self) -> &'a [Attribute] {
55 FnKind::ItemFn(.., attrs) => attrs,
56 FnKind::Method(.., attrs) => attrs,
57 FnKind::Closure(attrs) => attrs,
61 pub fn header(&self) -> Option<&FnHeader> {
63 FnKind::ItemFn(_, _, ref header, _, _) => Some(header),
64 FnKind::Method(_, ref sig, _, _) => Some(&sig.header),
65 FnKind::Closure(_) => None,
70 /// Specifies what nested things a visitor wants to visit. The most
71 /// common choice is `OnlyBodies`, which will cause the visitor to
72 /// visit fn bodies for fns that it encounters, but skip over nested
75 /// See the comments on `ItemLikeVisitor` for more details on the overall
77 pub enum NestedVisitorMap<'this, 'tcx> {
78 /// Do not visit any nested things. When you add a new
79 /// "non-nested" thing, you will want to audit such uses to see if
80 /// they remain valid.
82 /// Use this if you are only walking some particular kind of tree
83 /// (i.e., a type, or fn signature) and you don't want to thread a
87 /// Do not visit nested item-like things, but visit nested things
88 /// that are inside of an item-like.
90 /// **This is the most common choice.** A very common pattern is
91 /// to use `visit_all_item_likes()` as an outer loop,
92 /// and to have the visitor that visits the contents of each item
93 /// using this setting.
94 OnlyBodies(&'this Map<'tcx>),
96 /// Visits all nested things, including item-likes.
98 /// **This is an unusual choice.** It is used when you want to
99 /// process everything within their lexical context. Typically you
100 /// kick off the visit by doing `walk_krate()`.
101 All(&'this Map<'tcx>),
104 impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
105 /// Returns the map to use for an "intra item-like" thing (if any).
106 /// E.g., function body.
107 pub fn intra(self) -> Option<&'this Map<'tcx>> {
109 NestedVisitorMap::None => None,
110 NestedVisitorMap::OnlyBodies(map) => Some(map),
111 NestedVisitorMap::All(map) => Some(map),
115 /// Returns the map to use for an "item-like" thing (if any).
116 /// E.g., item, impl-item.
117 pub fn inter(self) -> Option<&'this Map<'tcx>> {
119 NestedVisitorMap::None => None,
120 NestedVisitorMap::OnlyBodies(_) => None,
121 NestedVisitorMap::All(map) => Some(map),
126 /// Each method of the Visitor trait is a hook to be potentially
127 /// overridden. Each method's default implementation recursively visits
128 /// the substructure of the input via the corresponding `walk` method;
129 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
131 /// Note that this visitor does NOT visit nested items by default
132 /// (this is why the module is called `intravisit`, to distinguish it
133 /// from the AST's `visit` module, which acts differently). If you
134 /// simply want to visit all items in the crate in some order, you
135 /// should call `Crate::visit_all_items`. Otherwise, see the comment
136 /// on `visit_nested_item` for details on how to visit nested items.
138 /// If you want to ensure that your code handles every variant
139 /// explicitly, you need to override each method. (And you also need
140 /// to monitor future changes to `Visitor` in case a new method with a
141 /// new default implementation gets introduced.)
142 pub trait Visitor<'v> : Sized {
143 ///////////////////////////////////////////////////////////////////////////
146 /// The default versions of the `visit_nested_XXX` routines invoke
147 /// this method to get a map to use. By selecting an enum variant,
148 /// you control which kinds of nested HIR are visited; see
149 /// `NestedVisitorMap` for details. By "nested HIR", we are
150 /// referring to bits of HIR that are not directly embedded within
151 /// one another but rather indirectly, through a table in the
152 /// crate. This is done to control dependencies during incremental
153 /// compilation: the non-inline bits of HIR can be tracked and
154 /// hashed separately.
156 /// **If for some reason you want the nested behavior, but don't
157 /// have a `Map` at your disposal:** then you should override the
158 /// `visit_nested_XXX` methods, and override this method to
159 /// `panic!()`. This way, if a new `visit_nested_XXX` variant is
160 /// added in the future, we will see the panic in your code and
161 /// fix it appropriately.
162 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'v>;
164 /// Invoked when a nested item is encountered. By default does
165 /// nothing unless you override `nested_visit_map` to return
166 /// `Some(_)`, in which case it will walk the item. **You probably
167 /// don't want to override this method** -- instead, override
168 /// `nested_visit_map` or use the "shallow" or "deep" visit
169 /// patterns described on `itemlikevisit::ItemLikeVisitor`. The only
170 /// reason to override this method is if you want a nested pattern
171 /// but cannot supply a `Map`; see `nested_visit_map` for advice.
172 #[allow(unused_variables)]
173 fn visit_nested_item(&mut self, id: ItemId) {
174 let opt_item = self.nested_visit_map().inter().map(|map| map.expect_item(id.id));
175 if let Some(item) = opt_item {
176 self.visit_item(item);
180 /// Like `visit_nested_item()`, but for trait items. See
181 /// `visit_nested_item()` for advice on when to override this
183 #[allow(unused_variables)]
184 fn visit_nested_trait_item(&mut self, id: TraitItemId) {
185 let opt_item = self.nested_visit_map().inter().map(|map| map.trait_item(id));
186 if let Some(item) = opt_item {
187 self.visit_trait_item(item);
191 /// Like `visit_nested_item()`, but for impl items. See
192 /// `visit_nested_item()` for advice on when to override this
194 #[allow(unused_variables)]
195 fn visit_nested_impl_item(&mut self, id: ImplItemId) {
196 let opt_item = self.nested_visit_map().inter().map(|map| map.impl_item(id));
197 if let Some(item) = opt_item {
198 self.visit_impl_item(item);
202 /// Invoked to visit the body of a function, method or closure. Like
203 /// visit_nested_item, does nothing by default unless you override
204 /// `nested_visit_map` to return `Some(_)`, in which case it will walk the
206 fn visit_nested_body(&mut self, id: BodyId) {
207 let opt_body = self.nested_visit_map().intra().map(|map| map.body(id));
208 if let Some(body) = opt_body {
209 self.visit_body(body);
213 /// Visits the top-level item and (optionally) nested items / impl items. See
214 /// `visit_nested_item` for details.
215 fn visit_item(&mut self, i: &'v Item) {
219 fn visit_body(&mut self, b: &'v Body) {
223 /// When invoking `visit_all_item_likes()`, you need to supply an
224 /// item-like visitor. This method converts a "intra-visit"
225 /// visitor into an item-like visitor that walks the entire tree.
226 /// If you use this, you probably don't want to process the
227 /// contents of nested item-like things, since the outer loop will
228 /// visit them as well.
229 fn as_deep_visitor<'s>(&'s mut self) -> DeepVisitor<'s, Self> {
230 DeepVisitor::new(self)
233 ///////////////////////////////////////////////////////////////////////////
235 fn visit_id(&mut self, _hir_id: HirId) {
238 fn visit_name(&mut self, _span: Span, _name: Name) {
241 fn visit_ident(&mut self, ident: Ident) {
242 walk_ident(self, ident)
244 fn visit_mod(&mut self, m: &'v Mod, _s: Span, n: HirId) {
247 fn visit_foreign_item(&mut self, i: &'v ForeignItem) {
248 walk_foreign_item(self, i)
250 fn visit_local(&mut self, l: &'v Local) {
253 fn visit_block(&mut self, b: &'v Block) {
256 fn visit_stmt(&mut self, s: &'v Stmt) {
259 fn visit_arm(&mut self, a: &'v Arm) {
262 fn visit_pat(&mut self, p: &'v Pat) {
265 fn visit_anon_const(&mut self, c: &'v AnonConst) {
266 walk_anon_const(self, c)
268 fn visit_expr(&mut self, ex: &'v Expr) {
271 fn visit_ty(&mut self, t: &'v Ty) {
274 fn visit_generic_param(&mut self, p: &'v GenericParam) {
275 walk_generic_param(self, p)
277 fn visit_generics(&mut self, g: &'v Generics) {
278 walk_generics(self, g)
280 fn visit_where_predicate(&mut self, predicate: &'v WherePredicate) {
281 walk_where_predicate(self, predicate)
283 fn visit_fn_decl(&mut self, fd: &'v FnDecl) {
284 walk_fn_decl(self, fd)
286 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl, b: BodyId, s: Span, id: HirId) {
287 walk_fn(self, fk, fd, b, s, id)
289 fn visit_use(&mut self, path: &'v Path, hir_id: HirId) {
290 walk_use(self, path, hir_id)
292 fn visit_trait_item(&mut self, ti: &'v TraitItem) {
293 walk_trait_item(self, ti)
295 fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
296 walk_trait_item_ref(self, ii)
298 fn visit_impl_item(&mut self, ii: &'v ImplItem) {
299 walk_impl_item(self, ii)
301 fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) {
302 walk_impl_item_ref(self, ii)
304 fn visit_trait_ref(&mut self, t: &'v TraitRef) {
305 walk_trait_ref(self, t)
307 fn visit_param_bound(&mut self, bounds: &'v GenericBound) {
308 walk_param_bound(self, bounds)
310 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef, m: TraitBoundModifier) {
311 walk_poly_trait_ref(self, t, m)
313 fn visit_variant_data(&mut self,
319 walk_struct_def(self, s)
321 fn visit_struct_field(&mut self, s: &'v StructField) {
322 walk_struct_field(self, s)
324 fn visit_enum_def(&mut self,
325 enum_definition: &'v EnumDef,
326 generics: &'v Generics,
329 walk_enum_def(self, enum_definition, generics, item_id)
331 fn visit_variant(&mut self, v: &'v Variant, g: &'v Generics, item_id: HirId) {
332 walk_variant(self, v, g, item_id)
334 fn visit_label(&mut self, label: &'v Label) {
335 walk_label(self, label)
337 fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg) {
339 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
340 GenericArg::Type(ty) => self.visit_ty(ty),
341 GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
344 fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
345 walk_lifetime(self, lifetime)
347 fn visit_qpath(&mut self, qpath: &'v QPath, id: HirId, span: Span) {
348 walk_qpath(self, qpath, id, span)
350 fn visit_path(&mut self, path: &'v Path, _id: HirId) {
351 walk_path(self, path)
353 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment) {
354 walk_path_segment(self, path_span, path_segment)
356 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs) {
357 walk_generic_args(self, path_span, generic_args)
359 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding) {
360 walk_assoc_type_binding(self, type_binding)
362 fn visit_attribute(&mut self, _attr: &'v Attribute) {
364 fn visit_macro_def(&mut self, macro_def: &'v MacroDef) {
365 walk_macro_def(self, macro_def)
367 fn visit_vis(&mut self, vis: &'v Visibility) {
370 fn visit_associated_item_kind(&mut self, kind: &'v AssocItemKind) {
371 walk_associated_item_kind(self, kind);
373 fn visit_defaultness(&mut self, defaultness: &'v Defaultness) {
374 walk_defaultness(self, defaultness);
378 /// Walks the contents of a crate. See also `Crate::visit_all_items`.
379 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate) {
380 visitor.visit_mod(&krate.module, krate.span, CRATE_HIR_ID);
381 walk_list!(visitor, visit_attribute, &krate.attrs);
382 walk_list!(visitor, visit_macro_def, &krate.exported_macros);
385 pub fn walk_macro_def<'v, V: Visitor<'v>>(visitor: &mut V, macro_def: &'v MacroDef) {
386 visitor.visit_id(macro_def.hir_id);
387 visitor.visit_name(macro_def.span, macro_def.name);
388 walk_list!(visitor, visit_attribute, ¯o_def.attrs);
391 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod, mod_hir_id: HirId) {
392 visitor.visit_id(mod_hir_id);
393 for &item_id in &module.item_ids {
394 visitor.visit_nested_item(item_id);
398 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body) {
399 for argument in &body.arguments {
400 visitor.visit_id(argument.hir_id);
401 visitor.visit_pat(&argument.pat);
403 visitor.visit_expr(&body.value);
406 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local) {
407 // Intentionally visiting the expr first - the initialization expr
408 // dominates the local's definition.
409 walk_list!(visitor, visit_expr, &local.init);
410 walk_list!(visitor, visit_attribute, local.attrs.iter());
411 visitor.visit_id(local.hir_id);
412 visitor.visit_pat(&local.pat);
413 walk_list!(visitor, visit_ty, &local.ty);
416 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
417 visitor.visit_name(ident.span, ident.name);
420 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
421 visitor.visit_ident(label.ident);
424 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
425 visitor.visit_id(lifetime.hir_id);
426 match lifetime.name {
427 LifetimeName::Param(ParamName::Plain(ident)) => {
428 visitor.visit_ident(ident);
430 LifetimeName::Param(ParamName::Fresh(_)) |
431 LifetimeName::Param(ParamName::Error) |
432 LifetimeName::Static |
433 LifetimeName::Error |
434 LifetimeName::Implicit |
435 LifetimeName::Underscore => {}
439 pub fn walk_poly_trait_ref<'v, V>(visitor: &mut V,
440 trait_ref: &'v PolyTraitRef,
441 _modifier: TraitBoundModifier)
444 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
445 visitor.visit_trait_ref(&trait_ref.trait_ref);
448 pub fn walk_trait_ref<'v, V>(visitor: &mut V, trait_ref: &'v TraitRef)
451 visitor.visit_id(trait_ref.hir_ref_id);
452 visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
455 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
456 visitor.visit_vis(&item.vis);
457 visitor.visit_ident(item.ident);
459 ItemKind::ExternCrate(orig_name) => {
460 visitor.visit_id(item.hir_id);
461 if let Some(orig_name) = orig_name {
462 visitor.visit_name(item.span, orig_name);
465 ItemKind::Use(ref path, _) => {
466 visitor.visit_use(path, item.hir_id);
468 ItemKind::Static(ref typ, _, body) |
469 ItemKind::Const(ref typ, body) => {
470 visitor.visit_id(item.hir_id);
471 visitor.visit_ty(typ);
472 visitor.visit_nested_body(body);
474 ItemKind::Fn(ref declaration, header, ref generics, body_id) => {
475 visitor.visit_fn(FnKind::ItemFn(item.ident,
485 ItemKind::Mod(ref module) => {
486 // `visit_mod()` takes care of visiting the `Item`'s `HirId`.
487 visitor.visit_mod(module, item.span, item.hir_id)
489 ItemKind::ForeignMod(ref foreign_module) => {
490 visitor.visit_id(item.hir_id);
491 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
493 ItemKind::GlobalAsm(_) => {
494 visitor.visit_id(item.hir_id);
496 ItemKind::Ty(ref ty, ref generics) => {
497 visitor.visit_id(item.hir_id);
498 visitor.visit_ty(ty);
499 visitor.visit_generics(generics)
501 ItemKind::Existential(ExistTy {
506 visitor.visit_id(item.hir_id);
507 walk_generics(visitor, generics);
508 walk_list!(visitor, visit_param_bound, bounds);
510 ItemKind::Enum(ref enum_definition, ref generics) => {
511 visitor.visit_generics(generics);
512 // `visit_enum_def()` takes care of visiting the `Item`'s `HirId`.
513 visitor.visit_enum_def(enum_definition, generics, item.hir_id, item.span)
518 ref opt_trait_reference,
522 visitor.visit_id(item.hir_id);
523 visitor.visit_generics(generics);
524 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
525 visitor.visit_ty(typ);
526 walk_list!(visitor, visit_impl_item_ref, impl_item_refs);
528 ItemKind::Struct(ref struct_definition, ref generics) |
529 ItemKind::Union(ref struct_definition, ref generics) => {
530 visitor.visit_generics(generics);
531 visitor.visit_id(item.hir_id);
532 visitor.visit_variant_data(struct_definition, item.ident.name, generics, item.hir_id,
535 ItemKind::Trait(.., ref generics, ref bounds, ref trait_item_refs) => {
536 visitor.visit_id(item.hir_id);
537 visitor.visit_generics(generics);
538 walk_list!(visitor, visit_param_bound, bounds);
539 walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
541 ItemKind::TraitAlias(ref generics, ref bounds) => {
542 visitor.visit_id(item.hir_id);
543 visitor.visit_generics(generics);
544 walk_list!(visitor, visit_param_bound, bounds);
547 walk_list!(visitor, visit_attribute, &item.attrs);
550 pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V,
553 visitor.visit_id(hir_id);
554 visitor.visit_path(path, hir_id);
557 pub fn walk_enum_def<'v, V: Visitor<'v>>(visitor: &mut V,
558 enum_definition: &'v EnumDef,
559 generics: &'v Generics,
561 visitor.visit_id(item_id);
564 &enum_definition.variants,
569 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V,
570 variant: &'v Variant,
571 generics: &'v Generics,
572 parent_item_id: HirId) {
573 visitor.visit_ident(variant.node.ident);
574 visitor.visit_id(variant.node.id);
575 visitor.visit_variant_data(&variant.node.data,
576 variant.node.ident.name,
580 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
581 walk_list!(visitor, visit_attribute, &variant.node.attrs);
584 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
585 visitor.visit_id(typ.hir_id);
588 TyKind::Slice(ref ty) => {
591 TyKind::Ptr(ref mutable_type) => {
592 visitor.visit_ty(&mutable_type.ty)
594 TyKind::Rptr(ref lifetime, ref mutable_type) => {
595 visitor.visit_lifetime(lifetime);
596 visitor.visit_ty(&mutable_type.ty)
599 TyKind::Tup(ref tuple_element_types) => {
600 walk_list!(visitor, visit_ty, tuple_element_types);
602 TyKind::BareFn(ref function_declaration) => {
603 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
604 visitor.visit_fn_decl(&function_declaration.decl);
606 TyKind::Path(ref qpath) => {
607 visitor.visit_qpath(qpath, typ.hir_id, typ.span);
609 TyKind::Def(item_id, ref lifetimes) => {
610 visitor.visit_nested_item(item_id);
611 walk_list!(visitor, visit_generic_arg, lifetimes);
613 TyKind::Array(ref ty, ref length) => {
614 visitor.visit_ty(ty);
615 visitor.visit_anon_const(length)
617 TyKind::TraitObject(ref bounds, ref lifetime) => {
618 for bound in bounds {
619 visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
621 visitor.visit_lifetime(lifetime);
623 TyKind::Typeof(ref expression) => {
624 visitor.visit_anon_const(expression)
626 TyKind::CVarArgs(ref lt) => {
627 visitor.visit_lifetime(lt)
629 TyKind::Infer | TyKind::Err => {}
633 pub fn walk_qpath<'v, V: Visitor<'v>>(visitor: &mut V, qpath: &'v QPath, id: HirId, span: Span) {
635 QPath::Resolved(ref maybe_qself, ref path) => {
636 if let Some(ref qself) = *maybe_qself {
637 visitor.visit_ty(qself);
639 visitor.visit_path(path, id)
641 QPath::TypeRelative(ref qself, ref segment) => {
642 visitor.visit_ty(qself);
643 visitor.visit_path_segment(span, segment);
648 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path) {
649 for segment in &path.segments {
650 visitor.visit_path_segment(path.span, segment);
654 pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V,
656 segment: &'v PathSegment) {
657 visitor.visit_ident(segment.ident);
658 if let Some(id) = segment.hir_id {
659 visitor.visit_id(id);
661 if let Some(ref args) = segment.args {
662 visitor.visit_generic_args(path_span, args);
666 pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V,
668 generic_args: &'v GenericArgs) {
669 walk_list!(visitor, visit_generic_arg, &generic_args.args);
670 walk_list!(visitor, visit_assoc_type_binding, &generic_args.bindings);
673 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(visitor: &mut V,
674 type_binding: &'v TypeBinding) {
675 visitor.visit_id(type_binding.hir_id);
676 visitor.visit_ident(type_binding.ident);
677 match type_binding.kind {
678 TypeBindingKind::Equality { ref ty } => {
679 visitor.visit_ty(ty);
681 TypeBindingKind::Constraint { ref bounds } => {
682 walk_list!(visitor, visit_param_bound, bounds);
687 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat) {
688 visitor.visit_id(pattern.hir_id);
690 PatKind::TupleStruct(ref qpath, ref children, _) => {
691 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
692 walk_list!(visitor, visit_pat, children);
694 PatKind::Path(ref qpath) => {
695 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
697 PatKind::Struct(ref qpath, ref fields, _) => {
698 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
699 for field in fields {
700 visitor.visit_id(field.node.hir_id);
701 visitor.visit_ident(field.node.ident);
702 visitor.visit_pat(&field.node.pat)
705 PatKind::Tuple(ref tuple_elements, _) => {
706 walk_list!(visitor, visit_pat, tuple_elements);
708 PatKind::Box(ref subpattern) |
709 PatKind::Ref(ref subpattern, _) => {
710 visitor.visit_pat(subpattern)
712 PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
713 visitor.visit_ident(ident);
714 walk_list!(visitor, visit_pat, optional_subpattern);
716 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
717 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
718 visitor.visit_expr(lower_bound);
719 visitor.visit_expr(upper_bound)
722 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
723 walk_list!(visitor, visit_pat, prepatterns);
724 walk_list!(visitor, visit_pat, slice_pattern);
725 walk_list!(visitor, visit_pat, postpatterns);
730 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem) {
731 visitor.visit_id(foreign_item.hir_id);
732 visitor.visit_vis(&foreign_item.vis);
733 visitor.visit_ident(foreign_item.ident);
735 match foreign_item.node {
736 ForeignItemKind::Fn(ref function_declaration, ref param_names, ref generics) => {
737 visitor.visit_generics(generics);
738 visitor.visit_fn_decl(function_declaration);
739 for ¶m_name in param_names {
740 visitor.visit_ident(param_name);
743 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
744 ForeignItemKind::Type => (),
747 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
750 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound) {
752 GenericBound::Trait(ref typ, modifier) => {
753 visitor.visit_poly_trait_ref(typ, modifier);
755 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
759 pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam) {
760 visitor.visit_id(param.hir_id);
761 walk_list!(visitor, visit_attribute, ¶m.attrs);
763 ParamName::Plain(ident) => visitor.visit_ident(ident),
764 ParamName::Error | ParamName::Fresh(_) => {}
767 GenericParamKind::Lifetime { .. } => {}
768 GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
769 GenericParamKind::Const { ref ty } => visitor.visit_ty(ty),
771 walk_list!(visitor, visit_param_bound, ¶m.bounds);
774 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics) {
775 walk_list!(visitor, visit_generic_param, &generics.params);
776 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
779 pub fn walk_where_predicate<'v, V: Visitor<'v>>(
781 predicate: &'v WherePredicate)
784 &WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
786 ref bound_generic_params,
788 visitor.visit_ty(bounded_ty);
789 walk_list!(visitor, visit_param_bound, bounds);
790 walk_list!(visitor, visit_generic_param, bound_generic_params);
792 &WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
795 visitor.visit_lifetime(lifetime);
796 walk_list!(visitor, visit_param_bound, bounds);
798 &WherePredicate::EqPredicate(WhereEqPredicate{hir_id,
802 visitor.visit_id(hir_id);
803 visitor.visit_ty(lhs_ty);
804 visitor.visit_ty(rhs_ty);
809 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FunctionRetTy) {
810 if let Return(ref output_ty) = *ret_ty {
811 visitor.visit_ty(output_ty)
815 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl) {
816 for ty in &function_declaration.inputs {
819 walk_fn_ret_ty(visitor, &function_declaration.output)
822 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
823 match function_kind {
824 FnKind::ItemFn(_, generics, ..) => {
825 visitor.visit_generics(generics);
828 FnKind::Closure(_) => {}
832 pub fn walk_fn<'v, V: Visitor<'v>>(visitor: &mut V,
833 function_kind: FnKind<'v>,
834 function_declaration: &'v FnDecl,
838 visitor.visit_id(id);
839 visitor.visit_fn_decl(function_declaration);
840 walk_fn_kind(visitor, function_kind);
841 visitor.visit_nested_body(body_id)
844 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem) {
845 visitor.visit_ident(trait_item.ident);
846 walk_list!(visitor, visit_attribute, &trait_item.attrs);
847 visitor.visit_generics(&trait_item.generics);
848 match trait_item.node {
849 TraitItemKind::Const(ref ty, default) => {
850 visitor.visit_id(trait_item.hir_id);
851 visitor.visit_ty(ty);
852 walk_list!(visitor, visit_nested_body, default);
854 TraitItemKind::Method(ref sig, TraitMethod::Required(ref param_names)) => {
855 visitor.visit_id(trait_item.hir_id);
856 visitor.visit_fn_decl(&sig.decl);
857 for ¶m_name in param_names {
858 visitor.visit_ident(param_name);
861 TraitItemKind::Method(ref sig, TraitMethod::Provided(body_id)) => {
862 visitor.visit_fn(FnKind::Method(trait_item.ident,
871 TraitItemKind::Type(ref bounds, ref default) => {
872 visitor.visit_id(trait_item.hir_id);
873 walk_list!(visitor, visit_param_bound, bounds);
874 walk_list!(visitor, visit_ty, default);
879 pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
880 // N.B., deliberately force a compilation error if/when new fields are added.
881 let TraitItemRef { id, ident, ref kind, span: _, ref defaultness } = *trait_item_ref;
882 visitor.visit_nested_trait_item(id);
883 visitor.visit_ident(ident);
884 visitor.visit_associated_item_kind(kind);
885 visitor.visit_defaultness(defaultness);
888 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem) {
889 // N.B., deliberately force a compilation error if/when new fields are added.
901 visitor.visit_ident(ident);
902 visitor.visit_vis(vis);
903 visitor.visit_defaultness(defaultness);
904 walk_list!(visitor, visit_attribute, attrs);
905 visitor.visit_generics(generics);
907 ImplItemKind::Const(ref ty, body) => {
908 visitor.visit_id(impl_item.hir_id);
909 visitor.visit_ty(ty);
910 visitor.visit_nested_body(body);
912 ImplItemKind::Method(ref sig, body_id) => {
913 visitor.visit_fn(FnKind::Method(impl_item.ident,
915 Some(&impl_item.vis),
922 ImplItemKind::Type(ref ty) => {
923 visitor.visit_id(impl_item.hir_id);
924 visitor.visit_ty(ty);
926 ImplItemKind::Existential(ref bounds) => {
927 visitor.visit_id(impl_item.hir_id);
928 walk_list!(visitor, visit_param_bound, bounds);
933 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef) {
934 // N.B., deliberately force a compilation error if/when new fields are added.
935 let ImplItemRef { id, ident, ref kind, span: _, ref vis, ref defaultness } = *impl_item_ref;
936 visitor.visit_nested_impl_item(id);
937 visitor.visit_ident(ident);
938 visitor.visit_associated_item_kind(kind);
939 visitor.visit_vis(vis);
940 visitor.visit_defaultness(defaultness);
943 pub fn walk_struct_def<'v, V: Visitor<'v>>(visitor: &mut V, struct_definition: &'v VariantData) {
944 if let Some(ctor_hir_id) = struct_definition.ctor_hir_id() {
945 visitor.visit_id(ctor_hir_id);
947 walk_list!(visitor, visit_struct_field, struct_definition.fields());
950 pub fn walk_struct_field<'v, V: Visitor<'v>>(visitor: &mut V, struct_field: &'v StructField) {
951 visitor.visit_id(struct_field.hir_id);
952 visitor.visit_vis(&struct_field.vis);
953 visitor.visit_ident(struct_field.ident);
954 visitor.visit_ty(&struct_field.ty);
955 walk_list!(visitor, visit_attribute, &struct_field.attrs);
958 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block) {
959 visitor.visit_id(block.hir_id);
960 walk_list!(visitor, visit_stmt, &block.stmts);
961 walk_list!(visitor, visit_expr, &block.expr);
964 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
965 visitor.visit_id(statement.hir_id);
966 match statement.node {
967 StmtKind::Local(ref local) => visitor.visit_local(local),
968 StmtKind::Item(item) => visitor.visit_nested_item(item),
969 StmtKind::Expr(ref expression) |
970 StmtKind::Semi(ref expression) => {
971 visitor.visit_expr(expression)
976 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
977 visitor.visit_id(constant.hir_id);
978 visitor.visit_nested_body(constant.body);
981 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
982 visitor.visit_id(expression.hir_id);
983 walk_list!(visitor, visit_attribute, expression.attrs.iter());
984 match expression.node {
985 ExprKind::Box(ref subexpression) => {
986 visitor.visit_expr(subexpression)
988 ExprKind::Array(ref subexpressions) => {
989 walk_list!(visitor, visit_expr, subexpressions);
991 ExprKind::Repeat(ref element, ref count) => {
992 visitor.visit_expr(element);
993 visitor.visit_anon_const(count)
995 ExprKind::Struct(ref qpath, ref fields, ref optional_base) => {
996 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
997 for field in fields {
998 visitor.visit_id(field.hir_id);
999 visitor.visit_ident(field.ident);
1000 visitor.visit_expr(&field.expr)
1002 walk_list!(visitor, visit_expr, optional_base);
1004 ExprKind::Tup(ref subexpressions) => {
1005 walk_list!(visitor, visit_expr, subexpressions);
1007 ExprKind::Call(ref callee_expression, ref arguments) => {
1008 visitor.visit_expr(callee_expression);
1009 walk_list!(visitor, visit_expr, arguments);
1011 ExprKind::MethodCall(ref segment, _, ref arguments) => {
1012 visitor.visit_path_segment(expression.span, segment);
1013 walk_list!(visitor, visit_expr, arguments);
1015 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
1016 visitor.visit_expr(left_expression);
1017 visitor.visit_expr(right_expression)
1019 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
1020 visitor.visit_expr(subexpression)
1022 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
1023 visitor.visit_expr(subexpression);
1024 visitor.visit_ty(typ)
1026 ExprKind::DropTemps(ref subexpression) => {
1027 visitor.visit_expr(subexpression);
1029 ExprKind::Loop(ref block, ref opt_label, _) => {
1030 walk_list!(visitor, visit_label, opt_label);
1031 visitor.visit_block(block);
1033 ExprKind::Match(ref subexpression, ref arms, _) => {
1034 visitor.visit_expr(subexpression);
1035 walk_list!(visitor, visit_arm, arms);
1037 ExprKind::Closure(_, ref function_declaration, body, _fn_decl_span, _gen) => {
1038 visitor.visit_fn(FnKind::Closure(&expression.attrs),
1039 function_declaration,
1044 ExprKind::Block(ref block, ref opt_label) => {
1045 walk_list!(visitor, visit_label, opt_label);
1046 visitor.visit_block(block);
1048 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
1049 visitor.visit_expr(right_hand_expression);
1050 visitor.visit_expr(left_hand_expression)
1052 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
1053 visitor.visit_expr(right_expression);
1054 visitor.visit_expr(left_expression);
1056 ExprKind::Field(ref subexpression, ident) => {
1057 visitor.visit_expr(subexpression);
1058 visitor.visit_ident(ident);
1060 ExprKind::Index(ref main_expression, ref index_expression) => {
1061 visitor.visit_expr(main_expression);
1062 visitor.visit_expr(index_expression)
1064 ExprKind::Path(ref qpath) => {
1065 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1067 ExprKind::Break(ref destination, ref opt_expr) => {
1068 if let Some(ref label) = destination.label {
1069 visitor.visit_label(label);
1071 walk_list!(visitor, visit_expr, opt_expr);
1073 ExprKind::Continue(ref destination) => {
1074 if let Some(ref label) = destination.label {
1075 visitor.visit_label(label);
1078 ExprKind::Ret(ref optional_expression) => {
1079 walk_list!(visitor, visit_expr, optional_expression);
1081 ExprKind::InlineAsm(_, ref outputs, ref inputs) => {
1082 for expr in outputs.iter().chain(inputs.iter()) {
1083 visitor.visit_expr(expr)
1086 ExprKind::Yield(ref subexpression, _) => {
1087 visitor.visit_expr(subexpression);
1089 ExprKind::Lit(_) | ExprKind::Err => {}
1093 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm) {
1094 visitor.visit_id(arm.hir_id);
1095 walk_list!(visitor, visit_pat, &arm.pats);
1096 if let Some(ref g) = arm.guard {
1098 Guard::If(ref e) => visitor.visit_expr(e),
1101 visitor.visit_expr(&arm.body);
1102 walk_list!(visitor, visit_attribute, &arm.attrs);
1105 pub fn walk_vis<'v, V: Visitor<'v>>(visitor: &mut V, vis: &'v Visibility) {
1106 if let VisibilityKind::Restricted { ref path, hir_id } = vis.node {
1107 visitor.visit_id(hir_id);
1108 visitor.visit_path(path, hir_id)
1112 pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssocItemKind) {
1113 // No visitable content here: this fn exists so you can call it if
1114 // the right thing to do, should content be added in the future,
1115 // would be to walk it.
1118 pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
1119 // No visitable content here: this fn exists so you can call it if
1120 // the right thing to do, should content be added in the future,
1121 // would be to walk it.