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.
35 use crate::hir_id::CRATE_HIR_ID;
36 use crate::itemlikevisit::{ItemLikeVisitor, ParItemLikeVisitor};
38 use syntax::ast::{Attribute, Ident, Label, Name};
39 use syntax::walk_list;
41 pub struct DeepVisitor<'v, V> {
45 impl<'v, V> DeepVisitor<'v, V> {
46 pub fn new(base: &'v mut V) -> Self {
47 DeepVisitor { visitor: base }
51 impl<'v, 'hir, V> ItemLikeVisitor<'hir> for DeepVisitor<'v, V>
55 fn visit_item(&mut self, item: &'hir Item<'hir>) {
56 self.visitor.visit_item(item);
59 fn visit_trait_item(&mut self, trait_item: &'hir TraitItem<'hir>) {
60 self.visitor.visit_trait_item(trait_item);
63 fn visit_impl_item(&mut self, impl_item: &'hir ImplItem<'hir>) {
64 self.visitor.visit_impl_item(impl_item);
68 pub trait IntoVisitor<'hir> {
69 type Visitor: Visitor<'hir>;
70 fn into_visitor(&self) -> Self::Visitor;
73 pub struct ParDeepVisitor<V>(pub V);
75 impl<'hir, V> ParItemLikeVisitor<'hir> for ParDeepVisitor<V>
79 fn visit_item(&self, item: &'hir Item<'hir>) {
80 self.0.into_visitor().visit_item(item);
83 fn visit_trait_item(&self, trait_item: &'hir TraitItem<'hir>) {
84 self.0.into_visitor().visit_trait_item(trait_item);
87 fn visit_impl_item(&self, impl_item: &'hir ImplItem<'hir>) {
88 self.0.into_visitor().visit_impl_item(impl_item);
92 #[derive(Copy, Clone)]
94 /// `#[xxx] pub async/const/extern "Abi" fn foo()`
95 ItemFn(Ident, &'a Generics<'a>, FnHeader, &'a Visibility<'a>, &'a [Attribute]),
98 Method(Ident, &'a FnSig<'a>, Option<&'a Visibility<'a>>, &'a [Attribute]),
101 Closure(&'a [Attribute]),
104 impl<'a> FnKind<'a> {
105 pub fn attrs(&self) -> &'a [Attribute] {
107 FnKind::ItemFn(.., attrs) => attrs,
108 FnKind::Method(.., attrs) => attrs,
109 FnKind::Closure(attrs) => attrs,
113 pub fn header(&self) -> Option<&FnHeader> {
115 FnKind::ItemFn(_, _, ref header, _, _) => Some(header),
116 FnKind::Method(_, ref sig, _, _) => Some(&sig.header),
117 FnKind::Closure(_) => None,
122 /// An abstract representation of the HIR `rustc::hir::map::Map`.
123 pub trait Map<'hir> {
124 fn body(&self, id: BodyId) -> &'hir Body<'hir>;
125 fn item(&self, id: HirId) -> &'hir Item<'hir>;
126 fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
127 fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir>;
130 /// Specifies what nested things a visitor wants to visit. The most
131 /// common choice is `OnlyBodies`, which will cause the visitor to
132 /// visit fn bodies for fns that it encounters, but skip over nested
133 /// item-like things.
135 /// See the comments on `ItemLikeVisitor` for more details on the overall
137 pub enum NestedVisitorMap<'this, M> {
138 /// Do not visit any nested things. When you add a new
139 /// "non-nested" thing, you will want to audit such uses to see if
140 /// they remain valid.
142 /// Use this if you are only walking some particular kind of tree
143 /// (i.e., a type, or fn signature) and you don't want to thread a
147 /// Do not visit nested item-like things, but visit nested things
148 /// that are inside of an item-like.
150 /// **This is the most common choice.** A very common pattern is
151 /// to use `visit_all_item_likes()` as an outer loop,
152 /// and to have the visitor that visits the contents of each item
153 /// using this setting.
154 OnlyBodies(&'this M),
156 /// Visits all nested things, including item-likes.
158 /// **This is an unusual choice.** It is used when you want to
159 /// process everything within their lexical context. Typically you
160 /// kick off the visit by doing `walk_krate()`.
164 impl<'this, M> NestedVisitorMap<'this, M> {
165 /// Returns the map to use for an "intra item-like" thing (if any).
166 /// E.g., function body.
167 fn intra(self) -> Option<&'this M> {
169 NestedVisitorMap::None => None,
170 NestedVisitorMap::OnlyBodies(map) => Some(map),
171 NestedVisitorMap::All(map) => Some(map),
175 /// Returns the map to use for an "item-like" thing (if any).
176 /// E.g., item, impl-item.
177 fn inter(self) -> Option<&'this M> {
179 NestedVisitorMap::None => None,
180 NestedVisitorMap::OnlyBodies(_) => None,
181 NestedVisitorMap::All(map) => Some(map),
186 /// Each method of the Visitor trait is a hook to be potentially
187 /// overridden. Each method's default implementation recursively visits
188 /// the substructure of the input via the corresponding `walk` method;
189 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
191 /// Note that this visitor does NOT visit nested items by default
192 /// (this is why the module is called `intravisit`, to distinguish it
193 /// from the AST's `visit` module, which acts differently). If you
194 /// simply want to visit all items in the crate in some order, you
195 /// should call `Crate::visit_all_items`. Otherwise, see the comment
196 /// on `visit_nested_item` for details on how to visit nested items.
198 /// If you want to ensure that your code handles every variant
199 /// explicitly, you need to override each method. (And you also need
200 /// to monitor future changes to `Visitor` in case a new method with a
201 /// new default implementation gets introduced.)
202 pub trait Visitor<'v>: Sized {
205 ///////////////////////////////////////////////////////////////////////////
208 /// The default versions of the `visit_nested_XXX` routines invoke
209 /// this method to get a map to use. By selecting an enum variant,
210 /// you control which kinds of nested HIR are visited; see
211 /// `NestedVisitorMap` for details. By "nested HIR", we are
212 /// referring to bits of HIR that are not directly embedded within
213 /// one another but rather indirectly, through a table in the
214 /// crate. This is done to control dependencies during incremental
215 /// compilation: the non-inline bits of HIR can be tracked and
216 /// hashed separately.
218 /// **If for some reason you want the nested behavior, but don't
219 /// have a `Map` at your disposal:** then you should override the
220 /// `visit_nested_XXX` methods, and override this method to
221 /// `panic!()`. This way, if a new `visit_nested_XXX` variant is
222 /// added in the future, we will see the panic in your code and
223 /// fix it appropriately.
224 fn nested_visit_map(&mut self) -> NestedVisitorMap<'_, Self::Map>;
226 /// Invoked when a nested item is encountered. By default does
227 /// nothing unless you override `nested_visit_map` to return other than
228 /// `None`, in which case it will walk the item. **You probably
229 /// don't want to override this method** -- instead, override
230 /// `nested_visit_map` or use the "shallow" or "deep" visit
231 /// patterns described on `itemlikevisit::ItemLikeVisitor`. The only
232 /// reason to override this method is if you want a nested pattern
233 /// but cannot supply a `Map`; see `nested_visit_map` for advice.
234 #[allow(unused_variables)]
235 fn visit_nested_item(&mut self, id: ItemId) {
236 let opt_item = self.nested_visit_map().inter().map(|map| map.item(id.id));
237 if let Some(item) = opt_item {
238 self.visit_item(item);
242 /// Like `visit_nested_item()`, but for trait items. See
243 /// `visit_nested_item()` for advice on when to override this
245 #[allow(unused_variables)]
246 fn visit_nested_trait_item(&mut self, id: TraitItemId) {
247 let opt_item = self.nested_visit_map().inter().map(|map| map.trait_item(id));
248 if let Some(item) = opt_item {
249 self.visit_trait_item(item);
253 /// Like `visit_nested_item()`, but for impl items. See
254 /// `visit_nested_item()` for advice on when to override this
256 #[allow(unused_variables)]
257 fn visit_nested_impl_item(&mut self, id: ImplItemId) {
258 let opt_item = self.nested_visit_map().inter().map(|map| map.impl_item(id));
259 if let Some(item) = opt_item {
260 self.visit_impl_item(item);
264 /// Invoked to visit the body of a function, method or closure. Like
265 /// visit_nested_item, does nothing by default unless you override
266 /// `nested_visit_map` to return other than `None`, in which case it will walk
268 fn visit_nested_body(&mut self, id: BodyId) {
269 let opt_body = self.nested_visit_map().intra().map(|map| map.body(id));
270 if let Some(body) = opt_body {
271 self.visit_body(body);
275 fn visit_param(&mut self, param: &'v Param<'v>) {
276 walk_param(self, param)
279 /// Visits the top-level item and (optionally) nested items / impl items. See
280 /// `visit_nested_item` for details.
281 fn visit_item(&mut self, i: &'v Item<'v>) {
285 fn visit_body(&mut self, b: &'v Body<'v>) {
289 /// When invoking `visit_all_item_likes()`, you need to supply an
290 /// item-like visitor. This method converts a "intra-visit"
291 /// visitor into an item-like visitor that walks the entire tree.
292 /// If you use this, you probably don't want to process the
293 /// contents of nested item-like things, since the outer loop will
294 /// visit them as well.
295 fn as_deep_visitor<'s>(&'s mut self) -> DeepVisitor<'s, Self> {
296 DeepVisitor::new(self)
299 ///////////////////////////////////////////////////////////////////////////
301 fn visit_id(&mut self, _hir_id: HirId) {
304 fn visit_name(&mut self, _span: Span, _name: Name) {
307 fn visit_ident(&mut self, ident: Ident) {
308 walk_ident(self, ident)
310 fn visit_mod(&mut self, m: &'v Mod<'v>, _s: Span, n: HirId) {
313 fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>) {
314 walk_foreign_item(self, i)
316 fn visit_local(&mut self, l: &'v Local<'v>) {
319 fn visit_block(&mut self, b: &'v Block<'v>) {
322 fn visit_stmt(&mut self, s: &'v Stmt<'v>) {
325 fn visit_arm(&mut self, a: &'v Arm<'v>) {
328 fn visit_pat(&mut self, p: &'v Pat<'v>) {
331 fn visit_anon_const(&mut self, c: &'v AnonConst) {
332 walk_anon_const(self, c)
334 fn visit_expr(&mut self, ex: &'v Expr<'v>) {
337 fn visit_ty(&mut self, t: &'v Ty<'v>) {
340 fn visit_generic_param(&mut self, p: &'v GenericParam<'v>) {
341 walk_generic_param(self, p)
343 fn visit_generics(&mut self, g: &'v Generics<'v>) {
344 walk_generics(self, g)
346 fn visit_where_predicate(&mut self, predicate: &'v WherePredicate<'v>) {
347 walk_where_predicate(self, predicate)
349 fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>) {
350 walk_fn_decl(self, fd)
352 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, s: Span, id: HirId) {
353 walk_fn(self, fk, fd, b, s, id)
355 fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId) {
356 walk_use(self, path, hir_id)
358 fn visit_trait_item(&mut self, ti: &'v TraitItem<'v>) {
359 walk_trait_item(self, ti)
361 fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
362 walk_trait_item_ref(self, ii)
364 fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) {
365 walk_impl_item(self, ii)
367 fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef<'v>) {
368 walk_impl_item_ref(self, ii)
370 fn visit_trait_ref(&mut self, t: &'v TraitRef<'v>) {
371 walk_trait_ref(self, t)
373 fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>) {
374 walk_param_bound(self, bounds)
376 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>, m: TraitBoundModifier) {
377 walk_poly_trait_ref(self, t, m)
379 fn visit_variant_data(
381 s: &'v VariantData<'v>,
387 walk_struct_def(self, s)
389 fn visit_struct_field(&mut self, s: &'v StructField<'v>) {
390 walk_struct_field(self, s)
394 enum_definition: &'v EnumDef<'v>,
395 generics: &'v Generics<'v>,
399 walk_enum_def(self, enum_definition, generics, item_id)
401 fn visit_variant(&mut self, v: &'v Variant<'v>, g: &'v Generics<'v>, item_id: HirId) {
402 walk_variant(self, v, g, item_id)
404 fn visit_label(&mut self, label: &'v Label) {
405 walk_label(self, label)
407 fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>) {
409 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
410 GenericArg::Type(ty) => self.visit_ty(ty),
411 GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
414 fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
415 walk_lifetime(self, lifetime)
417 fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) {
418 walk_qpath(self, qpath, id, span)
420 fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
421 walk_path(self, path)
423 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) {
424 walk_path_segment(self, path_span, path_segment)
426 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) {
427 walk_generic_args(self, path_span, generic_args)
429 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
430 walk_assoc_type_binding(self, type_binding)
432 fn visit_attribute(&mut self, _attr: &'v Attribute) {}
433 fn visit_macro_def(&mut self, macro_def: &'v MacroDef<'v>) {
434 walk_macro_def(self, macro_def)
436 fn visit_vis(&mut self, vis: &'v Visibility<'v>) {
439 fn visit_associated_item_kind(&mut self, kind: &'v AssocItemKind) {
440 walk_associated_item_kind(self, kind);
442 fn visit_defaultness(&mut self, defaultness: &'v Defaultness) {
443 walk_defaultness(self, defaultness);
447 /// Walks the contents of a crate. See also `Crate::visit_all_items`.
448 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate<'v>) {
449 visitor.visit_mod(&krate.module, krate.span, CRATE_HIR_ID);
450 walk_list!(visitor, visit_attribute, krate.attrs);
451 walk_list!(visitor, visit_macro_def, krate.exported_macros);
454 pub fn walk_macro_def<'v, V: Visitor<'v>>(visitor: &mut V, macro_def: &'v MacroDef<'v>) {
455 visitor.visit_id(macro_def.hir_id);
456 visitor.visit_name(macro_def.span, macro_def.name);
457 walk_list!(visitor, visit_attribute, macro_def.attrs);
460 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod<'v>, mod_hir_id: HirId) {
461 visitor.visit_id(mod_hir_id);
462 for &item_id in module.item_ids {
463 visitor.visit_nested_item(item_id);
467 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body<'v>) {
468 walk_list!(visitor, visit_param, body.params);
469 visitor.visit_expr(&body.value);
472 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
473 // Intentionally visiting the expr first - the initialization expr
474 // dominates the local's definition.
475 walk_list!(visitor, visit_expr, &local.init);
476 walk_list!(visitor, visit_attribute, local.attrs.iter());
477 visitor.visit_id(local.hir_id);
478 visitor.visit_pat(&local.pat);
479 walk_list!(visitor, visit_ty, &local.ty);
482 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
483 visitor.visit_name(ident.span, ident.name);
486 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
487 visitor.visit_ident(label.ident);
490 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
491 visitor.visit_id(lifetime.hir_id);
492 match lifetime.name {
493 LifetimeName::Param(ParamName::Plain(ident)) => {
494 visitor.visit_ident(ident);
496 LifetimeName::Param(ParamName::Fresh(_))
497 | LifetimeName::Param(ParamName::Error)
498 | LifetimeName::Static
499 | LifetimeName::Error
500 | LifetimeName::Implicit
501 | LifetimeName::ImplicitObjectLifetimeDefault
502 | LifetimeName::Underscore => {}
506 pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(
508 trait_ref: &'v PolyTraitRef<'v>,
509 _modifier: TraitBoundModifier,
511 walk_list!(visitor, visit_generic_param, trait_ref.bound_generic_params);
512 visitor.visit_trait_ref(&trait_ref.trait_ref);
515 pub fn walk_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v TraitRef<'v>) {
516 visitor.visit_id(trait_ref.hir_ref_id);
517 visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
520 pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) {
521 visitor.visit_id(param.hir_id);
522 visitor.visit_pat(¶m.pat);
523 walk_list!(visitor, visit_attribute, param.attrs);
526 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
527 visitor.visit_vis(&item.vis);
528 visitor.visit_ident(item.ident);
530 ItemKind::ExternCrate(orig_name) => {
531 visitor.visit_id(item.hir_id);
532 if let Some(orig_name) = orig_name {
533 visitor.visit_name(item.span, orig_name);
536 ItemKind::Use(ref path, _) => {
537 visitor.visit_use(path, item.hir_id);
539 ItemKind::Static(ref typ, _, body) | ItemKind::Const(ref typ, body) => {
540 visitor.visit_id(item.hir_id);
541 visitor.visit_ty(typ);
542 visitor.visit_nested_body(body);
544 ItemKind::Fn(ref sig, ref generics, body_id) => visitor.visit_fn(
545 FnKind::ItemFn(item.ident, generics, sig.header, &item.vis, &item.attrs),
551 ItemKind::Mod(ref module) => {
552 // `visit_mod()` takes care of visiting the `Item`'s `HirId`.
553 visitor.visit_mod(module, item.span, item.hir_id)
555 ItemKind::ForeignMod(ref foreign_module) => {
556 visitor.visit_id(item.hir_id);
557 walk_list!(visitor, visit_foreign_item, foreign_module.items);
559 ItemKind::GlobalAsm(_) => {
560 visitor.visit_id(item.hir_id);
562 ItemKind::TyAlias(ref ty, ref generics) => {
563 visitor.visit_id(item.hir_id);
564 visitor.visit_ty(ty);
565 visitor.visit_generics(generics)
567 ItemKind::OpaqueTy(OpaqueTy { ref generics, bounds, .. }) => {
568 visitor.visit_id(item.hir_id);
569 walk_generics(visitor, generics);
570 walk_list!(visitor, visit_param_bound, bounds);
572 ItemKind::Enum(ref enum_definition, ref generics) => {
573 visitor.visit_generics(generics);
574 // `visit_enum_def()` takes care of visiting the `Item`'s `HirId`.
575 visitor.visit_enum_def(enum_definition, generics, item.hir_id, item.span)
577 ItemKind::Impl(.., ref generics, ref opt_trait_reference, ref typ, impl_item_refs) => {
578 visitor.visit_id(item.hir_id);
579 visitor.visit_generics(generics);
580 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
581 visitor.visit_ty(typ);
582 walk_list!(visitor, visit_impl_item_ref, impl_item_refs);
584 ItemKind::Struct(ref struct_definition, ref generics)
585 | ItemKind::Union(ref struct_definition, ref generics) => {
586 visitor.visit_generics(generics);
587 visitor.visit_id(item.hir_id);
588 visitor.visit_variant_data(
596 ItemKind::Trait(.., ref generics, bounds, trait_item_refs) => {
597 visitor.visit_id(item.hir_id);
598 visitor.visit_generics(generics);
599 walk_list!(visitor, visit_param_bound, bounds);
600 walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
602 ItemKind::TraitAlias(ref generics, bounds) => {
603 visitor.visit_id(item.hir_id);
604 visitor.visit_generics(generics);
605 walk_list!(visitor, visit_param_bound, bounds);
608 walk_list!(visitor, visit_attribute, item.attrs);
611 pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>, hir_id: HirId) {
612 visitor.visit_id(hir_id);
613 visitor.visit_path(path, hir_id);
616 pub fn walk_enum_def<'v, V: Visitor<'v>>(
618 enum_definition: &'v EnumDef<'v>,
619 generics: &'v Generics<'v>,
622 visitor.visit_id(item_id);
623 walk_list!(visitor, visit_variant, enum_definition.variants, generics, item_id);
626 pub fn walk_variant<'v, V: Visitor<'v>>(
628 variant: &'v Variant<'v>,
629 generics: &'v Generics<'v>,
630 parent_item_id: HirId,
632 visitor.visit_ident(variant.ident);
633 visitor.visit_id(variant.id);
634 visitor.visit_variant_data(
641 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
642 walk_list!(visitor, visit_attribute, variant.attrs);
645 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
646 visitor.visit_id(typ.hir_id);
649 TyKind::Slice(ref ty) => visitor.visit_ty(ty),
650 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
651 TyKind::Rptr(ref lifetime, ref mutable_type) => {
652 visitor.visit_lifetime(lifetime);
653 visitor.visit_ty(&mutable_type.ty)
656 TyKind::Tup(tuple_element_types) => {
657 walk_list!(visitor, visit_ty, tuple_element_types);
659 TyKind::BareFn(ref function_declaration) => {
660 walk_list!(visitor, visit_generic_param, function_declaration.generic_params);
661 visitor.visit_fn_decl(&function_declaration.decl);
663 TyKind::Path(ref qpath) => {
664 visitor.visit_qpath(qpath, typ.hir_id, typ.span);
666 TyKind::Def(item_id, lifetimes) => {
667 visitor.visit_nested_item(item_id);
668 walk_list!(visitor, visit_generic_arg, lifetimes);
670 TyKind::Array(ref ty, ref length) => {
671 visitor.visit_ty(ty);
672 visitor.visit_anon_const(length)
674 TyKind::TraitObject(bounds, ref lifetime) => {
675 for bound in bounds {
676 visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
678 visitor.visit_lifetime(lifetime);
680 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
681 TyKind::Infer | TyKind::Err => {}
685 pub fn walk_qpath<'v, V: Visitor<'v>>(
687 qpath: &'v QPath<'v>,
692 QPath::Resolved(ref maybe_qself, ref path) => {
693 if let Some(ref qself) = *maybe_qself {
694 visitor.visit_ty(qself);
696 visitor.visit_path(path, id)
698 QPath::TypeRelative(ref qself, ref segment) => {
699 visitor.visit_ty(qself);
700 visitor.visit_path_segment(span, segment);
705 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
706 for segment in path.segments {
707 visitor.visit_path_segment(path.span, segment);
711 pub fn walk_path_segment<'v, V: Visitor<'v>>(
714 segment: &'v PathSegment<'v>,
716 visitor.visit_ident(segment.ident);
717 if let Some(id) = segment.hir_id {
718 visitor.visit_id(id);
720 if let Some(ref args) = segment.args {
721 visitor.visit_generic_args(path_span, args);
725 pub fn walk_generic_args<'v, V: Visitor<'v>>(
728 generic_args: &'v GenericArgs<'v>,
730 walk_list!(visitor, visit_generic_arg, generic_args.args);
731 walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
734 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
736 type_binding: &'v TypeBinding<'v>,
738 visitor.visit_id(type_binding.hir_id);
739 visitor.visit_ident(type_binding.ident);
740 match type_binding.kind {
741 TypeBindingKind::Equality { ref ty } => {
742 visitor.visit_ty(ty);
744 TypeBindingKind::Constraint { bounds } => {
745 walk_list!(visitor, visit_param_bound, bounds);
750 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
751 visitor.visit_id(pattern.hir_id);
753 PatKind::TupleStruct(ref qpath, children, _) => {
754 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
755 walk_list!(visitor, visit_pat, children);
757 PatKind::Path(ref qpath) => {
758 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
760 PatKind::Struct(ref qpath, fields, _) => {
761 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
762 for field in fields {
763 visitor.visit_id(field.hir_id);
764 visitor.visit_ident(field.ident);
765 visitor.visit_pat(&field.pat)
768 PatKind::Or(pats) => walk_list!(visitor, visit_pat, pats),
769 PatKind::Tuple(tuple_elements, _) => {
770 walk_list!(visitor, visit_pat, tuple_elements);
772 PatKind::Box(ref subpattern) | PatKind::Ref(ref subpattern, _) => {
773 visitor.visit_pat(subpattern)
775 PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
776 visitor.visit_ident(ident);
777 walk_list!(visitor, visit_pat, optional_subpattern);
779 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
780 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
781 visitor.visit_expr(lower_bound);
782 visitor.visit_expr(upper_bound)
785 PatKind::Slice(prepatterns, ref slice_pattern, postpatterns) => {
786 walk_list!(visitor, visit_pat, prepatterns);
787 walk_list!(visitor, visit_pat, slice_pattern);
788 walk_list!(visitor, visit_pat, postpatterns);
793 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem<'v>) {
794 visitor.visit_id(foreign_item.hir_id);
795 visitor.visit_vis(&foreign_item.vis);
796 visitor.visit_ident(foreign_item.ident);
798 match foreign_item.kind {
799 ForeignItemKind::Fn(ref function_declaration, param_names, ref generics) => {
800 visitor.visit_generics(generics);
801 visitor.visit_fn_decl(function_declaration);
802 for ¶m_name in param_names {
803 visitor.visit_ident(param_name);
806 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
807 ForeignItemKind::Type => (),
810 walk_list!(visitor, visit_attribute, foreign_item.attrs);
813 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
815 GenericBound::Trait(ref typ, modifier) => {
816 visitor.visit_poly_trait_ref(typ, modifier);
818 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
822 pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam<'v>) {
823 visitor.visit_id(param.hir_id);
824 walk_list!(visitor, visit_attribute, param.attrs);
826 ParamName::Plain(ident) => visitor.visit_ident(ident),
827 ParamName::Error | ParamName::Fresh(_) => {}
830 GenericParamKind::Lifetime { .. } => {}
831 GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
832 GenericParamKind::Const { ref ty } => visitor.visit_ty(ty),
834 walk_list!(visitor, visit_param_bound, param.bounds);
837 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics<'v>) {
838 walk_list!(visitor, visit_generic_param, generics.params);
839 walk_list!(visitor, visit_where_predicate, generics.where_clause.predicates);
842 pub fn walk_where_predicate<'v, V: Visitor<'v>>(
844 predicate: &'v WherePredicate<'v>,
847 &WherePredicate::BoundPredicate(WhereBoundPredicate {
850 bound_generic_params,
853 visitor.visit_ty(bounded_ty);
854 walk_list!(visitor, visit_param_bound, bounds);
855 walk_list!(visitor, visit_generic_param, bound_generic_params);
857 &WherePredicate::RegionPredicate(WhereRegionPredicate { ref lifetime, bounds, .. }) => {
858 visitor.visit_lifetime(lifetime);
859 walk_list!(visitor, visit_param_bound, bounds);
861 &WherePredicate::EqPredicate(WhereEqPredicate {
862 hir_id, ref lhs_ty, ref rhs_ty, ..
864 visitor.visit_id(hir_id);
865 visitor.visit_ty(lhs_ty);
866 visitor.visit_ty(rhs_ty);
871 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FunctionRetTy<'v>) {
872 if let FunctionRetTy::Return(ref output_ty) = *ret_ty {
873 visitor.visit_ty(output_ty)
877 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl<'v>) {
878 for ty in function_declaration.inputs {
881 walk_fn_ret_ty(visitor, &function_declaration.output)
884 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
885 match function_kind {
886 FnKind::ItemFn(_, generics, ..) => {
887 visitor.visit_generics(generics);
889 FnKind::Method(..) | FnKind::Closure(_) => {}
893 pub fn walk_fn<'v, V: Visitor<'v>>(
895 function_kind: FnKind<'v>,
896 function_declaration: &'v FnDecl<'v>,
901 visitor.visit_id(id);
902 visitor.visit_fn_decl(function_declaration);
903 walk_fn_kind(visitor, function_kind);
904 visitor.visit_nested_body(body_id)
907 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem<'v>) {
908 visitor.visit_ident(trait_item.ident);
909 walk_list!(visitor, visit_attribute, trait_item.attrs);
910 visitor.visit_generics(&trait_item.generics);
911 match trait_item.kind {
912 TraitItemKind::Const(ref ty, default) => {
913 visitor.visit_id(trait_item.hir_id);
914 visitor.visit_ty(ty);
915 walk_list!(visitor, visit_nested_body, default);
917 TraitItemKind::Method(ref sig, TraitMethod::Required(param_names)) => {
918 visitor.visit_id(trait_item.hir_id);
919 visitor.visit_fn_decl(&sig.decl);
920 for ¶m_name in param_names {
921 visitor.visit_ident(param_name);
924 TraitItemKind::Method(ref sig, TraitMethod::Provided(body_id)) => {
926 FnKind::Method(trait_item.ident, sig, None, &trait_item.attrs),
933 TraitItemKind::Type(bounds, ref default) => {
934 visitor.visit_id(trait_item.hir_id);
935 walk_list!(visitor, visit_param_bound, bounds);
936 walk_list!(visitor, visit_ty, default);
941 pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
942 // N.B., deliberately force a compilation error if/when new fields are added.
943 let TraitItemRef { id, ident, ref kind, span: _, ref defaultness } = *trait_item_ref;
944 visitor.visit_nested_trait_item(id);
945 visitor.visit_ident(ident);
946 visitor.visit_associated_item_kind(kind);
947 visitor.visit_defaultness(defaultness);
950 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem<'v>) {
951 // N.B., deliberately force a compilation error if/when new fields are added.
963 visitor.visit_ident(ident);
964 visitor.visit_vis(vis);
965 visitor.visit_defaultness(defaultness);
966 walk_list!(visitor, visit_attribute, attrs);
967 visitor.visit_generics(generics);
969 ImplItemKind::Const(ref ty, body) => {
970 visitor.visit_id(impl_item.hir_id);
971 visitor.visit_ty(ty);
972 visitor.visit_nested_body(body);
974 ImplItemKind::Method(ref sig, body_id) => {
976 FnKind::Method(impl_item.ident, sig, Some(&impl_item.vis), &impl_item.attrs),
983 ImplItemKind::TyAlias(ref ty) => {
984 visitor.visit_id(impl_item.hir_id);
985 visitor.visit_ty(ty);
987 ImplItemKind::OpaqueTy(bounds) => {
988 visitor.visit_id(impl_item.hir_id);
989 walk_list!(visitor, visit_param_bound, bounds);
994 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef<'v>) {
995 // N.B., deliberately force a compilation error if/when new fields are added.
996 let ImplItemRef { id, ident, ref kind, span: _, ref vis, ref defaultness } = *impl_item_ref;
997 visitor.visit_nested_impl_item(id);
998 visitor.visit_ident(ident);
999 visitor.visit_associated_item_kind(kind);
1000 visitor.visit_vis(vis);
1001 visitor.visit_defaultness(defaultness);
1004 pub fn walk_struct_def<'v, V: Visitor<'v>>(
1006 struct_definition: &'v VariantData<'v>,
1008 if let Some(ctor_hir_id) = struct_definition.ctor_hir_id() {
1009 visitor.visit_id(ctor_hir_id);
1011 walk_list!(visitor, visit_struct_field, struct_definition.fields());
1014 pub fn walk_struct_field<'v, V: Visitor<'v>>(visitor: &mut V, struct_field: &'v StructField<'v>) {
1015 visitor.visit_id(struct_field.hir_id);
1016 visitor.visit_vis(&struct_field.vis);
1017 visitor.visit_ident(struct_field.ident);
1018 visitor.visit_ty(&struct_field.ty);
1019 walk_list!(visitor, visit_attribute, struct_field.attrs);
1022 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block<'v>) {
1023 visitor.visit_id(block.hir_id);
1024 walk_list!(visitor, visit_stmt, block.stmts);
1025 walk_list!(visitor, visit_expr, &block.expr);
1028 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt<'v>) {
1029 visitor.visit_id(statement.hir_id);
1030 match statement.kind {
1031 StmtKind::Local(ref local) => visitor.visit_local(local),
1032 StmtKind::Item(item) => visitor.visit_nested_item(item),
1033 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
1034 visitor.visit_expr(expression)
1039 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
1040 visitor.visit_id(constant.hir_id);
1041 visitor.visit_nested_body(constant.body);
1044 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>) {
1045 visitor.visit_id(expression.hir_id);
1046 walk_list!(visitor, visit_attribute, expression.attrs.iter());
1047 match expression.kind {
1048 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
1049 ExprKind::Array(subexpressions) => {
1050 walk_list!(visitor, visit_expr, subexpressions);
1052 ExprKind::Repeat(ref element, ref count) => {
1053 visitor.visit_expr(element);
1054 visitor.visit_anon_const(count)
1056 ExprKind::Struct(ref qpath, fields, ref optional_base) => {
1057 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1058 for field in fields {
1059 visitor.visit_id(field.hir_id);
1060 visitor.visit_ident(field.ident);
1061 visitor.visit_expr(&field.expr)
1063 walk_list!(visitor, visit_expr, optional_base);
1065 ExprKind::Tup(subexpressions) => {
1066 walk_list!(visitor, visit_expr, subexpressions);
1068 ExprKind::Call(ref callee_expression, arguments) => {
1069 visitor.visit_expr(callee_expression);
1070 walk_list!(visitor, visit_expr, arguments);
1072 ExprKind::MethodCall(ref segment, _, arguments) => {
1073 visitor.visit_path_segment(expression.span, segment);
1074 walk_list!(visitor, visit_expr, arguments);
1076 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
1077 visitor.visit_expr(left_expression);
1078 visitor.visit_expr(right_expression)
1080 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
1081 visitor.visit_expr(subexpression)
1083 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
1084 visitor.visit_expr(subexpression);
1085 visitor.visit_ty(typ)
1087 ExprKind::DropTemps(ref subexpression) => {
1088 visitor.visit_expr(subexpression);
1090 ExprKind::Loop(ref block, ref opt_label, _) => {
1091 walk_list!(visitor, visit_label, opt_label);
1092 visitor.visit_block(block);
1094 ExprKind::Match(ref subexpression, arms, _) => {
1095 visitor.visit_expr(subexpression);
1096 walk_list!(visitor, visit_arm, arms);
1098 ExprKind::Closure(_, ref function_declaration, body, _fn_decl_span, _gen) => visitor
1100 FnKind::Closure(&expression.attrs),
1101 function_declaration,
1106 ExprKind::Block(ref block, ref opt_label) => {
1107 walk_list!(visitor, visit_label, opt_label);
1108 visitor.visit_block(block);
1110 ExprKind::Assign(ref lhs, ref rhs, _) => {
1111 visitor.visit_expr(rhs);
1112 visitor.visit_expr(lhs)
1114 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
1115 visitor.visit_expr(right_expression);
1116 visitor.visit_expr(left_expression);
1118 ExprKind::Field(ref subexpression, ident) => {
1119 visitor.visit_expr(subexpression);
1120 visitor.visit_ident(ident);
1122 ExprKind::Index(ref main_expression, ref index_expression) => {
1123 visitor.visit_expr(main_expression);
1124 visitor.visit_expr(index_expression)
1126 ExprKind::Path(ref qpath) => {
1127 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1129 ExprKind::Break(ref destination, ref opt_expr) => {
1130 if let Some(ref label) = destination.label {
1131 visitor.visit_label(label);
1133 walk_list!(visitor, visit_expr, opt_expr);
1135 ExprKind::Continue(ref destination) => {
1136 if let Some(ref label) = destination.label {
1137 visitor.visit_label(label);
1140 ExprKind::Ret(ref optional_expression) => {
1141 walk_list!(visitor, visit_expr, optional_expression);
1143 ExprKind::InlineAsm(ref asm) => {
1144 walk_list!(visitor, visit_expr, asm.outputs_exprs);
1145 walk_list!(visitor, visit_expr, asm.inputs_exprs);
1147 ExprKind::Yield(ref subexpression, _) => {
1148 visitor.visit_expr(subexpression);
1150 ExprKind::Lit(_) | ExprKind::Err => {}
1154 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
1155 visitor.visit_id(arm.hir_id);
1156 visitor.visit_pat(&arm.pat);
1157 if let Some(ref g) = arm.guard {
1159 Guard::If(ref e) => visitor.visit_expr(e),
1162 visitor.visit_expr(&arm.body);
1163 walk_list!(visitor, visit_attribute, arm.attrs);
1166 pub fn walk_vis<'v, V: Visitor<'v>>(visitor: &mut V, vis: &'v Visibility<'v>) {
1167 if let VisibilityKind::Restricted { ref path, hir_id } = vis.node {
1168 visitor.visit_id(hir_id);
1169 visitor.visit_path(path, hir_id)
1173 pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssocItemKind) {
1174 // No visitable content here: this fn exists so you can call it if
1175 // the right thing to do, should content be added in the future,
1176 // would be to walk it.
1179 pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
1180 // No visitable content here: this fn exists so you can call it if
1181 // the right thing to do, should content be added in the future,
1182 // would be to walk it.