1 //! HIR walker for walking the contents of nodes.
3 //! Here are the three available patterns for the visitor strategy,
4 //! in roughly the order of desirability:
6 //! 1. **Shallow visit**: Get a simple callback for every item (or item-like thing) in the HIR.
7 //! - Example: find all items with a `#[foo]` attribute on them.
8 //! - How: Use the `hir_crate_items` or `hir_module_items` query to traverse over item-like ids
9 //! (ItemId, TraitItemId, etc.) and use tcx.def_kind and `tcx.hir().item*(id)` to filter and
10 //! access actual item-like thing, respectively.
11 //! - Pro: Efficient; just walks the lists of item ids and gives users control whether to access
12 //! the hir_owners themselves or not.
13 //! - Con: Don't get information about nesting
14 //! - Con: Don't have methods for specific bits of HIR, like "on
15 //! every expr, do this".
16 //! 2. **Deep visit**: Want to scan for specific kinds of HIR nodes within
17 //! an item, but don't care about how item-like things are nested
18 //! within one another.
19 //! - Example: Examine each expression to look for its type and do some check or other.
20 //! - How: Implement `intravisit::Visitor` and override the `NestedFilter` type to
21 //! `nested_filter::OnlyBodies` (and implement `nested_visit_map`), and use
22 //! `tcx.hir().visit_all_item_likes_in_crate(&mut visitor)`. Within your
23 //! `intravisit::Visitor` impl, implement methods like `visit_expr()` (don't forget to invoke
24 //! `intravisit::walk_expr()` to keep walking the subparts).
25 //! - Pro: Visitor methods for any kind of HIR node, not just item-like things.
26 //! - Pro: Integrates well into dependency tracking.
27 //! - Con: Don't get information about nesting between items
28 //! 3. **Nested visit**: Want to visit the whole HIR and you care about the nesting between
30 //! - Example: Lifetime resolution, which wants to bring lifetimes declared on the
31 //! impl into scope while visiting the impl-items, and then back out again.
32 //! - How: Implement `intravisit::Visitor` and override the `NestedFilter` type to
33 //! `nested_filter::All` (and implement `nested_visit_map`). Walk your crate with
34 //! `tcx.hir().walk_toplevel_module(visitor)` invoked on `tcx.hir().krate()`.
35 //! - Pro: Visitor methods for any kind of HIR node, not just item-like things.
36 //! - Pro: Preserves nesting information
37 //! - Con: Does not integrate well into dependency tracking.
39 //! If you have decided to use this visitor, here are some general
40 //! notes on how to do so:
42 //! Each overridden visit method has full control over what
43 //! happens with its node, it can do its own traversal of the node's children,
44 //! call `intravisit::walk_*` to apply the default traversal algorithm, or prevent
45 //! deeper traversal by doing nothing.
47 //! When visiting the HIR, the contents of nested items are NOT visited
48 //! by default. This is different from the AST visitor, which does a deep walk.
49 //! Hence this module is called `intravisit`; see the method `visit_nested_item`
52 //! Note: it is an important invariant that the default visitor walks
53 //! the body of a function in "execution order" - more concretely, if
54 //! we consider the reverse post-order (RPO) of the CFG implied by the HIR,
55 //! then a pre-order traversal of the HIR is consistent with the CFG RPO
56 //! on the *initial CFG point* of each HIR node, while a post-order traversal
57 //! of the HIR is consistent with the CFG RPO on each *final CFG point* of
60 //! One thing that follows is that if HIR node A always starts/ends executing
61 //! before HIR node B, then A appears in traversal pre/postorder before B,
62 //! respectively. (This follows from RPO respecting CFG domination).
64 //! This order consistency is required in a few places in rustc, for
65 //! example generator inference, and possibly also HIR borrowck.
68 use rustc_ast::walk_list;
69 use rustc_ast::{Attribute, Label};
70 use rustc_span::symbol::{Ident, Symbol};
73 pub trait IntoVisitor<'hir> {
74 type Visitor: Visitor<'hir>;
75 fn into_visitor(&self) -> Self::Visitor;
78 #[derive(Copy, Clone, Debug)]
80 /// `#[xxx] pub async/const/extern "Abi" fn foo()`
81 ItemFn(Ident, &'a Generics<'a>, FnHeader),
84 Method(Ident, &'a FnSig<'a>),
91 pub fn header(&self) -> Option<&FnHeader> {
93 FnKind::ItemFn(_, _, ref header) => Some(header),
94 FnKind::Method(_, ref sig) => Some(&sig.header),
95 FnKind::Closure => None,
99 pub fn constness(self) -> Constness {
100 self.header().map_or(Constness::NotConst, |header| header.constness)
103 pub fn asyncness(self) -> IsAsync {
104 self.header().map_or(IsAsync::NotAsync, |header| header.asyncness)
108 /// An abstract representation of the HIR `rustc_middle::hir::map::Map`.
109 pub trait Map<'hir> {
110 /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
111 fn find(&self, hir_id: HirId) -> Option<Node<'hir>>;
112 fn body(&self, id: BodyId) -> &'hir Body<'hir>;
113 fn item(&self, id: ItemId) -> &'hir Item<'hir>;
114 fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
115 fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir>;
116 fn foreign_item(&self, id: ForeignItemId) -> &'hir ForeignItem<'hir>;
119 // Used when no map is actually available, forcing manual implementation of nested visitors.
120 impl<'hir> Map<'hir> for ! {
121 fn find(&self, _: HirId) -> Option<Node<'hir>> {
124 fn body(&self, _: BodyId) -> &'hir Body<'hir> {
127 fn item(&self, _: ItemId) -> &'hir Item<'hir> {
130 fn trait_item(&self, _: TraitItemId) -> &'hir TraitItem<'hir> {
133 fn impl_item(&self, _: ImplItemId) -> &'hir ImplItem<'hir> {
136 fn foreign_item(&self, _: ForeignItemId) -> &'hir ForeignItem<'hir> {
141 pub mod nested_filter {
144 /// Specifies what nested things a visitor wants to visit. By "nested
145 /// things", we are referring to bits of HIR that are not directly embedded
146 /// within one another but rather indirectly, through a table in the crate.
147 /// This is done to control dependencies during incremental compilation: the
148 /// non-inline bits of HIR can be tracked and hashed separately.
150 /// The most common choice is `OnlyBodies`, which will cause the visitor to
151 /// visit fn bodies for fns that it encounters, and closure bodies, but
152 /// skip over nested item-like things.
154 /// See the comments on `ItemLikeVisitor` for more details on the overall
156 pub trait NestedFilter<'hir> {
159 /// Whether the visitor visits nested "item-like" things.
160 /// E.g., item, impl-item.
162 /// Whether the visitor visits "intra item-like" things.
163 /// E.g., function body, closure, `AnonConst`
167 /// Do not visit any nested things. When you add a new
168 /// "non-nested" thing, you will want to audit such uses to see if
169 /// they remain valid.
171 /// Use this if you are only walking some particular kind of tree
172 /// (i.e., a type, or fn signature) and you don't want to thread a
175 impl NestedFilter<'_> for None {
177 const INTER: bool = false;
178 const INTRA: bool = false;
182 use nested_filter::NestedFilter;
184 /// Each method of the Visitor trait is a hook to be potentially
185 /// overridden. Each method's default implementation recursively visits
186 /// the substructure of the input via the corresponding `walk` method;
187 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
189 /// Note that this visitor does NOT visit nested items by default
190 /// (this is why the module is called `intravisit`, to distinguish it
191 /// from the AST's `visit` module, which acts differently). If you
192 /// simply want to visit all items in the crate in some order, you
193 /// should call `tcx.hir().visit_all_item_likes_in_crate`. Otherwise, see the comment
194 /// on `visit_nested_item` for details on how to visit nested items.
196 /// If you want to ensure that your code handles every variant
197 /// explicitly, you need to override each method. (And you also need
198 /// to monitor future changes to `Visitor` in case a new method with a
199 /// new default implementation gets introduced.)
200 pub trait Visitor<'v>: Sized {
201 // this type should not be overridden, it exists for convenient usage as `Self::Map`
202 type Map: Map<'v> = <Self::NestedFilter as NestedFilter<'v>>::Map;
204 ///////////////////////////////////////////////////////////////////////////
207 /// Override this type to control which nested HIR are visited; see
208 /// [`NestedFilter`] for details. If you override this type, you
209 /// must also override [`nested_visit_map`](Self::nested_visit_map).
211 /// **If for some reason you want the nested behavior, but don't
212 /// have a `Map` at your disposal:** then override the
213 /// `visit_nested_XXX` methods. If a new `visit_nested_XXX` variant is
214 /// added in the future, it will cause a panic which can be detected
215 /// and fixed appropriately.
216 type NestedFilter: NestedFilter<'v> = nested_filter::None;
218 /// If `type NestedFilter` is set to visit nested items, this method
219 /// must also be overridden to provide a map to retrieve nested items.
220 fn nested_visit_map(&mut self) -> Self::Map {
222 "nested_visit_map must be implemented or consider using \
223 `type NestedFilter = nested_filter::None` (the default)"
227 /// Invoked when a nested item is encountered. By default, when
228 /// `Self::NestedFilter` is `nested_filter::None`, this method does
229 /// nothing. **You probably don't want to override this method** --
230 /// instead, override [`Self::NestedFilter`] or use the "shallow" or
231 /// "deep" visit patterns described on
232 /// `itemlikevisit::ItemLikeVisitor`. The only reason to override
233 /// this method is if you want a nested pattern but cannot supply a
234 /// [`Map`]; see `nested_visit_map` for advice.
235 fn visit_nested_item(&mut self, id: ItemId) {
236 if Self::NestedFilter::INTER {
237 let item = self.nested_visit_map().item(id);
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 fn visit_nested_trait_item(&mut self, id: TraitItemId) {
246 if Self::NestedFilter::INTER {
247 let item = self.nested_visit_map().trait_item(id);
248 self.visit_trait_item(item);
252 /// Like `visit_nested_item()`, but for impl items. See
253 /// `visit_nested_item()` for advice on when to override this
255 fn visit_nested_impl_item(&mut self, id: ImplItemId) {
256 if Self::NestedFilter::INTER {
257 let item = self.nested_visit_map().impl_item(id);
258 self.visit_impl_item(item);
262 /// Like `visit_nested_item()`, but for foreign items. See
263 /// `visit_nested_item()` for advice on when to override this
265 fn visit_nested_foreign_item(&mut self, id: ForeignItemId) {
266 if Self::NestedFilter::INTER {
267 let item = self.nested_visit_map().foreign_item(id);
268 self.visit_foreign_item(item);
272 /// Invoked to visit the body of a function, method or closure. Like
273 /// `visit_nested_item`, does nothing by default unless you override
274 /// `Self::NestedFilter`.
275 fn visit_nested_body(&mut self, id: BodyId) {
276 if Self::NestedFilter::INTRA {
277 let body = self.nested_visit_map().body(id);
278 self.visit_body(body);
282 fn visit_param(&mut self, param: &'v Param<'v>) {
283 walk_param(self, param)
286 /// Visits the top-level item and (optionally) nested items / impl items. See
287 /// `visit_nested_item` for details.
288 fn visit_item(&mut self, i: &'v Item<'v>) {
292 fn visit_body(&mut self, b: &'v Body<'v>) {
296 ///////////////////////////////////////////////////////////////////////////
298 fn visit_id(&mut self, _hir_id: HirId) {
301 fn visit_name(&mut self, _span: Span, _name: Symbol) {
304 fn visit_ident(&mut self, ident: Ident) {
305 walk_ident(self, ident)
307 fn visit_mod(&mut self, m: &'v Mod<'v>, _s: Span, n: HirId) {
310 fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>) {
311 walk_foreign_item(self, i)
313 fn visit_local(&mut self, l: &'v Local<'v>) {
316 fn visit_block(&mut self, b: &'v Block<'v>) {
319 fn visit_stmt(&mut self, s: &'v Stmt<'v>) {
322 fn visit_arm(&mut self, a: &'v Arm<'v>) {
325 fn visit_pat(&mut self, p: &'v Pat<'v>) {
328 fn visit_pat_field(&mut self, f: &'v PatField<'v>) {
329 walk_pat_field(self, f)
331 fn visit_array_length(&mut self, len: &'v ArrayLen) {
332 walk_array_len(self, len)
334 fn visit_anon_const(&mut self, c: &'v AnonConst) {
335 walk_anon_const(self, c)
337 fn visit_expr(&mut self, ex: &'v Expr<'v>) {
340 fn visit_let_expr(&mut self, lex: &'v Let<'v>) {
341 walk_let_expr(self, lex)
343 fn visit_expr_field(&mut self, field: &'v ExprField<'v>) {
344 walk_expr_field(self, field)
346 fn visit_ty(&mut self, t: &'v Ty<'v>) {
349 fn visit_generic_param(&mut self, p: &'v GenericParam<'v>) {
350 walk_generic_param(self, p)
352 fn visit_const_param_default(&mut self, _param: HirId, ct: &'v AnonConst) {
353 walk_const_param_default(self, ct)
355 fn visit_generics(&mut self, g: &'v Generics<'v>) {
356 walk_generics(self, g)
358 fn visit_where_predicate(&mut self, predicate: &'v WherePredicate<'v>) {
359 walk_where_predicate(self, predicate)
361 fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>) {
362 walk_fn_decl(self, fd)
364 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, s: Span, id: HirId) {
365 walk_fn(self, fk, fd, b, s, id)
367 fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId) {
368 walk_use(self, path, hir_id)
370 fn visit_trait_item(&mut self, ti: &'v TraitItem<'v>) {
371 walk_trait_item(self, ti)
373 fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
374 walk_trait_item_ref(self, ii)
376 fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) {
377 walk_impl_item(self, ii)
379 fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemRef) {
380 walk_foreign_item_ref(self, ii)
382 fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) {
383 walk_impl_item_ref(self, ii)
385 fn visit_trait_ref(&mut self, t: &'v TraitRef<'v>) {
386 walk_trait_ref(self, t)
388 fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>) {
389 walk_param_bound(self, bounds)
391 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>, m: TraitBoundModifier) {
392 walk_poly_trait_ref(self, t, m)
394 fn visit_variant_data(&mut self, s: &'v VariantData<'v>) {
395 walk_struct_def(self, s)
397 fn visit_field_def(&mut self, s: &'v FieldDef<'v>) {
398 walk_field_def(self, s)
400 fn visit_enum_def(&mut self, enum_definition: &'v EnumDef<'v>, item_id: HirId) {
401 walk_enum_def(self, enum_definition, item_id)
403 fn visit_variant(&mut self, v: &'v Variant<'v>) {
404 walk_variant(self, v)
406 fn visit_label(&mut self, label: &'v Label) {
407 walk_label(self, label)
409 fn visit_infer(&mut self, inf: &'v InferArg) {
412 fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>) {
414 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
415 GenericArg::Type(ty) => self.visit_ty(ty),
416 GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
417 GenericArg::Infer(inf) => self.visit_infer(inf),
420 fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
421 walk_lifetime(self, lifetime)
423 fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) {
424 walk_qpath(self, qpath, id, span)
426 fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
427 walk_path(self, path)
429 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) {
430 walk_path_segment(self, path_span, path_segment)
432 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) {
433 walk_generic_args(self, path_span, generic_args)
435 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
436 walk_assoc_type_binding(self, type_binding)
438 fn visit_attribute(&mut self, _attr: &'v Attribute) {}
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);
445 fn visit_inline_asm(&mut self, asm: &'v InlineAsm<'v>, id: HirId) {
446 walk_inline_asm(self, asm, id);
450 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod<'v>, mod_hir_id: HirId) {
451 visitor.visit_id(mod_hir_id);
452 for &item_id in module.item_ids {
453 visitor.visit_nested_item(item_id);
457 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body<'v>) {
458 walk_list!(visitor, visit_param, body.params);
459 visitor.visit_expr(&body.value);
462 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
463 // Intentionally visiting the expr first - the initialization expr
464 // dominates the local's definition.
465 walk_list!(visitor, visit_expr, &local.init);
466 visitor.visit_id(local.hir_id);
467 visitor.visit_pat(&local.pat);
468 if let Some(els) = local.els {
469 visitor.visit_block(els);
471 walk_list!(visitor, visit_ty, &local.ty);
474 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
475 visitor.visit_name(ident.span, ident.name);
478 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
479 visitor.visit_ident(label.ident);
482 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
483 visitor.visit_id(lifetime.hir_id);
484 match lifetime.name {
485 LifetimeName::Param(_, ParamName::Plain(ident)) => {
486 visitor.visit_ident(ident);
488 LifetimeName::Param(_, ParamName::Fresh)
489 | LifetimeName::Param(_, ParamName::Error)
490 | LifetimeName::Static
491 | LifetimeName::Error
492 | LifetimeName::ImplicitObjectLifetimeDefault
493 | LifetimeName::Infer => {}
497 pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(
499 trait_ref: &'v PolyTraitRef<'v>,
500 _modifier: TraitBoundModifier,
502 walk_list!(visitor, visit_generic_param, trait_ref.bound_generic_params);
503 visitor.visit_trait_ref(&trait_ref.trait_ref);
506 pub fn walk_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v TraitRef<'v>) {
507 visitor.visit_id(trait_ref.hir_ref_id);
508 visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
511 pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) {
512 visitor.visit_id(param.hir_id);
513 visitor.visit_pat(¶m.pat);
516 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
517 visitor.visit_ident(item.ident);
519 ItemKind::ExternCrate(orig_name) => {
520 visitor.visit_id(item.hir_id());
521 if let Some(orig_name) = orig_name {
522 visitor.visit_name(item.span, orig_name);
525 ItemKind::Use(ref path, _) => {
526 visitor.visit_use(path, item.hir_id());
528 ItemKind::Static(ref typ, _, body) | ItemKind::Const(ref typ, body) => {
529 visitor.visit_id(item.hir_id());
530 visitor.visit_ty(typ);
531 visitor.visit_nested_body(body);
533 ItemKind::Fn(ref sig, ref generics, body_id) => visitor.visit_fn(
534 FnKind::ItemFn(item.ident, generics, sig.header),
540 ItemKind::Macro(..) => {
541 visitor.visit_id(item.hir_id());
543 ItemKind::Mod(ref module) => {
544 // `visit_mod()` takes care of visiting the `Item`'s `HirId`.
545 visitor.visit_mod(module, item.span, item.hir_id())
547 ItemKind::ForeignMod { abi: _, items } => {
548 visitor.visit_id(item.hir_id());
549 walk_list!(visitor, visit_foreign_item_ref, items);
551 ItemKind::GlobalAsm(asm) => {
552 visitor.visit_id(item.hir_id());
553 visitor.visit_inline_asm(asm, item.hir_id());
555 ItemKind::TyAlias(ref ty, ref generics) => {
556 visitor.visit_id(item.hir_id());
557 visitor.visit_ty(ty);
558 visitor.visit_generics(generics)
560 ItemKind::OpaqueTy(OpaqueTy { ref generics, bounds, .. }) => {
561 visitor.visit_id(item.hir_id());
562 walk_generics(visitor, generics);
563 walk_list!(visitor, visit_param_bound, bounds);
565 ItemKind::Enum(ref enum_definition, ref generics) => {
566 visitor.visit_generics(generics);
567 // `visit_enum_def()` takes care of visiting the `Item`'s `HirId`.
568 visitor.visit_enum_def(enum_definition, item.hir_id())
570 ItemKind::Impl(Impl {
581 visitor.visit_id(item.hir_id());
582 visitor.visit_generics(generics);
583 walk_list!(visitor, visit_trait_ref, of_trait);
584 visitor.visit_ty(self_ty);
585 walk_list!(visitor, visit_impl_item_ref, *items);
587 ItemKind::Struct(ref struct_definition, ref generics)
588 | ItemKind::Union(ref struct_definition, ref generics) => {
589 visitor.visit_generics(generics);
590 visitor.visit_id(item.hir_id());
591 visitor.visit_variant_data(struct_definition);
593 ItemKind::Trait(.., ref generics, bounds, trait_item_refs) => {
594 visitor.visit_id(item.hir_id());
595 visitor.visit_generics(generics);
596 walk_list!(visitor, visit_param_bound, bounds);
597 walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
599 ItemKind::TraitAlias(ref generics, bounds) => {
600 visitor.visit_id(item.hir_id());
601 visitor.visit_generics(generics);
602 walk_list!(visitor, visit_param_bound, bounds);
607 pub fn walk_inline_asm<'v, V: Visitor<'v>>(visitor: &mut V, asm: &'v InlineAsm<'v>, id: HirId) {
608 for (op, op_sp) in asm.operands {
610 InlineAsmOperand::In { expr, .. } | InlineAsmOperand::InOut { expr, .. } => {
611 visitor.visit_expr(expr)
613 InlineAsmOperand::Out { expr, .. } => {
614 if let Some(expr) = expr {
615 visitor.visit_expr(expr);
618 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
619 visitor.visit_expr(in_expr);
620 if let Some(out_expr) = out_expr {
621 visitor.visit_expr(out_expr);
624 InlineAsmOperand::Const { anon_const, .. }
625 | InlineAsmOperand::SymFn { anon_const, .. } => visitor.visit_anon_const(anon_const),
626 InlineAsmOperand::SymStatic { path, .. } => visitor.visit_qpath(path, id, *op_sp),
631 pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>, hir_id: HirId) {
632 visitor.visit_id(hir_id);
633 visitor.visit_path(path, hir_id);
636 pub fn walk_enum_def<'v, V: Visitor<'v>>(
638 enum_definition: &'v EnumDef<'v>,
641 visitor.visit_id(item_id);
642 walk_list!(visitor, visit_variant, enum_definition.variants);
645 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V, variant: &'v Variant<'v>) {
646 visitor.visit_ident(variant.ident);
647 visitor.visit_id(variant.id);
648 visitor.visit_variant_data(&variant.data);
649 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
652 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
653 visitor.visit_id(typ.hir_id);
656 TyKind::Slice(ref ty) => visitor.visit_ty(ty),
657 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
658 TyKind::Rptr(ref lifetime, ref mutable_type) => {
659 visitor.visit_lifetime(lifetime);
660 visitor.visit_ty(&mutable_type.ty)
663 TyKind::Tup(tuple_element_types) => {
664 walk_list!(visitor, visit_ty, tuple_element_types);
666 TyKind::BareFn(ref function_declaration) => {
667 walk_list!(visitor, visit_generic_param, function_declaration.generic_params);
668 visitor.visit_fn_decl(&function_declaration.decl);
670 TyKind::Path(ref qpath) => {
671 visitor.visit_qpath(qpath, typ.hir_id, typ.span);
673 TyKind::OpaqueDef(item_id, lifetimes) => {
674 visitor.visit_nested_item(item_id);
675 walk_list!(visitor, visit_generic_arg, lifetimes);
677 TyKind::Array(ref ty, ref length) => {
678 visitor.visit_ty(ty);
679 visitor.visit_array_length(length)
681 TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
682 for bound in bounds {
683 visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
685 visitor.visit_lifetime(lifetime);
687 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
688 TyKind::Infer | TyKind::Err => {}
692 pub fn walk_inf<'v, V: Visitor<'v>>(visitor: &mut V, inf: &'v InferArg) {
693 visitor.visit_id(inf.hir_id);
696 pub fn walk_qpath<'v, V: Visitor<'v>>(
698 qpath: &'v QPath<'v>,
703 QPath::Resolved(ref maybe_qself, ref path) => {
704 walk_list!(visitor, visit_ty, maybe_qself);
705 visitor.visit_path(path, id)
707 QPath::TypeRelative(ref qself, ref segment) => {
708 visitor.visit_ty(qself);
709 visitor.visit_path_segment(span, segment);
711 QPath::LangItem(..) => {}
715 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
716 for segment in path.segments {
717 visitor.visit_path_segment(path.span, segment);
721 pub fn walk_path_segment<'v, V: Visitor<'v>>(
724 segment: &'v PathSegment<'v>,
726 visitor.visit_ident(segment.ident);
727 walk_list!(visitor, visit_id, segment.hir_id);
728 if let Some(ref args) = segment.args {
729 visitor.visit_generic_args(path_span, args);
733 pub fn walk_generic_args<'v, V: Visitor<'v>>(
736 generic_args: &'v GenericArgs<'v>,
738 walk_list!(visitor, visit_generic_arg, generic_args.args);
739 walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
742 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
744 type_binding: &'v TypeBinding<'v>,
746 visitor.visit_id(type_binding.hir_id);
747 visitor.visit_ident(type_binding.ident);
748 visitor.visit_generic_args(type_binding.span, type_binding.gen_args);
749 match type_binding.kind {
750 TypeBindingKind::Equality { ref term } => match term {
751 Term::Ty(ref ty) => visitor.visit_ty(ty),
752 Term::Const(ref c) => visitor.visit_anon_const(c),
754 TypeBindingKind::Constraint { bounds } => walk_list!(visitor, visit_param_bound, bounds),
758 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
759 visitor.visit_id(pattern.hir_id);
761 PatKind::TupleStruct(ref qpath, children, _) => {
762 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
763 walk_list!(visitor, visit_pat, children);
765 PatKind::Path(ref qpath) => {
766 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
768 PatKind::Struct(ref qpath, fields, _) => {
769 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
770 walk_list!(visitor, visit_pat_field, fields);
772 PatKind::Or(pats) => walk_list!(visitor, visit_pat, pats),
773 PatKind::Tuple(tuple_elements, _) => {
774 walk_list!(visitor, visit_pat, tuple_elements);
776 PatKind::Box(ref subpattern) | PatKind::Ref(ref subpattern, _) => {
777 visitor.visit_pat(subpattern)
779 PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
780 visitor.visit_ident(ident);
781 walk_list!(visitor, visit_pat, optional_subpattern);
783 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
784 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
785 walk_list!(visitor, visit_expr, lower_bound);
786 walk_list!(visitor, visit_expr, upper_bound);
789 PatKind::Slice(prepatterns, ref slice_pattern, postpatterns) => {
790 walk_list!(visitor, visit_pat, prepatterns);
791 walk_list!(visitor, visit_pat, slice_pattern);
792 walk_list!(visitor, visit_pat, postpatterns);
797 pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'v>) {
798 visitor.visit_id(field.hir_id);
799 visitor.visit_ident(field.ident);
800 visitor.visit_pat(&field.pat)
803 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem<'v>) {
804 visitor.visit_id(foreign_item.hir_id());
805 visitor.visit_ident(foreign_item.ident);
807 match foreign_item.kind {
808 ForeignItemKind::Fn(ref function_declaration, param_names, ref generics) => {
809 visitor.visit_generics(generics);
810 visitor.visit_fn_decl(function_declaration);
811 for ¶m_name in param_names {
812 visitor.visit_ident(param_name);
815 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
816 ForeignItemKind::Type => (),
820 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
822 GenericBound::Trait(ref typ, modifier) => {
823 visitor.visit_poly_trait_ref(typ, modifier);
825 GenericBound::LangItemTrait(_, span, hir_id, args) => {
826 visitor.visit_id(hir_id);
827 visitor.visit_generic_args(span, args);
829 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
833 pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam<'v>) {
834 visitor.visit_id(param.hir_id);
836 ParamName::Plain(ident) => visitor.visit_ident(ident),
837 ParamName::Error | ParamName::Fresh => {}
840 GenericParamKind::Lifetime { .. } => {}
841 GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
842 GenericParamKind::Const { ref ty, ref default } => {
843 visitor.visit_ty(ty);
844 if let Some(ref default) = default {
845 visitor.visit_const_param_default(param.hir_id, default);
851 pub fn walk_const_param_default<'v, V: Visitor<'v>>(visitor: &mut V, ct: &'v AnonConst) {
852 visitor.visit_anon_const(ct)
855 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics<'v>) {
856 walk_list!(visitor, visit_generic_param, generics.params);
857 walk_list!(visitor, visit_where_predicate, generics.predicates);
860 pub fn walk_where_predicate<'v, V: Visitor<'v>>(
862 predicate: &'v WherePredicate<'v>,
865 WherePredicate::BoundPredicate(WhereBoundPredicate {
868 bound_generic_params,
871 visitor.visit_ty(bounded_ty);
872 walk_list!(visitor, visit_param_bound, bounds);
873 walk_list!(visitor, visit_generic_param, bound_generic_params);
875 WherePredicate::RegionPredicate(WhereRegionPredicate { ref lifetime, bounds, .. }) => {
876 visitor.visit_lifetime(lifetime);
877 walk_list!(visitor, visit_param_bound, bounds);
879 WherePredicate::EqPredicate(WhereEqPredicate { ref lhs_ty, ref rhs_ty, .. }) => {
880 visitor.visit_ty(lhs_ty);
881 visitor.visit_ty(rhs_ty);
886 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FnRetTy<'v>) {
887 if let FnRetTy::Return(ref output_ty) = *ret_ty {
888 visitor.visit_ty(output_ty)
892 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl<'v>) {
893 for ty in function_declaration.inputs {
896 walk_fn_ret_ty(visitor, &function_declaration.output)
899 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
900 match function_kind {
901 FnKind::ItemFn(_, generics, ..) => {
902 visitor.visit_generics(generics);
904 FnKind::Closure | FnKind::Method(..) => {}
908 pub fn walk_fn<'v, V: Visitor<'v>>(
910 function_kind: FnKind<'v>,
911 function_declaration: &'v FnDecl<'v>,
916 visitor.visit_id(id);
917 visitor.visit_fn_decl(function_declaration);
918 walk_fn_kind(visitor, function_kind);
919 visitor.visit_nested_body(body_id)
922 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem<'v>) {
923 // N.B., deliberately force a compilation error if/when new fields are added.
924 let TraitItem { ident, generics, ref defaultness, ref kind, span, def_id: _ } = *trait_item;
925 let hir_id = trait_item.hir_id();
926 visitor.visit_ident(ident);
927 visitor.visit_generics(&generics);
928 visitor.visit_defaultness(&defaultness);
930 TraitItemKind::Const(ref ty, default) => {
931 visitor.visit_id(hir_id);
932 visitor.visit_ty(ty);
933 walk_list!(visitor, visit_nested_body, default);
935 TraitItemKind::Fn(ref sig, TraitFn::Required(param_names)) => {
936 visitor.visit_id(hir_id);
937 visitor.visit_fn_decl(&sig.decl);
938 for ¶m_name in param_names {
939 visitor.visit_ident(param_name);
942 TraitItemKind::Fn(ref sig, TraitFn::Provided(body_id)) => {
943 visitor.visit_fn(FnKind::Method(ident, sig), &sig.decl, body_id, span, hir_id);
945 TraitItemKind::Type(bounds, ref default) => {
946 visitor.visit_id(hir_id);
947 walk_list!(visitor, visit_param_bound, bounds);
948 walk_list!(visitor, visit_ty, default);
953 pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
954 // N.B., deliberately force a compilation error if/when new fields are added.
955 let TraitItemRef { id, ident, ref kind, span: _ } = *trait_item_ref;
956 visitor.visit_nested_trait_item(id);
957 visitor.visit_ident(ident);
958 visitor.visit_associated_item_kind(kind);
961 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem<'v>) {
962 // N.B., deliberately force a compilation error if/when new fields are added.
973 visitor.visit_ident(ident);
974 visitor.visit_generics(generics);
975 visitor.visit_defaultness(defaultness);
977 ImplItemKind::Const(ref ty, body) => {
978 visitor.visit_id(impl_item.hir_id());
979 visitor.visit_ty(ty);
980 visitor.visit_nested_body(body);
982 ImplItemKind::Fn(ref sig, body_id) => {
984 FnKind::Method(impl_item.ident, sig),
991 ImplItemKind::TyAlias(ref ty) => {
992 visitor.visit_id(impl_item.hir_id());
993 visitor.visit_ty(ty);
998 pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(
1000 foreign_item_ref: &'v ForeignItemRef,
1002 // N.B., deliberately force a compilation error if/when new fields are added.
1003 let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;
1004 visitor.visit_nested_foreign_item(id);
1005 visitor.visit_ident(ident);
1008 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef) {
1009 // N.B., deliberately force a compilation error if/when new fields are added.
1010 let ImplItemRef { id, ident, ref kind, span: _, trait_item_def_id: _ } = *impl_item_ref;
1011 visitor.visit_nested_impl_item(id);
1012 visitor.visit_ident(ident);
1013 visitor.visit_associated_item_kind(kind);
1016 pub fn walk_struct_def<'v, V: Visitor<'v>>(
1018 struct_definition: &'v VariantData<'v>,
1020 walk_list!(visitor, visit_id, struct_definition.ctor_hir_id());
1021 walk_list!(visitor, visit_field_def, struct_definition.fields());
1024 pub fn walk_field_def<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v FieldDef<'v>) {
1025 visitor.visit_id(field.hir_id);
1026 visitor.visit_ident(field.ident);
1027 visitor.visit_ty(&field.ty);
1030 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block<'v>) {
1031 visitor.visit_id(block.hir_id);
1032 walk_list!(visitor, visit_stmt, block.stmts);
1033 walk_list!(visitor, visit_expr, &block.expr);
1036 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt<'v>) {
1037 visitor.visit_id(statement.hir_id);
1038 match statement.kind {
1039 StmtKind::Local(ref local) => visitor.visit_local(local),
1040 StmtKind::Item(item) => visitor.visit_nested_item(item),
1041 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
1042 visitor.visit_expr(expression)
1047 pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) {
1049 &ArrayLen::Infer(hir_id, _span) => visitor.visit_id(hir_id),
1050 ArrayLen::Body(c) => visitor.visit_anon_const(c),
1054 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
1055 visitor.visit_id(constant.hir_id);
1056 visitor.visit_nested_body(constant.body);
1059 pub fn walk_let_expr<'v, V: Visitor<'v>>(visitor: &mut V, let_expr: &'v Let<'v>) {
1060 // match the visit order in walk_local
1061 visitor.visit_expr(let_expr.init);
1062 visitor.visit_id(let_expr.hir_id);
1063 visitor.visit_pat(let_expr.pat);
1064 walk_list!(visitor, visit_ty, let_expr.ty);
1067 pub fn walk_expr_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v ExprField<'v>) {
1068 visitor.visit_id(field.hir_id);
1069 visitor.visit_ident(field.ident);
1070 visitor.visit_expr(&field.expr)
1073 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>) {
1074 visitor.visit_id(expression.hir_id);
1075 match expression.kind {
1076 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
1077 ExprKind::Array(subexpressions) => {
1078 walk_list!(visitor, visit_expr, subexpressions);
1080 ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
1081 ExprKind::Repeat(ref element, ref count) => {
1082 visitor.visit_expr(element);
1083 visitor.visit_array_length(count)
1085 ExprKind::Struct(ref qpath, fields, ref optional_base) => {
1086 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1087 walk_list!(visitor, visit_expr_field, fields);
1088 walk_list!(visitor, visit_expr, optional_base);
1090 ExprKind::Tup(subexpressions) => {
1091 walk_list!(visitor, visit_expr, subexpressions);
1093 ExprKind::Call(ref callee_expression, arguments) => {
1094 visitor.visit_expr(callee_expression);
1095 walk_list!(visitor, visit_expr, arguments);
1097 ExprKind::MethodCall(ref segment, arguments, _) => {
1098 visitor.visit_path_segment(expression.span, segment);
1099 walk_list!(visitor, visit_expr, arguments);
1101 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
1102 visitor.visit_expr(left_expression);
1103 visitor.visit_expr(right_expression)
1105 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
1106 visitor.visit_expr(subexpression)
1108 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
1109 visitor.visit_expr(subexpression);
1110 visitor.visit_ty(typ)
1112 ExprKind::DropTemps(ref subexpression) => {
1113 visitor.visit_expr(subexpression);
1115 ExprKind::Let(ref let_expr) => visitor.visit_let_expr(let_expr),
1116 ExprKind::If(ref cond, ref then, ref else_opt) => {
1117 visitor.visit_expr(cond);
1118 visitor.visit_expr(then);
1119 walk_list!(visitor, visit_expr, else_opt);
1121 ExprKind::Loop(ref block, ref opt_label, _, _) => {
1122 walk_list!(visitor, visit_label, opt_label);
1123 visitor.visit_block(block);
1125 ExprKind::Match(ref subexpression, arms, _) => {
1126 visitor.visit_expr(subexpression);
1127 walk_list!(visitor, visit_arm, arms);
1129 ExprKind::Closure(&Closure {
1131 bound_generic_params,
1138 walk_list!(visitor, visit_generic_param, bound_generic_params);
1139 visitor.visit_fn(FnKind::Closure, fn_decl, body, expression.span, expression.hir_id)
1141 ExprKind::Block(ref block, ref opt_label) => {
1142 walk_list!(visitor, visit_label, opt_label);
1143 visitor.visit_block(block);
1145 ExprKind::Assign(ref lhs, ref rhs, _) => {
1146 visitor.visit_expr(rhs);
1147 visitor.visit_expr(lhs)
1149 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
1150 visitor.visit_expr(right_expression);
1151 visitor.visit_expr(left_expression);
1153 ExprKind::Field(ref subexpression, ident) => {
1154 visitor.visit_expr(subexpression);
1155 visitor.visit_ident(ident);
1157 ExprKind::Index(ref main_expression, ref index_expression) => {
1158 visitor.visit_expr(main_expression);
1159 visitor.visit_expr(index_expression)
1161 ExprKind::Path(ref qpath) => {
1162 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1164 ExprKind::Break(ref destination, ref opt_expr) => {
1165 walk_list!(visitor, visit_label, &destination.label);
1166 walk_list!(visitor, visit_expr, opt_expr);
1168 ExprKind::Continue(ref destination) => {
1169 walk_list!(visitor, visit_label, &destination.label);
1171 ExprKind::Ret(ref optional_expression) => {
1172 walk_list!(visitor, visit_expr, optional_expression);
1174 ExprKind::InlineAsm(ref asm) => {
1175 visitor.visit_inline_asm(asm, expression.hir_id);
1177 ExprKind::Yield(ref subexpression, _) => {
1178 visitor.visit_expr(subexpression);
1180 ExprKind::Lit(_) | ExprKind::Err => {}
1184 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
1185 visitor.visit_id(arm.hir_id);
1186 visitor.visit_pat(&arm.pat);
1187 if let Some(ref g) = arm.guard {
1189 Guard::If(ref e) => visitor.visit_expr(e),
1190 Guard::IfLet(ref l) => {
1191 visitor.visit_let_expr(l);
1195 visitor.visit_expr(&arm.body);
1198 pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssocItemKind) {
1199 // No visitable content here: this fn exists so you can call it if
1200 // the right thing to do, should content be added in the future,
1201 // would be to walk it.
1204 pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
1205 // No visitable content here: this fn exists so you can call it if
1206 // the right thing to do, should content be added in the future,
1207 // would be to walk it.