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().deep_visit_all_item_likes(&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 crate::itemlikevisit::ParItemLikeVisitor;
69 use rustc_ast::walk_list;
70 use rustc_ast::{Attribute, Label};
71 use rustc_span::symbol::{Ident, Symbol};
74 pub trait IntoVisitor<'hir> {
75 type Visitor: Visitor<'hir>;
76 fn into_visitor(&self) -> Self::Visitor;
79 pub struct ParDeepVisitor<V>(pub V);
81 impl<'hir, V> ParItemLikeVisitor<'hir> for ParDeepVisitor<V>
85 fn visit_item(&self, item: &'hir Item<'hir>) {
86 self.0.into_visitor().visit_item(item);
89 fn visit_trait_item(&self, trait_item: &'hir TraitItem<'hir>) {
90 self.0.into_visitor().visit_trait_item(trait_item);
93 fn visit_impl_item(&self, impl_item: &'hir ImplItem<'hir>) {
94 self.0.into_visitor().visit_impl_item(impl_item);
97 fn visit_foreign_item(&self, foreign_item: &'hir ForeignItem<'hir>) {
98 self.0.into_visitor().visit_foreign_item(foreign_item);
102 #[derive(Copy, Clone, Debug)]
103 pub enum FnKind<'a> {
104 /// `#[xxx] pub async/const/extern "Abi" fn foo()`
105 ItemFn(Ident, &'a Generics<'a>, FnHeader),
108 Method(Ident, &'a FnSig<'a>),
114 impl<'a> FnKind<'a> {
115 pub fn header(&self) -> Option<&FnHeader> {
117 FnKind::ItemFn(_, _, ref header) => Some(header),
118 FnKind::Method(_, ref sig) => Some(&sig.header),
119 FnKind::Closure => None,
123 pub fn constness(self) -> Constness {
124 self.header().map_or(Constness::NotConst, |header| header.constness)
127 pub fn asyncness(self) -> IsAsync {
128 self.header().map_or(IsAsync::NotAsync, |header| header.asyncness)
132 /// An abstract representation of the HIR `rustc_middle::hir::map::Map`.
133 pub trait Map<'hir> {
134 /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
135 fn find(&self, hir_id: HirId) -> Option<Node<'hir>>;
136 fn body(&self, id: BodyId) -> &'hir Body<'hir>;
137 fn item(&self, id: ItemId) -> &'hir Item<'hir>;
138 fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
139 fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir>;
140 fn foreign_item(&self, id: ForeignItemId) -> &'hir ForeignItem<'hir>;
143 // Used when no map is actually available, forcing manual implementation of nested visitors.
144 impl<'hir> Map<'hir> for ! {
145 fn find(&self, _: HirId) -> Option<Node<'hir>> {
148 fn body(&self, _: BodyId) -> &'hir Body<'hir> {
151 fn item(&self, _: ItemId) -> &'hir Item<'hir> {
154 fn trait_item(&self, _: TraitItemId) -> &'hir TraitItem<'hir> {
157 fn impl_item(&self, _: ImplItemId) -> &'hir ImplItem<'hir> {
160 fn foreign_item(&self, _: ForeignItemId) -> &'hir ForeignItem<'hir> {
165 pub mod nested_filter {
168 /// Specifies what nested things a visitor wants to visit. By "nested
169 /// things", we are referring to bits of HIR that are not directly embedded
170 /// within one another but rather indirectly, through a table in the crate.
171 /// This is done to control dependencies during incremental compilation: the
172 /// non-inline bits of HIR can be tracked and hashed separately.
174 /// The most common choice is `OnlyBodies`, which will cause the visitor to
175 /// visit fn bodies for fns that it encounters, and closure bodies, but
176 /// skip over nested item-like things.
178 /// See the comments on `ItemLikeVisitor` for more details on the overall
180 pub trait NestedFilter<'hir> {
183 /// Whether the visitor visits nested "item-like" things.
184 /// E.g., item, impl-item.
186 /// Whether the visitor visits "intra item-like" things.
187 /// E.g., function body, closure, `AnonConst`
191 /// Do not visit any nested things. When you add a new
192 /// "non-nested" thing, you will want to audit such uses to see if
193 /// they remain valid.
195 /// Use this if you are only walking some particular kind of tree
196 /// (i.e., a type, or fn signature) and you don't want to thread a
199 impl NestedFilter<'_> for None {
201 const INTER: bool = false;
202 const INTRA: bool = false;
206 use nested_filter::NestedFilter;
208 /// Each method of the Visitor trait is a hook to be potentially
209 /// overridden. Each method's default implementation recursively visits
210 /// the substructure of the input via the corresponding `walk` method;
211 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
213 /// Note that this visitor does NOT visit nested items by default
214 /// (this is why the module is called `intravisit`, to distinguish it
215 /// from the AST's `visit` module, which acts differently). If you
216 /// simply want to visit all items in the crate in some order, you
217 /// should call `Crate::visit_all_items`. Otherwise, see the comment
218 /// on `visit_nested_item` for details on how to visit nested items.
220 /// If you want to ensure that your code handles every variant
221 /// explicitly, you need to override each method. (And you also need
222 /// to monitor future changes to `Visitor` in case a new method with a
223 /// new default implementation gets introduced.)
224 pub trait Visitor<'v>: Sized {
225 // this type should not be overridden, it exists for convenient usage as `Self::Map`
226 type Map: Map<'v> = <Self::NestedFilter as NestedFilter<'v>>::Map;
228 ///////////////////////////////////////////////////////////////////////////
231 /// Override this type to control which nested HIR are visited; see
232 /// [`NestedFilter`] for details. If you override this type, you
233 /// must also override [`nested_visit_map`](Self::nested_visit_map).
235 /// **If for some reason you want the nested behavior, but don't
236 /// have a `Map` at your disposal:** then override the
237 /// `visit_nested_XXX` methods. If a new `visit_nested_XXX` variant is
238 /// added in the future, it will cause a panic which can be detected
239 /// and fixed appropriately.
240 type NestedFilter: NestedFilter<'v> = nested_filter::None;
242 /// If `type NestedFilter` is set to visit nested items, this method
243 /// must also be overridden to provide a map to retrieve nested items.
244 fn nested_visit_map(&mut self) -> Self::Map {
246 "nested_visit_map must be implemented or consider using \
247 `type NestedFilter = nested_filter::None` (the default)"
251 /// Invoked when a nested item is encountered. By default, when
252 /// `Self::NestedFilter` is `nested_filter::None`, this method does
253 /// nothing. **You probably don't want to override this method** --
254 /// instead, override [`Self::NestedFilter`] or use the "shallow" or
255 /// "deep" visit patterns described on
256 /// `itemlikevisit::ItemLikeVisitor`. The only reason to override
257 /// this method is if you want a nested pattern but cannot supply a
258 /// [`Map`]; see `nested_visit_map` for advice.
259 fn visit_nested_item(&mut self, id: ItemId) {
260 if Self::NestedFilter::INTER {
261 let item = self.nested_visit_map().item(id);
262 self.visit_item(item);
266 /// Like `visit_nested_item()`, but for trait items. See
267 /// `visit_nested_item()` for advice on when to override this
269 fn visit_nested_trait_item(&mut self, id: TraitItemId) {
270 if Self::NestedFilter::INTER {
271 let item = self.nested_visit_map().trait_item(id);
272 self.visit_trait_item(item);
276 /// Like `visit_nested_item()`, but for impl items. See
277 /// `visit_nested_item()` for advice on when to override this
279 fn visit_nested_impl_item(&mut self, id: ImplItemId) {
280 if Self::NestedFilter::INTER {
281 let item = self.nested_visit_map().impl_item(id);
282 self.visit_impl_item(item);
286 /// Like `visit_nested_item()`, but for foreign items. See
287 /// `visit_nested_item()` for advice on when to override this
289 fn visit_nested_foreign_item(&mut self, id: ForeignItemId) {
290 if Self::NestedFilter::INTER {
291 let item = self.nested_visit_map().foreign_item(id);
292 self.visit_foreign_item(item);
296 /// Invoked to visit the body of a function, method or closure. Like
297 /// `visit_nested_item`, does nothing by default unless you override
298 /// `Self::NestedFilter`.
299 fn visit_nested_body(&mut self, id: BodyId) {
300 if Self::NestedFilter::INTRA {
301 let body = self.nested_visit_map().body(id);
302 self.visit_body(body);
306 fn visit_param(&mut self, param: &'v Param<'v>) {
307 walk_param(self, param)
310 /// Visits the top-level item and (optionally) nested items / impl items. See
311 /// `visit_nested_item` for details.
312 fn visit_item(&mut self, i: &'v Item<'v>) {
316 fn visit_body(&mut self, b: &'v Body<'v>) {
320 ///////////////////////////////////////////////////////////////////////////
322 fn visit_id(&mut self, _hir_id: HirId) {
325 fn visit_name(&mut self, _span: Span, _name: Symbol) {
328 fn visit_ident(&mut self, ident: Ident) {
329 walk_ident(self, ident)
331 fn visit_mod(&mut self, m: &'v Mod<'v>, _s: Span, n: HirId) {
334 fn visit_foreign_item(&mut self, i: &'v ForeignItem<'v>) {
335 walk_foreign_item(self, i)
337 fn visit_local(&mut self, l: &'v Local<'v>) {
340 fn visit_block(&mut self, b: &'v Block<'v>) {
343 fn visit_stmt(&mut self, s: &'v Stmt<'v>) {
346 fn visit_arm(&mut self, a: &'v Arm<'v>) {
349 fn visit_pat(&mut self, p: &'v Pat<'v>) {
352 fn visit_array_length(&mut self, len: &'v ArrayLen) {
353 walk_array_len(self, len)
355 fn visit_anon_const(&mut self, c: &'v AnonConst) {
356 walk_anon_const(self, c)
358 fn visit_expr(&mut self, ex: &'v Expr<'v>) {
361 fn visit_let_expr(&mut self, lex: &'v Let<'v>) {
362 walk_let_expr(self, lex)
364 fn visit_ty(&mut self, t: &'v Ty<'v>) {
367 fn visit_generic_param(&mut self, p: &'v GenericParam<'v>) {
368 walk_generic_param(self, p)
370 fn visit_const_param_default(&mut self, _param: HirId, ct: &'v AnonConst) {
371 walk_const_param_default(self, ct)
373 fn visit_generics(&mut self, g: &'v Generics<'v>) {
374 walk_generics(self, g)
376 fn visit_where_predicate(&mut self, predicate: &'v WherePredicate<'v>) {
377 walk_where_predicate(self, predicate)
379 fn visit_fn_decl(&mut self, fd: &'v FnDecl<'v>) {
380 walk_fn_decl(self, fd)
382 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl<'v>, b: BodyId, s: Span, id: HirId) {
383 walk_fn(self, fk, fd, b, s, id)
385 fn visit_use(&mut self, path: &'v Path<'v>, hir_id: HirId) {
386 walk_use(self, path, hir_id)
388 fn visit_trait_item(&mut self, ti: &'v TraitItem<'v>) {
389 walk_trait_item(self, ti)
391 fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
392 walk_trait_item_ref(self, ii)
394 fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) {
395 walk_impl_item(self, ii)
397 fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemRef) {
398 walk_foreign_item_ref(self, ii)
400 fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) {
401 walk_impl_item_ref(self, ii)
403 fn visit_trait_ref(&mut self, t: &'v TraitRef<'v>) {
404 walk_trait_ref(self, t)
406 fn visit_param_bound(&mut self, bounds: &'v GenericBound<'v>) {
407 walk_param_bound(self, bounds)
409 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef<'v>, m: TraitBoundModifier) {
410 walk_poly_trait_ref(self, t, m)
412 fn visit_variant_data(
414 s: &'v VariantData<'v>,
420 walk_struct_def(self, s)
422 fn visit_field_def(&mut self, s: &'v FieldDef<'v>) {
423 walk_field_def(self, s)
427 enum_definition: &'v EnumDef<'v>,
428 generics: &'v Generics<'v>,
432 walk_enum_def(self, enum_definition, generics, item_id)
434 fn visit_variant(&mut self, v: &'v Variant<'v>, g: &'v Generics<'v>, item_id: HirId) {
435 walk_variant(self, v, g, item_id)
437 fn visit_label(&mut self, label: &'v Label) {
438 walk_label(self, label)
440 fn visit_infer(&mut self, inf: &'v InferArg) {
443 fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>) {
445 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
446 GenericArg::Type(ty) => self.visit_ty(ty),
447 GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
448 GenericArg::Infer(inf) => self.visit_infer(inf),
451 fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
452 walk_lifetime(self, lifetime)
454 fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) {
455 walk_qpath(self, qpath, id, span)
457 fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
458 walk_path(self, path)
460 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) {
461 walk_path_segment(self, path_span, path_segment)
463 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) {
464 walk_generic_args(self, path_span, generic_args)
466 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
467 walk_assoc_type_binding(self, type_binding)
469 fn visit_attribute(&mut self, _id: HirId, _attr: &'v Attribute) {}
470 fn visit_associated_item_kind(&mut self, kind: &'v AssocItemKind) {
471 walk_associated_item_kind(self, kind);
473 fn visit_defaultness(&mut self, defaultness: &'v Defaultness) {
474 walk_defaultness(self, defaultness);
476 fn visit_inline_asm(&mut self, asm: &'v InlineAsm<'v>, id: HirId) {
477 walk_inline_asm(self, asm, id);
481 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod<'v>, mod_hir_id: HirId) {
482 visitor.visit_id(mod_hir_id);
483 for &item_id in module.item_ids {
484 visitor.visit_nested_item(item_id);
488 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body<'v>) {
489 walk_list!(visitor, visit_param, body.params);
490 visitor.visit_expr(&body.value);
493 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local<'v>) {
494 // Intentionally visiting the expr first - the initialization expr
495 // dominates the local's definition.
496 walk_list!(visitor, visit_expr, &local.init);
497 visitor.visit_id(local.hir_id);
498 visitor.visit_pat(&local.pat);
499 walk_list!(visitor, visit_ty, &local.ty);
502 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
503 visitor.visit_name(ident.span, ident.name);
506 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
507 visitor.visit_ident(label.ident);
510 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
511 visitor.visit_id(lifetime.hir_id);
512 match lifetime.name {
513 LifetimeName::Param(_, ParamName::Plain(ident)) => {
514 visitor.visit_ident(ident);
516 LifetimeName::Param(_, ParamName::Fresh)
517 | LifetimeName::Param(_, ParamName::Error)
518 | LifetimeName::Static
519 | LifetimeName::Error
520 | LifetimeName::Implicit
521 | LifetimeName::ImplicitObjectLifetimeDefault
522 | LifetimeName::Underscore => {}
526 pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(
528 trait_ref: &'v PolyTraitRef<'v>,
529 _modifier: TraitBoundModifier,
531 walk_list!(visitor, visit_generic_param, trait_ref.bound_generic_params);
532 visitor.visit_trait_ref(&trait_ref.trait_ref);
535 pub fn walk_trait_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_ref: &'v TraitRef<'v>) {
536 visitor.visit_id(trait_ref.hir_ref_id);
537 visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
540 pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) {
541 visitor.visit_id(param.hir_id);
542 visitor.visit_pat(¶m.pat);
545 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
546 visitor.visit_ident(item.ident);
548 ItemKind::ExternCrate(orig_name) => {
549 visitor.visit_id(item.hir_id());
550 if let Some(orig_name) = orig_name {
551 visitor.visit_name(item.span, orig_name);
554 ItemKind::Use(ref path, _) => {
555 visitor.visit_use(path, item.hir_id());
557 ItemKind::Static(ref typ, _, body) | ItemKind::Const(ref typ, body) => {
558 visitor.visit_id(item.hir_id());
559 visitor.visit_ty(typ);
560 visitor.visit_nested_body(body);
562 ItemKind::Fn(ref sig, ref generics, body_id) => visitor.visit_fn(
563 FnKind::ItemFn(item.ident, generics, sig.header),
569 ItemKind::Macro(..) => {
570 visitor.visit_id(item.hir_id());
572 ItemKind::Mod(ref module) => {
573 // `visit_mod()` takes care of visiting the `Item`'s `HirId`.
574 visitor.visit_mod(module, item.span, item.hir_id())
576 ItemKind::ForeignMod { abi: _, items } => {
577 visitor.visit_id(item.hir_id());
578 walk_list!(visitor, visit_foreign_item_ref, items);
580 ItemKind::GlobalAsm(asm) => {
581 visitor.visit_id(item.hir_id());
582 visitor.visit_inline_asm(asm, item.hir_id());
584 ItemKind::TyAlias(ref ty, ref generics) => {
585 visitor.visit_id(item.hir_id());
586 visitor.visit_ty(ty);
587 visitor.visit_generics(generics)
589 ItemKind::OpaqueTy(OpaqueTy { ref generics, bounds, .. }) => {
590 visitor.visit_id(item.hir_id());
591 walk_generics(visitor, generics);
592 walk_list!(visitor, visit_param_bound, bounds);
594 ItemKind::Enum(ref enum_definition, ref generics) => {
595 visitor.visit_generics(generics);
596 // `visit_enum_def()` takes care of visiting the `Item`'s `HirId`.
597 visitor.visit_enum_def(enum_definition, generics, item.hir_id(), item.span)
599 ItemKind::Impl(Impl {
610 visitor.visit_id(item.hir_id());
611 visitor.visit_generics(generics);
612 walk_list!(visitor, visit_trait_ref, of_trait);
613 visitor.visit_ty(self_ty);
614 walk_list!(visitor, visit_impl_item_ref, *items);
616 ItemKind::Struct(ref struct_definition, ref generics)
617 | ItemKind::Union(ref struct_definition, ref generics) => {
618 visitor.visit_generics(generics);
619 visitor.visit_id(item.hir_id());
620 visitor.visit_variant_data(
628 ItemKind::Trait(.., ref generics, bounds, trait_item_refs) => {
629 visitor.visit_id(item.hir_id());
630 visitor.visit_generics(generics);
631 walk_list!(visitor, visit_param_bound, bounds);
632 walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
634 ItemKind::TraitAlias(ref generics, bounds) => {
635 visitor.visit_id(item.hir_id());
636 visitor.visit_generics(generics);
637 walk_list!(visitor, visit_param_bound, bounds);
642 pub fn walk_inline_asm<'v, V: Visitor<'v>>(visitor: &mut V, asm: &'v InlineAsm<'v>, id: HirId) {
643 for (op, op_sp) in asm.operands {
645 InlineAsmOperand::In { expr, .. } | InlineAsmOperand::InOut { expr, .. } => {
646 visitor.visit_expr(expr)
648 InlineAsmOperand::Out { expr, .. } => {
649 if let Some(expr) = expr {
650 visitor.visit_expr(expr);
653 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
654 visitor.visit_expr(in_expr);
655 if let Some(out_expr) = out_expr {
656 visitor.visit_expr(out_expr);
659 InlineAsmOperand::Const { anon_const, .. }
660 | InlineAsmOperand::SymFn { anon_const, .. } => visitor.visit_anon_const(anon_const),
661 InlineAsmOperand::SymStatic { path, .. } => visitor.visit_qpath(path, id, *op_sp),
666 pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>, hir_id: HirId) {
667 visitor.visit_id(hir_id);
668 visitor.visit_path(path, hir_id);
671 pub fn walk_enum_def<'v, V: Visitor<'v>>(
673 enum_definition: &'v EnumDef<'v>,
674 generics: &'v Generics<'v>,
677 visitor.visit_id(item_id);
678 walk_list!(visitor, visit_variant, enum_definition.variants, generics, item_id);
681 pub fn walk_variant<'v, V: Visitor<'v>>(
683 variant: &'v Variant<'v>,
684 generics: &'v Generics<'v>,
685 parent_item_id: HirId,
687 visitor.visit_ident(variant.ident);
688 visitor.visit_id(variant.id);
689 visitor.visit_variant_data(
696 walk_list!(visitor, visit_anon_const, &variant.disr_expr);
699 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
700 visitor.visit_id(typ.hir_id);
703 TyKind::Slice(ref ty) => visitor.visit_ty(ty),
704 TyKind::Ptr(ref mutable_type) => visitor.visit_ty(&mutable_type.ty),
705 TyKind::Rptr(ref lifetime, ref mutable_type) => {
706 visitor.visit_lifetime(lifetime);
707 visitor.visit_ty(&mutable_type.ty)
710 TyKind::Tup(tuple_element_types) => {
711 walk_list!(visitor, visit_ty, tuple_element_types);
713 TyKind::BareFn(ref function_declaration) => {
714 walk_list!(visitor, visit_generic_param, function_declaration.generic_params);
715 visitor.visit_fn_decl(&function_declaration.decl);
717 TyKind::Path(ref qpath) => {
718 visitor.visit_qpath(qpath, typ.hir_id, typ.span);
720 TyKind::OpaqueDef(item_id, lifetimes) => {
721 visitor.visit_nested_item(item_id);
722 walk_list!(visitor, visit_generic_arg, lifetimes);
724 TyKind::Array(ref ty, ref length) => {
725 visitor.visit_ty(ty);
726 visitor.visit_array_length(length)
728 TyKind::TraitObject(bounds, ref lifetime, _syntax) => {
729 for bound in bounds {
730 visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
732 visitor.visit_lifetime(lifetime);
734 TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
735 TyKind::Infer | TyKind::Err => {}
739 pub fn walk_inf<'v, V: Visitor<'v>>(visitor: &mut V, inf: &'v InferArg) {
740 visitor.visit_id(inf.hir_id);
743 pub fn walk_qpath<'v, V: Visitor<'v>>(
745 qpath: &'v QPath<'v>,
750 QPath::Resolved(ref maybe_qself, ref path) => {
751 walk_list!(visitor, visit_ty, maybe_qself);
752 visitor.visit_path(path, id)
754 QPath::TypeRelative(ref qself, ref segment) => {
755 visitor.visit_ty(qself);
756 visitor.visit_path_segment(span, segment);
758 QPath::LangItem(..) => {}
762 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
763 for segment in path.segments {
764 visitor.visit_path_segment(path.span, segment);
768 pub fn walk_path_segment<'v, V: Visitor<'v>>(
771 segment: &'v PathSegment<'v>,
773 visitor.visit_ident(segment.ident);
774 walk_list!(visitor, visit_id, segment.hir_id);
775 if let Some(ref args) = segment.args {
776 visitor.visit_generic_args(path_span, args);
780 pub fn walk_generic_args<'v, V: Visitor<'v>>(
783 generic_args: &'v GenericArgs<'v>,
785 walk_list!(visitor, visit_generic_arg, generic_args.args);
786 walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
789 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
791 type_binding: &'v TypeBinding<'v>,
793 visitor.visit_id(type_binding.hir_id);
794 visitor.visit_ident(type_binding.ident);
795 visitor.visit_generic_args(type_binding.span, type_binding.gen_args);
796 match type_binding.kind {
797 TypeBindingKind::Equality { ref term } => match term {
798 Term::Ty(ref ty) => visitor.visit_ty(ty),
799 Term::Const(ref c) => visitor.visit_anon_const(c),
801 TypeBindingKind::Constraint { bounds } => walk_list!(visitor, visit_param_bound, bounds),
805 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) {
806 visitor.visit_id(pattern.hir_id);
808 PatKind::TupleStruct(ref qpath, children, _) => {
809 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
810 walk_list!(visitor, visit_pat, children);
812 PatKind::Path(ref qpath) => {
813 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
815 PatKind::Struct(ref qpath, fields, _) => {
816 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
817 for field in fields {
818 visitor.visit_id(field.hir_id);
819 visitor.visit_ident(field.ident);
820 visitor.visit_pat(&field.pat)
823 PatKind::Or(pats) => walk_list!(visitor, visit_pat, pats),
824 PatKind::Tuple(tuple_elements, _) => {
825 walk_list!(visitor, visit_pat, tuple_elements);
827 PatKind::Box(ref subpattern) | PatKind::Ref(ref subpattern, _) => {
828 visitor.visit_pat(subpattern)
830 PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
831 visitor.visit_ident(ident);
832 walk_list!(visitor, visit_pat, optional_subpattern);
834 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
835 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
836 walk_list!(visitor, visit_expr, lower_bound);
837 walk_list!(visitor, visit_expr, upper_bound);
840 PatKind::Slice(prepatterns, ref slice_pattern, postpatterns) => {
841 walk_list!(visitor, visit_pat, prepatterns);
842 walk_list!(visitor, visit_pat, slice_pattern);
843 walk_list!(visitor, visit_pat, postpatterns);
848 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem<'v>) {
849 visitor.visit_id(foreign_item.hir_id());
850 visitor.visit_ident(foreign_item.ident);
852 match foreign_item.kind {
853 ForeignItemKind::Fn(ref function_declaration, param_names, ref generics) => {
854 visitor.visit_generics(generics);
855 visitor.visit_fn_decl(function_declaration);
856 for ¶m_name in param_names {
857 visitor.visit_ident(param_name);
860 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
861 ForeignItemKind::Type => (),
865 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound<'v>) {
867 GenericBound::Trait(ref typ, modifier) => {
868 visitor.visit_poly_trait_ref(typ, modifier);
870 GenericBound::LangItemTrait(_, span, hir_id, args) => {
871 visitor.visit_id(hir_id);
872 visitor.visit_generic_args(span, args);
874 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
878 pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam<'v>) {
879 visitor.visit_id(param.hir_id);
881 ParamName::Plain(ident) => visitor.visit_ident(ident),
882 ParamName::Error | ParamName::Fresh => {}
885 GenericParamKind::Lifetime { .. } => {}
886 GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
887 GenericParamKind::Const { ref ty, ref default } => {
888 visitor.visit_ty(ty);
889 if let Some(ref default) = default {
890 visitor.visit_const_param_default(param.hir_id, default);
896 pub fn walk_const_param_default<'v, V: Visitor<'v>>(visitor: &mut V, ct: &'v AnonConst) {
897 visitor.visit_anon_const(ct)
900 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics<'v>) {
901 walk_list!(visitor, visit_generic_param, generics.params);
902 walk_list!(visitor, visit_where_predicate, generics.predicates);
905 pub fn walk_where_predicate<'v, V: Visitor<'v>>(
907 predicate: &'v WherePredicate<'v>,
910 WherePredicate::BoundPredicate(WhereBoundPredicate {
913 bound_generic_params,
916 visitor.visit_ty(bounded_ty);
917 walk_list!(visitor, visit_param_bound, bounds);
918 walk_list!(visitor, visit_generic_param, bound_generic_params);
920 WherePredicate::RegionPredicate(WhereRegionPredicate { ref lifetime, bounds, .. }) => {
921 visitor.visit_lifetime(lifetime);
922 walk_list!(visitor, visit_param_bound, bounds);
924 WherePredicate::EqPredicate(WhereEqPredicate {
925 hir_id, ref lhs_ty, ref rhs_ty, ..
927 visitor.visit_id(hir_id);
928 visitor.visit_ty(lhs_ty);
929 visitor.visit_ty(rhs_ty);
934 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FnRetTy<'v>) {
935 if let FnRetTy::Return(ref output_ty) = *ret_ty {
936 visitor.visit_ty(output_ty)
940 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl<'v>) {
941 for ty in function_declaration.inputs {
944 walk_fn_ret_ty(visitor, &function_declaration.output)
947 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
948 match function_kind {
949 FnKind::ItemFn(_, generics, ..) => {
950 visitor.visit_generics(generics);
952 FnKind::Method(..) | FnKind::Closure => {}
956 pub fn walk_fn<'v, V: Visitor<'v>>(
958 function_kind: FnKind<'v>,
959 function_declaration: &'v FnDecl<'v>,
964 visitor.visit_id(id);
965 visitor.visit_fn_decl(function_declaration);
966 walk_fn_kind(visitor, function_kind);
967 visitor.visit_nested_body(body_id)
970 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem<'v>) {
971 visitor.visit_ident(trait_item.ident);
972 visitor.visit_generics(&trait_item.generics);
973 match trait_item.kind {
974 TraitItemKind::Const(ref ty, default) => {
975 visitor.visit_id(trait_item.hir_id());
976 visitor.visit_ty(ty);
977 walk_list!(visitor, visit_nested_body, default);
979 TraitItemKind::Fn(ref sig, TraitFn::Required(param_names)) => {
980 visitor.visit_id(trait_item.hir_id());
981 visitor.visit_fn_decl(&sig.decl);
982 for ¶m_name in param_names {
983 visitor.visit_ident(param_name);
986 TraitItemKind::Fn(ref sig, TraitFn::Provided(body_id)) => {
988 FnKind::Method(trait_item.ident, sig),
995 TraitItemKind::Type(bounds, ref default) => {
996 visitor.visit_id(trait_item.hir_id());
997 walk_list!(visitor, visit_param_bound, bounds);
998 walk_list!(visitor, visit_ty, default);
1003 pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
1004 // N.B., deliberately force a compilation error if/when new fields are added.
1005 let TraitItemRef { id, ident, ref kind, span: _, ref defaultness } = *trait_item_ref;
1006 visitor.visit_nested_trait_item(id);
1007 visitor.visit_ident(ident);
1008 visitor.visit_associated_item_kind(kind);
1009 visitor.visit_defaultness(defaultness);
1012 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem<'v>) {
1013 // N.B., deliberately force a compilation error if/when new fields are added.
1014 let ImplItem { def_id: _, ident, ref generics, ref kind, span: _, vis_span: _ } = *impl_item;
1016 visitor.visit_ident(ident);
1017 visitor.visit_generics(generics);
1019 ImplItemKind::Const(ref ty, body) => {
1020 visitor.visit_id(impl_item.hir_id());
1021 visitor.visit_ty(ty);
1022 visitor.visit_nested_body(body);
1024 ImplItemKind::Fn(ref sig, body_id) => {
1026 FnKind::Method(impl_item.ident, sig),
1033 ImplItemKind::TyAlias(ref ty) => {
1034 visitor.visit_id(impl_item.hir_id());
1035 visitor.visit_ty(ty);
1040 pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(
1042 foreign_item_ref: &'v ForeignItemRef,
1044 // N.B., deliberately force a compilation error if/when new fields are added.
1045 let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;
1046 visitor.visit_nested_foreign_item(id);
1047 visitor.visit_ident(ident);
1050 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef) {
1051 // N.B., deliberately force a compilation error if/when new fields are added.
1052 let ImplItemRef { id, ident, ref kind, span: _, ref defaultness, trait_item_def_id: _ } =
1054 visitor.visit_nested_impl_item(id);
1055 visitor.visit_ident(ident);
1056 visitor.visit_associated_item_kind(kind);
1057 visitor.visit_defaultness(defaultness);
1060 pub fn walk_struct_def<'v, V: Visitor<'v>>(
1062 struct_definition: &'v VariantData<'v>,
1064 walk_list!(visitor, visit_id, struct_definition.ctor_hir_id());
1065 walk_list!(visitor, visit_field_def, struct_definition.fields());
1068 pub fn walk_field_def<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v FieldDef<'v>) {
1069 visitor.visit_id(field.hir_id);
1070 visitor.visit_ident(field.ident);
1071 visitor.visit_ty(&field.ty);
1074 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block<'v>) {
1075 visitor.visit_id(block.hir_id);
1076 walk_list!(visitor, visit_stmt, block.stmts);
1077 walk_list!(visitor, visit_expr, &block.expr);
1080 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt<'v>) {
1081 visitor.visit_id(statement.hir_id);
1082 match statement.kind {
1083 StmtKind::Local(ref local) => visitor.visit_local(local),
1084 StmtKind::Item(item) => visitor.visit_nested_item(item),
1085 StmtKind::Expr(ref expression) | StmtKind::Semi(ref expression) => {
1086 visitor.visit_expr(expression)
1091 pub fn walk_array_len<'v, V: Visitor<'v>>(visitor: &mut V, len: &'v ArrayLen) {
1093 &ArrayLen::Infer(hir_id, _span) => visitor.visit_id(hir_id),
1094 ArrayLen::Body(c) => visitor.visit_anon_const(c),
1098 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
1099 visitor.visit_id(constant.hir_id);
1100 visitor.visit_nested_body(constant.body);
1103 pub fn walk_let_expr<'v, V: Visitor<'v>>(visitor: &mut V, let_expr: &'v Let<'v>) {
1104 // match the visit order in walk_local
1105 visitor.visit_expr(let_expr.init);
1106 visitor.visit_id(let_expr.hir_id);
1107 visitor.visit_pat(let_expr.pat);
1108 walk_list!(visitor, visit_ty, let_expr.ty);
1111 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>) {
1112 visitor.visit_id(expression.hir_id);
1113 match expression.kind {
1114 ExprKind::Box(ref subexpression) => visitor.visit_expr(subexpression),
1115 ExprKind::Array(subexpressions) => {
1116 walk_list!(visitor, visit_expr, subexpressions);
1118 ExprKind::ConstBlock(ref anon_const) => visitor.visit_anon_const(anon_const),
1119 ExprKind::Repeat(ref element, ref count) => {
1120 visitor.visit_expr(element);
1121 visitor.visit_array_length(count)
1123 ExprKind::Struct(ref qpath, fields, ref optional_base) => {
1124 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1125 for field in fields {
1126 visitor.visit_id(field.hir_id);
1127 visitor.visit_ident(field.ident);
1128 visitor.visit_expr(&field.expr)
1130 walk_list!(visitor, visit_expr, optional_base);
1132 ExprKind::Tup(subexpressions) => {
1133 walk_list!(visitor, visit_expr, subexpressions);
1135 ExprKind::Call(ref callee_expression, arguments) => {
1136 visitor.visit_expr(callee_expression);
1137 walk_list!(visitor, visit_expr, arguments);
1139 ExprKind::MethodCall(ref segment, arguments, _) => {
1140 visitor.visit_path_segment(expression.span, segment);
1141 walk_list!(visitor, visit_expr, arguments);
1143 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
1144 visitor.visit_expr(left_expression);
1145 visitor.visit_expr(right_expression)
1147 ExprKind::AddrOf(_, _, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
1148 visitor.visit_expr(subexpression)
1150 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
1151 visitor.visit_expr(subexpression);
1152 visitor.visit_ty(typ)
1154 ExprKind::DropTemps(ref subexpression) => {
1155 visitor.visit_expr(subexpression);
1157 ExprKind::Let(ref let_expr) => visitor.visit_let_expr(let_expr),
1158 ExprKind::If(ref cond, ref then, ref else_opt) => {
1159 visitor.visit_expr(cond);
1160 visitor.visit_expr(then);
1161 walk_list!(visitor, visit_expr, else_opt);
1163 ExprKind::Loop(ref block, ref opt_label, _, _) => {
1164 walk_list!(visitor, visit_label, opt_label);
1165 visitor.visit_block(block);
1167 ExprKind::Match(ref subexpression, arms, _) => {
1168 visitor.visit_expr(subexpression);
1169 walk_list!(visitor, visit_arm, arms);
1171 ExprKind::Closure(_, ref function_declaration, body, _fn_decl_span, _gen) => visitor
1174 function_declaration,
1179 ExprKind::Block(ref block, ref opt_label) => {
1180 walk_list!(visitor, visit_label, opt_label);
1181 visitor.visit_block(block);
1183 ExprKind::Assign(ref lhs, ref rhs, _) => {
1184 visitor.visit_expr(rhs);
1185 visitor.visit_expr(lhs)
1187 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
1188 visitor.visit_expr(right_expression);
1189 visitor.visit_expr(left_expression);
1191 ExprKind::Field(ref subexpression, ident) => {
1192 visitor.visit_expr(subexpression);
1193 visitor.visit_ident(ident);
1195 ExprKind::Index(ref main_expression, ref index_expression) => {
1196 visitor.visit_expr(main_expression);
1197 visitor.visit_expr(index_expression)
1199 ExprKind::Path(ref qpath) => {
1200 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1202 ExprKind::Break(ref destination, ref opt_expr) => {
1203 walk_list!(visitor, visit_label, &destination.label);
1204 walk_list!(visitor, visit_expr, opt_expr);
1206 ExprKind::Continue(ref destination) => {
1207 walk_list!(visitor, visit_label, &destination.label);
1209 ExprKind::Ret(ref optional_expression) => {
1210 walk_list!(visitor, visit_expr, optional_expression);
1212 ExprKind::InlineAsm(ref asm) => {
1213 visitor.visit_inline_asm(asm, expression.hir_id);
1215 ExprKind::Yield(ref subexpression, _) => {
1216 visitor.visit_expr(subexpression);
1218 ExprKind::Lit(_) | ExprKind::Err => {}
1222 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm<'v>) {
1223 visitor.visit_id(arm.hir_id);
1224 visitor.visit_pat(&arm.pat);
1225 if let Some(ref g) = arm.guard {
1227 Guard::If(ref e) => visitor.visit_expr(e),
1228 Guard::IfLet(ref l) => {
1229 visitor.visit_let_expr(l);
1233 visitor.visit_expr(&arm.body);
1236 pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssocItemKind) {
1237 // No visitable content here: this fn exists so you can call it if
1238 // the right thing to do, should content be added in the future,
1239 // would be to walk it.
1242 pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
1243 // No visitable content here: this fn exists so you can call it if
1244 // the right thing to do, should content be added in the future,
1245 // would be to walk it.