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 it:
9 //! Each overridden visit method has full control over what
10 //! happens with its node, it can do its own traversal of the node's children,
11 //! call `intravisit::walk_*` to apply the default traversal algorithm, or prevent
12 //! deeper traversal by doing nothing.
14 //! When visiting the HIR, the contents of nested items are NOT visited
15 //! by default. This is different from the AST visitor, which does a deep walk.
16 //! Hence this module is called `intravisit`; see the method `visit_nested_item`
19 //! Note: it is an important invariant that the default visitor walks
20 //! the body of a function in "execution order" - more concretely, if
21 //! we consider the reverse post-order (RPO) of the CFG implied by the HIR,
22 //! then a pre-order traversal of the HIR is consistent with the CFG RPO
23 //! on the *initial CFG point* of each HIR node, while a post-order traversal
24 //! of the HIR is consistent with the CFG RPO on each *final CFG point* of
27 //! One thing that follows is that if HIR node A always starts/ends executing
28 //! before HIR node B, then A appears in traversal pre/postorder before B,
29 //! respectively. (This follows from RPO respecting CFG domination).
31 //! This order consistency is required in a few places in rustc, for
32 //! example generator inference, and possibly also HIR borrowck.
34 use syntax::ast::{NodeId, CRATE_NODE_ID, Ident, Name, Attribute};
37 use crate::hir::def::Def;
38 use crate::hir::map::Map;
39 use super::itemlikevisit::DeepVisitor;
41 #[derive(Copy, Clone)]
43 /// `#[xxx] pub async/const/extern "Abi" fn foo()`
44 ItemFn(Ident, &'a Generics, FnHeader, &'a Visibility, &'a [Attribute]),
47 Method(Ident, &'a MethodSig, Option<&'a Visibility>, &'a [Attribute]),
50 Closure(&'a [Attribute]),
54 pub fn attrs(&self) -> &'a [Attribute] {
56 FnKind::ItemFn(.., attrs) => attrs,
57 FnKind::Method(.., attrs) => attrs,
58 FnKind::Closure(attrs) => attrs,
63 /// Specifies what nested things a visitor wants to visit. The most
64 /// common choice is `OnlyBodies`, which will cause the visitor to
65 /// visit fn bodies for fns that it encounters, but skip over nested
68 /// See the comments on `ItemLikeVisitor` for more details on the overall
70 pub enum NestedVisitorMap<'this, 'tcx: 'this> {
71 /// Do not visit any nested things. When you add a new
72 /// "non-nested" thing, you will want to audit such uses to see if
73 /// they remain valid.
75 /// Use this if you are only walking some particular kind of tree
76 /// (i.e., a type, or fn signature) and you don't want to thread a
80 /// Do not visit nested item-like things, but visit nested things
81 /// that are inside of an item-like.
83 /// **This is the most common choice.** A very common pattern is
84 /// to use `visit_all_item_likes()` as an outer loop,
85 /// and to have the visitor that visits the contents of each item
86 /// using this setting.
87 OnlyBodies(&'this Map<'tcx>),
89 /// Visit all nested things, including item-likes.
91 /// **This is an unusual choice.** It is used when you want to
92 /// process everything within their lexical context. Typically you
93 /// kick off the visit by doing `walk_krate()`.
94 All(&'this Map<'tcx>),
97 impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
98 /// Returns the map to use for an "intra item-like" thing (if any).
99 /// e.g., function body.
100 pub fn intra(self) -> Option<&'this Map<'tcx>> {
102 NestedVisitorMap::None => None,
103 NestedVisitorMap::OnlyBodies(map) => Some(map),
104 NestedVisitorMap::All(map) => Some(map),
108 /// Returns the map to use for an "item-like" thing (if any).
109 /// e.g., item, impl-item.
110 pub fn inter(self) -> Option<&'this Map<'tcx>> {
112 NestedVisitorMap::None => None,
113 NestedVisitorMap::OnlyBodies(_) => None,
114 NestedVisitorMap::All(map) => Some(map),
119 /// Each method of the Visitor trait is a hook to be potentially
120 /// overridden. Each method's default implementation recursively visits
121 /// the substructure of the input via the corresponding `walk` method;
122 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
124 /// Note that this visitor does NOT visit nested items by default
125 /// (this is why the module is called `intravisit`, to distinguish it
126 /// from the AST's `visit` module, which acts differently). If you
127 /// simply want to visit all items in the crate in some order, you
128 /// should call `Crate::visit_all_items`. Otherwise, see the comment
129 /// on `visit_nested_item` for details on how to visit nested items.
131 /// If you want to ensure that your code handles every variant
132 /// explicitly, you need to override each method. (And you also need
133 /// to monitor future changes to `Visitor` in case a new method with a
134 /// new default implementation gets introduced.)
135 pub trait Visitor<'v> : Sized {
136 ///////////////////////////////////////////////////////////////////////////
139 /// The default versions of the `visit_nested_XXX` routines invoke
140 /// this method to get a map to use. By selecting an enum variant,
141 /// you control which kinds of nested HIR are visited; see
142 /// `NestedVisitorMap` for details. By "nested HIR", we are
143 /// referring to bits of HIR that are not directly embedded within
144 /// one another but rather indirectly, through a table in the
145 /// crate. This is done to control dependencies during incremental
146 /// compilation: the non-inline bits of HIR can be tracked and
147 /// hashed separately.
149 /// **If for some reason you want the nested behavior, but don't
150 /// have a `Map` at your disposal:** then you should override the
151 /// `visit_nested_XXX` methods, and override this method to
152 /// `panic!()`. This way, if a new `visit_nested_XXX` variant is
153 /// added in the future, we will see the panic in your code and
154 /// fix it appropriately.
155 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'v>;
157 /// Invoked when a nested item is encountered. By default does
158 /// nothing unless you override `nested_visit_map` to return
159 /// `Some(_)`, in which case it will walk the item. **You probably
160 /// don't want to override this method** -- instead, override
161 /// `nested_visit_map` or use the "shallow" or "deep" visit
162 /// patterns described on `itemlikevisit::ItemLikeVisitor`. The only
163 /// reason to override this method is if you want a nested pattern
164 /// but cannot supply a `Map`; see `nested_visit_map` for advice.
165 #[allow(unused_variables)]
166 fn visit_nested_item(&mut self, id: ItemId) {
167 let opt_item = self.nested_visit_map().inter().map(|map| map.expect_item(id.id));
168 if let Some(item) = opt_item {
169 self.visit_item(item);
173 /// Like `visit_nested_item()`, but for trait items. See
174 /// `visit_nested_item()` for advice on when to override this
176 #[allow(unused_variables)]
177 fn visit_nested_trait_item(&mut self, id: TraitItemId) {
178 let opt_item = self.nested_visit_map().inter().map(|map| map.trait_item(id));
179 if let Some(item) = opt_item {
180 self.visit_trait_item(item);
184 /// Like `visit_nested_item()`, but for impl items. See
185 /// `visit_nested_item()` for advice on when to override this
187 #[allow(unused_variables)]
188 fn visit_nested_impl_item(&mut self, id: ImplItemId) {
189 let opt_item = self.nested_visit_map().inter().map(|map| map.impl_item(id));
190 if let Some(item) = opt_item {
191 self.visit_impl_item(item);
195 /// Invoked to visit the body of a function, method or closure. Like
196 /// visit_nested_item, does nothing by default unless you override
197 /// `nested_visit_map` to return `Some(_)`, in which case it will walk the
199 fn visit_nested_body(&mut self, id: BodyId) {
200 let opt_body = self.nested_visit_map().intra().map(|map| map.body(id));
201 if let Some(body) = opt_body {
202 self.visit_body(body);
206 /// Visit the top-level item and (optionally) nested items / impl items. See
207 /// `visit_nested_item` for details.
208 fn visit_item(&mut self, i: &'v Item) {
212 fn visit_body(&mut self, b: &'v Body) {
216 /// When invoking `visit_all_item_likes()`, you need to supply an
217 /// item-like visitor. This method converts a "intra-visit"
218 /// visitor into an item-like visitor that walks the entire tree.
219 /// If you use this, you probably don't want to process the
220 /// contents of nested item-like things, since the outer loop will
221 /// visit them as well.
222 fn as_deep_visitor<'s>(&'s mut self) -> DeepVisitor<'s, Self> {
223 DeepVisitor::new(self)
226 ///////////////////////////////////////////////////////////////////////////
228 fn visit_id(&mut self, _node_id: NodeId) {
231 fn visit_def_mention(&mut self, _def: Def) {
234 fn visit_name(&mut self, _span: Span, _name: Name) {
237 fn visit_ident(&mut self, ident: Ident) {
238 walk_ident(self, ident)
240 fn visit_mod(&mut self, m: &'v Mod, _s: Span, n: NodeId) {
243 fn visit_foreign_item(&mut self, i: &'v ForeignItem) {
244 walk_foreign_item(self, i)
246 fn visit_local(&mut self, l: &'v Local) {
249 fn visit_block(&mut self, b: &'v Block) {
252 fn visit_stmt(&mut self, s: &'v Stmt) {
255 fn visit_arm(&mut self, a: &'v Arm) {
258 fn visit_pat(&mut self, p: &'v Pat) {
261 fn visit_anon_const(&mut self, c: &'v AnonConst) {
262 walk_anon_const(self, c)
264 fn visit_expr(&mut self, ex: &'v Expr) {
267 fn visit_ty(&mut self, t: &'v Ty) {
270 fn visit_generic_param(&mut self, p: &'v GenericParam) {
271 walk_generic_param(self, p)
273 fn visit_generics(&mut self, g: &'v Generics) {
274 walk_generics(self, g)
276 fn visit_where_predicate(&mut self, predicate: &'v WherePredicate) {
277 walk_where_predicate(self, predicate)
279 fn visit_fn_decl(&mut self, fd: &'v FnDecl) {
280 walk_fn_decl(self, fd)
282 fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl, b: BodyId, s: Span, id: NodeId) {
283 walk_fn(self, fk, fd, b, s, id)
285 fn visit_use(&mut self, path: &'v Path, id: NodeId, hir_id: HirId) {
286 walk_use(self, path, id, hir_id)
288 fn visit_trait_item(&mut self, ti: &'v TraitItem) {
289 walk_trait_item(self, ti)
291 fn visit_trait_item_ref(&mut self, ii: &'v TraitItemRef) {
292 walk_trait_item_ref(self, ii)
294 fn visit_impl_item(&mut self, ii: &'v ImplItem) {
295 walk_impl_item(self, ii)
297 fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) {
298 walk_impl_item_ref(self, ii)
300 fn visit_trait_ref(&mut self, t: &'v TraitRef) {
301 walk_trait_ref(self, t)
303 fn visit_param_bound(&mut self, bounds: &'v GenericBound) {
304 walk_param_bound(self, bounds)
306 fn visit_poly_trait_ref(&mut self, t: &'v PolyTraitRef, m: TraitBoundModifier) {
307 walk_poly_trait_ref(self, t, m)
309 fn visit_variant_data(&mut self,
315 walk_struct_def(self, s)
317 fn visit_struct_field(&mut self, s: &'v StructField) {
318 walk_struct_field(self, s)
320 fn visit_enum_def(&mut self,
321 enum_definition: &'v EnumDef,
322 generics: &'v Generics,
325 walk_enum_def(self, enum_definition, generics, item_id)
327 fn visit_variant(&mut self, v: &'v Variant, g: &'v Generics, item_id: NodeId) {
328 walk_variant(self, v, g, item_id)
330 fn visit_label(&mut self, label: &'v Label) {
331 walk_label(self, label)
333 fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg) {
335 GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
336 GenericArg::Type(ty) => self.visit_ty(ty),
339 fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
340 walk_lifetime(self, lifetime)
342 fn visit_qpath(&mut self, qpath: &'v QPath, id: HirId, span: Span) {
343 walk_qpath(self, qpath, id, span)
345 fn visit_path(&mut self, path: &'v Path, _id: HirId) {
346 walk_path(self, path)
348 fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment) {
349 walk_path_segment(self, path_span, path_segment)
351 fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs) {
352 walk_generic_args(self, path_span, generic_args)
354 fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding) {
355 walk_assoc_type_binding(self, type_binding)
357 fn visit_attribute(&mut self, _attr: &'v Attribute) {
359 fn visit_macro_def(&mut self, macro_def: &'v MacroDef) {
360 walk_macro_def(self, macro_def)
362 fn visit_vis(&mut self, vis: &'v Visibility) {
365 fn visit_associated_item_kind(&mut self, kind: &'v AssociatedItemKind) {
366 walk_associated_item_kind(self, kind);
368 fn visit_defaultness(&mut self, defaultness: &'v Defaultness) {
369 walk_defaultness(self, defaultness);
373 /// Walks the contents of a crate. See also `Crate::visit_all_items`.
374 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate) {
375 visitor.visit_mod(&krate.module, krate.span, CRATE_NODE_ID);
376 walk_list!(visitor, visit_attribute, &krate.attrs);
377 walk_list!(visitor, visit_macro_def, &krate.exported_macros);
380 pub fn walk_macro_def<'v, V: Visitor<'v>>(visitor: &mut V, macro_def: &'v MacroDef) {
381 visitor.visit_id(macro_def.id);
382 visitor.visit_name(macro_def.span, macro_def.name);
383 walk_list!(visitor, visit_attribute, ¯o_def.attrs);
386 pub fn walk_mod<'v, V: Visitor<'v>>(visitor: &mut V, module: &'v Mod, mod_node_id: NodeId) {
387 visitor.visit_id(mod_node_id);
388 for &item_id in &module.item_ids {
389 visitor.visit_nested_item(item_id);
393 pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body) {
394 for argument in &body.arguments {
395 visitor.visit_id(argument.id);
396 visitor.visit_pat(&argument.pat);
398 visitor.visit_expr(&body.value);
401 pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local) {
402 // Intentionally visiting the expr first - the initialization expr
403 // dominates the local's definition.
404 walk_list!(visitor, visit_expr, &local.init);
405 walk_list!(visitor, visit_attribute, local.attrs.iter());
406 visitor.visit_id(local.id);
407 visitor.visit_pat(&local.pat);
408 walk_list!(visitor, visit_ty, &local.ty);
411 pub fn walk_ident<'v, V: Visitor<'v>>(visitor: &mut V, ident: Ident) {
412 visitor.visit_name(ident.span, ident.name);
415 pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
416 visitor.visit_ident(label.ident);
419 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
420 visitor.visit_id(lifetime.id);
421 match lifetime.name {
422 LifetimeName::Param(ParamName::Plain(ident)) => {
423 visitor.visit_ident(ident);
425 LifetimeName::Param(ParamName::Fresh(_)) |
426 LifetimeName::Param(ParamName::Error) |
427 LifetimeName::Static |
428 LifetimeName::Error |
429 LifetimeName::Implicit |
430 LifetimeName::Underscore => {}
434 pub fn walk_poly_trait_ref<'v, V>(visitor: &mut V,
435 trait_ref: &'v PolyTraitRef,
436 _modifier: TraitBoundModifier)
439 walk_list!(visitor, visit_generic_param, &trait_ref.bound_generic_params);
440 visitor.visit_trait_ref(&trait_ref.trait_ref);
443 pub fn walk_trait_ref<'v, V>(visitor: &mut V, trait_ref: &'v TraitRef)
446 visitor.visit_id(trait_ref.ref_id);
447 visitor.visit_path(&trait_ref.path, trait_ref.hir_ref_id)
450 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
451 visitor.visit_vis(&item.vis);
452 visitor.visit_ident(item.ident);
454 ItemKind::ExternCrate(orig_name) => {
455 visitor.visit_id(item.id);
456 if let Some(orig_name) = orig_name {
457 visitor.visit_name(item.span, orig_name);
460 ItemKind::Use(ref path, _) => {
461 visitor.visit_use(path, item.id, item.hir_id);
463 ItemKind::Static(ref typ, _, body) |
464 ItemKind::Const(ref typ, body) => {
465 visitor.visit_id(item.id);
466 visitor.visit_ty(typ);
467 visitor.visit_nested_body(body);
469 ItemKind::Fn(ref declaration, header, ref generics, body_id) => {
470 visitor.visit_fn(FnKind::ItemFn(item.ident,
480 ItemKind::Mod(ref module) => {
481 // `visit_mod()` takes care of visiting the `Item`'s `NodeId`.
482 visitor.visit_mod(module, item.span, item.id)
484 ItemKind::ForeignMod(ref foreign_module) => {
485 visitor.visit_id(item.id);
486 walk_list!(visitor, visit_foreign_item, &foreign_module.items);
488 ItemKind::GlobalAsm(_) => {
489 visitor.visit_id(item.id);
491 ItemKind::Ty(ref typ, ref type_parameters) => {
492 visitor.visit_id(item.id);
493 visitor.visit_ty(typ);
494 visitor.visit_generics(type_parameters)
496 ItemKind::Existential(ExistTy {ref generics, ref bounds, impl_trait_fn}) => {
497 visitor.visit_id(item.id);
498 walk_generics(visitor, generics);
499 walk_list!(visitor, visit_param_bound, bounds);
500 if let Some(impl_trait_fn) = impl_trait_fn {
501 visitor.visit_def_mention(Def::Fn(impl_trait_fn))
504 ItemKind::Enum(ref enum_definition, ref type_parameters) => {
505 visitor.visit_generics(type_parameters);
506 // `visit_enum_def()` takes care of visiting the `Item`'s `NodeId`.
507 visitor.visit_enum_def(enum_definition, type_parameters, item.id, item.span)
512 ref opt_trait_reference,
516 visitor.visit_id(item.id);
517 visitor.visit_generics(type_parameters);
518 walk_list!(visitor, visit_trait_ref, opt_trait_reference);
519 visitor.visit_ty(typ);
520 walk_list!(visitor, visit_impl_item_ref, impl_item_refs);
522 ItemKind::Struct(ref struct_definition, ref generics) |
523 ItemKind::Union(ref struct_definition, ref generics) => {
524 visitor.visit_generics(generics);
525 visitor.visit_id(item.id);
526 visitor.visit_variant_data(struct_definition, item.ident.name, generics, item.id,
529 ItemKind::Trait(.., ref generics, ref bounds, ref trait_item_refs) => {
530 visitor.visit_id(item.id);
531 visitor.visit_generics(generics);
532 walk_list!(visitor, visit_param_bound, bounds);
533 walk_list!(visitor, visit_trait_item_ref, trait_item_refs);
535 ItemKind::TraitAlias(ref generics, ref bounds) => {
536 visitor.visit_id(item.id);
537 visitor.visit_generics(generics);
538 walk_list!(visitor, visit_param_bound, bounds);
541 walk_list!(visitor, visit_attribute, &item.attrs);
544 pub fn walk_use<'v, V: Visitor<'v>>(visitor: &mut V,
548 visitor.visit_id(item_id);
549 visitor.visit_path(path, hir_id);
552 pub fn walk_enum_def<'v, V: Visitor<'v>>(visitor: &mut V,
553 enum_definition: &'v EnumDef,
554 generics: &'v Generics,
556 visitor.visit_id(item_id);
559 &enum_definition.variants,
564 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V,
565 variant: &'v Variant,
566 generics: &'v Generics,
567 parent_item_id: NodeId) {
568 visitor.visit_ident(variant.node.ident);
569 visitor.visit_variant_data(&variant.node.data,
570 variant.node.ident.name,
574 walk_list!(visitor, visit_anon_const, &variant.node.disr_expr);
575 walk_list!(visitor, visit_attribute, &variant.node.attrs);
578 pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
579 visitor.visit_id(typ.id);
582 TyKind::Slice(ref ty) => {
585 TyKind::Ptr(ref mutable_type) => {
586 visitor.visit_ty(&mutable_type.ty)
588 TyKind::Rptr(ref lifetime, ref mutable_type) => {
589 visitor.visit_lifetime(lifetime);
590 visitor.visit_ty(&mutable_type.ty)
593 TyKind::Tup(ref tuple_element_types) => {
594 walk_list!(visitor, visit_ty, tuple_element_types);
596 TyKind::BareFn(ref function_declaration) => {
597 walk_list!(visitor, visit_generic_param, &function_declaration.generic_params);
598 visitor.visit_fn_decl(&function_declaration.decl);
600 TyKind::Path(ref qpath) => {
601 visitor.visit_qpath(qpath, typ.hir_id, typ.span);
603 TyKind::Def(item_id, ref lifetimes) => {
604 visitor.visit_nested_item(item_id);
605 walk_list!(visitor, visit_generic_arg, lifetimes);
607 TyKind::Array(ref ty, ref length) => {
608 visitor.visit_ty(ty);
609 visitor.visit_anon_const(length)
611 TyKind::TraitObject(ref bounds, ref lifetime) => {
612 for bound in bounds {
613 visitor.visit_poly_trait_ref(bound, TraitBoundModifier::None);
615 visitor.visit_lifetime(lifetime);
617 TyKind::Typeof(ref expression) => {
618 visitor.visit_anon_const(expression)
620 TyKind::Infer | TyKind::Err => {}
624 pub fn walk_qpath<'v, V: Visitor<'v>>(visitor: &mut V, qpath: &'v QPath, id: HirId, span: Span) {
626 QPath::Resolved(ref maybe_qself, ref path) => {
627 if let Some(ref qself) = *maybe_qself {
628 visitor.visit_ty(qself);
630 visitor.visit_path(path, id)
632 QPath::TypeRelative(ref qself, ref segment) => {
633 visitor.visit_ty(qself);
634 visitor.visit_path_segment(span, segment);
639 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path) {
640 visitor.visit_def_mention(path.def);
641 for segment in &path.segments {
642 visitor.visit_path_segment(path.span, segment);
646 pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V,
648 segment: &'v PathSegment) {
649 visitor.visit_ident(segment.ident);
650 if let Some(id) = segment.id {
651 visitor.visit_id(id);
653 if let Some(ref args) = segment.args {
654 visitor.visit_generic_args(path_span, args);
658 pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V,
660 generic_args: &'v GenericArgs) {
661 walk_list!(visitor, visit_generic_arg, &generic_args.args);
662 walk_list!(visitor, visit_assoc_type_binding, &generic_args.bindings);
665 pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(visitor: &mut V,
666 type_binding: &'v TypeBinding) {
667 visitor.visit_id(type_binding.id);
668 visitor.visit_ident(type_binding.ident);
669 visitor.visit_ty(&type_binding.ty);
672 pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat) {
673 visitor.visit_id(pattern.id);
675 PatKind::TupleStruct(ref qpath, ref children, _) => {
676 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
677 walk_list!(visitor, visit_pat, children);
679 PatKind::Path(ref qpath) => {
680 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
682 PatKind::Struct(ref qpath, ref fields, _) => {
683 visitor.visit_qpath(qpath, pattern.hir_id, pattern.span);
684 for field in fields {
685 visitor.visit_id(field.node.id);
686 visitor.visit_ident(field.node.ident);
687 visitor.visit_pat(&field.node.pat)
690 PatKind::Tuple(ref tuple_elements, _) => {
691 walk_list!(visitor, visit_pat, tuple_elements);
693 PatKind::Box(ref subpattern) |
694 PatKind::Ref(ref subpattern, _) => {
695 visitor.visit_pat(subpattern)
697 PatKind::Binding(_, canonical_id, _hir_id, ident, ref optional_subpattern) => {
698 visitor.visit_def_mention(Def::Local(canonical_id));
699 visitor.visit_ident(ident);
700 walk_list!(visitor, visit_pat, optional_subpattern);
702 PatKind::Lit(ref expression) => visitor.visit_expr(expression),
703 PatKind::Range(ref lower_bound, ref upper_bound, _) => {
704 visitor.visit_expr(lower_bound);
705 visitor.visit_expr(upper_bound)
708 PatKind::Slice(ref prepatterns, ref slice_pattern, ref postpatterns) => {
709 walk_list!(visitor, visit_pat, prepatterns);
710 walk_list!(visitor, visit_pat, slice_pattern);
711 walk_list!(visitor, visit_pat, postpatterns);
716 pub fn walk_foreign_item<'v, V: Visitor<'v>>(visitor: &mut V, foreign_item: &'v ForeignItem) {
717 visitor.visit_id(foreign_item.id);
718 visitor.visit_vis(&foreign_item.vis);
719 visitor.visit_ident(foreign_item.ident);
721 match foreign_item.node {
722 ForeignItemKind::Fn(ref function_declaration, ref param_names, ref generics) => {
723 visitor.visit_generics(generics);
724 visitor.visit_fn_decl(function_declaration);
725 for ¶m_name in param_names {
726 visitor.visit_ident(param_name);
729 ForeignItemKind::Static(ref typ, _) => visitor.visit_ty(typ),
730 ForeignItemKind::Type => (),
733 walk_list!(visitor, visit_attribute, &foreign_item.attrs);
736 pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericBound) {
738 GenericBound::Trait(ref typ, modifier) => {
739 visitor.visit_poly_trait_ref(typ, modifier);
741 GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
745 pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v GenericParam) {
746 visitor.visit_id(param.id);
747 walk_list!(visitor, visit_attribute, ¶m.attrs);
749 ParamName::Plain(ident) => visitor.visit_ident(ident),
750 ParamName::Error | ParamName::Fresh(_) => {}
753 GenericParamKind::Lifetime { .. } => {}
754 GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
756 walk_list!(visitor, visit_param_bound, ¶m.bounds);
759 pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics) {
760 walk_list!(visitor, visit_generic_param, &generics.params);
761 visitor.visit_id(generics.where_clause.id);
762 walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
765 pub fn walk_where_predicate<'v, V: Visitor<'v>>(
767 predicate: &'v WherePredicate)
770 &WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
772 ref bound_generic_params,
774 visitor.visit_ty(bounded_ty);
775 walk_list!(visitor, visit_param_bound, bounds);
776 walk_list!(visitor, visit_generic_param, bound_generic_params);
778 &WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
781 visitor.visit_lifetime(lifetime);
782 walk_list!(visitor, visit_param_bound, bounds);
784 &WherePredicate::EqPredicate(WhereEqPredicate{id,
788 visitor.visit_id(id);
789 visitor.visit_ty(lhs_ty);
790 visitor.visit_ty(rhs_ty);
795 pub fn walk_fn_ret_ty<'v, V: Visitor<'v>>(visitor: &mut V, ret_ty: &'v FunctionRetTy) {
796 if let Return(ref output_ty) = *ret_ty {
797 visitor.visit_ty(output_ty)
801 pub fn walk_fn_decl<'v, V: Visitor<'v>>(visitor: &mut V, function_declaration: &'v FnDecl) {
802 for ty in &function_declaration.inputs {
805 walk_fn_ret_ty(visitor, &function_declaration.output)
808 pub fn walk_fn_kind<'v, V: Visitor<'v>>(visitor: &mut V, function_kind: FnKind<'v>) {
809 match function_kind {
810 FnKind::ItemFn(_, generics, ..) => {
811 visitor.visit_generics(generics);
814 FnKind::Closure(_) => {}
818 pub fn walk_fn<'v, V: Visitor<'v>>(visitor: &mut V,
819 function_kind: FnKind<'v>,
820 function_declaration: &'v FnDecl,
824 visitor.visit_id(id);
825 visitor.visit_fn_decl(function_declaration);
826 walk_fn_kind(visitor, function_kind);
827 visitor.visit_nested_body(body_id)
830 pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v TraitItem) {
831 visitor.visit_ident(trait_item.ident);
832 walk_list!(visitor, visit_attribute, &trait_item.attrs);
833 visitor.visit_generics(&trait_item.generics);
834 match trait_item.node {
835 TraitItemKind::Const(ref ty, default) => {
836 visitor.visit_id(trait_item.id);
837 visitor.visit_ty(ty);
838 walk_list!(visitor, visit_nested_body, default);
840 TraitItemKind::Method(ref sig, TraitMethod::Required(ref param_names)) => {
841 visitor.visit_id(trait_item.id);
842 visitor.visit_fn_decl(&sig.decl);
843 for ¶m_name in param_names {
844 visitor.visit_ident(param_name);
847 TraitItemKind::Method(ref sig, TraitMethod::Provided(body_id)) => {
848 visitor.visit_fn(FnKind::Method(trait_item.ident,
857 TraitItemKind::Type(ref bounds, ref default) => {
858 visitor.visit_id(trait_item.id);
859 walk_list!(visitor, visit_param_bound, bounds);
860 walk_list!(visitor, visit_ty, default);
865 pub fn walk_trait_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, trait_item_ref: &'v TraitItemRef) {
866 // N.B., deliberately force a compilation error if/when new fields are added.
867 let TraitItemRef { id, ident, ref kind, span: _, ref defaultness } = *trait_item_ref;
868 visitor.visit_nested_trait_item(id);
869 visitor.visit_ident(ident);
870 visitor.visit_associated_item_kind(kind);
871 visitor.visit_defaultness(defaultness);
874 pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplItem) {
875 // N.B., deliberately force a compilation error if/when new fields are added.
888 visitor.visit_ident(ident);
889 visitor.visit_vis(vis);
890 visitor.visit_defaultness(defaultness);
891 walk_list!(visitor, visit_attribute, attrs);
892 visitor.visit_generics(generics);
894 ImplItemKind::Const(ref ty, body) => {
895 visitor.visit_id(impl_item.id);
896 visitor.visit_ty(ty);
897 visitor.visit_nested_body(body);
899 ImplItemKind::Method(ref sig, body_id) => {
900 visitor.visit_fn(FnKind::Method(impl_item.ident,
902 Some(&impl_item.vis),
909 ImplItemKind::Type(ref ty) => {
910 visitor.visit_id(impl_item.id);
911 visitor.visit_ty(ty);
913 ImplItemKind::Existential(ref bounds) => {
914 visitor.visit_id(impl_item.id);
915 walk_list!(visitor, visit_param_bound, bounds);
920 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, impl_item_ref: &'v ImplItemRef) {
921 // N.B., deliberately force a compilation error if/when new fields are added.
922 let ImplItemRef { id, ident, ref kind, span: _, ref vis, ref defaultness } = *impl_item_ref;
923 visitor.visit_nested_impl_item(id);
924 visitor.visit_ident(ident);
925 visitor.visit_associated_item_kind(kind);
926 visitor.visit_vis(vis);
927 visitor.visit_defaultness(defaultness);
931 pub fn walk_struct_def<'v, V: Visitor<'v>>(visitor: &mut V, struct_definition: &'v VariantData) {
932 visitor.visit_id(struct_definition.id());
933 walk_list!(visitor, visit_struct_field, struct_definition.fields());
936 pub fn walk_struct_field<'v, V: Visitor<'v>>(visitor: &mut V, struct_field: &'v StructField) {
937 visitor.visit_id(struct_field.id);
938 visitor.visit_vis(&struct_field.vis);
939 visitor.visit_ident(struct_field.ident);
940 visitor.visit_ty(&struct_field.ty);
941 walk_list!(visitor, visit_attribute, &struct_field.attrs);
944 pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block) {
945 visitor.visit_id(block.id);
946 walk_list!(visitor, visit_stmt, &block.stmts);
947 walk_list!(visitor, visit_expr, &block.expr);
950 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
951 visitor.visit_id(statement.id);
952 match statement.node {
953 StmtKind::Local(ref local) => visitor.visit_local(local),
954 StmtKind::Item(ref item) => visitor.visit_nested_item(**item),
955 StmtKind::Expr(ref expression) |
956 StmtKind::Semi(ref expression) => {
957 visitor.visit_expr(expression)
962 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
963 visitor.visit_id(constant.id);
964 visitor.visit_nested_body(constant.body);
967 pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
968 visitor.visit_id(expression.id);
969 walk_list!(visitor, visit_attribute, expression.attrs.iter());
970 match expression.node {
971 ExprKind::Box(ref subexpression) => {
972 visitor.visit_expr(subexpression)
974 ExprKind::Array(ref subexpressions) => {
975 walk_list!(visitor, visit_expr, subexpressions);
977 ExprKind::Repeat(ref element, ref count) => {
978 visitor.visit_expr(element);
979 visitor.visit_anon_const(count)
981 ExprKind::Struct(ref qpath, ref fields, ref optional_base) => {
982 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
983 for field in fields {
984 visitor.visit_id(field.id);
985 visitor.visit_ident(field.ident);
986 visitor.visit_expr(&field.expr)
988 walk_list!(visitor, visit_expr, optional_base);
990 ExprKind::Tup(ref subexpressions) => {
991 walk_list!(visitor, visit_expr, subexpressions);
993 ExprKind::Call(ref callee_expression, ref arguments) => {
994 visitor.visit_expr(callee_expression);
995 walk_list!(visitor, visit_expr, arguments);
997 ExprKind::MethodCall(ref segment, _, ref arguments) => {
998 visitor.visit_path_segment(expression.span, segment);
999 walk_list!(visitor, visit_expr, arguments);
1001 ExprKind::Binary(_, ref left_expression, ref right_expression) => {
1002 visitor.visit_expr(left_expression);
1003 visitor.visit_expr(right_expression)
1005 ExprKind::AddrOf(_, ref subexpression) | ExprKind::Unary(_, ref subexpression) => {
1006 visitor.visit_expr(subexpression)
1008 ExprKind::Lit(_) => {}
1009 ExprKind::Cast(ref subexpression, ref typ) | ExprKind::Type(ref subexpression, ref typ) => {
1010 visitor.visit_expr(subexpression);
1011 visitor.visit_ty(typ)
1013 ExprKind::If(ref head_expression, ref if_block, ref optional_else) => {
1014 visitor.visit_expr(head_expression);
1015 visitor.visit_expr(if_block);
1016 walk_list!(visitor, visit_expr, optional_else);
1018 ExprKind::While(ref subexpression, ref block, ref opt_label) => {
1019 walk_list!(visitor, visit_label, opt_label);
1020 visitor.visit_expr(subexpression);
1021 visitor.visit_block(block);
1023 ExprKind::Loop(ref block, ref opt_label, _) => {
1024 walk_list!(visitor, visit_label, opt_label);
1025 visitor.visit_block(block);
1027 ExprKind::Match(ref subexpression, ref arms, _) => {
1028 visitor.visit_expr(subexpression);
1029 walk_list!(visitor, visit_arm, arms);
1031 ExprKind::Closure(_, ref function_declaration, body, _fn_decl_span, _gen) => {
1032 visitor.visit_fn(FnKind::Closure(&expression.attrs),
1033 function_declaration,
1038 ExprKind::Block(ref block, ref opt_label) => {
1039 walk_list!(visitor, visit_label, opt_label);
1040 visitor.visit_block(block);
1042 ExprKind::Assign(ref left_hand_expression, ref right_hand_expression) => {
1043 visitor.visit_expr(right_hand_expression);
1044 visitor.visit_expr(left_hand_expression)
1046 ExprKind::AssignOp(_, ref left_expression, ref right_expression) => {
1047 visitor.visit_expr(right_expression);
1048 visitor.visit_expr(left_expression)
1050 ExprKind::Field(ref subexpression, ident) => {
1051 visitor.visit_expr(subexpression);
1052 visitor.visit_ident(ident);
1054 ExprKind::Index(ref main_expression, ref index_expression) => {
1055 visitor.visit_expr(main_expression);
1056 visitor.visit_expr(index_expression)
1058 ExprKind::Path(ref qpath) => {
1059 visitor.visit_qpath(qpath, expression.hir_id, expression.span);
1061 ExprKind::Break(ref destination, ref opt_expr) => {
1062 if let Some(ref label) = destination.label {
1063 visitor.visit_label(label);
1064 if let Ok(node_id) = destination.target_id {
1065 visitor.visit_def_mention(Def::Label(node_id))
1068 walk_list!(visitor, visit_expr, opt_expr);
1070 ExprKind::Continue(ref destination) => {
1071 if let Some(ref label) = destination.label {
1072 visitor.visit_label(label);
1073 if let Ok(node_id) = destination.target_id {
1074 visitor.visit_def_mention(Def::Label(node_id))
1078 ExprKind::Ret(ref optional_expression) => {
1079 walk_list!(visitor, visit_expr, optional_expression);
1081 ExprKind::InlineAsm(_, ref outputs, ref inputs) => {
1082 for expr in outputs.iter().chain(inputs.iter()) {
1083 visitor.visit_expr(expr)
1086 ExprKind::Yield(ref subexpression) => {
1087 visitor.visit_expr(subexpression);
1093 pub fn walk_arm<'v, V: Visitor<'v>>(visitor: &mut V, arm: &'v Arm) {
1094 walk_list!(visitor, visit_pat, &arm.pats);
1095 if let Some(ref g) = arm.guard {
1097 Guard::If(ref e) => visitor.visit_expr(e),
1100 visitor.visit_expr(&arm.body);
1101 walk_list!(visitor, visit_attribute, &arm.attrs);
1104 pub fn walk_vis<'v, V: Visitor<'v>>(visitor: &mut V, vis: &'v Visibility) {
1105 if let VisibilityKind::Restricted { ref path, id, hir_id } = vis.node {
1106 visitor.visit_id(id);
1107 visitor.visit_path(path, hir_id)
1111 pub fn walk_associated_item_kind<'v, V: Visitor<'v>>(_: &mut V, _: &'v AssociatedItemKind) {
1112 // No visitable content here: this fn exists so you can call it if
1113 // the right thing to do, should content be added in the future,
1114 // would be to walk it.
1117 pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
1118 // No visitable content here: this fn exists so you can call it if
1119 // the right thing to do, should content be added in the future,
1120 // would be to walk it.