1 //! A `MutVisitor` represents an AST modification; it accepts an AST piece and
2 //! and mutates it in place. So, for instance, macro expansion is a `MutVisitor`
3 //! that walks over an AST and modifies it.
5 //! Note: using a `MutVisitor` (other than the `MacroExpander` `MutVisitor`) on
6 //! an AST before macro expansion is probably a bad idea. For instance,
7 //! a `MutVisitor` renaming item names in a module will miss all of those
8 //! that are created by the expansion of a macro.
12 use crate::token::{self, Token};
13 use crate::tokenstream::*;
15 use rustc_data_structures::map_in_place::MapInPlace;
16 use rustc_data_structures::sync::Lrc;
17 use rustc_span::source_map::Spanned;
18 use rustc_span::symbol::Ident;
21 use smallvec::{smallvec, Array, SmallVec};
22 use std::ops::DerefMut;
23 use std::{panic, process, ptr};
25 pub trait ExpectOne<A: Array> {
26 fn expect_one(self, err: &'static str) -> A::Item;
29 impl<A: Array> ExpectOne<A> for SmallVec<A> {
30 fn expect_one(self, err: &'static str) -> A::Item {
31 assert!(self.len() == 1, "{}", err);
32 self.into_iter().next().unwrap()
36 pub trait MutVisitor: Sized {
37 /// Mutable token visiting only exists for the `macro_rules` token marker and should not be
38 /// used otherwise. Token visitor would be entirely separate from the regular visitor if
39 /// the marker didn't have to visit AST fragments in nonterminal tokens.
40 const VISIT_TOKENS: bool = false;
42 // Methods in this trait have one of three forms:
44 // fn visit_t(&mut self, t: &mut T); // common
45 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
46 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
48 // Any additions to this trait should happen in form of a call to a public
49 // `noop_*` function that only calls out to the visitor again, not other
50 // `noop_*` functions. This is a necessary API workaround to the problem of
51 // not being able to call out to the super default method in an overridden
54 // When writing these methods, it is better to use destructuring like this:
56 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
61 // than to use field access like this:
63 // fn visit_abc(&mut self, abc: &mut ABC) {
64 // visit_a(&mut abc.a);
65 // visit_b(&mut abc.b);
69 // As well as being more concise, the former is explicit about which fields
70 // are skipped. Furthermore, if a new field is added, the destructuring
71 // version will cause a compile error, which is good. In comparison, the
72 // field access version will continue working and it would be easy to
73 // forget to add handling for it.
75 fn visit_crate(&mut self, c: &mut Crate) {
76 noop_visit_crate(c, self)
79 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
80 noop_visit_meta_list_item(list_item, self);
83 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
84 noop_visit_meta_item(meta_item, self);
87 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
88 noop_visit_use_tree(use_tree, self);
91 fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
92 noop_flat_map_foreign_item(ni, self)
95 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
96 noop_flat_map_item(i, self)
99 fn visit_fn_header(&mut self, header: &mut FnHeader) {
100 noop_visit_fn_header(header, self);
103 fn flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
104 noop_flat_map_field_def(fd, self)
107 fn visit_item_kind(&mut self, i: &mut ItemKind) {
108 noop_visit_item_kind(i, self);
111 fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
112 noop_flat_map_assoc_item(i, self)
115 fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
116 noop_flat_map_assoc_item(i, self)
119 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
120 noop_visit_fn_decl(d, self);
123 fn visit_asyncness(&mut self, a: &mut Async) {
124 noop_visit_asyncness(a, self);
127 fn visit_block(&mut self, b: &mut P<Block>) {
128 noop_visit_block(b, self);
131 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
132 noop_flat_map_stmt(s, self)
135 fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
136 noop_flat_map_arm(arm, self)
139 fn visit_pat(&mut self, p: &mut P<Pat>) {
140 noop_visit_pat(p, self);
143 fn visit_anon_const(&mut self, c: &mut AnonConst) {
144 noop_visit_anon_const(c, self);
147 fn visit_expr(&mut self, e: &mut P<Expr>) {
148 noop_visit_expr(e, self);
151 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
152 noop_filter_map_expr(e, self)
155 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
156 noop_visit_generic_arg(arg, self);
159 fn visit_ty(&mut self, t: &mut P<Ty>) {
160 noop_visit_ty(t, self);
163 fn visit_lifetime(&mut self, l: &mut Lifetime) {
164 noop_visit_lifetime(l, self);
167 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
168 noop_visit_ty_constraint(t, self);
171 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
172 noop_visit_foreign_mod(nm, self);
175 fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
176 noop_flat_map_variant(v, self)
179 fn visit_ident(&mut self, i: &mut Ident) {
180 noop_visit_ident(i, self);
183 fn visit_path(&mut self, p: &mut Path) {
184 noop_visit_path(p, self);
187 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
188 noop_visit_qself(qs, self);
191 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
192 noop_visit_generic_args(p, self);
195 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
196 noop_visit_angle_bracketed_parameter_data(p, self);
199 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
200 noop_visit_parenthesized_parameter_data(p, self);
203 fn visit_local(&mut self, l: &mut P<Local>) {
204 noop_visit_local(l, self);
207 fn visit_mac_call(&mut self, mac: &mut MacCall) {
208 noop_visit_mac(mac, self);
211 fn visit_macro_def(&mut self, def: &mut MacroDef) {
212 noop_visit_macro_def(def, self);
215 fn visit_label(&mut self, label: &mut Label) {
216 noop_visit_label(label, self);
219 fn visit_attribute(&mut self, at: &mut Attribute) {
220 noop_visit_attribute(at, self);
223 fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
224 noop_flat_map_param(param, self)
227 fn visit_generics(&mut self, generics: &mut Generics) {
228 noop_visit_generics(generics, self);
231 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
232 noop_visit_trait_ref(tr, self);
235 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
236 noop_visit_poly_trait_ref(p, self);
239 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
240 noop_visit_variant_data(vdata, self);
243 fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
244 noop_flat_map_generic_param(param, self)
247 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
248 noop_visit_param_bound(tpb, self);
251 fn visit_mt(&mut self, mt: &mut MutTy) {
252 noop_visit_mt(mt, self);
255 fn flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
256 noop_flat_map_expr_field(f, self)
259 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
260 noop_visit_where_clause(where_clause, self);
263 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
264 noop_visit_where_predicate(where_predicate, self);
267 fn visit_vis(&mut self, vis: &mut Visibility) {
268 noop_visit_vis(vis, self);
271 fn visit_id(&mut self, _id: &mut NodeId) {
275 fn visit_span(&mut self, _sp: &mut Span) {
279 fn flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
280 noop_flat_map_pat_field(fp, self)
284 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
285 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
286 /// method. Abort the program if the closure panics.
288 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
289 pub fn visit_clobber<T, F>(t: &mut T, f: F)
294 // Safe because `t` is used in a read-only fashion by `read()` before
295 // being overwritten by `write()`.
296 let old_t = ptr::read(t);
297 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
298 .unwrap_or_else(|_| process::abort());
299 ptr::write(t, new_t);
303 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
305 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
314 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
316 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
320 if let Some(elem) = opt {
325 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
326 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
327 visit_vec(attrs, |attr| vis.visit_attribute(attr));
330 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
331 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
332 for attr in attrs.iter_mut() {
333 vis.visit_attribute(attr);
337 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
338 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
339 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
342 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
343 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
344 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
347 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
348 pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
349 vis.visit_fn_header(header);
350 vis.visit_fn_decl(decl);
351 vis.visit_span(span);
354 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
355 pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
358 MacArgs::Delimited(dspan, _delim, tokens) => {
359 visit_delim_span(dspan, vis);
360 visit_tts(tokens, vis);
362 MacArgs::Eq(eq_span, token) => {
363 vis.visit_span(eq_span);
365 visit_token(token, vis);
367 // The value in `#[key = VALUE]` must be visited as an expression for backward
368 // compatibility, so that macros can be expanded in that position.
369 match &mut token.kind {
370 token::Interpolated(nt) => match Lrc::make_mut(nt) {
371 token::NtExpr(expr) => vis.visit_expr(expr),
372 t => panic!("unexpected token in key-value attribute: {:?}", t),
374 t => panic!("unexpected token in key-value attribute: {:?}", t),
381 pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
382 vis.visit_span(&mut dspan.open);
383 vis.visit_span(&mut dspan.close);
386 pub fn noop_flat_map_pat_field<T: MutVisitor>(
389 ) -> SmallVec<[PatField; 1]> {
390 let PatField { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
392 vis.visit_ident(ident);
394 vis.visit_span(span);
395 visit_thin_attrs(attrs, vis);
399 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
400 let UseTree { prefix, kind, span } = use_tree;
401 vis.visit_path(prefix);
403 UseTreeKind::Simple(rename, id1, id2) => {
404 visit_opt(rename, |rename| vis.visit_ident(rename));
408 UseTreeKind::Nested(items) => {
409 for (tree, id) in items {
410 vis.visit_use_tree(tree);
414 UseTreeKind::Glob => {}
416 vis.visit_span(span);
419 pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
420 let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
421 visit_thin_attrs(attrs, vis);
424 visit_opt(guard, |guard| vis.visit_expr(guard));
425 vis.visit_expr(body);
426 vis.visit_span(span);
430 pub fn noop_visit_ty_constraint<T: MutVisitor>(
431 AssocTyConstraint { id, ident, gen_args, kind, span }: &mut AssocTyConstraint,
435 vis.visit_ident(ident);
436 if let Some(ref mut gen_args) = gen_args {
437 vis.visit_generic_args(gen_args);
440 AssocTyConstraintKind::Equality { ref mut ty } => {
443 AssocTyConstraintKind::Bound { ref mut bounds } => {
444 visit_bounds(bounds, vis);
447 vis.visit_span(span);
450 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
451 let Ty { id, kind, span, tokens } = ty.deref_mut();
454 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
455 TyKind::Slice(ty) => vis.visit_ty(ty),
456 TyKind::Ptr(mt) => vis.visit_mt(mt),
457 TyKind::Rptr(lt, mt) => {
458 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
461 TyKind::BareFn(bft) => {
462 let BareFnTy { unsafety: _, ext: _, generic_params, decl } = bft.deref_mut();
463 generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
464 vis.visit_fn_decl(decl);
466 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
467 TyKind::Paren(ty) => vis.visit_ty(ty),
468 TyKind::Path(qself, path) => {
469 vis.visit_qself(qself);
470 vis.visit_path(path);
472 TyKind::Array(ty, length) => {
474 vis.visit_anon_const(length);
476 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
477 TyKind::TraitObject(bounds, _syntax) => {
478 visit_vec(bounds, |bound| vis.visit_param_bound(bound))
480 TyKind::ImplTrait(id, bounds) => {
482 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
484 TyKind::MacCall(mac) => vis.visit_mac_call(mac),
486 vis.visit_span(span);
487 visit_lazy_tts(tokens, vis);
490 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
491 let ForeignMod { unsafety: _, abi: _, items } = foreign_mod;
492 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
495 pub fn noop_flat_map_variant<T: MutVisitor>(
496 mut variant: Variant,
498 ) -> SmallVec<[Variant; 1]> {
499 let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
500 visitor.visit_ident(ident);
501 visitor.visit_vis(vis);
502 visit_thin_attrs(attrs, visitor);
503 visitor.visit_id(id);
504 visitor.visit_variant_data(data);
505 visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
506 visitor.visit_span(span);
510 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
511 vis.visit_span(span);
514 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
515 vis.visit_span(span);
516 for PathSegment { ident, id, args } in segments {
517 vis.visit_ident(ident);
519 visit_opt(args, |args| vis.visit_generic_args(args));
521 visit_lazy_tts(tokens, vis);
524 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
525 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
527 vis.visit_span(path_span);
531 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
533 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
534 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
538 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
540 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
541 GenericArg::Type(ty) => vis.visit_ty(ty),
542 GenericArg::Const(ct) => vis.visit_anon_const(ct),
546 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
547 data: &mut AngleBracketedArgs,
550 let AngleBracketedArgs { args, span } = data;
551 visit_vec(args, |arg| match arg {
552 AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
553 AngleBracketedArg::Constraint(constraint) => vis.visit_ty_constraint(constraint),
555 vis.visit_span(span);
558 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
559 args: &mut ParenthesizedArgs,
562 let ParenthesizedArgs { inputs, output, span, .. } = args;
563 visit_vec(inputs, |input| vis.visit_ty(input));
564 noop_visit_fn_ret_ty(output, vis);
565 vis.visit_span(span);
568 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
569 let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
572 visit_opt(ty, |ty| vis.visit_ty(ty));
574 LocalKind::Decl => {}
575 LocalKind::Init(init) => {
576 vis.visit_expr(init);
578 LocalKind::InitElse(init, els) => {
579 vis.visit_expr(init);
580 vis.visit_block(els);
583 vis.visit_span(span);
584 visit_thin_attrs(attrs, vis);
585 visit_lazy_tts(tokens, vis);
588 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
589 let Attribute { kind, id: _, style: _, span } = attr;
591 AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
592 vis.visit_path(path);
593 visit_mac_args(args, vis);
594 visit_lazy_tts(tokens, vis);
595 visit_lazy_tts(attr_tokens, vis);
597 AttrKind::DocComment(..) => {}
599 vis.visit_span(span);
602 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
603 let MacCall { path, args, prior_type_ascription: _ } = mac;
604 vis.visit_path(path);
605 visit_mac_args(args, vis);
608 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
609 let MacroDef { body, macro_rules: _ } = macro_def;
610 visit_mac_args(body, vis);
613 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
615 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
616 NestedMetaItem::Literal(_lit) => {}
620 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
621 let MetaItem { path: _, kind, span } = mi;
623 MetaItemKind::Word => {}
624 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
625 MetaItemKind::NameValue(_s) => {}
627 vis.visit_span(span);
630 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
631 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
633 visit_thin_attrs(attrs, vis);
635 vis.visit_span(span);
640 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
641 pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
643 AttrAnnotatedTokenTree::Token(token) => {
644 visit_token(token, vis);
646 AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
647 vis.visit_span(open);
648 vis.visit_span(close);
649 visit_attr_annotated_tts(tts, vis);
651 AttrAnnotatedTokenTree::Attributes(data) => {
652 for attr in &mut *data.attrs {
653 match &mut attr.kind {
654 AttrKind::Normal(_, attr_tokens) => {
655 visit_lazy_tts(attr_tokens, vis);
657 AttrKind::DocComment(..) => {
658 vis.visit_span(&mut attr.span);
662 visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
667 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
668 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
670 TokenTree::Token(token) => {
671 visit_token(token, vis);
673 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
674 vis.visit_span(open);
675 vis.visit_span(close);
681 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
682 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
683 if T::VISIT_TOKENS && !tts.is_empty() {
684 let tts = Lrc::make_mut(tts);
685 visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis));
689 pub fn visit_attr_annotated_tts<T: MutVisitor>(
690 AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
693 if T::VISIT_TOKENS && !tts.is_empty() {
694 let tts = Lrc::make_mut(tts);
695 visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
699 pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
701 if let Some(lazy_tts) = lazy_tts {
702 let mut tts = lazy_tts.create_token_stream();
703 visit_attr_annotated_tts(&mut tts, vis);
704 *lazy_tts = LazyTokenStream::new(tts);
709 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
710 visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
713 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
714 // Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
715 // In practice the ident part is not actually used by specific visitors right now,
716 // but there's a test below checking that it works.
717 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
718 let Token { kind, span } = t;
720 token::Ident(name, _) | token::Lifetime(name) => {
721 let mut ident = Ident::new(*name, *span);
722 vis.visit_ident(&mut ident);
725 return; // Avoid visiting the span for the second time.
727 token::Interpolated(nt) => {
728 let mut nt = Lrc::make_mut(nt);
729 visit_interpolated(&mut nt, vis);
733 vis.visit_span(span);
736 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
737 /// Applies the visitor to elements of interpolated nodes.
739 // N.B., this can occur only when applying a visitor to partially expanded
740 // code, where parsed pieces have gotten implanted ito *other* macro
741 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
743 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
744 // etc., allow the visitor to return *multiple* items; this is a problem for the
745 // nodes here, because they insist on having exactly one piece. One solution
746 // would be to mangle the MutVisitor trait to include one-to-many and
747 // one-to-one versions of these entry points, but that would probably confuse a
748 // lot of people and help very few. Instead, I'm just going to put in dynamic
749 // checks. I think the performance impact of this will be pretty much
750 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
751 // partially expanded node, and will be confused by the fact that their
752 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
753 // nodes. Hopefully they'll wind up reading this comment, and doing something
756 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
757 // contain multiple items, but decided against it when I looked at
758 // `parse_item_or_view_item` and tried to figure out what I would do with
759 // multiple items there....
760 pub fn visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
762 token::NtItem(item) => visit_clobber(item, |item| {
763 // This is probably okay, because the only visitors likely to
764 // peek inside interpolated nodes will be renamings/markings,
765 // which map single items to single items.
766 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
768 token::NtBlock(block) => vis.visit_block(block),
769 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
770 // See reasoning above.
771 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
773 token::NtPat(pat) => vis.visit_pat(pat),
774 token::NtExpr(expr) => vis.visit_expr(expr),
775 token::NtTy(ty) => vis.visit_ty(ty),
776 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
777 token::NtLifetime(ident) => vis.visit_ident(ident),
778 token::NtLiteral(expr) => vis.visit_expr(expr),
779 token::NtMeta(item) => {
780 let AttrItem { path, args, tokens } = item.deref_mut();
781 vis.visit_path(path);
782 visit_mac_args(args, vis);
783 visit_lazy_tts(tokens, vis);
785 token::NtPath(path) => vis.visit_path(path),
786 token::NtTT(tt) => visit_tt(tt, vis),
787 token::NtVis(visib) => vis.visit_vis(visib),
791 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
793 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
794 vis.visit_id(closure_id);
795 vis.visit_id(return_impl_trait_id);
801 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
802 let FnDecl { inputs, output } = decl.deref_mut();
803 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
804 noop_visit_fn_ret_ty(output, vis);
807 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
809 FnRetTy::Default(span) => vis.visit_span(span),
810 FnRetTy::Ty(ty) => vis.visit_ty(ty),
814 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
816 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
817 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
821 pub fn noop_flat_map_generic_param<T: MutVisitor>(
822 mut param: GenericParam,
824 ) -> SmallVec<[GenericParam; 1]> {
825 let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
827 vis.visit_ident(ident);
828 visit_thin_attrs(attrs, vis);
829 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
831 GenericParamKind::Lifetime => {}
832 GenericParamKind::Type { default } => {
833 visit_opt(default, |default| vis.visit_ty(default));
835 GenericParamKind::Const { ty, kw_span: _, default } => {
837 visit_opt(default, |default| vis.visit_anon_const(default));
843 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
844 vis.visit_ident(ident);
847 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
849 vis.visit_ident(ident);
852 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
853 let Generics { params, where_clause, span } = generics;
854 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
855 vis.visit_where_clause(where_clause);
856 vis.visit_span(span);
859 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
860 let WhereClause { has_where_token: _, predicates, span } = wc;
861 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
862 vis.visit_span(span);
865 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
867 WherePredicate::BoundPredicate(bp) => {
868 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
869 vis.visit_span(span);
870 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
871 vis.visit_ty(bounded_ty);
872 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
874 WherePredicate::RegionPredicate(rp) => {
875 let WhereRegionPredicate { span, lifetime, bounds } = rp;
876 vis.visit_span(span);
877 noop_visit_lifetime(lifetime, vis);
878 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
880 WherePredicate::EqPredicate(ep) => {
881 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
883 vis.visit_span(span);
884 vis.visit_ty(lhs_ty);
885 vis.visit_ty(rhs_ty);
890 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
892 VariantData::Struct(fields, ..) => {
893 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
895 VariantData::Tuple(fields, id) => {
896 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
899 VariantData::Unit(id) => vis.visit_id(id),
903 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
904 vis.visit_path(path);
905 vis.visit_id(ref_id);
908 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
909 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
910 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
911 vis.visit_trait_ref(trait_ref);
912 vis.visit_span(span);
915 pub fn noop_flat_map_field_def<T: MutVisitor>(
918 ) -> SmallVec<[FieldDef; 1]> {
919 let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
920 visitor.visit_span(span);
921 visit_opt(ident, |ident| visitor.visit_ident(ident));
922 visitor.visit_vis(vis);
923 visitor.visit_id(id);
924 visitor.visit_ty(ty);
925 visit_thin_attrs(attrs, visitor);
929 pub fn noop_flat_map_expr_field<T: MutVisitor>(
932 ) -> SmallVec<[ExprField; 1]> {
933 let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
934 vis.visit_ident(ident);
935 vis.visit_expr(expr);
937 vis.visit_span(span);
938 visit_thin_attrs(attrs, vis);
942 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
946 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
947 let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
949 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
950 vis.visit_span(span);
951 visit_lazy_tts(tokens, vis);
954 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
956 ItemKind::ExternCrate(_orig_name) => {}
957 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
958 ItemKind::Static(ty, _, expr) | ItemKind::Const(_, ty, expr) => {
960 visit_opt(expr, |expr| vis.visit_expr(expr));
962 ItemKind::Fn(box FnKind(_, sig, generics, body)) => {
963 visit_fn_sig(sig, vis);
964 vis.visit_generics(generics);
965 visit_opt(body, |body| vis.visit_block(body));
967 ItemKind::Mod(_unsafety, mod_kind) => match mod_kind {
968 ModKind::Loaded(items, _inline, inner_span) => {
969 vis.visit_span(inner_span);
970 items.flat_map_in_place(|item| vis.flat_map_item(item));
972 ModKind::Unloaded => {}
974 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
975 ItemKind::GlobalAsm(asm) => noop_visit_inline_asm(asm, vis),
976 ItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
977 vis.visit_generics(generics);
978 visit_bounds(bounds, vis);
979 visit_opt(ty, |ty| vis.visit_ty(ty));
981 ItemKind::Enum(EnumDef { variants }, generics) => {
982 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
983 vis.visit_generics(generics);
985 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
986 vis.visit_variant_data(variant_data);
987 vis.visit_generics(generics);
989 ItemKind::Impl(box ImplKind {
999 vis.visit_generics(generics);
1000 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
1001 vis.visit_ty(self_ty);
1002 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
1004 ItemKind::Trait(box TraitKind(.., generics, bounds, items)) => {
1005 vis.visit_generics(generics);
1006 visit_bounds(bounds, vis);
1007 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
1009 ItemKind::TraitAlias(generics, bounds) => {
1010 vis.visit_generics(generics);
1011 visit_bounds(bounds, vis);
1013 ItemKind::MacCall(m) => vis.visit_mac_call(m),
1014 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1018 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
1019 mut item: P<AssocItem>,
1021 ) -> SmallVec<[P<AssocItem>; 1]> {
1022 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
1023 visitor.visit_id(id);
1024 visitor.visit_ident(ident);
1025 visitor.visit_vis(vis);
1026 visit_attrs(attrs, visitor);
1028 AssocItemKind::Const(_, ty, expr) => {
1029 visitor.visit_ty(ty);
1030 visit_opt(expr, |expr| visitor.visit_expr(expr));
1032 AssocItemKind::Fn(box FnKind(_, sig, generics, body)) => {
1033 visitor.visit_generics(generics);
1034 visit_fn_sig(sig, visitor);
1035 visit_opt(body, |body| visitor.visit_block(body));
1037 AssocItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
1038 visitor.visit_generics(generics);
1039 visit_bounds(bounds, visitor);
1040 visit_opt(ty, |ty| visitor.visit_ty(ty));
1042 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1044 visitor.visit_span(span);
1045 visit_lazy_tts(tokens, visitor);
1049 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
1050 let FnHeader { unsafety: _, asyncness, constness: _, ext: _ } = header;
1051 vis.visit_asyncness(asyncness);
1054 // FIXME: Avoid visiting the crate as a `Mod` item, flat map only the inner items if possible,
1055 // or make crate visiting first class if necessary.
1056 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1057 visit_clobber(krate, |Crate { attrs, items, span }| {
1059 Visibility { kind: VisibilityKind::Public, span: span.shrink_to_lo(), tokens: None };
1061 ident: Ident::empty(),
1066 kind: ItemKind::Mod(Unsafe::No, ModKind::Loaded(items, Inline::Yes, span)),
1069 let items = vis.flat_map_item(item);
1071 let len = items.len();
1073 Crate { attrs: vec![], items: vec![], span }
1074 } else if len == 1 {
1075 let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner();
1077 ItemKind::Mod(_, ModKind::Loaded(items, ..)) => Crate { attrs, items, span },
1078 _ => panic!("visitor converted a module to not a module"),
1081 panic!("a crate cannot expand to more than one item");
1086 // Mutates one item into possibly many items.
1087 pub fn noop_flat_map_item<T: MutVisitor>(
1090 ) -> SmallVec<[P<Item>; 1]> {
1091 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1092 visitor.visit_ident(ident);
1093 visit_attrs(attrs, visitor);
1094 visitor.visit_id(id);
1095 visitor.visit_item_kind(kind);
1096 visitor.visit_vis(vis);
1097 visitor.visit_span(span);
1098 visit_lazy_tts(tokens, visitor);
1103 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1104 mut item: P<ForeignItem>,
1106 ) -> SmallVec<[P<ForeignItem>; 1]> {
1107 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1108 visitor.visit_id(id);
1109 visitor.visit_ident(ident);
1110 visitor.visit_vis(vis);
1111 visit_attrs(attrs, visitor);
1113 ForeignItemKind::Static(ty, _, expr) => {
1114 visitor.visit_ty(ty);
1115 visit_opt(expr, |expr| visitor.visit_expr(expr));
1117 ForeignItemKind::Fn(box FnKind(_, sig, generics, body)) => {
1118 visitor.visit_generics(generics);
1119 visit_fn_sig(sig, visitor);
1120 visit_opt(body, |body| visitor.visit_block(body));
1122 ForeignItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
1123 visitor.visit_generics(generics);
1124 visit_bounds(bounds, visitor);
1125 visit_opt(ty, |ty| visitor.visit_ty(ty));
1127 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1129 visitor.visit_span(span);
1130 visit_lazy_tts(tokens, visitor);
1134 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1135 let Pat { id, kind, span, tokens } = pat.deref_mut();
1138 PatKind::Wild | PatKind::Rest => {}
1139 PatKind::Ident(_binding_mode, ident, sub) => {
1140 vis.visit_ident(ident);
1141 visit_opt(sub, |sub| vis.visit_pat(sub));
1143 PatKind::Lit(e) => vis.visit_expr(e),
1144 PatKind::TupleStruct(qself, path, elems) => {
1145 vis.visit_qself(qself);
1146 vis.visit_path(path);
1147 visit_vec(elems, |elem| vis.visit_pat(elem));
1149 PatKind::Path(qself, path) => {
1150 vis.visit_qself(qself);
1151 vis.visit_path(path);
1153 PatKind::Struct(qself, path, fields, _etc) => {
1154 vis.visit_qself(qself);
1155 vis.visit_path(path);
1156 fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
1158 PatKind::Box(inner) => vis.visit_pat(inner),
1159 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1160 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1161 visit_opt(e1, |e| vis.visit_expr(e));
1162 visit_opt(e2, |e| vis.visit_expr(e));
1163 vis.visit_span(span);
1165 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1166 visit_vec(elems, |elem| vis.visit_pat(elem))
1168 PatKind::Paren(inner) => vis.visit_pat(inner),
1169 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1171 vis.visit_span(span);
1172 visit_lazy_tts(tokens, vis);
1175 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1177 vis.visit_expr(value);
1180 fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
1181 for (op, _) in &mut asm.operands {
1183 InlineAsmOperand::In { expr, .. }
1184 | InlineAsmOperand::Out { expr: Some(expr), .. }
1185 | InlineAsmOperand::InOut { expr, .. }
1186 | InlineAsmOperand::Sym { expr, .. } => vis.visit_expr(expr),
1187 InlineAsmOperand::Out { expr: None, .. } => {}
1188 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1189 vis.visit_expr(in_expr);
1190 if let Some(out_expr) = out_expr {
1191 vis.visit_expr(out_expr);
1194 InlineAsmOperand::Const { anon_const, .. } => vis.visit_anon_const(anon_const),
1199 pub fn noop_visit_expr<T: MutVisitor>(
1200 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1204 ExprKind::Box(expr) => vis.visit_expr(expr),
1205 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1206 ExprKind::ConstBlock(anon_const) => {
1207 vis.visit_anon_const(anon_const);
1209 ExprKind::Repeat(expr, count) => {
1210 vis.visit_expr(expr);
1211 vis.visit_anon_const(count);
1213 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1214 ExprKind::Call(f, args) => {
1216 visit_exprs(args, vis);
1218 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
1219 vis.visit_ident(ident);
1221 visit_opt(args, |args| vis.visit_generic_args(args));
1222 visit_exprs(exprs, vis);
1223 vis.visit_span(span);
1225 ExprKind::Binary(_binop, lhs, rhs) => {
1226 vis.visit_expr(lhs);
1227 vis.visit_expr(rhs);
1229 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1230 ExprKind::Cast(expr, ty) => {
1231 vis.visit_expr(expr);
1234 ExprKind::Type(expr, ty) => {
1235 vis.visit_expr(expr);
1238 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1239 ExprKind::Let(pat, scrutinee, _) => {
1241 vis.visit_expr(scrutinee);
1243 ExprKind::If(cond, tr, fl) => {
1244 vis.visit_expr(cond);
1245 vis.visit_block(tr);
1246 visit_opt(fl, |fl| vis.visit_expr(fl));
1248 ExprKind::While(cond, body, label) => {
1249 vis.visit_expr(cond);
1250 vis.visit_block(body);
1251 visit_opt(label, |label| vis.visit_label(label));
1253 ExprKind::ForLoop(pat, iter, body, label) => {
1255 vis.visit_expr(iter);
1256 vis.visit_block(body);
1257 visit_opt(label, |label| vis.visit_label(label));
1259 ExprKind::Loop(body, label) => {
1260 vis.visit_block(body);
1261 visit_opt(label, |label| vis.visit_label(label));
1263 ExprKind::Match(expr, arms) => {
1264 vis.visit_expr(expr);
1265 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1267 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1268 vis.visit_asyncness(asyncness);
1269 vis.visit_fn_decl(decl);
1270 vis.visit_expr(body);
1271 vis.visit_span(span);
1273 ExprKind::Block(blk, label) => {
1274 vis.visit_block(blk);
1275 visit_opt(label, |label| vis.visit_label(label));
1277 ExprKind::Async(_capture_by, node_id, body) => {
1278 vis.visit_id(node_id);
1279 vis.visit_block(body);
1281 ExprKind::Await(expr) => vis.visit_expr(expr),
1282 ExprKind::Assign(el, er, _) => {
1286 ExprKind::AssignOp(_op, el, er) => {
1290 ExprKind::Field(el, ident) => {
1292 vis.visit_ident(ident);
1294 ExprKind::Index(el, er) => {
1298 ExprKind::Range(e1, e2, _lim) => {
1299 visit_opt(e1, |e1| vis.visit_expr(e1));
1300 visit_opt(e2, |e2| vis.visit_expr(e2));
1302 ExprKind::Underscore => {}
1303 ExprKind::Path(qself, path) => {
1304 vis.visit_qself(qself);
1305 vis.visit_path(path);
1307 ExprKind::Break(label, expr) => {
1308 visit_opt(label, |label| vis.visit_label(label));
1309 visit_opt(expr, |expr| vis.visit_expr(expr));
1311 ExprKind::Continue(label) => {
1312 visit_opt(label, |label| vis.visit_label(label));
1314 ExprKind::Ret(expr) => {
1315 visit_opt(expr, |expr| vis.visit_expr(expr));
1317 ExprKind::InlineAsm(asm) => noop_visit_inline_asm(asm, vis),
1318 ExprKind::LlvmInlineAsm(asm) => {
1328 } = asm.deref_mut();
1329 for out in outputs {
1330 let LlvmInlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1331 vis.visit_expr(expr);
1333 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1335 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1336 ExprKind::Struct(se) => {
1337 let StructExpr { qself, path, fields, rest } = se.deref_mut();
1338 vis.visit_qself(qself);
1339 vis.visit_path(path);
1340 fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
1342 StructRest::Base(expr) => vis.visit_expr(expr),
1343 StructRest::Rest(_span) => {}
1344 StructRest::None => {}
1347 ExprKind::Paren(expr) => {
1348 vis.visit_expr(expr);
1350 ExprKind::Yield(expr) => {
1351 visit_opt(expr, |expr| vis.visit_expr(expr));
1353 ExprKind::Try(expr) => vis.visit_expr(expr),
1354 ExprKind::TryBlock(body) => vis.visit_block(body),
1355 ExprKind::Lit(_) | ExprKind::Err => {}
1358 vis.visit_span(span);
1359 visit_thin_attrs(attrs, vis);
1360 visit_lazy_tts(tokens, vis);
1363 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1365 vis.visit_expr(&mut e);
1370 pub fn noop_flat_map_stmt<T: MutVisitor>(
1371 Stmt { kind, mut span, mut id }: Stmt,
1373 ) -> SmallVec<[Stmt; 1]> {
1374 vis.visit_id(&mut id);
1375 vis.visit_span(&mut span);
1376 let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
1378 .map(|kind| Stmt { id, kind, span })
1380 if stmts.len() > 1 {
1382 "cloning statement `NodeId`s is prohibited by default, \
1383 the visitor should implement custom statement visiting"
1389 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1392 ) -> SmallVec<[StmtKind; 1]> {
1394 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1395 vis.visit_local(&mut local);
1398 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1399 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1400 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1401 StmtKind::Empty => smallvec![StmtKind::Empty],
1402 StmtKind::MacCall(mut mac) => {
1403 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1404 vis.visit_mac_call(mac_);
1405 visit_thin_attrs(attrs, vis);
1406 visit_lazy_tts(tokens, vis);
1407 smallvec![StmtKind::MacCall(mac)]
1412 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1413 match &mut visibility.kind {
1414 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1415 VisibilityKind::Restricted { path, id } => {
1416 vis.visit_path(path);
1420 vis.visit_span(&mut visibility.span);