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 fn token_visiting_enabled(&self) -> bool {
44 // Methods in this trait have one of three forms:
46 // fn visit_t(&mut self, t: &mut T); // common
47 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
48 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
50 // Any additions to this trait should happen in form of a call to a public
51 // `noop_*` function that only calls out to the visitor again, not other
52 // `noop_*` functions. This is a necessary API workaround to the problem of
53 // not being able to call out to the super default method in an overridden
56 // When writing these methods, it is better to use destructuring like this:
58 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
63 // than to use field access like this:
65 // fn visit_abc(&mut self, abc: &mut ABC) {
66 // visit_a(&mut abc.a);
67 // visit_b(&mut abc.b);
71 // As well as being more concise, the former is explicit about which fields
72 // are skipped. Furthermore, if a new field is added, the destructuring
73 // version will cause a compile error, which is good. In comparison, the
74 // field access version will continue working and it would be easy to
75 // forget to add handling for it.
77 fn visit_crate(&mut self, c: &mut Crate) {
78 noop_visit_crate(c, self)
81 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
82 noop_visit_meta_list_item(list_item, self);
85 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
86 noop_visit_meta_item(meta_item, self);
89 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
90 noop_visit_use_tree(use_tree, self);
93 fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
94 noop_flat_map_foreign_item(ni, self)
97 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
98 noop_flat_map_item(i, self)
101 fn visit_fn_header(&mut self, header: &mut FnHeader) {
102 noop_visit_fn_header(header, self);
105 fn flat_map_struct_field(&mut self, sf: StructField) -> SmallVec<[StructField; 1]> {
106 noop_flat_map_struct_field(sf, self)
109 fn visit_item_kind(&mut self, i: &mut ItemKind) {
110 noop_visit_item_kind(i, self);
113 fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
114 noop_flat_map_assoc_item(i, self)
117 fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
118 noop_flat_map_assoc_item(i, self)
121 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
122 noop_visit_fn_decl(d, self);
125 fn visit_asyncness(&mut self, a: &mut Async) {
126 noop_visit_asyncness(a, self);
129 fn visit_block(&mut self, b: &mut P<Block>) {
130 noop_visit_block(b, self);
133 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
134 noop_flat_map_stmt(s, self)
137 fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
138 noop_flat_map_arm(arm, self)
141 fn visit_pat(&mut self, p: &mut P<Pat>) {
142 noop_visit_pat(p, self);
145 fn visit_anon_const(&mut self, c: &mut AnonConst) {
146 noop_visit_anon_const(c, self);
149 fn visit_expr(&mut self, e: &mut P<Expr>) {
150 noop_visit_expr(e, self);
153 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
154 noop_filter_map_expr(e, self)
157 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
158 noop_visit_generic_arg(arg, self);
161 fn visit_ty(&mut self, t: &mut P<Ty>) {
162 noop_visit_ty(t, self);
165 fn visit_lifetime(&mut self, l: &mut Lifetime) {
166 noop_visit_lifetime(l, self);
169 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
170 noop_visit_ty_constraint(t, self);
173 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
174 noop_visit_foreign_mod(nm, self);
177 fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
178 noop_flat_map_variant(v, self)
181 fn visit_ident(&mut self, i: &mut Ident) {
182 noop_visit_ident(i, self);
185 fn visit_path(&mut self, p: &mut Path) {
186 noop_visit_path(p, self);
189 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
190 noop_visit_qself(qs, self);
193 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
194 noop_visit_generic_args(p, self);
197 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
198 noop_visit_angle_bracketed_parameter_data(p, self);
201 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
202 noop_visit_parenthesized_parameter_data(p, self);
205 fn visit_local(&mut self, l: &mut P<Local>) {
206 noop_visit_local(l, self);
209 fn visit_mac_call(&mut self, mac: &mut MacCall) {
210 noop_visit_mac(mac, self);
213 fn visit_macro_def(&mut self, def: &mut MacroDef) {
214 noop_visit_macro_def(def, self);
217 fn visit_label(&mut self, label: &mut Label) {
218 noop_visit_label(label, self);
221 fn visit_attribute(&mut self, at: &mut Attribute) {
222 noop_visit_attribute(at, self);
225 fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
226 noop_flat_map_param(param, self)
229 fn visit_generics(&mut self, generics: &mut Generics) {
230 noop_visit_generics(generics, self);
233 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
234 noop_visit_trait_ref(tr, self);
237 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
238 noop_visit_poly_trait_ref(p, self);
241 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
242 noop_visit_variant_data(vdata, self);
245 fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
246 noop_flat_map_generic_param(param, self)
249 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
250 noop_visit_param_bound(tpb, self);
253 fn visit_mt(&mut self, mt: &mut MutTy) {
254 noop_visit_mt(mt, self);
257 fn flat_map_field(&mut self, f: Field) -> SmallVec<[Field; 1]> {
258 noop_flat_map_field(f, self)
261 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
262 noop_visit_where_clause(where_clause, self);
265 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
266 noop_visit_where_predicate(where_predicate, self);
269 fn visit_vis(&mut self, vis: &mut Visibility) {
270 noop_visit_vis(vis, self);
273 fn visit_id(&mut self, _id: &mut NodeId) {
277 fn visit_span(&mut self, _sp: &mut Span) {
281 fn flat_map_field_pattern(&mut self, fp: FieldPat) -> SmallVec<[FieldPat; 1]> {
282 noop_flat_map_field_pattern(fp, self)
286 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
287 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
288 /// method. Abort the program if the closure panics.
290 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
291 pub fn visit_clobber<T, F>(t: &mut T, f: F)
296 // Safe because `t` is used in a read-only fashion by `read()` before
297 // being overwritten by `write()`.
298 let old_t = ptr::read(t);
299 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
300 .unwrap_or_else(|_| process::abort());
301 ptr::write(t, new_t);
305 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
307 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
316 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
318 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
322 if let Some(elem) = opt {
327 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
328 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
329 visit_vec(attrs, |attr| vis.visit_attribute(attr));
332 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
333 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
334 for attr in attrs.iter_mut() {
335 vis.visit_attribute(attr);
339 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
340 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
341 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
344 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
345 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
346 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
349 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
350 pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
351 vis.visit_fn_header(header);
352 vis.visit_fn_decl(decl);
353 vis.visit_span(span);
356 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
357 pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
360 MacArgs::Delimited(dspan, _delim, tokens) => {
361 visit_delim_span(dspan, vis);
362 visit_tts(tokens, vis);
364 MacArgs::Eq(eq_span, token) => {
365 vis.visit_span(eq_span);
366 if vis.token_visiting_enabled() {
367 visit_token(token, vis);
369 // The value in `#[key = VALUE]` must be visited as an expression for backward
370 // compatibility, so that macros can be expanded in that position.
371 match &mut token.kind {
372 token::Interpolated(nt) => match Lrc::make_mut(nt) {
373 token::NtExpr(expr) => vis.visit_expr(expr),
374 t => panic!("unexpected token in key-value attribute: {:?}", t),
376 t => panic!("unexpected token in key-value attribute: {:?}", t),
383 pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
384 vis.visit_span(&mut dspan.open);
385 vis.visit_span(&mut dspan.close);
388 pub fn noop_flat_map_field_pattern<T: MutVisitor>(
391 ) -> SmallVec<[FieldPat; 1]> {
392 let FieldPat { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
394 vis.visit_ident(ident);
396 vis.visit_span(span);
397 visit_thin_attrs(attrs, vis);
401 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
402 let UseTree { prefix, kind, span } = use_tree;
403 vis.visit_path(prefix);
405 UseTreeKind::Simple(rename, id1, id2) => {
406 visit_opt(rename, |rename| vis.visit_ident(rename));
410 UseTreeKind::Nested(items) => {
411 for (tree, id) in items {
412 vis.visit_use_tree(tree);
416 UseTreeKind::Glob => {}
418 vis.visit_span(span);
421 pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
422 let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
423 visit_attrs(attrs, vis);
426 visit_opt(guard, |guard| vis.visit_expr(guard));
427 vis.visit_expr(body);
428 vis.visit_span(span);
432 pub fn noop_visit_ty_constraint<T: MutVisitor>(
433 AssocTyConstraint { id, ident, gen_args, kind, span }: &mut AssocTyConstraint,
437 vis.visit_ident(ident);
438 if let Some(ref mut gen_args) = gen_args {
439 vis.visit_generic_args(gen_args);
442 AssocTyConstraintKind::Equality { ref mut ty } => {
445 AssocTyConstraintKind::Bound { ref mut bounds } => {
446 visit_bounds(bounds, vis);
449 vis.visit_span(span);
452 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
453 let Ty { id, kind, span, tokens } = ty.deref_mut();
456 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
457 TyKind::Slice(ty) => vis.visit_ty(ty),
458 TyKind::Ptr(mt) => vis.visit_mt(mt),
459 TyKind::Rptr(lt, mt) => {
460 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
463 TyKind::BareFn(bft) => {
464 let BareFnTy { unsafety: _, ext: _, generic_params, decl } = bft.deref_mut();
465 generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
466 vis.visit_fn_decl(decl);
468 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
469 TyKind::Paren(ty) => vis.visit_ty(ty),
470 TyKind::Path(qself, path) => {
471 vis.visit_qself(qself);
472 vis.visit_path(path);
474 TyKind::Array(ty, length) => {
476 vis.visit_anon_const(length);
478 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
479 TyKind::TraitObject(bounds, _syntax) => {
480 visit_vec(bounds, |bound| vis.visit_param_bound(bound))
482 TyKind::ImplTrait(id, bounds) => {
484 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
486 TyKind::MacCall(mac) => vis.visit_mac_call(mac),
488 vis.visit_span(span);
489 visit_lazy_tts(tokens, vis);
492 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
493 let ForeignMod { unsafety: _, abi: _, items } = foreign_mod;
494 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
497 pub fn noop_flat_map_variant<T: MutVisitor>(
498 mut variant: Variant,
500 ) -> SmallVec<[Variant; 1]> {
501 let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
502 visitor.visit_ident(ident);
503 visitor.visit_vis(vis);
504 visit_attrs(attrs, visitor);
505 visitor.visit_id(id);
506 visitor.visit_variant_data(data);
507 visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
508 visitor.visit_span(span);
512 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
513 vis.visit_span(span);
516 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
517 vis.visit_span(span);
518 for PathSegment { ident, id, args } in segments {
519 vis.visit_ident(ident);
521 visit_opt(args, |args| vis.visit_generic_args(args));
523 visit_lazy_tts(tokens, vis);
526 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
527 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
529 vis.visit_span(path_span);
533 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
535 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
536 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
540 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
542 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
543 GenericArg::Type(ty) => vis.visit_ty(ty),
544 GenericArg::Const(ct) => vis.visit_anon_const(ct),
548 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
549 data: &mut AngleBracketedArgs,
552 let AngleBracketedArgs { args, span } = data;
553 visit_vec(args, |arg| match arg {
554 AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
555 AngleBracketedArg::Constraint(constraint) => vis.visit_ty_constraint(constraint),
557 vis.visit_span(span);
560 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
561 args: &mut ParenthesizedArgs,
564 let ParenthesizedArgs { inputs, output, span, .. } = args;
565 visit_vec(inputs, |input| vis.visit_ty(input));
566 noop_visit_fn_ret_ty(output, vis);
567 vis.visit_span(span);
570 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
571 let Local { id, pat, ty, init, span, attrs, tokens } = local.deref_mut();
574 visit_opt(ty, |ty| vis.visit_ty(ty));
575 visit_opt(init, |init| vis.visit_expr(init));
576 vis.visit_span(span);
577 visit_thin_attrs(attrs, vis);
578 visit_lazy_tts(tokens, vis);
581 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
582 let Attribute { kind, id: _, style: _, span } = attr;
584 AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
585 vis.visit_path(path);
586 visit_mac_args(args, vis);
587 visit_lazy_tts(tokens, vis);
588 visit_lazy_tts(attr_tokens, vis);
590 AttrKind::DocComment(..) => {}
592 vis.visit_span(span);
595 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
596 let MacCall { path, args, prior_type_ascription: _ } = mac;
597 vis.visit_path(path);
598 visit_mac_args(args, vis);
601 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
602 let MacroDef { body, macro_rules: _ } = macro_def;
603 visit_mac_args(body, vis);
606 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
608 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
609 NestedMetaItem::Literal(_lit) => {}
613 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
614 let MetaItem { path: _, kind, span } = mi;
616 MetaItemKind::Word => {}
617 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
618 MetaItemKind::NameValue(_s) => {}
620 vis.visit_span(span);
623 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
624 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
626 visit_thin_attrs(attrs, vis);
628 vis.visit_span(span);
633 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
634 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
636 TokenTree::Token(token) => {
637 visit_token(token, vis);
639 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
640 vis.visit_span(open);
641 vis.visit_span(close);
647 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
648 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
649 if vis.token_visiting_enabled() && !tts.is_empty() {
650 let tts = Lrc::make_mut(tts);
651 visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis));
655 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
656 if vis.token_visiting_enabled() {
657 visit_opt(lazy_tts, |lazy_tts| {
658 let mut tts = lazy_tts.create_token_stream();
659 visit_tts(&mut tts, vis);
660 *lazy_tts = LazyTokenStream::new(tts);
665 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
666 // Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
667 // In practice the ident part is not actually used by specific visitors right now,
668 // but there's a test below checking that it works.
669 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
670 let Token { kind, span } = t;
672 token::Ident(name, _) | token::Lifetime(name) => {
673 let mut ident = Ident::new(*name, *span);
674 vis.visit_ident(&mut ident);
677 return; // Avoid visiting the span for the second time.
679 token::Interpolated(nt) => {
680 let mut nt = Lrc::make_mut(nt);
681 visit_interpolated(&mut nt, vis);
685 vis.visit_span(span);
688 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
689 /// Applies the visitor to elements of interpolated nodes.
691 // N.B., this can occur only when applying a visitor to partially expanded
692 // code, where parsed pieces have gotten implanted ito *other* macro
693 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
695 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
696 // etc., allow the visitor to return *multiple* items; this is a problem for the
697 // nodes here, because they insist on having exactly one piece. One solution
698 // would be to mangle the MutVisitor trait to include one-to-many and
699 // one-to-one versions of these entry points, but that would probably confuse a
700 // lot of people and help very few. Instead, I'm just going to put in dynamic
701 // checks. I think the performance impact of this will be pretty much
702 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
703 // partially expanded node, and will be confused by the fact that their
704 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
705 // nodes. Hopefully they'll wind up reading this comment, and doing something
708 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
709 // contain multiple items, but decided against it when I looked at
710 // `parse_item_or_view_item` and tried to figure out what I would do with
711 // multiple items there....
712 pub fn visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
714 token::NtItem(item) => visit_clobber(item, |item| {
715 // This is probably okay, because the only visitors likely to
716 // peek inside interpolated nodes will be renamings/markings,
717 // which map single items to single items.
718 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
720 token::NtBlock(block) => vis.visit_block(block),
721 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
722 // See reasoning above.
723 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
725 token::NtPat(pat) => vis.visit_pat(pat),
726 token::NtExpr(expr) => vis.visit_expr(expr),
727 token::NtTy(ty) => vis.visit_ty(ty),
728 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
729 token::NtLifetime(ident) => vis.visit_ident(ident),
730 token::NtLiteral(expr) => vis.visit_expr(expr),
731 token::NtMeta(item) => {
732 let AttrItem { path, args, tokens } = item.deref_mut();
733 vis.visit_path(path);
734 visit_mac_args(args, vis);
735 visit_lazy_tts(tokens, vis);
737 token::NtPath(path) => vis.visit_path(path),
738 token::NtTT(tt) => visit_tt(tt, vis),
739 token::NtVis(visib) => vis.visit_vis(visib),
743 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
745 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
746 vis.visit_id(closure_id);
747 vis.visit_id(return_impl_trait_id);
753 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
754 let FnDecl { inputs, output } = decl.deref_mut();
755 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
756 noop_visit_fn_ret_ty(output, vis);
759 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
761 FnRetTy::Default(span) => vis.visit_span(span),
762 FnRetTy::Ty(ty) => vis.visit_ty(ty),
766 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
768 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
769 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
773 pub fn noop_flat_map_generic_param<T: MutVisitor>(
774 mut param: GenericParam,
776 ) -> SmallVec<[GenericParam; 1]> {
777 let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
779 vis.visit_ident(ident);
780 visit_thin_attrs(attrs, vis);
781 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
783 GenericParamKind::Lifetime => {}
784 GenericParamKind::Type { default } => {
785 visit_opt(default, |default| vis.visit_ty(default));
787 GenericParamKind::Const { ty, kw_span: _, default } => {
789 visit_opt(default, |default| vis.visit_anon_const(default));
795 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
796 vis.visit_ident(ident);
799 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
801 vis.visit_ident(ident);
804 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
805 let Generics { params, where_clause, span } = generics;
806 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
807 vis.visit_where_clause(where_clause);
808 vis.visit_span(span);
811 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
812 let WhereClause { has_where_token: _, predicates, span } = wc;
813 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
814 vis.visit_span(span);
817 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
819 WherePredicate::BoundPredicate(bp) => {
820 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
821 vis.visit_span(span);
822 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
823 vis.visit_ty(bounded_ty);
824 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
826 WherePredicate::RegionPredicate(rp) => {
827 let WhereRegionPredicate { span, lifetime, bounds } = rp;
828 vis.visit_span(span);
829 noop_visit_lifetime(lifetime, vis);
830 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
832 WherePredicate::EqPredicate(ep) => {
833 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
835 vis.visit_span(span);
836 vis.visit_ty(lhs_ty);
837 vis.visit_ty(rhs_ty);
842 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
844 VariantData::Struct(fields, ..) => {
845 fields.flat_map_in_place(|field| vis.flat_map_struct_field(field));
847 VariantData::Tuple(fields, id) => {
848 fields.flat_map_in_place(|field| vis.flat_map_struct_field(field));
851 VariantData::Unit(id) => vis.visit_id(id),
855 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
856 vis.visit_path(path);
857 vis.visit_id(ref_id);
860 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
861 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
862 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
863 vis.visit_trait_ref(trait_ref);
864 vis.visit_span(span);
867 pub fn noop_flat_map_struct_field<T: MutVisitor>(
870 ) -> SmallVec<[StructField; 1]> {
871 let StructField { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut sf;
872 visitor.visit_span(span);
873 visit_opt(ident, |ident| visitor.visit_ident(ident));
874 visitor.visit_vis(vis);
875 visitor.visit_id(id);
876 visitor.visit_ty(ty);
877 visit_attrs(attrs, visitor);
881 pub fn noop_flat_map_field<T: MutVisitor>(mut f: Field, vis: &mut T) -> SmallVec<[Field; 1]> {
882 let Field { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
883 vis.visit_ident(ident);
884 vis.visit_expr(expr);
886 vis.visit_span(span);
887 visit_thin_attrs(attrs, vis);
891 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
895 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
896 let Block { id, stmts, rules: _, span, tokens } = block.deref_mut();
898 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
899 vis.visit_span(span);
900 visit_lazy_tts(tokens, vis);
903 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
905 ItemKind::ExternCrate(_orig_name) => {}
906 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
907 ItemKind::Static(ty, _, expr) | ItemKind::Const(_, ty, expr) => {
909 visit_opt(expr, |expr| vis.visit_expr(expr));
911 ItemKind::Fn(box FnKind(_, sig, generics, body)) => {
912 visit_fn_sig(sig, vis);
913 vis.visit_generics(generics);
914 visit_opt(body, |body| vis.visit_block(body));
916 ItemKind::Mod(_unsafety, mod_kind) => match mod_kind {
917 ModKind::Loaded(items, _inline, inner_span) => {
918 vis.visit_span(inner_span);
919 items.flat_map_in_place(|item| vis.flat_map_item(item));
921 ModKind::Unloaded => {}
923 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
924 ItemKind::GlobalAsm(_ga) => {}
925 ItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
926 vis.visit_generics(generics);
927 visit_bounds(bounds, vis);
928 visit_opt(ty, |ty| vis.visit_ty(ty));
930 ItemKind::Enum(EnumDef { variants }, generics) => {
931 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
932 vis.visit_generics(generics);
934 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
935 vis.visit_variant_data(variant_data);
936 vis.visit_generics(generics);
938 ItemKind::Impl(box ImplKind {
948 vis.visit_generics(generics);
949 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
950 vis.visit_ty(self_ty);
951 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
953 ItemKind::Trait(box TraitKind(.., generics, bounds, items)) => {
954 vis.visit_generics(generics);
955 visit_bounds(bounds, vis);
956 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
958 ItemKind::TraitAlias(generics, bounds) => {
959 vis.visit_generics(generics);
960 visit_bounds(bounds, vis);
962 ItemKind::MacCall(m) => vis.visit_mac_call(m),
963 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
967 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
968 mut item: P<AssocItem>,
970 ) -> SmallVec<[P<AssocItem>; 1]> {
971 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
972 visitor.visit_id(id);
973 visitor.visit_ident(ident);
974 visitor.visit_vis(vis);
975 visit_attrs(attrs, visitor);
977 AssocItemKind::Const(_, ty, expr) => {
978 visitor.visit_ty(ty);
979 visit_opt(expr, |expr| visitor.visit_expr(expr));
981 AssocItemKind::Fn(box FnKind(_, sig, generics, body)) => {
982 visitor.visit_generics(generics);
983 visit_fn_sig(sig, visitor);
984 visit_opt(body, |body| visitor.visit_block(body));
986 AssocItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
987 visitor.visit_generics(generics);
988 visit_bounds(bounds, visitor);
989 visit_opt(ty, |ty| visitor.visit_ty(ty));
991 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
993 visitor.visit_span(span);
994 visit_lazy_tts(tokens, visitor);
998 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
999 let FnHeader { unsafety: _, asyncness, constness: _, ext: _ } = header;
1000 vis.visit_asyncness(asyncness);
1003 // FIXME: Avoid visiting the crate as a `Mod` item, flat map only the inner items if possible,
1004 // or make crate visiting first class if necessary.
1005 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1006 visit_clobber(krate, |Crate { attrs, items, span, proc_macros }| {
1008 Visibility { kind: VisibilityKind::Public, span: span.shrink_to_lo(), tokens: None };
1010 ident: Ident::invalid(),
1015 kind: ItemKind::Mod(Unsafe::No, ModKind::Loaded(items, Inline::Yes, span)),
1018 let items = vis.flat_map_item(item);
1020 let len = items.len();
1022 Crate { attrs: vec![], items: vec![], span, proc_macros }
1023 } else if len == 1 {
1024 let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner();
1026 ItemKind::Mod(_, ModKind::Loaded(items, ..)) => {
1027 Crate { attrs, items, span, proc_macros }
1029 _ => panic!("visitor converted a module to not a module"),
1032 panic!("a crate cannot expand to more than one item");
1037 // Mutates one item into possibly many items.
1038 pub fn noop_flat_map_item<T: MutVisitor>(
1041 ) -> SmallVec<[P<Item>; 1]> {
1042 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1043 visitor.visit_ident(ident);
1044 visit_attrs(attrs, visitor);
1045 visitor.visit_id(id);
1046 visitor.visit_item_kind(kind);
1047 visitor.visit_vis(vis);
1048 visitor.visit_span(span);
1049 visit_lazy_tts(tokens, visitor);
1054 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1055 mut item: P<ForeignItem>,
1057 ) -> SmallVec<[P<ForeignItem>; 1]> {
1058 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1059 visitor.visit_id(id);
1060 visitor.visit_ident(ident);
1061 visitor.visit_vis(vis);
1062 visit_attrs(attrs, visitor);
1064 ForeignItemKind::Static(ty, _, expr) => {
1065 visitor.visit_ty(ty);
1066 visit_opt(expr, |expr| visitor.visit_expr(expr));
1068 ForeignItemKind::Fn(box FnKind(_, sig, generics, body)) => {
1069 visitor.visit_generics(generics);
1070 visit_fn_sig(sig, visitor);
1071 visit_opt(body, |body| visitor.visit_block(body));
1073 ForeignItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
1074 visitor.visit_generics(generics);
1075 visit_bounds(bounds, visitor);
1076 visit_opt(ty, |ty| visitor.visit_ty(ty));
1078 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1080 visitor.visit_span(span);
1081 visit_lazy_tts(tokens, visitor);
1085 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1086 let Pat { id, kind, span, tokens } = pat.deref_mut();
1089 PatKind::Wild | PatKind::Rest => {}
1090 PatKind::Ident(_binding_mode, ident, sub) => {
1091 vis.visit_ident(ident);
1092 visit_opt(sub, |sub| vis.visit_pat(sub));
1094 PatKind::Lit(e) => vis.visit_expr(e),
1095 PatKind::TupleStruct(path, elems) => {
1096 vis.visit_path(path);
1097 visit_vec(elems, |elem| vis.visit_pat(elem));
1099 PatKind::Path(qself, path) => {
1100 vis.visit_qself(qself);
1101 vis.visit_path(path);
1103 PatKind::Struct(path, fields, _etc) => {
1104 vis.visit_path(path);
1105 fields.flat_map_in_place(|field| vis.flat_map_field_pattern(field));
1107 PatKind::Box(inner) => vis.visit_pat(inner),
1108 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1109 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1110 visit_opt(e1, |e| vis.visit_expr(e));
1111 visit_opt(e2, |e| vis.visit_expr(e));
1112 vis.visit_span(span);
1114 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1115 visit_vec(elems, |elem| vis.visit_pat(elem))
1117 PatKind::Paren(inner) => vis.visit_pat(inner),
1118 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1120 vis.visit_span(span);
1121 visit_lazy_tts(tokens, vis);
1124 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1126 vis.visit_expr(value);
1129 pub fn noop_visit_expr<T: MutVisitor>(
1130 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1134 ExprKind::Box(expr) => vis.visit_expr(expr),
1135 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1136 ExprKind::ConstBlock(anon_const) => {
1137 vis.visit_anon_const(anon_const);
1139 ExprKind::Repeat(expr, count) => {
1140 vis.visit_expr(expr);
1141 vis.visit_anon_const(count);
1143 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1144 ExprKind::Call(f, args) => {
1146 visit_exprs(args, vis);
1148 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
1149 vis.visit_ident(ident);
1151 visit_opt(args, |args| vis.visit_generic_args(args));
1152 visit_exprs(exprs, vis);
1153 vis.visit_span(span);
1155 ExprKind::Binary(_binop, lhs, rhs) => {
1156 vis.visit_expr(lhs);
1157 vis.visit_expr(rhs);
1159 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1160 ExprKind::Cast(expr, ty) => {
1161 vis.visit_expr(expr);
1164 ExprKind::Type(expr, ty) => {
1165 vis.visit_expr(expr);
1168 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1169 ExprKind::Let(pat, scrutinee) => {
1171 vis.visit_expr(scrutinee);
1173 ExprKind::If(cond, tr, fl) => {
1174 vis.visit_expr(cond);
1175 vis.visit_block(tr);
1176 visit_opt(fl, |fl| vis.visit_expr(fl));
1178 ExprKind::While(cond, body, label) => {
1179 vis.visit_expr(cond);
1180 vis.visit_block(body);
1181 visit_opt(label, |label| vis.visit_label(label));
1183 ExprKind::ForLoop(pat, iter, body, label) => {
1185 vis.visit_expr(iter);
1186 vis.visit_block(body);
1187 visit_opt(label, |label| vis.visit_label(label));
1189 ExprKind::Loop(body, label) => {
1190 vis.visit_block(body);
1191 visit_opt(label, |label| vis.visit_label(label));
1193 ExprKind::Match(expr, arms) => {
1194 vis.visit_expr(expr);
1195 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1197 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1198 vis.visit_asyncness(asyncness);
1199 vis.visit_fn_decl(decl);
1200 vis.visit_expr(body);
1201 vis.visit_span(span);
1203 ExprKind::Block(blk, label) => {
1204 vis.visit_block(blk);
1205 visit_opt(label, |label| vis.visit_label(label));
1207 ExprKind::Async(_capture_by, node_id, body) => {
1208 vis.visit_id(node_id);
1209 vis.visit_block(body);
1211 ExprKind::Await(expr) => vis.visit_expr(expr),
1212 ExprKind::Assign(el, er, _) => {
1216 ExprKind::AssignOp(_op, el, er) => {
1220 ExprKind::Field(el, ident) => {
1222 vis.visit_ident(ident);
1224 ExprKind::Index(el, er) => {
1228 ExprKind::Range(e1, e2, _lim) => {
1229 visit_opt(e1, |e1| vis.visit_expr(e1));
1230 visit_opt(e2, |e2| vis.visit_expr(e2));
1232 ExprKind::Underscore => {}
1233 ExprKind::Path(qself, path) => {
1234 vis.visit_qself(qself);
1235 vis.visit_path(path);
1237 ExprKind::Break(label, expr) => {
1238 visit_opt(label, |label| vis.visit_label(label));
1239 visit_opt(expr, |expr| vis.visit_expr(expr));
1241 ExprKind::Continue(label) => {
1242 visit_opt(label, |label| vis.visit_label(label));
1244 ExprKind::Ret(expr) => {
1245 visit_opt(expr, |expr| vis.visit_expr(expr));
1247 ExprKind::InlineAsm(asm) => {
1248 for (op, _) in &mut asm.operands {
1250 InlineAsmOperand::In { expr, .. }
1251 | InlineAsmOperand::InOut { expr, .. }
1252 | InlineAsmOperand::Const { expr, .. }
1253 | InlineAsmOperand::Sym { expr, .. } => vis.visit_expr(expr),
1254 InlineAsmOperand::Out { expr, .. } => {
1255 if let Some(expr) = expr {
1256 vis.visit_expr(expr);
1259 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1260 vis.visit_expr(in_expr);
1261 if let Some(out_expr) = out_expr {
1262 vis.visit_expr(out_expr);
1268 ExprKind::LlvmInlineAsm(asm) => {
1278 } = asm.deref_mut();
1279 for out in outputs {
1280 let LlvmInlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1281 vis.visit_expr(expr);
1283 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1285 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1286 ExprKind::Struct(path, fields, expr) => {
1287 vis.visit_path(path);
1288 fields.flat_map_in_place(|field| vis.flat_map_field(field));
1290 StructRest::Base(expr) => vis.visit_expr(expr),
1291 StructRest::Rest(_span) => {}
1292 StructRest::None => {}
1295 ExprKind::Paren(expr) => {
1296 vis.visit_expr(expr);
1298 // Nodes that are equal modulo `Paren` sugar no-ops should have the same IDs.
1300 vis.visit_span(span);
1301 visit_thin_attrs(attrs, vis);
1304 ExprKind::Yield(expr) => {
1305 visit_opt(expr, |expr| vis.visit_expr(expr));
1307 ExprKind::Try(expr) => vis.visit_expr(expr),
1308 ExprKind::TryBlock(body) => vis.visit_block(body),
1309 ExprKind::Lit(_) | ExprKind::Err => {}
1312 vis.visit_span(span);
1313 visit_thin_attrs(attrs, vis);
1314 visit_lazy_tts(tokens, vis);
1317 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1319 vis.visit_expr(&mut e);
1324 pub fn noop_flat_map_stmt<T: MutVisitor>(
1325 Stmt { kind, mut span, mut id }: Stmt,
1327 ) -> SmallVec<[Stmt; 1]> {
1328 vis.visit_id(&mut id);
1329 vis.visit_span(&mut span);
1330 noop_flat_map_stmt_kind(kind, vis).into_iter().map(|kind| Stmt { id, kind, span }).collect()
1333 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1336 ) -> SmallVec<[StmtKind; 1]> {
1338 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1339 vis.visit_local(&mut local);
1342 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1343 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1344 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1345 StmtKind::Empty => smallvec![StmtKind::Empty],
1346 StmtKind::MacCall(mut mac) => {
1347 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1348 vis.visit_mac_call(mac_);
1349 visit_thin_attrs(attrs, vis);
1350 visit_lazy_tts(tokens, vis);
1351 smallvec![StmtKind::MacCall(mac)]
1356 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1357 match &mut visibility.kind {
1358 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1359 VisibilityKind::Restricted { path, id } => {
1360 vis.visit_path(path);
1364 vis.visit_span(&mut visibility.span);