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_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
106 noop_flat_map_field_def(fd, 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_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
258 noop_flat_map_expr_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_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
282 noop_flat_map_pat_field(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_pat_field<T: MutVisitor>(
391 ) -> SmallVec<[PatField; 1]> {
392 let PatField { 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_thin_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_thin_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, kind, span, attrs, tokens } = local.deref_mut();
574 visit_opt(ty, |ty| vis.visit_ty(ty));
576 LocalKind::Decl => {}
577 LocalKind::Init(init) => {
578 vis.visit_expr(init);
580 LocalKind::InitElse(init, els) => {
581 vis.visit_expr(init);
582 vis.visit_block(els);
585 vis.visit_span(span);
586 visit_thin_attrs(attrs, vis);
587 visit_lazy_tts(tokens, vis);
590 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
591 let Attribute { kind, id: _, style: _, span } = attr;
593 AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
594 vis.visit_path(path);
595 visit_mac_args(args, vis);
596 visit_lazy_tts(tokens, vis);
597 visit_lazy_tts(attr_tokens, vis);
599 AttrKind::DocComment(..) => {}
601 vis.visit_span(span);
604 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
605 let MacCall { path, args, prior_type_ascription: _ } = mac;
606 vis.visit_path(path);
607 visit_mac_args(args, vis);
610 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
611 let MacroDef { body, macro_rules: _ } = macro_def;
612 visit_mac_args(body, vis);
615 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
617 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
618 NestedMetaItem::Literal(_lit) => {}
622 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
623 let MetaItem { path: _, kind, span } = mi;
625 MetaItemKind::Word => {}
626 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
627 MetaItemKind::NameValue(_s) => {}
629 vis.visit_span(span);
632 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
633 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
635 visit_thin_attrs(attrs, vis);
637 vis.visit_span(span);
642 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
643 pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
645 AttrAnnotatedTokenTree::Token(token) => {
646 visit_token(token, vis);
648 AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
649 vis.visit_span(open);
650 vis.visit_span(close);
651 visit_attr_annotated_tts(tts, vis);
653 AttrAnnotatedTokenTree::Attributes(data) => {
654 for attr in &mut *data.attrs {
655 match &mut attr.kind {
656 AttrKind::Normal(_, attr_tokens) => {
657 visit_lazy_tts(attr_tokens, vis);
659 AttrKind::DocComment(..) => {
660 vis.visit_span(&mut attr.span);
664 visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
669 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
670 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
672 TokenTree::Token(token) => {
673 visit_token(token, vis);
675 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
676 vis.visit_span(open);
677 vis.visit_span(close);
683 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
684 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
685 if vis.token_visiting_enabled() && !tts.is_empty() {
686 let tts = Lrc::make_mut(tts);
687 visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis));
691 pub fn visit_attr_annotated_tts<T: MutVisitor>(
692 AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
695 if vis.token_visiting_enabled() && !tts.is_empty() {
696 let tts = Lrc::make_mut(tts);
697 visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
701 pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
702 if vis.token_visiting_enabled() {
703 if let Some(lazy_tts) = lazy_tts {
704 let mut tts = lazy_tts.create_token_stream();
705 visit_attr_annotated_tts(&mut tts, vis);
706 *lazy_tts = LazyTokenStream::new(tts);
711 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
712 visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
715 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
716 // Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
717 // In practice the ident part is not actually used by specific visitors right now,
718 // but there's a test below checking that it works.
719 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
720 let Token { kind, span } = t;
722 token::Ident(name, _) | token::Lifetime(name) => {
723 let mut ident = Ident::new(*name, *span);
724 vis.visit_ident(&mut ident);
727 return; // Avoid visiting the span for the second time.
729 token::Interpolated(nt) => {
730 let mut nt = Lrc::make_mut(nt);
731 visit_interpolated(&mut nt, vis);
735 vis.visit_span(span);
738 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
739 /// Applies the visitor to elements of interpolated nodes.
741 // N.B., this can occur only when applying a visitor to partially expanded
742 // code, where parsed pieces have gotten implanted ito *other* macro
743 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
745 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
746 // etc., allow the visitor to return *multiple* items; this is a problem for the
747 // nodes here, because they insist on having exactly one piece. One solution
748 // would be to mangle the MutVisitor trait to include one-to-many and
749 // one-to-one versions of these entry points, but that would probably confuse a
750 // lot of people and help very few. Instead, I'm just going to put in dynamic
751 // checks. I think the performance impact of this will be pretty much
752 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
753 // partially expanded node, and will be confused by the fact that their
754 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
755 // nodes. Hopefully they'll wind up reading this comment, and doing something
758 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
759 // contain multiple items, but decided against it when I looked at
760 // `parse_item_or_view_item` and tried to figure out what I would do with
761 // multiple items there....
762 pub fn visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
764 token::NtItem(item) => visit_clobber(item, |item| {
765 // This is probably okay, because the only visitors likely to
766 // peek inside interpolated nodes will be renamings/markings,
767 // which map single items to single items.
768 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
770 token::NtBlock(block) => vis.visit_block(block),
771 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
772 // See reasoning above.
773 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
775 token::NtPat(pat) => vis.visit_pat(pat),
776 token::NtExpr(expr) => vis.visit_expr(expr),
777 token::NtTy(ty) => vis.visit_ty(ty),
778 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
779 token::NtLifetime(ident) => vis.visit_ident(ident),
780 token::NtLiteral(expr) => vis.visit_expr(expr),
781 token::NtMeta(item) => {
782 let AttrItem { path, args, tokens } = item.deref_mut();
783 vis.visit_path(path);
784 visit_mac_args(args, vis);
785 visit_lazy_tts(tokens, vis);
787 token::NtPath(path) => vis.visit_path(path),
788 token::NtTT(tt) => visit_tt(tt, vis),
789 token::NtVis(visib) => vis.visit_vis(visib),
793 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
795 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
796 vis.visit_id(closure_id);
797 vis.visit_id(return_impl_trait_id);
803 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
804 let FnDecl { inputs, output } = decl.deref_mut();
805 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
806 noop_visit_fn_ret_ty(output, vis);
809 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
811 FnRetTy::Default(span) => vis.visit_span(span),
812 FnRetTy::Ty(ty) => vis.visit_ty(ty),
816 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
818 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
819 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
823 pub fn noop_flat_map_generic_param<T: MutVisitor>(
824 mut param: GenericParam,
826 ) -> SmallVec<[GenericParam; 1]> {
827 let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
829 vis.visit_ident(ident);
830 visit_thin_attrs(attrs, vis);
831 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
833 GenericParamKind::Lifetime => {}
834 GenericParamKind::Type { default } => {
835 visit_opt(default, |default| vis.visit_ty(default));
837 GenericParamKind::Const { ty, kw_span: _, default } => {
839 visit_opt(default, |default| vis.visit_anon_const(default));
845 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
846 vis.visit_ident(ident);
849 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
851 vis.visit_ident(ident);
854 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
855 let Generics { params, where_clause, span } = generics;
856 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
857 vis.visit_where_clause(where_clause);
858 vis.visit_span(span);
861 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
862 let WhereClause { has_where_token: _, predicates, span } = wc;
863 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
864 vis.visit_span(span);
867 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
869 WherePredicate::BoundPredicate(bp) => {
870 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
871 vis.visit_span(span);
872 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
873 vis.visit_ty(bounded_ty);
874 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
876 WherePredicate::RegionPredicate(rp) => {
877 let WhereRegionPredicate { span, lifetime, bounds } = rp;
878 vis.visit_span(span);
879 noop_visit_lifetime(lifetime, vis);
880 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
882 WherePredicate::EqPredicate(ep) => {
883 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
885 vis.visit_span(span);
886 vis.visit_ty(lhs_ty);
887 vis.visit_ty(rhs_ty);
892 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
894 VariantData::Struct(fields, ..) => {
895 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
897 VariantData::Tuple(fields, id) => {
898 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
901 VariantData::Unit(id) => vis.visit_id(id),
905 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
906 vis.visit_path(path);
907 vis.visit_id(ref_id);
910 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
911 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
912 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
913 vis.visit_trait_ref(trait_ref);
914 vis.visit_span(span);
917 pub fn noop_flat_map_field_def<T: MutVisitor>(
920 ) -> SmallVec<[FieldDef; 1]> {
921 let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
922 visitor.visit_span(span);
923 visit_opt(ident, |ident| visitor.visit_ident(ident));
924 visitor.visit_vis(vis);
925 visitor.visit_id(id);
926 visitor.visit_ty(ty);
927 visit_thin_attrs(attrs, visitor);
931 pub fn noop_flat_map_expr_field<T: MutVisitor>(
934 ) -> SmallVec<[ExprField; 1]> {
935 let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
936 vis.visit_ident(ident);
937 vis.visit_expr(expr);
939 vis.visit_span(span);
940 visit_thin_attrs(attrs, vis);
944 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
948 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
949 let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
951 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
952 vis.visit_span(span);
953 visit_lazy_tts(tokens, vis);
956 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
958 ItemKind::ExternCrate(_orig_name) => {}
959 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
960 ItemKind::Static(ty, _, expr) | ItemKind::Const(_, ty, expr) => {
962 visit_opt(expr, |expr| vis.visit_expr(expr));
964 ItemKind::Fn(box FnKind(_, sig, generics, body)) => {
965 visit_fn_sig(sig, vis);
966 vis.visit_generics(generics);
967 visit_opt(body, |body| vis.visit_block(body));
969 ItemKind::Mod(_unsafety, mod_kind) => match mod_kind {
970 ModKind::Loaded(items, _inline, inner_span) => {
971 vis.visit_span(inner_span);
972 items.flat_map_in_place(|item| vis.flat_map_item(item));
974 ModKind::Unloaded => {}
976 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
977 ItemKind::GlobalAsm(asm) => noop_visit_inline_asm(asm, vis),
978 ItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
979 vis.visit_generics(generics);
980 visit_bounds(bounds, vis);
981 visit_opt(ty, |ty| vis.visit_ty(ty));
983 ItemKind::Enum(EnumDef { variants }, generics) => {
984 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
985 vis.visit_generics(generics);
987 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
988 vis.visit_variant_data(variant_data);
989 vis.visit_generics(generics);
991 ItemKind::Impl(box ImplKind {
1001 vis.visit_generics(generics);
1002 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
1003 vis.visit_ty(self_ty);
1004 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
1006 ItemKind::Trait(box TraitKind(.., generics, bounds, items)) => {
1007 vis.visit_generics(generics);
1008 visit_bounds(bounds, vis);
1009 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
1011 ItemKind::TraitAlias(generics, bounds) => {
1012 vis.visit_generics(generics);
1013 visit_bounds(bounds, vis);
1015 ItemKind::MacCall(m) => vis.visit_mac_call(m),
1016 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1020 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
1021 mut item: P<AssocItem>,
1023 ) -> SmallVec<[P<AssocItem>; 1]> {
1024 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
1025 visitor.visit_id(id);
1026 visitor.visit_ident(ident);
1027 visitor.visit_vis(vis);
1028 visit_attrs(attrs, visitor);
1030 AssocItemKind::Const(_, ty, expr) => {
1031 visitor.visit_ty(ty);
1032 visit_opt(expr, |expr| visitor.visit_expr(expr));
1034 AssocItemKind::Fn(box FnKind(_, sig, generics, body)) => {
1035 visitor.visit_generics(generics);
1036 visit_fn_sig(sig, visitor);
1037 visit_opt(body, |body| visitor.visit_block(body));
1039 AssocItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
1040 visitor.visit_generics(generics);
1041 visit_bounds(bounds, visitor);
1042 visit_opt(ty, |ty| visitor.visit_ty(ty));
1044 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1046 visitor.visit_span(span);
1047 visit_lazy_tts(tokens, visitor);
1051 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
1052 let FnHeader { unsafety: _, asyncness, constness: _, ext: _ } = header;
1053 vis.visit_asyncness(asyncness);
1056 // FIXME: Avoid visiting the crate as a `Mod` item, flat map only the inner items if possible,
1057 // or make crate visiting first class if necessary.
1058 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1059 visit_clobber(krate, |Crate { attrs, items, span }| {
1061 Visibility { kind: VisibilityKind::Public, span: span.shrink_to_lo(), tokens: None };
1063 ident: Ident::invalid(),
1068 kind: ItemKind::Mod(Unsafe::No, ModKind::Loaded(items, Inline::Yes, span)),
1071 let items = vis.flat_map_item(item);
1073 let len = items.len();
1075 Crate { attrs: vec![], items: vec![], span }
1076 } else if len == 1 {
1077 let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner();
1079 ItemKind::Mod(_, ModKind::Loaded(items, ..)) => Crate { attrs, items, span },
1080 _ => panic!("visitor converted a module to not a module"),
1083 panic!("a crate cannot expand to more than one item");
1088 // Mutates one item into possibly many items.
1089 pub fn noop_flat_map_item<T: MutVisitor>(
1092 ) -> SmallVec<[P<Item>; 1]> {
1093 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1094 visitor.visit_ident(ident);
1095 visit_attrs(attrs, visitor);
1096 visitor.visit_id(id);
1097 visitor.visit_item_kind(kind);
1098 visitor.visit_vis(vis);
1099 visitor.visit_span(span);
1100 visit_lazy_tts(tokens, visitor);
1105 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1106 mut item: P<ForeignItem>,
1108 ) -> SmallVec<[P<ForeignItem>; 1]> {
1109 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1110 visitor.visit_id(id);
1111 visitor.visit_ident(ident);
1112 visitor.visit_vis(vis);
1113 visit_attrs(attrs, visitor);
1115 ForeignItemKind::Static(ty, _, expr) => {
1116 visitor.visit_ty(ty);
1117 visit_opt(expr, |expr| visitor.visit_expr(expr));
1119 ForeignItemKind::Fn(box FnKind(_, sig, generics, body)) => {
1120 visitor.visit_generics(generics);
1121 visit_fn_sig(sig, visitor);
1122 visit_opt(body, |body| visitor.visit_block(body));
1124 ForeignItemKind::TyAlias(box TyAliasKind(_, generics, bounds, ty)) => {
1125 visitor.visit_generics(generics);
1126 visit_bounds(bounds, visitor);
1127 visit_opt(ty, |ty| visitor.visit_ty(ty));
1129 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1131 visitor.visit_span(span);
1132 visit_lazy_tts(tokens, visitor);
1136 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1137 let Pat { id, kind, span, tokens } = pat.deref_mut();
1140 PatKind::Wild | PatKind::Rest => {}
1141 PatKind::Ident(_binding_mode, ident, sub) => {
1142 vis.visit_ident(ident);
1143 visit_opt(sub, |sub| vis.visit_pat(sub));
1145 PatKind::Lit(e) => vis.visit_expr(e),
1146 PatKind::TupleStruct(qself, path, elems) => {
1147 vis.visit_qself(qself);
1148 vis.visit_path(path);
1149 visit_vec(elems, |elem| vis.visit_pat(elem));
1151 PatKind::Path(qself, path) => {
1152 vis.visit_qself(qself);
1153 vis.visit_path(path);
1155 PatKind::Struct(qself, path, fields, _etc) => {
1156 vis.visit_qself(qself);
1157 vis.visit_path(path);
1158 fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
1160 PatKind::Box(inner) => vis.visit_pat(inner),
1161 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1162 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1163 visit_opt(e1, |e| vis.visit_expr(e));
1164 visit_opt(e2, |e| vis.visit_expr(e));
1165 vis.visit_span(span);
1167 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1168 visit_vec(elems, |elem| vis.visit_pat(elem))
1170 PatKind::Paren(inner) => vis.visit_pat(inner),
1171 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1173 vis.visit_span(span);
1174 visit_lazy_tts(tokens, vis);
1177 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1179 vis.visit_expr(value);
1182 fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
1183 for (op, _) in &mut asm.operands {
1185 InlineAsmOperand::In { expr, .. }
1186 | InlineAsmOperand::Out { expr: Some(expr), .. }
1187 | InlineAsmOperand::InOut { expr, .. }
1188 | InlineAsmOperand::Sym { expr, .. } => vis.visit_expr(expr),
1189 InlineAsmOperand::Out { expr: None, .. } => {}
1190 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1191 vis.visit_expr(in_expr);
1192 if let Some(out_expr) = out_expr {
1193 vis.visit_expr(out_expr);
1196 InlineAsmOperand::Const { anon_const, .. } => vis.visit_anon_const(anon_const),
1201 pub fn noop_visit_expr<T: MutVisitor>(
1202 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1206 ExprKind::Box(expr) => vis.visit_expr(expr),
1207 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1208 ExprKind::ConstBlock(anon_const) => {
1209 vis.visit_anon_const(anon_const);
1211 ExprKind::Repeat(expr, count) => {
1212 vis.visit_expr(expr);
1213 vis.visit_anon_const(count);
1215 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1216 ExprKind::Call(f, args) => {
1218 visit_exprs(args, vis);
1220 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
1221 vis.visit_ident(ident);
1223 visit_opt(args, |args| vis.visit_generic_args(args));
1224 visit_exprs(exprs, vis);
1225 vis.visit_span(span);
1227 ExprKind::Binary(_binop, lhs, rhs) => {
1228 vis.visit_expr(lhs);
1229 vis.visit_expr(rhs);
1231 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1232 ExprKind::Cast(expr, ty) => {
1233 vis.visit_expr(expr);
1236 ExprKind::Type(expr, ty) => {
1237 vis.visit_expr(expr);
1240 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1241 ExprKind::Let(pat, scrutinee, _) => {
1243 vis.visit_expr(scrutinee);
1245 ExprKind::If(cond, tr, fl) => {
1246 vis.visit_expr(cond);
1247 vis.visit_block(tr);
1248 visit_opt(fl, |fl| vis.visit_expr(fl));
1250 ExprKind::While(cond, body, label) => {
1251 vis.visit_expr(cond);
1252 vis.visit_block(body);
1253 visit_opt(label, |label| vis.visit_label(label));
1255 ExprKind::ForLoop(pat, iter, body, label) => {
1257 vis.visit_expr(iter);
1258 vis.visit_block(body);
1259 visit_opt(label, |label| vis.visit_label(label));
1261 ExprKind::Loop(body, label) => {
1262 vis.visit_block(body);
1263 visit_opt(label, |label| vis.visit_label(label));
1265 ExprKind::Match(expr, arms) => {
1266 vis.visit_expr(expr);
1267 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1269 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1270 vis.visit_asyncness(asyncness);
1271 vis.visit_fn_decl(decl);
1272 vis.visit_expr(body);
1273 vis.visit_span(span);
1275 ExprKind::Block(blk, label) => {
1276 vis.visit_block(blk);
1277 visit_opt(label, |label| vis.visit_label(label));
1279 ExprKind::Async(_capture_by, node_id, body) => {
1280 vis.visit_id(node_id);
1281 vis.visit_block(body);
1283 ExprKind::Await(expr) => vis.visit_expr(expr),
1284 ExprKind::Assign(el, er, _) => {
1288 ExprKind::AssignOp(_op, el, er) => {
1292 ExprKind::Field(el, ident) => {
1294 vis.visit_ident(ident);
1296 ExprKind::Index(el, er) => {
1300 ExprKind::Range(e1, e2, _lim) => {
1301 visit_opt(e1, |e1| vis.visit_expr(e1));
1302 visit_opt(e2, |e2| vis.visit_expr(e2));
1304 ExprKind::Underscore => {}
1305 ExprKind::Path(qself, path) => {
1306 vis.visit_qself(qself);
1307 vis.visit_path(path);
1309 ExprKind::Break(label, expr) => {
1310 visit_opt(label, |label| vis.visit_label(label));
1311 visit_opt(expr, |expr| vis.visit_expr(expr));
1313 ExprKind::Continue(label) => {
1314 visit_opt(label, |label| vis.visit_label(label));
1316 ExprKind::Ret(expr) => {
1317 visit_opt(expr, |expr| vis.visit_expr(expr));
1319 ExprKind::InlineAsm(asm) => noop_visit_inline_asm(asm, vis),
1320 ExprKind::LlvmInlineAsm(asm) => {
1330 } = asm.deref_mut();
1331 for out in outputs {
1332 let LlvmInlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1333 vis.visit_expr(expr);
1335 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1337 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1338 ExprKind::Struct(se) => {
1339 let StructExpr { qself, path, fields, rest } = se.deref_mut();
1340 vis.visit_qself(qself);
1341 vis.visit_path(path);
1342 fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
1344 StructRest::Base(expr) => vis.visit_expr(expr),
1345 StructRest::Rest(_span) => {}
1346 StructRest::None => {}
1349 ExprKind::Paren(expr) => {
1350 vis.visit_expr(expr);
1352 ExprKind::Yield(expr) => {
1353 visit_opt(expr, |expr| vis.visit_expr(expr));
1355 ExprKind::Try(expr) => vis.visit_expr(expr),
1356 ExprKind::TryBlock(body) => vis.visit_block(body),
1357 ExprKind::Lit(_) | ExprKind::Err => {}
1360 vis.visit_span(span);
1361 visit_thin_attrs(attrs, vis);
1362 visit_lazy_tts(tokens, vis);
1365 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1367 vis.visit_expr(&mut e);
1372 pub fn noop_flat_map_stmt<T: MutVisitor>(
1373 Stmt { kind, mut span, mut id }: Stmt,
1375 ) -> SmallVec<[Stmt; 1]> {
1376 vis.visit_id(&mut id);
1377 vis.visit_span(&mut span);
1378 let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
1380 .map(|kind| Stmt { id, kind, span })
1382 if stmts.len() > 1 {
1384 "cloning statement `NodeId`s is prohibited by default, \
1385 the visitor should implement custom statement visiting"
1391 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1394 ) -> SmallVec<[StmtKind; 1]> {
1396 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1397 vis.visit_local(&mut local);
1400 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1401 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1402 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1403 StmtKind::Empty => smallvec![StmtKind::Empty],
1404 StmtKind::MacCall(mut mac) => {
1405 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1406 vis.visit_mac_call(mac_);
1407 visit_thin_attrs(attrs, vis);
1408 visit_lazy_tts(tokens, vis);
1409 smallvec![StmtKind::MacCall(mac)]
1414 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1415 match &mut visibility.kind {
1416 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1417 VisibilityKind::Restricted { path, id } => {
1418 vis.visit_path(path);
1422 vis.visit_span(&mut visibility.span);