1 //! A `MutVisitor` represents an AST modification; it accepts an AST piece and
2 //! 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_data_structures::thin_vec::ThinVec;
18 use rustc_span::source_map::Spanned;
19 use rustc_span::symbol::Ident;
22 use smallvec::{smallvec, Array, SmallVec};
23 use std::ops::DerefMut;
24 use std::{panic, ptr};
26 pub trait ExpectOne<A: Array> {
27 fn expect_one(self, err: &'static str) -> A::Item;
30 impl<A: Array> ExpectOne<A> for SmallVec<A> {
31 fn expect_one(self, err: &'static str) -> A::Item {
32 assert!(self.len() == 1, "{}", err);
33 self.into_iter().next().unwrap()
37 pub trait MutVisitor: Sized {
38 /// Mutable token visiting only exists for the `macro_rules` token marker and should not be
39 /// used otherwise. Token visitor would be entirely separate from the regular visitor if
40 /// the marker didn't have to visit AST fragments in nonterminal tokens.
41 const VISIT_TOKENS: bool = false;
43 // Methods in this trait have one of three forms:
45 // fn visit_t(&mut self, t: &mut T); // common
46 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
47 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
49 // Any additions to this trait should happen in form of a call to a public
50 // `noop_*` function that only calls out to the visitor again, not other
51 // `noop_*` functions. This is a necessary API workaround to the problem of
52 // not being able to call out to the super default method in an overridden
55 // When writing these methods, it is better to use destructuring like this:
57 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
62 // than to use field access like this:
64 // fn visit_abc(&mut self, abc: &mut ABC) {
65 // visit_a(&mut abc.a);
66 // visit_b(&mut abc.b);
70 // As well as being more concise, the former is explicit about which fields
71 // are skipped. Furthermore, if a new field is added, the destructuring
72 // version will cause a compile error, which is good. In comparison, the
73 // field access version will continue working and it would be easy to
74 // forget to add handling for it.
76 fn visit_crate(&mut self, c: &mut Crate) {
77 noop_visit_crate(c, self)
80 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
81 noop_visit_meta_list_item(list_item, self);
84 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
85 noop_visit_meta_item(meta_item, self);
88 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
89 noop_visit_use_tree(use_tree, self);
92 fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
93 noop_flat_map_foreign_item(ni, self)
96 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
97 noop_flat_map_item(i, self)
100 fn visit_fn_header(&mut self, header: &mut FnHeader) {
101 noop_visit_fn_header(header, self);
104 fn flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
105 noop_flat_map_field_def(fd, self)
108 fn visit_item_kind(&mut self, i: &mut ItemKind) {
109 noop_visit_item_kind(i, self);
112 fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
113 noop_flat_map_assoc_item(i, self)
116 fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
117 noop_flat_map_assoc_item(i, self)
120 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
121 noop_visit_fn_decl(d, self);
124 fn visit_asyncness(&mut self, a: &mut Async) {
125 noop_visit_asyncness(a, self);
128 fn visit_block(&mut self, b: &mut P<Block>) {
129 noop_visit_block(b, self);
132 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
133 noop_flat_map_stmt(s, self)
136 fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
137 noop_flat_map_arm(arm, self)
140 fn visit_pat(&mut self, p: &mut P<Pat>) {
141 noop_visit_pat(p, self);
144 fn visit_anon_const(&mut self, c: &mut AnonConst) {
145 noop_visit_anon_const(c, self);
148 fn visit_expr(&mut self, e: &mut P<Expr>) {
149 noop_visit_expr(e, self);
152 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
153 noop_filter_map_expr(e, self)
156 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
157 noop_visit_generic_arg(arg, self);
160 fn visit_ty(&mut self, t: &mut P<Ty>) {
161 noop_visit_ty(t, self);
164 fn visit_lifetime(&mut self, l: &mut Lifetime) {
165 noop_visit_lifetime(l, self);
168 fn visit_constraint(&mut self, t: &mut AssocConstraint) {
169 noop_visit_constraint(t, self);
172 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
173 noop_visit_foreign_mod(nm, self);
176 fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
177 noop_flat_map_variant(v, self)
180 fn visit_ident(&mut self, i: &mut Ident) {
181 noop_visit_ident(i, self);
184 fn visit_path(&mut self, p: &mut Path) {
185 noop_visit_path(p, self);
188 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
189 noop_visit_qself(qs, self);
192 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
193 noop_visit_generic_args(p, self);
196 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
197 noop_visit_angle_bracketed_parameter_data(p, self);
200 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
201 noop_visit_parenthesized_parameter_data(p, self);
204 fn visit_local(&mut self, l: &mut P<Local>) {
205 noop_visit_local(l, self);
208 fn visit_mac_call(&mut self, mac: &mut MacCall) {
209 noop_visit_mac(mac, self);
212 fn visit_macro_def(&mut self, def: &mut MacroDef) {
213 noop_visit_macro_def(def, self);
216 fn visit_label(&mut self, label: &mut Label) {
217 noop_visit_label(label, self);
220 fn visit_attribute(&mut self, at: &mut Attribute) {
221 noop_visit_attribute(at, self);
224 fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
225 noop_flat_map_param(param, self)
228 fn visit_generics(&mut self, generics: &mut Generics) {
229 noop_visit_generics(generics, self);
232 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
233 noop_visit_trait_ref(tr, self);
236 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
237 noop_visit_poly_trait_ref(p, self);
240 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
241 noop_visit_variant_data(vdata, self);
244 fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
245 noop_flat_map_generic_param(param, self)
248 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
249 noop_visit_param_bound(tpb, self);
252 fn visit_mt(&mut self, mt: &mut MutTy) {
253 noop_visit_mt(mt, self);
256 fn flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
257 noop_flat_map_expr_field(f, self)
260 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
261 noop_visit_where_clause(where_clause, self);
264 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
265 noop_visit_where_predicate(where_predicate, self);
268 fn visit_vis(&mut self, vis: &mut Visibility) {
269 noop_visit_vis(vis, self);
272 fn visit_id(&mut self, _id: &mut NodeId) {
276 fn visit_span(&mut self, _sp: &mut Span) {
280 fn flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
281 noop_flat_map_pat_field(fp, self)
284 fn visit_inline_asm(&mut self, asm: &mut InlineAsm) {
285 noop_visit_inline_asm(asm, self)
288 fn visit_inline_asm_sym(&mut self, sym: &mut InlineAsmSym) {
289 noop_visit_inline_asm_sym(sym, self)
293 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
294 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
297 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
298 pub fn visit_clobber<T: DummyAstNode>(t: &mut T, f: impl FnOnce(T) -> T) {
300 // Safe because `t` is used in a read-only fashion by `read()` before
301 // being overwritten by `write()`.
302 let old_t = ptr::read(t);
304 panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t))).unwrap_or_else(|err| {
305 // Set `t` to some valid but possible meaningless value,
306 // and pass the fatal error further.
307 ptr::write(t, T::dummy());
308 panic::resume_unwind(err);
310 ptr::write(t, new_t);
314 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
316 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
325 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
327 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
331 if let Some(elem) = opt {
336 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
337 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
338 visit_vec(attrs, |attr| vis.visit_attribute(attr));
341 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
342 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
343 for attr in attrs.iter_mut() {
344 vis.visit_attribute(attr);
348 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
349 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
350 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
353 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
354 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
355 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
358 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
359 pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
360 vis.visit_fn_header(header);
361 vis.visit_fn_decl(decl);
362 vis.visit_span(span);
365 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
366 pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
369 MacArgs::Delimited(dspan, _delim, tokens) => {
370 visit_delim_span(dspan, vis);
371 visit_tts(tokens, vis);
373 MacArgs::Eq(eq_span, token) => {
374 vis.visit_span(eq_span);
376 visit_token(token, vis);
378 // The value in `#[key = VALUE]` must be visited as an expression for backward
379 // compatibility, so that macros can be expanded in that position.
380 match &mut token.kind {
381 token::Interpolated(nt) => match Lrc::make_mut(nt) {
382 token::NtExpr(expr) => vis.visit_expr(expr),
383 t => panic!("unexpected token in key-value attribute: {:?}", t),
385 t => panic!("unexpected token in key-value attribute: {:?}", t),
392 pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
393 vis.visit_span(&mut dspan.open);
394 vis.visit_span(&mut dspan.close);
397 pub fn noop_flat_map_pat_field<T: MutVisitor>(
400 ) -> SmallVec<[PatField; 1]> {
401 let PatField { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
403 vis.visit_ident(ident);
405 vis.visit_span(span);
406 visit_thin_attrs(attrs, vis);
410 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
411 let UseTree { prefix, kind, span } = use_tree;
412 vis.visit_path(prefix);
414 UseTreeKind::Simple(rename, id1, id2) => {
415 visit_opt(rename, |rename| vis.visit_ident(rename));
419 UseTreeKind::Nested(items) => {
420 for (tree, id) in items {
421 vis.visit_use_tree(tree);
425 UseTreeKind::Glob => {}
427 vis.visit_span(span);
430 pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
431 let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
432 visit_thin_attrs(attrs, vis);
435 visit_opt(guard, |guard| vis.visit_expr(guard));
436 vis.visit_expr(body);
437 vis.visit_span(span);
441 pub fn noop_visit_constraint<T: MutVisitor>(
442 AssocConstraint { id, ident, gen_args, kind, span }: &mut AssocConstraint,
446 vis.visit_ident(ident);
447 if let Some(ref mut gen_args) = gen_args {
448 vis.visit_generic_args(gen_args);
451 AssocConstraintKind::Equality { ref mut term } => match term {
452 Term::Ty(ty) => vis.visit_ty(ty),
453 Term::Const(c) => vis.visit_anon_const(c),
455 AssocConstraintKind::Bound { ref mut bounds } => visit_bounds(bounds, vis),
457 vis.visit_span(span);
460 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
461 let Ty { id, kind, span, tokens } = ty.deref_mut();
464 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
465 TyKind::Slice(ty) => vis.visit_ty(ty),
466 TyKind::Ptr(mt) => vis.visit_mt(mt),
467 TyKind::Rptr(lt, mt) => {
468 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
471 TyKind::BareFn(bft) => {
472 let BareFnTy { unsafety, ext: _, generic_params, decl } = bft.deref_mut();
473 visit_unsafety(unsafety, vis);
474 generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
475 vis.visit_fn_decl(decl);
477 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
478 TyKind::Paren(ty) => vis.visit_ty(ty),
479 TyKind::Path(qself, path) => {
480 vis.visit_qself(qself);
481 vis.visit_path(path);
483 TyKind::Array(ty, length) => {
485 vis.visit_anon_const(length);
487 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
488 TyKind::TraitObject(bounds, _syntax) => {
489 visit_vec(bounds, |bound| vis.visit_param_bound(bound))
491 TyKind::ImplTrait(id, bounds) => {
493 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
495 TyKind::MacCall(mac) => vis.visit_mac_call(mac),
497 vis.visit_span(span);
498 visit_lazy_tts(tokens, vis);
501 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
502 let ForeignMod { unsafety, abi: _, items } = foreign_mod;
503 visit_unsafety(unsafety, vis);
504 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
507 pub fn noop_flat_map_variant<T: MutVisitor>(
508 mut variant: Variant,
510 ) -> SmallVec<[Variant; 1]> {
511 let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
512 visitor.visit_ident(ident);
513 visitor.visit_vis(vis);
514 visit_thin_attrs(attrs, visitor);
515 visitor.visit_id(id);
516 visitor.visit_variant_data(data);
517 visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
518 visitor.visit_span(span);
522 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
523 vis.visit_span(span);
526 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
527 vis.visit_span(span);
528 for PathSegment { ident, id, args } in segments {
529 vis.visit_ident(ident);
531 visit_opt(args, |args| vis.visit_generic_args(args));
533 visit_lazy_tts(tokens, vis);
536 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
537 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
539 vis.visit_span(path_span);
543 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
545 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
546 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
550 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
552 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
553 GenericArg::Type(ty) => vis.visit_ty(ty),
554 GenericArg::Const(ct) => vis.visit_anon_const(ct),
558 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
559 data: &mut AngleBracketedArgs,
562 let AngleBracketedArgs { args, span } = data;
563 visit_vec(args, |arg| match arg {
564 AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
565 AngleBracketedArg::Constraint(constraint) => vis.visit_constraint(constraint),
567 vis.visit_span(span);
570 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
571 args: &mut ParenthesizedArgs,
574 let ParenthesizedArgs { inputs, output, span, .. } = args;
575 visit_vec(inputs, |input| vis.visit_ty(input));
576 noop_visit_fn_ret_ty(output, vis);
577 vis.visit_span(span);
580 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
581 let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
584 visit_opt(ty, |ty| vis.visit_ty(ty));
586 LocalKind::Decl => {}
587 LocalKind::Init(init) => {
588 vis.visit_expr(init);
590 LocalKind::InitElse(init, els) => {
591 vis.visit_expr(init);
592 vis.visit_block(els);
595 vis.visit_span(span);
596 visit_thin_attrs(attrs, vis);
597 visit_lazy_tts(tokens, vis);
600 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
601 let Attribute { kind, id: _, style: _, span } = attr;
603 AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
604 vis.visit_path(path);
605 visit_mac_args(args, vis);
606 visit_lazy_tts(tokens, vis);
607 visit_lazy_tts(attr_tokens, vis);
609 AttrKind::DocComment(..) => {}
611 vis.visit_span(span);
614 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
615 let MacCall { path, args, prior_type_ascription: _ } = mac;
616 vis.visit_path(path);
617 visit_mac_args(args, vis);
620 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
621 let MacroDef { body, macro_rules: _ } = macro_def;
622 visit_mac_args(body, vis);
625 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
627 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
628 NestedMetaItem::Literal(_lit) => {}
632 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
633 let MetaItem { path: _, kind, span } = mi;
635 MetaItemKind::Word => {}
636 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
637 MetaItemKind::NameValue(_s) => {}
639 vis.visit_span(span);
642 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
643 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
645 visit_thin_attrs(attrs, vis);
647 vis.visit_span(span);
652 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
653 pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
655 AttrAnnotatedTokenTree::Token(token) => {
656 visit_token(token, vis);
658 AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
659 vis.visit_span(open);
660 vis.visit_span(close);
661 visit_attr_annotated_tts(tts, vis);
663 AttrAnnotatedTokenTree::Attributes(data) => {
664 for attr in &mut *data.attrs {
665 match &mut attr.kind {
666 AttrKind::Normal(_, attr_tokens) => {
667 visit_lazy_tts(attr_tokens, vis);
669 AttrKind::DocComment(..) => {
670 vis.visit_span(&mut attr.span);
674 visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
679 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
680 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
682 TokenTree::Token(token) => {
683 visit_token(token, vis);
685 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
686 vis.visit_span(open);
687 vis.visit_span(close);
693 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
694 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
695 if T::VISIT_TOKENS && !tts.is_empty() {
696 let tts = Lrc::make_mut(tts);
697 visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis));
701 pub fn visit_attr_annotated_tts<T: MutVisitor>(
702 AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
705 if T::VISIT_TOKENS && !tts.is_empty() {
706 let tts = Lrc::make_mut(tts);
707 visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
711 pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
713 if let Some(lazy_tts) = lazy_tts {
714 let mut tts = lazy_tts.create_token_stream();
715 visit_attr_annotated_tts(&mut tts, vis);
716 *lazy_tts = LazyTokenStream::new(tts);
721 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
722 visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
725 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
726 // Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
727 // In practice the ident part is not actually used by specific visitors right now,
728 // but there's a test below checking that it works.
729 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
730 let Token { kind, span } = t;
732 token::Ident(name, _) | token::Lifetime(name) => {
733 let mut ident = Ident::new(*name, *span);
734 vis.visit_ident(&mut ident);
737 return; // Avoid visiting the span for the second time.
739 token::Interpolated(nt) => {
740 let mut nt = Lrc::make_mut(nt);
741 visit_interpolated(&mut nt, vis);
745 vis.visit_span(span);
748 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
749 /// Applies the visitor to elements of interpolated nodes.
751 // N.B., this can occur only when applying a visitor to partially expanded
752 // code, where parsed pieces have gotten implanted ito *other* macro
753 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
755 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
756 // etc., allow the visitor to return *multiple* items; this is a problem for the
757 // nodes here, because they insist on having exactly one piece. One solution
758 // would be to mangle the MutVisitor trait to include one-to-many and
759 // one-to-one versions of these entry points, but that would probably confuse a
760 // lot of people and help very few. Instead, I'm just going to put in dynamic
761 // checks. I think the performance impact of this will be pretty much
762 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
763 // partially expanded node, and will be confused by the fact that their
764 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
765 // nodes. Hopefully they'll wind up reading this comment, and doing something
768 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
769 // contain multiple items, but decided against it when I looked at
770 // `parse_item_or_view_item` and tried to figure out what I would do with
771 // multiple items there....
772 pub fn visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
774 token::NtItem(item) => visit_clobber(item, |item| {
775 // This is probably okay, because the only visitors likely to
776 // peek inside interpolated nodes will be renamings/markings,
777 // which map single items to single items.
778 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
780 token::NtBlock(block) => vis.visit_block(block),
781 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
782 // See reasoning above.
784 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
787 token::NtPat(pat) => vis.visit_pat(pat),
788 token::NtExpr(expr) => vis.visit_expr(expr),
789 token::NtTy(ty) => vis.visit_ty(ty),
790 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
791 token::NtLifetime(ident) => vis.visit_ident(ident),
792 token::NtLiteral(expr) => vis.visit_expr(expr),
793 token::NtMeta(item) => {
794 let AttrItem { path, args, tokens } = item.deref_mut();
795 vis.visit_path(path);
796 visit_mac_args(args, vis);
797 visit_lazy_tts(tokens, vis);
799 token::NtPath(path) => vis.visit_path(path),
800 token::NtVis(visib) => vis.visit_vis(visib),
804 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
805 pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
807 Defaultness::Default(span) => vis.visit_span(span),
808 Defaultness::Final => {}
812 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
813 pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
815 Unsafe::Yes(span) => vis.visit_span(span),
820 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
821 pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
823 ImplPolarity::Positive => {}
824 ImplPolarity::Negative(span) => vis.visit_span(span),
828 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
829 pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
831 Const::Yes(span) => vis.visit_span(span),
836 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
838 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
839 vis.visit_id(closure_id);
840 vis.visit_id(return_impl_trait_id);
846 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
847 let FnDecl { inputs, output } = decl.deref_mut();
848 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
849 noop_visit_fn_ret_ty(output, vis);
852 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
854 FnRetTy::Default(span) => vis.visit_span(span),
855 FnRetTy::Ty(ty) => vis.visit_ty(ty),
859 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
861 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
862 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
866 pub fn noop_flat_map_generic_param<T: MutVisitor>(
867 mut param: GenericParam,
869 ) -> SmallVec<[GenericParam; 1]> {
870 let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
872 vis.visit_ident(ident);
873 visit_thin_attrs(attrs, vis);
874 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
876 GenericParamKind::Lifetime => {}
877 GenericParamKind::Type { default } => {
878 visit_opt(default, |default| vis.visit_ty(default));
880 GenericParamKind::Const { ty, kw_span: _, default } => {
882 visit_opt(default, |default| vis.visit_anon_const(default));
888 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
889 vis.visit_ident(ident);
892 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
894 vis.visit_ident(ident);
897 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
898 let Generics { params, where_clause, span } = generics;
899 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
900 vis.visit_where_clause(where_clause);
901 vis.visit_span(span);
904 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
905 let WhereClause { has_where_token: _, predicates, span } = wc;
906 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
907 vis.visit_span(span);
910 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
912 WherePredicate::BoundPredicate(bp) => {
913 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
914 vis.visit_span(span);
915 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
916 vis.visit_ty(bounded_ty);
917 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
919 WherePredicate::RegionPredicate(rp) => {
920 let WhereRegionPredicate { span, lifetime, bounds } = rp;
921 vis.visit_span(span);
922 noop_visit_lifetime(lifetime, vis);
923 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
925 WherePredicate::EqPredicate(ep) => {
926 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
928 vis.visit_span(span);
929 vis.visit_ty(lhs_ty);
930 vis.visit_ty(rhs_ty);
935 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
937 VariantData::Struct(fields, ..) => {
938 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
940 VariantData::Tuple(fields, id) => {
941 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
944 VariantData::Unit(id) => vis.visit_id(id),
948 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
949 vis.visit_path(path);
950 vis.visit_id(ref_id);
953 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
954 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
955 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
956 vis.visit_trait_ref(trait_ref);
957 vis.visit_span(span);
960 pub fn noop_flat_map_field_def<T: MutVisitor>(
963 ) -> SmallVec<[FieldDef; 1]> {
964 let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
965 visitor.visit_span(span);
966 visit_opt(ident, |ident| visitor.visit_ident(ident));
967 visitor.visit_vis(vis);
968 visitor.visit_id(id);
969 visitor.visit_ty(ty);
970 visit_thin_attrs(attrs, visitor);
974 pub fn noop_flat_map_expr_field<T: MutVisitor>(
977 ) -> SmallVec<[ExprField; 1]> {
978 let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
979 vis.visit_ident(ident);
980 vis.visit_expr(expr);
982 vis.visit_span(span);
983 visit_thin_attrs(attrs, vis);
987 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
991 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
992 let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
994 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
995 vis.visit_span(span);
996 visit_lazy_tts(tokens, vis);
999 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
1001 ItemKind::ExternCrate(_orig_name) => {}
1002 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
1003 ItemKind::Static(ty, _, expr) => {
1005 visit_opt(expr, |expr| vis.visit_expr(expr));
1007 ItemKind::Const(defaultness, ty, expr) => {
1008 visit_defaultness(defaultness, vis);
1010 visit_opt(expr, |expr| vis.visit_expr(expr));
1012 ItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1013 visit_defaultness(defaultness, vis);
1014 visit_fn_sig(sig, vis);
1015 vis.visit_generics(generics);
1016 visit_opt(body, |body| vis.visit_block(body));
1018 ItemKind::Mod(unsafety, mod_kind) => {
1019 visit_unsafety(unsafety, vis);
1021 ModKind::Loaded(items, _inline, ModSpans { inner_span, inject_use_span }) => {
1022 vis.visit_span(inner_span);
1023 vis.visit_span(inject_use_span);
1024 items.flat_map_in_place(|item| vis.flat_map_item(item));
1026 ModKind::Unloaded => {}
1029 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
1030 ItemKind::GlobalAsm(asm) => vis.visit_inline_asm(asm),
1031 ItemKind::TyAlias(box TyAlias {
1032 defaultness, generics, where_clauses, bounds, ty, ..
1034 visit_defaultness(defaultness, vis);
1035 vis.visit_generics(generics);
1036 vis.visit_span(&mut where_clauses.0.1);
1037 vis.visit_span(&mut where_clauses.1.1);
1038 visit_bounds(bounds, vis);
1039 visit_opt(ty, |ty| vis.visit_ty(ty));
1041 ItemKind::Enum(EnumDef { variants }, generics) => {
1042 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
1043 vis.visit_generics(generics);
1045 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
1046 vis.visit_variant_data(variant_data);
1047 vis.visit_generics(generics);
1049 ItemKind::Impl(box Impl {
1059 visit_defaultness(defaultness, vis);
1060 visit_unsafety(unsafety, vis);
1061 vis.visit_generics(generics);
1062 visit_constness(constness, vis);
1063 visit_polarity(polarity, vis);
1064 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
1065 vis.visit_ty(self_ty);
1066 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
1068 ItemKind::Trait(box Trait { unsafety, is_auto: _, generics, bounds, items }) => {
1069 visit_unsafety(unsafety, vis);
1070 vis.visit_generics(generics);
1071 visit_bounds(bounds, vis);
1072 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
1074 ItemKind::TraitAlias(generics, bounds) => {
1075 vis.visit_generics(generics);
1076 visit_bounds(bounds, vis);
1078 ItemKind::MacCall(m) => vis.visit_mac_call(m),
1079 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1083 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
1084 mut item: P<AssocItem>,
1086 ) -> SmallVec<[P<AssocItem>; 1]> {
1087 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
1088 visitor.visit_id(id);
1089 visitor.visit_ident(ident);
1090 visitor.visit_vis(vis);
1091 visit_attrs(attrs, visitor);
1093 AssocItemKind::Const(defaultness, ty, expr) => {
1094 visit_defaultness(defaultness, visitor);
1095 visitor.visit_ty(ty);
1096 visit_opt(expr, |expr| visitor.visit_expr(expr));
1098 AssocItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1099 visit_defaultness(defaultness, visitor);
1100 visitor.visit_generics(generics);
1101 visit_fn_sig(sig, visitor);
1102 visit_opt(body, |body| visitor.visit_block(body));
1104 AssocItemKind::TyAlias(box TyAlias {
1112 visit_defaultness(defaultness, visitor);
1113 visitor.visit_generics(generics);
1114 visitor.visit_span(&mut where_clauses.0.1);
1115 visitor.visit_span(&mut where_clauses.1.1);
1116 visit_bounds(bounds, visitor);
1117 visit_opt(ty, |ty| visitor.visit_ty(ty));
1119 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1121 visitor.visit_span(span);
1122 visit_lazy_tts(tokens, visitor);
1126 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
1127 let FnHeader { unsafety, asyncness, constness, ext: _ } = header;
1128 visit_constness(constness, vis);
1129 vis.visit_asyncness(asyncness);
1130 visit_unsafety(unsafety, vis);
1133 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1134 let Crate { attrs, items, spans, id, is_placeholder: _ } = krate;
1136 visit_attrs(attrs, vis);
1137 items.flat_map_in_place(|item| vis.flat_map_item(item));
1138 let ModSpans { inner_span, inject_use_span } = spans;
1139 vis.visit_span(inner_span);
1140 vis.visit_span(inject_use_span);
1143 // Mutates one item into possibly many items.
1144 pub fn noop_flat_map_item<T: MutVisitor>(
1147 ) -> SmallVec<[P<Item>; 1]> {
1148 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1149 visitor.visit_ident(ident);
1150 visit_attrs(attrs, visitor);
1151 visitor.visit_id(id);
1152 visitor.visit_item_kind(kind);
1153 visitor.visit_vis(vis);
1154 visitor.visit_span(span);
1155 visit_lazy_tts(tokens, visitor);
1160 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1161 mut item: P<ForeignItem>,
1163 ) -> SmallVec<[P<ForeignItem>; 1]> {
1164 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1165 visitor.visit_id(id);
1166 visitor.visit_ident(ident);
1167 visitor.visit_vis(vis);
1168 visit_attrs(attrs, visitor);
1170 ForeignItemKind::Static(ty, _, expr) => {
1171 visitor.visit_ty(ty);
1172 visit_opt(expr, |expr| visitor.visit_expr(expr));
1174 ForeignItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1175 visit_defaultness(defaultness, visitor);
1176 visitor.visit_generics(generics);
1177 visit_fn_sig(sig, visitor);
1178 visit_opt(body, |body| visitor.visit_block(body));
1180 ForeignItemKind::TyAlias(box TyAlias {
1188 visit_defaultness(defaultness, visitor);
1189 visitor.visit_generics(generics);
1190 visitor.visit_span(&mut where_clauses.0.1);
1191 visitor.visit_span(&mut where_clauses.1.1);
1192 visit_bounds(bounds, visitor);
1193 visit_opt(ty, |ty| visitor.visit_ty(ty));
1195 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1197 visitor.visit_span(span);
1198 visit_lazy_tts(tokens, visitor);
1202 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1203 let Pat { id, kind, span, tokens } = pat.deref_mut();
1206 PatKind::Wild | PatKind::Rest => {}
1207 PatKind::Ident(_binding_mode, ident, sub) => {
1208 vis.visit_ident(ident);
1209 visit_opt(sub, |sub| vis.visit_pat(sub));
1211 PatKind::Lit(e) => vis.visit_expr(e),
1212 PatKind::TupleStruct(qself, path, elems) => {
1213 vis.visit_qself(qself);
1214 vis.visit_path(path);
1215 visit_vec(elems, |elem| vis.visit_pat(elem));
1217 PatKind::Path(qself, path) => {
1218 vis.visit_qself(qself);
1219 vis.visit_path(path);
1221 PatKind::Struct(qself, path, fields, _etc) => {
1222 vis.visit_qself(qself);
1223 vis.visit_path(path);
1224 fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
1226 PatKind::Box(inner) => vis.visit_pat(inner),
1227 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1228 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1229 visit_opt(e1, |e| vis.visit_expr(e));
1230 visit_opt(e2, |e| vis.visit_expr(e));
1231 vis.visit_span(span);
1233 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1234 visit_vec(elems, |elem| vis.visit_pat(elem))
1236 PatKind::Paren(inner) => vis.visit_pat(inner),
1237 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1239 vis.visit_span(span);
1240 visit_lazy_tts(tokens, vis);
1243 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1245 vis.visit_expr(value);
1248 pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
1249 for (op, _) in &mut asm.operands {
1251 InlineAsmOperand::In { expr, .. }
1252 | InlineAsmOperand::Out { expr: Some(expr), .. }
1253 | InlineAsmOperand::InOut { expr, .. } => vis.visit_expr(expr),
1254 InlineAsmOperand::Out { expr: None, .. } => {}
1255 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1256 vis.visit_expr(in_expr);
1257 if let Some(out_expr) = out_expr {
1258 vis.visit_expr(out_expr);
1261 InlineAsmOperand::Const { anon_const } => vis.visit_anon_const(anon_const),
1262 InlineAsmOperand::Sym { sym } => vis.visit_inline_asm_sym(sym),
1267 pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
1268 InlineAsmSym { id, qself, path }: &mut InlineAsmSym,
1272 vis.visit_qself(qself);
1273 vis.visit_path(path);
1276 pub fn noop_visit_expr<T: MutVisitor>(
1277 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1281 ExprKind::Box(expr) => vis.visit_expr(expr),
1282 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1283 ExprKind::ConstBlock(anon_const) => {
1284 vis.visit_anon_const(anon_const);
1286 ExprKind::Repeat(expr, count) => {
1287 vis.visit_expr(expr);
1288 vis.visit_anon_const(count);
1290 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1291 ExprKind::Call(f, args) => {
1293 visit_exprs(args, vis);
1295 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
1296 vis.visit_ident(ident);
1298 visit_opt(args, |args| vis.visit_generic_args(args));
1299 visit_exprs(exprs, vis);
1300 vis.visit_span(span);
1302 ExprKind::Binary(_binop, lhs, rhs) => {
1303 vis.visit_expr(lhs);
1304 vis.visit_expr(rhs);
1306 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1307 ExprKind::Cast(expr, ty) => {
1308 vis.visit_expr(expr);
1311 ExprKind::Type(expr, ty) => {
1312 vis.visit_expr(expr);
1315 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1316 ExprKind::Let(pat, scrutinee, _) => {
1318 vis.visit_expr(scrutinee);
1320 ExprKind::If(cond, tr, fl) => {
1321 vis.visit_expr(cond);
1322 vis.visit_block(tr);
1323 visit_opt(fl, |fl| vis.visit_expr(fl));
1325 ExprKind::While(cond, body, label) => {
1326 vis.visit_expr(cond);
1327 vis.visit_block(body);
1328 visit_opt(label, |label| vis.visit_label(label));
1330 ExprKind::ForLoop(pat, iter, body, label) => {
1332 vis.visit_expr(iter);
1333 vis.visit_block(body);
1334 visit_opt(label, |label| vis.visit_label(label));
1336 ExprKind::Loop(body, label) => {
1337 vis.visit_block(body);
1338 visit_opt(label, |label| vis.visit_label(label));
1340 ExprKind::Match(expr, arms) => {
1341 vis.visit_expr(expr);
1342 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1344 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1345 vis.visit_asyncness(asyncness);
1346 vis.visit_fn_decl(decl);
1347 vis.visit_expr(body);
1348 vis.visit_span(span);
1350 ExprKind::Block(blk, label) => {
1351 vis.visit_block(blk);
1352 visit_opt(label, |label| vis.visit_label(label));
1354 ExprKind::Async(_capture_by, node_id, body) => {
1355 vis.visit_id(node_id);
1356 vis.visit_block(body);
1358 ExprKind::Await(expr) => vis.visit_expr(expr),
1359 ExprKind::Assign(el, er, _) => {
1363 ExprKind::AssignOp(_op, el, er) => {
1367 ExprKind::Field(el, ident) => {
1369 vis.visit_ident(ident);
1371 ExprKind::Index(el, er) => {
1375 ExprKind::Range(e1, e2, _lim) => {
1376 visit_opt(e1, |e1| vis.visit_expr(e1));
1377 visit_opt(e2, |e2| vis.visit_expr(e2));
1379 ExprKind::Underscore => {}
1380 ExprKind::Path(qself, path) => {
1381 vis.visit_qself(qself);
1382 vis.visit_path(path);
1384 ExprKind::Break(label, expr) => {
1385 visit_opt(label, |label| vis.visit_label(label));
1386 visit_opt(expr, |expr| vis.visit_expr(expr));
1388 ExprKind::Continue(label) => {
1389 visit_opt(label, |label| vis.visit_label(label));
1391 ExprKind::Ret(expr) => {
1392 visit_opt(expr, |expr| vis.visit_expr(expr));
1394 ExprKind::InlineAsm(asm) => vis.visit_inline_asm(asm),
1395 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1396 ExprKind::Struct(se) => {
1397 let StructExpr { qself, path, fields, rest } = se.deref_mut();
1398 vis.visit_qself(qself);
1399 vis.visit_path(path);
1400 fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
1402 StructRest::Base(expr) => vis.visit_expr(expr),
1403 StructRest::Rest(_span) => {}
1404 StructRest::None => {}
1407 ExprKind::Paren(expr) => {
1408 vis.visit_expr(expr);
1410 ExprKind::Yield(expr) => {
1411 visit_opt(expr, |expr| vis.visit_expr(expr));
1413 ExprKind::Try(expr) => vis.visit_expr(expr),
1414 ExprKind::TryBlock(body) => vis.visit_block(body),
1415 ExprKind::Lit(_) | ExprKind::Err => {}
1418 vis.visit_span(span);
1419 visit_thin_attrs(attrs, vis);
1420 visit_lazy_tts(tokens, vis);
1423 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1425 vis.visit_expr(&mut e);
1430 pub fn noop_flat_map_stmt<T: MutVisitor>(
1431 Stmt { kind, mut span, mut id }: Stmt,
1433 ) -> SmallVec<[Stmt; 1]> {
1434 vis.visit_id(&mut id);
1435 vis.visit_span(&mut span);
1436 let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
1438 .map(|kind| Stmt { id, kind, span })
1440 if stmts.len() > 1 {
1442 "cloning statement `NodeId`s is prohibited by default, \
1443 the visitor should implement custom statement visiting"
1449 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1452 ) -> SmallVec<[StmtKind; 1]> {
1454 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1455 vis.visit_local(&mut local);
1458 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1459 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1460 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1461 StmtKind::Empty => smallvec![StmtKind::Empty],
1462 StmtKind::MacCall(mut mac) => {
1463 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1464 vis.visit_mac_call(mac_);
1465 visit_thin_attrs(attrs, vis);
1466 visit_lazy_tts(tokens, vis);
1467 smallvec![StmtKind::MacCall(mac)]
1472 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1473 match &mut visibility.kind {
1474 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1475 VisibilityKind::Restricted { path, id } => {
1476 vis.visit_path(path);
1480 vis.visit_span(&mut visibility.span);
1483 /// Some value for the AST node that is valid but possibly meaningless.
1484 pub trait DummyAstNode {
1488 impl<T> DummyAstNode for Option<T> {
1489 fn dummy() -> Self {
1494 impl<T: DummyAstNode + 'static> DummyAstNode for P<T> {
1495 fn dummy() -> Self {
1496 P(DummyAstNode::dummy())
1500 impl<T> DummyAstNode for ThinVec<T> {
1501 fn dummy() -> Self {
1506 impl DummyAstNode for Item {
1507 fn dummy() -> Self {
1509 attrs: Default::default(),
1511 span: Default::default(),
1513 kind: VisibilityKind::Public,
1514 span: Default::default(),
1515 tokens: Default::default(),
1517 ident: Ident::empty(),
1518 kind: ItemKind::ExternCrate(None),
1519 tokens: Default::default(),
1524 impl DummyAstNode for Expr {
1525 fn dummy() -> Self {
1528 kind: ExprKind::Err,
1529 span: Default::default(),
1530 attrs: Default::default(),
1531 tokens: Default::default(),
1536 impl DummyAstNode for Ty {
1537 fn dummy() -> Self {
1541 span: Default::default(),
1542 tokens: Default::default(),
1547 impl DummyAstNode for Pat {
1548 fn dummy() -> Self {
1551 kind: PatKind::Wild,
1552 span: Default::default(),
1553 tokens: Default::default(),
1558 impl DummyAstNode for Stmt {
1559 fn dummy() -> Self {
1560 Stmt { id: DUMMY_NODE_ID, kind: StmtKind::Empty, span: Default::default() }
1564 impl DummyAstNode for Block {
1565 fn dummy() -> Self {
1567 stmts: Default::default(),
1569 rules: BlockCheckMode::Default,
1570 span: Default::default(),
1571 tokens: Default::default(),
1572 could_be_bare_literal: Default::default(),
1577 impl DummyAstNode for Crate {
1578 fn dummy() -> Self {
1580 attrs: Default::default(),
1581 items: Default::default(),
1582 spans: Default::default(),
1584 is_placeholder: Default::default(),