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_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, ptr};
25 pub trait ExpectOne<A: Array> {
26 fn expect_one(self, err: &'static str) -> A::Item;
29 impl<A: Array> ExpectOne<A> for SmallVec<A> {
30 fn expect_one(self, err: &'static str) -> A::Item {
31 assert!(self.len() == 1, "{}", err);
32 self.into_iter().next().unwrap()
36 pub trait MutVisitor: Sized {
37 /// Mutable token visiting only exists for the `macro_rules` token marker and should not be
38 /// used otherwise. Token visitor would be entirely separate from the regular visitor if
39 /// the marker didn't have to visit AST fragments in nonterminal tokens.
40 const VISIT_TOKENS: bool = false;
42 // Methods in this trait have one of three forms:
44 // fn visit_t(&mut self, t: &mut T); // common
45 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
46 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
48 // Any additions to this trait should happen in form of a call to a public
49 // `noop_*` function that only calls out to the visitor again, not other
50 // `noop_*` functions. This is a necessary API workaround to the problem of
51 // not being able to call out to the super default method in an overridden
54 // When writing these methods, it is better to use destructuring like this:
56 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
61 // than to use field access like this:
63 // fn visit_abc(&mut self, abc: &mut ABC) {
64 // visit_a(&mut abc.a);
65 // visit_b(&mut abc.b);
69 // As well as being more concise, the former is explicit about which fields
70 // are skipped. Furthermore, if a new field is added, the destructuring
71 // version will cause a compile error, which is good. In comparison, the
72 // field access version will continue working and it would be easy to
73 // forget to add handling for it.
75 fn visit_crate(&mut self, c: &mut Crate) {
76 noop_visit_crate(c, self)
79 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
80 noop_visit_meta_list_item(list_item, self);
83 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
84 noop_visit_meta_item(meta_item, self);
87 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
88 noop_visit_use_tree(use_tree, self);
91 fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
92 noop_flat_map_foreign_item(ni, self)
95 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
96 noop_flat_map_item(i, self)
99 fn visit_fn_header(&mut self, header: &mut FnHeader) {
100 noop_visit_fn_header(header, self);
103 fn flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
104 noop_flat_map_field_def(fd, self)
107 fn visit_item_kind(&mut self, i: &mut ItemKind) {
108 noop_visit_item_kind(i, self);
111 fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
112 noop_flat_map_assoc_item(i, self)
115 fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
116 noop_flat_map_assoc_item(i, self)
119 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
120 noop_visit_fn_decl(d, self);
123 fn visit_asyncness(&mut self, a: &mut Async) {
124 noop_visit_asyncness(a, self);
127 fn visit_closure_binder(&mut self, b: &mut ClosureBinder) {
128 noop_visit_closure_binder(b, self);
131 fn visit_block(&mut self, b: &mut P<Block>) {
132 noop_visit_block(b, self);
135 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
136 noop_flat_map_stmt(s, self)
139 fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
140 noop_flat_map_arm(arm, self)
143 fn visit_pat(&mut self, p: &mut P<Pat>) {
144 noop_visit_pat(p, self);
147 fn visit_anon_const(&mut self, c: &mut AnonConst) {
148 noop_visit_anon_const(c, self);
151 fn visit_expr(&mut self, e: &mut P<Expr>) {
152 noop_visit_expr(e, self);
155 /// This method is a hack to workaround unstable of `stmt_expr_attributes`.
156 /// It can be removed once that feature is stabilized.
157 fn visit_method_receiver_expr(&mut self, ex: &mut P<Expr>) {
161 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
162 noop_filter_map_expr(e, self)
165 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
166 noop_visit_generic_arg(arg, self);
169 fn visit_ty(&mut self, t: &mut P<Ty>) {
170 noop_visit_ty(t, self);
173 fn visit_lifetime(&mut self, l: &mut Lifetime) {
174 noop_visit_lifetime(l, self);
177 fn visit_constraint(&mut self, t: &mut AssocConstraint) {
178 noop_visit_constraint(t, self);
181 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
182 noop_visit_foreign_mod(nm, self);
185 fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
186 noop_flat_map_variant(v, self)
189 fn visit_ident(&mut self, i: &mut Ident) {
190 noop_visit_ident(i, self);
193 fn visit_path(&mut self, p: &mut Path) {
194 noop_visit_path(p, self);
197 fn visit_qself(&mut self, qs: &mut Option<P<QSelf>>) {
198 noop_visit_qself(qs, self);
201 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
202 noop_visit_generic_args(p, self);
205 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
206 noop_visit_angle_bracketed_parameter_data(p, self);
209 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
210 noop_visit_parenthesized_parameter_data(p, self);
213 fn visit_local(&mut self, l: &mut P<Local>) {
214 noop_visit_local(l, self);
217 fn visit_mac_call(&mut self, mac: &mut MacCall) {
218 noop_visit_mac(mac, self);
221 fn visit_macro_def(&mut self, def: &mut MacroDef) {
222 noop_visit_macro_def(def, self);
225 fn visit_label(&mut self, label: &mut Label) {
226 noop_visit_label(label, self);
229 fn visit_attribute(&mut self, at: &mut Attribute) {
230 noop_visit_attribute(at, self);
233 fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
234 noop_flat_map_param(param, self)
237 fn visit_generics(&mut self, generics: &mut Generics) {
238 noop_visit_generics(generics, self);
241 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
242 noop_visit_trait_ref(tr, self);
245 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
246 noop_visit_poly_trait_ref(p, self);
249 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
250 noop_visit_variant_data(vdata, self);
253 fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
254 noop_flat_map_generic_param(param, self)
257 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
258 noop_visit_param_bound(tpb, self);
261 fn visit_mt(&mut self, mt: &mut MutTy) {
262 noop_visit_mt(mt, self);
265 fn flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
266 noop_flat_map_expr_field(f, self)
269 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
270 noop_visit_where_clause(where_clause, self);
273 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
274 noop_visit_where_predicate(where_predicate, self);
277 fn visit_vis(&mut self, vis: &mut Visibility) {
278 noop_visit_vis(vis, self);
281 fn visit_id(&mut self, _id: &mut NodeId) {
285 fn visit_span(&mut self, _sp: &mut Span) {
289 fn flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
290 noop_flat_map_pat_field(fp, self)
293 fn visit_inline_asm(&mut self, asm: &mut InlineAsm) {
294 noop_visit_inline_asm(asm, self)
297 fn visit_inline_asm_sym(&mut self, sym: &mut InlineAsmSym) {
298 noop_visit_inline_asm_sym(sym, self)
302 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
303 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
306 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
307 pub fn visit_clobber<T: DummyAstNode>(t: &mut T, f: impl FnOnce(T) -> T) {
309 // Safe because `t` is used in a read-only fashion by `read()` before
310 // being overwritten by `write()`.
311 let old_t = ptr::read(t);
313 panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t))).unwrap_or_else(|err| {
314 // Set `t` to some valid but possible meaningless value,
315 // and pass the fatal error further.
316 ptr::write(t, T::dummy());
317 panic::resume_unwind(err);
319 ptr::write(t, new_t);
323 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
325 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
334 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
336 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
340 if let Some(elem) = opt {
345 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
346 pub fn visit_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
347 for attr in attrs.iter_mut() {
348 vis.visit_attribute(attr);
352 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
353 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
354 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
357 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
358 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
359 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
362 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
363 pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
364 vis.visit_fn_header(header);
365 vis.visit_fn_decl(decl);
366 vis.visit_span(span);
369 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
370 pub fn visit_attr_args<T: MutVisitor>(args: &mut AttrArgs, vis: &mut T) {
372 AttrArgs::Empty => {}
373 AttrArgs::Delimited(args) => visit_delim_args(args, vis),
374 AttrArgs::Eq(eq_span, AttrArgsEq::Ast(expr)) => {
375 vis.visit_span(eq_span);
376 vis.visit_expr(expr);
378 AttrArgs::Eq(_, AttrArgsEq::Hir(lit)) => {
379 unreachable!("in literal form when visiting mac args eq: {:?}", lit)
384 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
385 pub fn visit_delim_args<T: MutVisitor>(args: &mut DelimArgs, vis: &mut T) {
386 let DelimArgs { dspan, delim: _, tokens } = args;
387 visit_delim_span(dspan, vis);
388 visit_tts(tokens, vis);
391 pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
392 vis.visit_span(&mut dspan.open);
393 vis.visit_span(&mut dspan.close);
396 pub fn noop_flat_map_pat_field<T: MutVisitor>(
399 ) -> SmallVec<[PatField; 1]> {
400 let PatField { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
402 vis.visit_ident(ident);
404 vis.visit_span(span);
405 visit_attrs(attrs, vis);
409 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
410 let UseTree { prefix, kind, span } = use_tree;
411 vis.visit_path(prefix);
413 UseTreeKind::Simple(rename) => visit_opt(rename, |rename| vis.visit_ident(rename)),
414 UseTreeKind::Nested(items) => {
415 for (tree, id) in items {
416 vis.visit_use_tree(tree);
420 UseTreeKind::Glob => {}
422 vis.visit_span(span);
425 pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
426 let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
427 visit_attrs(attrs, vis);
430 visit_opt(guard, |guard| vis.visit_expr(guard));
431 vis.visit_expr(body);
432 vis.visit_span(span);
436 pub fn noop_visit_constraint<T: MutVisitor>(
437 AssocConstraint { id, ident, gen_args, kind, span }: &mut AssocConstraint,
441 vis.visit_ident(ident);
442 if let Some(gen_args) = gen_args {
443 vis.visit_generic_args(gen_args);
446 AssocConstraintKind::Equality { term } => match term {
447 Term::Ty(ty) => vis.visit_ty(ty),
448 Term::Const(c) => vis.visit_anon_const(c),
450 AssocConstraintKind::Bound { bounds } => visit_bounds(bounds, vis),
452 vis.visit_span(span);
455 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
456 let Ty { id, kind, span, tokens } = ty.deref_mut();
459 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
460 TyKind::Slice(ty) => vis.visit_ty(ty),
461 TyKind::Ptr(mt) => vis.visit_mt(mt),
462 TyKind::Rptr(lt, mt) => {
463 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
466 TyKind::BareFn(bft) => {
467 let BareFnTy { unsafety, ext: _, generic_params, decl, decl_span } = bft.deref_mut();
468 visit_unsafety(unsafety, vis);
469 generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
470 vis.visit_fn_decl(decl);
471 vis.visit_span(decl_span);
473 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
474 TyKind::Paren(ty) => vis.visit_ty(ty),
475 TyKind::Path(qself, path) => {
476 vis.visit_qself(qself);
477 vis.visit_path(path);
479 TyKind::Array(ty, length) => {
481 vis.visit_anon_const(length);
483 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
484 TyKind::TraitObject(bounds, _syntax) => {
485 visit_vec(bounds, |bound| vis.visit_param_bound(bound))
487 TyKind::ImplTrait(id, bounds) => {
489 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
491 TyKind::MacCall(mac) => vis.visit_mac_call(mac),
493 vis.visit_span(span);
494 visit_lazy_tts(tokens, vis);
497 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
498 let ForeignMod { unsafety, abi: _, items } = foreign_mod;
499 visit_unsafety(unsafety, vis);
500 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
503 pub fn noop_flat_map_variant<T: MutVisitor>(
504 mut variant: Variant,
506 ) -> SmallVec<[Variant; 1]> {
507 let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
508 visitor.visit_ident(ident);
509 visitor.visit_vis(vis);
510 visit_attrs(attrs, visitor);
511 visitor.visit_id(id);
512 visitor.visit_variant_data(data);
513 visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
514 visitor.visit_span(span);
518 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
519 vis.visit_span(span);
522 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
523 vis.visit_span(span);
524 for PathSegment { ident, id, args } in segments {
525 vis.visit_ident(ident);
527 visit_opt(args, |args| vis.visit_generic_args(args));
529 visit_lazy_tts(tokens, vis);
532 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<P<QSelf>>, vis: &mut T) {
533 visit_opt(qself, |qself| {
534 let QSelf { ty, path_span, position: _ } = &mut **qself;
536 vis.visit_span(path_span);
540 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
542 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
543 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
547 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
549 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
550 GenericArg::Type(ty) => vis.visit_ty(ty),
551 GenericArg::Const(ct) => vis.visit_anon_const(ct),
555 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
556 data: &mut AngleBracketedArgs,
559 let AngleBracketedArgs { args, span } = data;
560 visit_vec(args, |arg| match arg {
561 AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
562 AngleBracketedArg::Constraint(constraint) => vis.visit_constraint(constraint),
564 vis.visit_span(span);
567 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
568 args: &mut ParenthesizedArgs,
571 let ParenthesizedArgs { inputs, output, span, .. } = args;
572 visit_vec(inputs, |input| vis.visit_ty(input));
573 noop_visit_fn_ret_ty(output, vis);
574 vis.visit_span(span);
577 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
578 let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
581 visit_opt(ty, |ty| vis.visit_ty(ty));
583 LocalKind::Decl => {}
584 LocalKind::Init(init) => {
585 vis.visit_expr(init);
587 LocalKind::InitElse(init, els) => {
588 vis.visit_expr(init);
589 vis.visit_block(els);
592 vis.visit_span(span);
593 visit_attrs(attrs, vis);
594 visit_lazy_tts(tokens, vis);
597 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
598 let Attribute { kind, id: _, style: _, span } = attr;
600 AttrKind::Normal(normal) => {
601 let NormalAttr { item: AttrItem { path, args, tokens }, tokens: attr_tokens } =
603 vis.visit_path(path);
604 visit_attr_args(args, vis);
605 visit_lazy_tts(tokens, vis);
606 visit_lazy_tts(attr_tokens, vis);
608 AttrKind::DocComment(..) => {}
610 vis.visit_span(span);
613 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
614 let MacCall { path, args, prior_type_ascription: _ } = mac;
615 vis.visit_path(path);
616 visit_delim_args(args, vis);
619 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
620 let MacroDef { body, macro_rules: _ } = macro_def;
621 visit_delim_args(body, vis);
624 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
626 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
627 NestedMetaItem::Lit(_lit) => {}
631 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
632 let MetaItem { path: _, kind, span } = mi;
634 MetaItemKind::Word => {}
635 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
636 MetaItemKind::NameValue(_s) => {}
638 vis.visit_span(span);
641 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
642 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
644 visit_attrs(attrs, vis);
646 vis.visit_span(span);
651 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
652 pub fn visit_attr_tt<T: MutVisitor>(tt: &mut AttrTokenTree, vis: &mut T) {
654 AttrTokenTree::Token(token, _) => {
655 visit_token(token, vis);
657 AttrTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
658 vis.visit_span(open);
659 vis.visit_span(close);
660 visit_attr_tts(tts, vis);
662 AttrTokenTree::Attributes(data) => {
663 for attr in &mut *data.attrs {
664 match &mut attr.kind {
665 AttrKind::Normal(normal) => {
666 visit_lazy_tts(&mut normal.tokens, vis);
668 AttrKind::DocComment(..) => {
669 vis.visit_span(&mut attr.span);
673 visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
678 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
679 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
681 TokenTree::Token(token, _) => {
682 visit_token(token, vis);
684 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
685 vis.visit_span(open);
686 vis.visit_span(close);
692 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
693 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
694 if T::VISIT_TOKENS && !tts.is_empty() {
695 let tts = Lrc::make_mut(tts);
696 visit_vec(tts, |tree| visit_tt(tree, vis));
700 pub fn visit_attr_tts<T: MutVisitor>(AttrTokenStream(tts): &mut AttrTokenStream, vis: &mut T) {
701 if T::VISIT_TOKENS && !tts.is_empty() {
702 let tts = Lrc::make_mut(tts);
703 visit_vec(tts, |tree| visit_attr_tt(tree, vis));
707 pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(
708 lazy_tts: Option<&mut LazyAttrTokenStream>,
712 if let Some(lazy_tts) = lazy_tts {
713 let mut tts = lazy_tts.to_attr_token_stream();
714 visit_attr_tts(&mut tts, vis);
715 *lazy_tts = LazyAttrTokenStream::new(tts);
720 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyAttrTokenStream>, vis: &mut T) {
721 visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
724 /// Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
725 /// In practice the ident part is not actually used by specific visitors right now,
726 /// but there's a test below checking that it works.
727 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
728 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
729 let Token { kind, span } = t;
731 token::Ident(name, _) | token::Lifetime(name) => {
732 let mut ident = Ident::new(*name, *span);
733 vis.visit_ident(&mut ident);
736 return; // Avoid visiting the span for the second time.
738 token::Interpolated(nt) => {
739 let mut nt = Lrc::make_mut(nt);
740 visit_nonterminal(&mut nt, vis);
744 vis.visit_span(span);
747 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
748 /// Applies the visitor to elements of interpolated nodes.
750 // N.B., this can occur only when applying a visitor to partially expanded
751 // code, where parsed pieces have gotten implanted ito *other* macro
752 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
754 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
755 // etc., allow the visitor to return *multiple* items; this is a problem for the
756 // nodes here, because they insist on having exactly one piece. One solution
757 // would be to mangle the MutVisitor trait to include one-to-many and
758 // one-to-one versions of these entry points, but that would probably confuse a
759 // lot of people and help very few. Instead, I'm just going to put in dynamic
760 // checks. I think the performance impact of this will be pretty much
761 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
762 // partially expanded node, and will be confused by the fact that their
763 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
764 // nodes. Hopefully they'll wind up reading this comment, and doing something
767 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
768 // contain multiple items, but decided against it when I looked at
769 // `parse_item_or_view_item` and tried to figure out what I would do with
770 // multiple items there....
771 pub fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
773 token::NtItem(item) => visit_clobber(item, |item| {
774 // This is probably okay, because the only visitors likely to
775 // peek inside interpolated nodes will be renamings/markings,
776 // which map single items to single items.
777 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
779 token::NtBlock(block) => vis.visit_block(block),
780 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
781 // See reasoning above.
783 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
786 token::NtPat(pat) => vis.visit_pat(pat),
787 token::NtExpr(expr) => vis.visit_expr(expr),
788 token::NtTy(ty) => vis.visit_ty(ty),
789 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
790 token::NtLifetime(ident) => vis.visit_ident(ident),
791 token::NtLiteral(expr) => vis.visit_expr(expr),
792 token::NtMeta(item) => {
793 let AttrItem { path, args, tokens } = item.deref_mut();
794 vis.visit_path(path);
795 visit_attr_args(args, vis);
796 visit_lazy_tts(tokens, vis);
798 token::NtPath(path) => vis.visit_path(path),
799 token::NtVis(visib) => vis.visit_vis(visib),
803 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
804 pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
806 Defaultness::Default(span) => vis.visit_span(span),
807 Defaultness::Final => {}
811 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
812 pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
814 Unsafe::Yes(span) => vis.visit_span(span),
819 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
820 pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
822 ImplPolarity::Positive => {}
823 ImplPolarity::Negative(span) => vis.visit_span(span),
827 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
828 pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
830 Const::Yes(span) => vis.visit_span(span),
835 pub fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis: &mut T) {
837 ClosureBinder::NotPresent => {}
838 ClosureBinder::For { span: _, generic_params } => {
839 let mut vec = std::mem::take(generic_params).into_vec();
840 vec.flat_map_in_place(|param| vis.flat_map_generic_param(param));
841 *generic_params = P::from_vec(vec);
846 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
848 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
849 vis.visit_id(closure_id);
850 vis.visit_id(return_impl_trait_id);
856 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
857 let FnDecl { inputs, output } = decl.deref_mut();
858 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
859 noop_visit_fn_ret_ty(output, vis);
862 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
864 FnRetTy::Default(span) => vis.visit_span(span),
865 FnRetTy::Ty(ty) => vis.visit_ty(ty),
869 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
871 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
872 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
876 pub fn noop_flat_map_generic_param<T: MutVisitor>(
877 mut param: GenericParam,
879 ) -> SmallVec<[GenericParam; 1]> {
880 let GenericParam { id, ident, attrs, bounds, kind, colon_span, is_placeholder: _ } = &mut param;
882 vis.visit_ident(ident);
883 if let Some(colon_span) = colon_span {
884 vis.visit_span(colon_span);
886 visit_attrs(attrs, vis);
887 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
889 GenericParamKind::Lifetime => {}
890 GenericParamKind::Type { default } => {
891 visit_opt(default, |default| vis.visit_ty(default));
893 GenericParamKind::Const { ty, kw_span: _, default } => {
895 visit_opt(default, |default| vis.visit_anon_const(default));
901 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
902 vis.visit_ident(ident);
905 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
907 vis.visit_ident(ident);
910 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
911 let Generics { params, where_clause, span } = generics;
912 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
913 vis.visit_where_clause(where_clause);
914 vis.visit_span(span);
917 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
918 let WhereClause { has_where_token: _, predicates, span } = wc;
919 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
920 vis.visit_span(span);
923 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
925 WherePredicate::BoundPredicate(bp) => {
926 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
927 vis.visit_span(span);
928 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
929 vis.visit_ty(bounded_ty);
930 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
932 WherePredicate::RegionPredicate(rp) => {
933 let WhereRegionPredicate { span, lifetime, bounds } = rp;
934 vis.visit_span(span);
935 noop_visit_lifetime(lifetime, vis);
936 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
938 WherePredicate::EqPredicate(ep) => {
939 let WhereEqPredicate { span, lhs_ty, rhs_ty } = ep;
940 vis.visit_span(span);
941 vis.visit_ty(lhs_ty);
942 vis.visit_ty(rhs_ty);
947 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
949 VariantData::Struct(fields, ..) => {
950 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
952 VariantData::Tuple(fields, id) => {
953 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
956 VariantData::Unit(id) => vis.visit_id(id),
960 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
961 vis.visit_path(path);
962 vis.visit_id(ref_id);
965 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
966 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
967 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
968 vis.visit_trait_ref(trait_ref);
969 vis.visit_span(span);
972 pub fn noop_flat_map_field_def<T: MutVisitor>(
975 ) -> SmallVec<[FieldDef; 1]> {
976 let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
977 visitor.visit_span(span);
978 visit_opt(ident, |ident| visitor.visit_ident(ident));
979 visitor.visit_vis(vis);
980 visitor.visit_id(id);
981 visitor.visit_ty(ty);
982 visit_attrs(attrs, visitor);
986 pub fn noop_flat_map_expr_field<T: MutVisitor>(
989 ) -> SmallVec<[ExprField; 1]> {
990 let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
991 vis.visit_ident(ident);
992 vis.visit_expr(expr);
994 vis.visit_span(span);
995 visit_attrs(attrs, vis);
999 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
1003 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
1004 let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
1006 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
1007 vis.visit_span(span);
1008 visit_lazy_tts(tokens, vis);
1011 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
1013 ItemKind::ExternCrate(_orig_name) => {}
1014 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
1015 ItemKind::Static(ty, _, expr) => {
1017 visit_opt(expr, |expr| vis.visit_expr(expr));
1019 ItemKind::Const(defaultness, ty, expr) => {
1020 visit_defaultness(defaultness, vis);
1022 visit_opt(expr, |expr| vis.visit_expr(expr));
1024 ItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1025 visit_defaultness(defaultness, vis);
1026 visit_fn_sig(sig, vis);
1027 vis.visit_generics(generics);
1028 visit_opt(body, |body| vis.visit_block(body));
1030 ItemKind::Mod(unsafety, mod_kind) => {
1031 visit_unsafety(unsafety, vis);
1033 ModKind::Loaded(items, _inline, ModSpans { inner_span, inject_use_span }) => {
1034 vis.visit_span(inner_span);
1035 vis.visit_span(inject_use_span);
1036 items.flat_map_in_place(|item| vis.flat_map_item(item));
1038 ModKind::Unloaded => {}
1041 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
1042 ItemKind::GlobalAsm(asm) => vis.visit_inline_asm(asm),
1043 ItemKind::TyAlias(box TyAlias {
1044 defaultness, generics, where_clauses, bounds, ty, ..
1046 visit_defaultness(defaultness, vis);
1047 vis.visit_generics(generics);
1048 vis.visit_span(&mut where_clauses.0.1);
1049 vis.visit_span(&mut where_clauses.1.1);
1050 visit_bounds(bounds, vis);
1051 visit_opt(ty, |ty| vis.visit_ty(ty));
1053 ItemKind::Enum(EnumDef { variants }, generics) => {
1054 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
1055 vis.visit_generics(generics);
1057 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
1058 vis.visit_variant_data(variant_data);
1059 vis.visit_generics(generics);
1061 ItemKind::Impl(box Impl {
1071 visit_defaultness(defaultness, vis);
1072 visit_unsafety(unsafety, vis);
1073 vis.visit_generics(generics);
1074 visit_constness(constness, vis);
1075 visit_polarity(polarity, vis);
1076 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
1077 vis.visit_ty(self_ty);
1078 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
1080 ItemKind::Trait(box Trait { unsafety, is_auto: _, generics, bounds, items }) => {
1081 visit_unsafety(unsafety, vis);
1082 vis.visit_generics(generics);
1083 visit_bounds(bounds, vis);
1084 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
1086 ItemKind::TraitAlias(generics, bounds) => {
1087 vis.visit_generics(generics);
1088 visit_bounds(bounds, vis);
1090 ItemKind::MacCall(m) => vis.visit_mac_call(m),
1091 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1095 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
1096 mut item: P<AssocItem>,
1098 ) -> SmallVec<[P<AssocItem>; 1]> {
1099 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
1100 visitor.visit_id(id);
1101 visitor.visit_ident(ident);
1102 visitor.visit_vis(vis);
1103 visit_attrs(attrs, visitor);
1105 AssocItemKind::Const(defaultness, ty, expr) => {
1106 visit_defaultness(defaultness, visitor);
1107 visitor.visit_ty(ty);
1108 visit_opt(expr, |expr| visitor.visit_expr(expr));
1110 AssocItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1111 visit_defaultness(defaultness, visitor);
1112 visitor.visit_generics(generics);
1113 visit_fn_sig(sig, visitor);
1114 visit_opt(body, |body| visitor.visit_block(body));
1116 AssocItemKind::Type(box TyAlias {
1124 visit_defaultness(defaultness, visitor);
1125 visitor.visit_generics(generics);
1126 visitor.visit_span(&mut where_clauses.0.1);
1127 visitor.visit_span(&mut where_clauses.1.1);
1128 visit_bounds(bounds, visitor);
1129 visit_opt(ty, |ty| visitor.visit_ty(ty));
1131 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1133 visitor.visit_span(span);
1134 visit_lazy_tts(tokens, visitor);
1138 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
1139 let FnHeader { unsafety, asyncness, constness, ext: _ } = header;
1140 visit_constness(constness, vis);
1141 vis.visit_asyncness(asyncness);
1142 visit_unsafety(unsafety, vis);
1145 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1146 let Crate { attrs, items, spans, id, is_placeholder: _ } = krate;
1148 visit_attrs(attrs, vis);
1149 items.flat_map_in_place(|item| vis.flat_map_item(item));
1150 let ModSpans { inner_span, inject_use_span } = spans;
1151 vis.visit_span(inner_span);
1152 vis.visit_span(inject_use_span);
1155 // Mutates one item into possibly many items.
1156 pub fn noop_flat_map_item<T: MutVisitor>(
1159 ) -> SmallVec<[P<Item>; 1]> {
1160 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1161 visitor.visit_ident(ident);
1162 visit_attrs(attrs, visitor);
1163 visitor.visit_id(id);
1164 visitor.visit_item_kind(kind);
1165 visitor.visit_vis(vis);
1166 visitor.visit_span(span);
1167 visit_lazy_tts(tokens, visitor);
1172 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1173 mut item: P<ForeignItem>,
1175 ) -> SmallVec<[P<ForeignItem>; 1]> {
1176 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1177 visitor.visit_id(id);
1178 visitor.visit_ident(ident);
1179 visitor.visit_vis(vis);
1180 visit_attrs(attrs, visitor);
1182 ForeignItemKind::Static(ty, _, expr) => {
1183 visitor.visit_ty(ty);
1184 visit_opt(expr, |expr| visitor.visit_expr(expr));
1186 ForeignItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1187 visit_defaultness(defaultness, visitor);
1188 visitor.visit_generics(generics);
1189 visit_fn_sig(sig, visitor);
1190 visit_opt(body, |body| visitor.visit_block(body));
1192 ForeignItemKind::TyAlias(box TyAlias {
1200 visit_defaultness(defaultness, visitor);
1201 visitor.visit_generics(generics);
1202 visitor.visit_span(&mut where_clauses.0.1);
1203 visitor.visit_span(&mut where_clauses.1.1);
1204 visit_bounds(bounds, visitor);
1205 visit_opt(ty, |ty| visitor.visit_ty(ty));
1207 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1209 visitor.visit_span(span);
1210 visit_lazy_tts(tokens, visitor);
1214 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1215 let Pat { id, kind, span, tokens } = pat.deref_mut();
1218 PatKind::Wild | PatKind::Rest => {}
1219 PatKind::Ident(_binding_mode, ident, sub) => {
1220 vis.visit_ident(ident);
1221 visit_opt(sub, |sub| vis.visit_pat(sub));
1223 PatKind::Lit(e) => vis.visit_expr(e),
1224 PatKind::TupleStruct(qself, path, elems) => {
1225 vis.visit_qself(qself);
1226 vis.visit_path(path);
1227 visit_vec(elems, |elem| vis.visit_pat(elem));
1229 PatKind::Path(qself, path) => {
1230 vis.visit_qself(qself);
1231 vis.visit_path(path);
1233 PatKind::Struct(qself, path, fields, _etc) => {
1234 vis.visit_qself(qself);
1235 vis.visit_path(path);
1236 fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
1238 PatKind::Box(inner) => vis.visit_pat(inner),
1239 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1240 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1241 visit_opt(e1, |e| vis.visit_expr(e));
1242 visit_opt(e2, |e| vis.visit_expr(e));
1243 vis.visit_span(span);
1245 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1246 visit_vec(elems, |elem| vis.visit_pat(elem))
1248 PatKind::Paren(inner) => vis.visit_pat(inner),
1249 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1251 vis.visit_span(span);
1252 visit_lazy_tts(tokens, vis);
1255 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1257 vis.visit_expr(value);
1260 pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
1261 for (op, _) in &mut asm.operands {
1263 InlineAsmOperand::In { expr, .. }
1264 | InlineAsmOperand::Out { expr: Some(expr), .. }
1265 | InlineAsmOperand::InOut { expr, .. } => vis.visit_expr(expr),
1266 InlineAsmOperand::Out { expr: None, .. } => {}
1267 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1268 vis.visit_expr(in_expr);
1269 if let Some(out_expr) = out_expr {
1270 vis.visit_expr(out_expr);
1273 InlineAsmOperand::Const { anon_const } => vis.visit_anon_const(anon_const),
1274 InlineAsmOperand::Sym { sym } => vis.visit_inline_asm_sym(sym),
1279 pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
1280 InlineAsmSym { id, qself, path }: &mut InlineAsmSym,
1284 vis.visit_qself(qself);
1285 vis.visit_path(path);
1288 pub fn noop_visit_expr<T: MutVisitor>(
1289 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1293 ExprKind::Box(expr) => vis.visit_expr(expr),
1294 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1295 ExprKind::ConstBlock(anon_const) => {
1296 vis.visit_anon_const(anon_const);
1298 ExprKind::Repeat(expr, count) => {
1299 vis.visit_expr(expr);
1300 vis.visit_anon_const(count);
1302 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1303 ExprKind::Call(f, args) => {
1305 visit_exprs(args, vis);
1307 ExprKind::MethodCall(box MethodCall {
1308 seg: PathSegment { ident, id, args: seg_args },
1313 vis.visit_ident(ident);
1315 visit_opt(seg_args, |args| vis.visit_generic_args(args));
1316 vis.visit_method_receiver_expr(receiver);
1317 visit_exprs(call_args, vis);
1318 vis.visit_span(span);
1320 ExprKind::Binary(_binop, lhs, rhs) => {
1321 vis.visit_expr(lhs);
1322 vis.visit_expr(rhs);
1324 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1325 ExprKind::Cast(expr, ty) => {
1326 vis.visit_expr(expr);
1329 ExprKind::Type(expr, ty) => {
1330 vis.visit_expr(expr);
1333 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1334 ExprKind::Let(pat, scrutinee, _) => {
1336 vis.visit_expr(scrutinee);
1338 ExprKind::If(cond, tr, fl) => {
1339 vis.visit_expr(cond);
1340 vis.visit_block(tr);
1341 visit_opt(fl, |fl| vis.visit_expr(fl));
1343 ExprKind::While(cond, body, label) => {
1344 vis.visit_expr(cond);
1345 vis.visit_block(body);
1346 visit_opt(label, |label| vis.visit_label(label));
1348 ExprKind::ForLoop(pat, iter, body, label) => {
1350 vis.visit_expr(iter);
1351 vis.visit_block(body);
1352 visit_opt(label, |label| vis.visit_label(label));
1354 ExprKind::Loop(body, label, span) => {
1355 vis.visit_block(body);
1356 visit_opt(label, |label| vis.visit_label(label));
1357 vis.visit_span(span);
1359 ExprKind::Match(expr, arms) => {
1360 vis.visit_expr(expr);
1361 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1363 ExprKind::Closure(box Closure {
1372 vis.visit_closure_binder(binder);
1373 vis.visit_asyncness(asyncness);
1374 vis.visit_fn_decl(fn_decl);
1375 vis.visit_expr(body);
1376 vis.visit_span(fn_decl_span);
1378 ExprKind::Block(blk, label) => {
1379 vis.visit_block(blk);
1380 visit_opt(label, |label| vis.visit_label(label));
1382 ExprKind::Async(_capture_by, node_id, body) => {
1383 vis.visit_id(node_id);
1384 vis.visit_block(body);
1386 ExprKind::Await(expr) => vis.visit_expr(expr),
1387 ExprKind::Assign(el, er, _) => {
1391 ExprKind::AssignOp(_op, el, er) => {
1395 ExprKind::Field(el, ident) => {
1397 vis.visit_ident(ident);
1399 ExprKind::Index(el, er) => {
1403 ExprKind::Range(e1, e2, _lim) => {
1404 visit_opt(e1, |e1| vis.visit_expr(e1));
1405 visit_opt(e2, |e2| vis.visit_expr(e2));
1407 ExprKind::Underscore => {}
1408 ExprKind::Path(qself, path) => {
1409 vis.visit_qself(qself);
1410 vis.visit_path(path);
1412 ExprKind::Break(label, expr) => {
1413 visit_opt(label, |label| vis.visit_label(label));
1414 visit_opt(expr, |expr| vis.visit_expr(expr));
1416 ExprKind::Continue(label) => {
1417 visit_opt(label, |label| vis.visit_label(label));
1419 ExprKind::Ret(expr) => {
1420 visit_opt(expr, |expr| vis.visit_expr(expr));
1422 ExprKind::Yeet(expr) => {
1423 visit_opt(expr, |expr| vis.visit_expr(expr));
1425 ExprKind::InlineAsm(asm) => vis.visit_inline_asm(asm),
1426 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1427 ExprKind::Struct(se) => {
1428 let StructExpr { qself, path, fields, rest } = se.deref_mut();
1429 vis.visit_qself(qself);
1430 vis.visit_path(path);
1431 fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
1433 StructRest::Base(expr) => vis.visit_expr(expr),
1434 StructRest::Rest(_span) => {}
1435 StructRest::None => {}
1438 ExprKind::Paren(expr) => {
1439 vis.visit_expr(expr);
1441 ExprKind::Yield(expr) => {
1442 visit_opt(expr, |expr| vis.visit_expr(expr));
1444 ExprKind::Try(expr) => vis.visit_expr(expr),
1445 ExprKind::TryBlock(body) => vis.visit_block(body),
1446 ExprKind::Lit(_) | ExprKind::IncludedBytes(..) | ExprKind::Err => {}
1449 vis.visit_span(span);
1450 visit_attrs(attrs, vis);
1451 visit_lazy_tts(tokens, vis);
1454 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1456 vis.visit_expr(&mut e);
1461 pub fn noop_flat_map_stmt<T: MutVisitor>(
1462 Stmt { kind, mut span, mut id }: Stmt,
1464 ) -> SmallVec<[Stmt; 1]> {
1465 vis.visit_id(&mut id);
1466 vis.visit_span(&mut span);
1467 let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
1469 .map(|kind| Stmt { id, kind, span })
1471 if stmts.len() > 1 {
1473 "cloning statement `NodeId`s is prohibited by default, \
1474 the visitor should implement custom statement visiting"
1480 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1483 ) -> SmallVec<[StmtKind; 1]> {
1485 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1486 vis.visit_local(&mut local);
1489 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1490 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1491 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1492 StmtKind::Empty => smallvec![StmtKind::Empty],
1493 StmtKind::MacCall(mut mac) => {
1494 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1495 vis.visit_mac_call(mac_);
1496 visit_attrs(attrs, vis);
1497 visit_lazy_tts(tokens, vis);
1498 smallvec![StmtKind::MacCall(mac)]
1503 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1504 match &mut visibility.kind {
1505 VisibilityKind::Public | VisibilityKind::Inherited => {}
1506 VisibilityKind::Restricted { path, id, shorthand: _ } => {
1507 vis.visit_path(path);
1511 vis.visit_span(&mut visibility.span);
1514 /// Some value for the AST node that is valid but possibly meaningless.
1515 pub trait DummyAstNode {
1519 impl<T> DummyAstNode for Option<T> {
1520 fn dummy() -> Self {
1525 impl<T: DummyAstNode + 'static> DummyAstNode for P<T> {
1526 fn dummy() -> Self {
1527 P(DummyAstNode::dummy())
1531 impl DummyAstNode for Item {
1532 fn dummy() -> Self {
1534 attrs: Default::default(),
1536 span: Default::default(),
1538 kind: VisibilityKind::Public,
1539 span: Default::default(),
1540 tokens: Default::default(),
1542 ident: Ident::empty(),
1543 kind: ItemKind::ExternCrate(None),
1544 tokens: Default::default(),
1549 impl DummyAstNode for Expr {
1550 fn dummy() -> Self {
1553 kind: ExprKind::Err,
1554 span: Default::default(),
1555 attrs: Default::default(),
1556 tokens: Default::default(),
1561 impl DummyAstNode for Ty {
1562 fn dummy() -> Self {
1566 span: Default::default(),
1567 tokens: Default::default(),
1572 impl DummyAstNode for Pat {
1573 fn dummy() -> Self {
1576 kind: PatKind::Wild,
1577 span: Default::default(),
1578 tokens: Default::default(),
1583 impl DummyAstNode for Stmt {
1584 fn dummy() -> Self {
1585 Stmt { id: DUMMY_NODE_ID, kind: StmtKind::Empty, span: Default::default() }
1589 impl DummyAstNode for Block {
1590 fn dummy() -> Self {
1592 stmts: Default::default(),
1594 rules: BlockCheckMode::Default,
1595 span: Default::default(),
1596 tokens: Default::default(),
1597 could_be_bare_literal: Default::default(),
1602 impl DummyAstNode for Crate {
1603 fn dummy() -> Self {
1605 attrs: Default::default(),
1606 items: Default::default(),
1607 spans: Default::default(),
1609 is_placeholder: Default::default(),
1614 impl<N: DummyAstNode, T: DummyAstNode> DummyAstNode for crate::ast_traits::AstNodeWrapper<N, T> {
1615 fn dummy() -> Self {
1616 crate::ast_traits::AstNodeWrapper::new(N::dummy(), T::dummy())