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.
11 use crate::source_map::{Spanned, respan};
12 use crate::parse::token::{self, Token};
15 use crate::tokenstream::*;
16 use crate::util::map_in_place::MapInPlace;
18 use smallvec::{smallvec, Array, SmallVec};
21 use rustc_data_structures::sync::Lrc;
22 use std::ops::DerefMut;
23 use std::{panic, process, ptr};
28 pub trait ExpectOne<A: Array> {
29 fn expect_one(self, err: &'static str) -> A::Item;
32 impl<A: Array> ExpectOne<A> for SmallVec<A> {
33 fn expect_one(self, err: &'static str) -> A::Item {
34 assert!(self.len() == 1, err);
35 self.into_iter().next().unwrap()
39 pub trait MutVisitor: Sized {
40 // Methods in this trait have one of three forms:
42 // fn visit_t(&mut self, t: &mut T); // common
43 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
44 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
46 // Any additions to this trait should happen in form of a call to a public
47 // `noop_*` function that only calls out to the visitor again, not other
48 // `noop_*` functions. This is a necessary API workaround to the problem of
49 // not being able to call out to the super default method in an overridden
52 // When writing these methods, it is better to use destructuring like this:
54 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
59 // than to use field access like this:
61 // fn visit_abc(&mut self, abc: &mut ABC) {
62 // visit_a(&mut abc.a);
63 // visit_b(&mut abc.b);
67 // As well as being more concise, the former is explicit about which fields
68 // are skipped. Furthermore, if a new field is added, the destructuring
69 // version will cause a compile error, which is good. In comparison, the
70 // field access version will continue working and it would be easy to
71 // forget to add handling for it.
73 fn visit_crate(&mut self, c: &mut Crate) {
74 noop_visit_crate(c, self)
77 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
78 noop_visit_meta_list_item(list_item, self);
81 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
82 noop_visit_meta_item(meta_item, self);
85 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
86 noop_visit_use_tree(use_tree, self);
89 fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
90 noop_flat_map_foreign_item(ni, self)
93 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
94 noop_flat_map_item(i, self)
97 fn visit_fn_header(&mut self, header: &mut FnHeader) {
98 noop_visit_fn_header(header, self);
101 fn visit_struct_field(&mut self, sf: &mut StructField) {
102 noop_visit_struct_field(sf, self);
105 fn visit_item_kind(&mut self, i: &mut ItemKind) {
106 noop_visit_item_kind(i, self);
109 fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
110 noop_flat_map_trait_item(i, self)
113 fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
114 noop_flat_map_impl_item(i, self)
117 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
118 noop_visit_fn_decl(d, self);
121 fn visit_asyncness(&mut self, a: &mut IsAsync) {
122 noop_visit_asyncness(a, self);
125 fn visit_block(&mut self, b: &mut P<Block>) {
126 noop_visit_block(b, self);
129 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
130 noop_flat_map_stmt(s, self)
133 fn visit_arm(&mut self, a: &mut Arm) {
134 noop_visit_arm(a, self);
137 fn visit_pat(&mut self, p: &mut P<Pat>) {
138 noop_visit_pat(p, self);
141 fn visit_anon_const(&mut self, c: &mut AnonConst) {
142 noop_visit_anon_const(c, self);
145 fn visit_expr(&mut self, e: &mut P<Expr>) {
146 noop_visit_expr(e, self);
149 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
150 noop_filter_map_expr(e, self)
153 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
154 noop_visit_generic_arg(arg, self);
157 fn visit_ty(&mut self, t: &mut P<Ty>) {
158 noop_visit_ty(t, self);
161 fn visit_lifetime(&mut self, l: &mut Lifetime) {
162 noop_visit_lifetime(l, self);
165 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
166 noop_visit_ty_constraint(t, self);
169 fn visit_mod(&mut self, m: &mut Mod) {
170 noop_visit_mod(m, self);
173 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
174 noop_visit_foreign_mod(nm, self);
177 fn visit_variant(&mut self, v: &mut Variant) {
178 noop_visit_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(&mut self, _mac: &mut Mac) {
210 panic!("visit_mac disabled by default");
211 // N.B., see note about macros above. If you really want a visitor that
212 // works on macros, use this definition in your trait impl:
213 // mut_visit::noop_visit_mac(_mac, self);
216 fn visit_macro_def(&mut self, def: &mut MacroDef) {
217 noop_visit_macro_def(def, self);
220 fn visit_label(&mut self, label: &mut Label) {
221 noop_visit_label(label, self);
224 fn visit_attribute(&mut self, at: &mut Attribute) {
225 noop_visit_attribute(at, self);
228 fn visit_arg(&mut self, a: &mut Arg) {
229 noop_visit_arg(a, self);
232 fn visit_generics(&mut self, generics: &mut Generics) {
233 noop_visit_generics(generics, self);
236 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
237 noop_visit_trait_ref(tr, self);
240 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
241 noop_visit_poly_trait_ref(p, self);
244 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
245 noop_visit_variant_data(vdata, self);
248 fn visit_generic_param(&mut self, param: &mut GenericParam) {
249 noop_visit_generic_param(param, self);
252 fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
253 noop_visit_generic_params(params, self);
256 fn visit_tt(&mut self, tt: &mut TokenTree) {
257 noop_visit_tt(tt, self);
260 fn visit_tts(&mut self, tts: &mut TokenStream) {
261 noop_visit_tts(tts, self);
264 fn visit_token(&mut self, t: &mut Token) {
265 noop_visit_token(t, self);
268 fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
269 noop_visit_interpolated(nt, self);
272 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
273 noop_visit_param_bound(tpb, self);
276 fn visit_mt(&mut self, mt: &mut MutTy) {
277 noop_visit_mt(mt, self);
280 fn visit_field(&mut self, field: &mut Field) {
281 noop_visit_field(field, self);
284 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
285 noop_visit_where_clause(where_clause, self);
288 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
289 noop_visit_where_predicate(where_predicate, self);
292 fn visit_vis(&mut self, vis: &mut Visibility) {
293 noop_visit_vis(vis, self);
296 fn visit_id(&mut self, _id: &mut NodeId) {
300 fn visit_span(&mut self, _sp: &mut Span) {
305 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
306 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
307 /// method. Abort the program if the closure panics.
309 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
310 pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
312 // Safe because `t` is used in a read-only fashion by `read()` before
313 // being overwritten by `write()`.
314 let old_t = ptr::read(t);
315 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
316 .unwrap_or_else(|_| process::abort());
317 ptr::write(t, new_t);
321 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
323 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
329 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
331 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
332 if let Some(elem) = opt {
337 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
338 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
339 visit_vec(attrs, |attr| vis.visit_attribute(attr));
342 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
343 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
344 for attr in attrs.iter_mut() {
345 vis.visit_attribute(attr);
349 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
350 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
351 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
354 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
355 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
356 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
359 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
360 pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
361 vis.visit_fn_header(header);
362 vis.visit_fn_decl(decl);
365 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
366 let UseTree { prefix, kind, span } = use_tree;
367 vis.visit_path(prefix);
369 UseTreeKind::Simple(rename, id1, id2) => {
370 visit_opt(rename, |rename| vis.visit_ident(rename));
374 UseTreeKind::Nested(items) => {
375 for (tree, id) in items {
376 vis.visit_use_tree(tree);
380 UseTreeKind::Glob => {}
382 vis.visit_span(span);
385 pub fn noop_visit_arm<T: MutVisitor>(
386 Arm { attrs, pats, guard, body, span, id }: &mut Arm,
389 visit_attrs(attrs, vis);
391 visit_vec(pats, |pat| vis.visit_pat(pat));
392 visit_opt(guard, |guard| vis.visit_expr(guard));
393 vis.visit_expr(body);
394 vis.visit_span(span);
397 pub fn noop_visit_ty_constraint<T: MutVisitor>(
398 AssocTyConstraint { id, ident, kind, span }: &mut AssocTyConstraint,
402 vis.visit_ident(ident);
404 AssocTyConstraintKind::Equality { ref mut ty } => {
407 AssocTyConstraintKind::Bound { ref mut bounds } => {
408 visit_bounds(bounds, vis);
411 vis.visit_span(span);
414 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
415 let Ty { id, node, span } = ty.deref_mut();
418 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err |
419 TyKind::Never | TyKind::CVarArgs => {}
420 TyKind::Slice(ty) => vis.visit_ty(ty),
421 TyKind::Ptr(mt) => vis.visit_mt(mt),
422 TyKind::Rptr(lt, mt) => {
423 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
426 TyKind::BareFn(bft) => {
427 let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
428 vis.visit_generic_params(generic_params);
429 vis.visit_fn_decl(decl);
431 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
432 TyKind::Paren(ty) => vis.visit_ty(ty),
433 TyKind::Path(qself, path) => {
434 vis.visit_qself(qself);
435 vis.visit_path(path);
437 TyKind::Array(ty, length) => {
439 vis.visit_anon_const(length);
441 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
442 TyKind::TraitObject(bounds, _syntax) =>
443 visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
444 TyKind::ImplTrait(id, bounds) => {
446 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
448 TyKind::Mac(mac) => vis.visit_mac(mac),
450 vis.visit_span(span);
453 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
454 let ForeignMod { abi: _, items} = foreign_mod;
455 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
458 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
459 let Spanned { node: Variant_ { ident, attrs, id, data, disr_expr }, span } = variant;
460 vis.visit_ident(ident);
461 visit_attrs(attrs, vis);
463 vis.visit_variant_data(data);
464 visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
465 vis.visit_span(span);
468 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
469 vis.visit_span(span);
472 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
473 vis.visit_span(span);
474 for PathSegment { ident, id, args } in segments {
475 vis.visit_ident(ident);
477 visit_opt(args, |args| vis.visit_generic_args(args));
481 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
482 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
484 vis.visit_span(path_span);
488 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
490 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
491 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
495 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
497 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
498 GenericArg::Type(ty) => vis.visit_ty(ty),
499 GenericArg::Const(ct) => vis.visit_anon_const(ct),
503 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
505 let AngleBracketedArgs { args, constraints, span } = data;
506 visit_vec(args, |arg| vis.visit_generic_arg(arg));
507 visit_vec(constraints, |constraint| vis.visit_ty_constraint(constraint));
508 vis.visit_span(span);
511 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
513 let ParenthesizedArgs { inputs, output, span } = args;
514 visit_vec(inputs, |input| vis.visit_ty(input));
515 visit_opt(output, |output| vis.visit_ty(output));
516 vis.visit_span(span);
519 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
520 let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
523 visit_opt(ty, |ty| vis.visit_ty(ty));
524 visit_opt(init, |init| vis.visit_expr(init));
525 vis.visit_span(span);
526 visit_thin_attrs(attrs, vis);
529 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
530 let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
531 vis.visit_path(path);
532 vis.visit_tts(tokens);
533 vis.visit_span(span);
536 pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
537 let Mac_ { path, delim: _, tts, .. } = node;
538 vis.visit_path(path);
540 vis.visit_span(span);
543 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
544 let MacroDef { tokens, legacy: _ } = macro_def;
545 vis.visit_tts(tokens);
548 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
550 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
551 NestedMetaItem::Literal(_lit) => {}
555 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
556 let MetaItem { path: _, node, span } = mi;
558 MetaItemKind::Word => {}
559 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
560 MetaItemKind::NameValue(_s) => {}
562 vis.visit_span(span);
565 pub fn noop_visit_arg<T: MutVisitor>(Arg { attrs, id, pat, span, ty }: &mut Arg, vis: &mut T) {
567 visit_thin_attrs(attrs, vis);
569 vis.visit_span(span);
573 pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
575 TokenTree::Token(token) => {
576 vis.visit_token(token);
578 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
579 vis.visit_span(open);
580 vis.visit_span(close);
586 pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
587 visit_opt(tts, |tts| {
588 let tts = Lrc::make_mut(tts);
589 visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
593 // Apply ident visitor if it's an ident, apply other visits to interpolated nodes.
594 // In practice the ident part is not actually used by specific visitors right now,
595 // but there's a test below checking that it works.
596 pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
597 let Token { kind, span } = t;
599 token::Ident(name, _) | token::Lifetime(name) => {
600 let mut ident = Ident::new(*name, *span);
601 vis.visit_ident(&mut ident);
604 return; // avoid visiting the span for the second time
606 token::Interpolated(nt) => {
607 let mut nt = Lrc::make_mut(nt);
608 vis.visit_interpolated(&mut nt);
612 vis.visit_span(span);
615 /// Apply visitor to elements of interpolated nodes.
617 // N.B., this can occur only when applying a visitor to partially expanded
618 // code, where parsed pieces have gotten implanted ito *other* macro
619 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
621 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
622 // etc. allow the visitor to return *multiple* items; this is a problem for the
623 // nodes here, because they insist on having exactly one piece. One solution
624 // would be to mangle the MutVisitor trait to include one-to-many and
625 // one-to-one versions of these entry points, but that would probably confuse a
626 // lot of people and help very few. Instead, I'm just going to put in dynamic
627 // checks. I think the performance impact of this will be pretty much
628 // nonexistent. The danger is that someone will apply a MutVisitor to a
629 // partially expanded node, and will be confused by the fact that their
630 // "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
631 // nodes. Hopefully they'll wind up reading this comment, and doing something
634 // BTW, design choice: I considered just changing the type of, e.g., NtItem to
635 // contain multiple items, but decided against it when I looked at
636 // parse_item_or_view_item and tried to figure out what I would do with
637 // multiple items there....
638 pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
640 token::NtItem(item) =>
641 visit_clobber(item, |item| {
642 // This is probably okay, because the only visitors likely to
643 // peek inside interpolated nodes will be renamings/markings,
644 // which map single items to single items.
645 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
647 token::NtBlock(block) => vis.visit_block(block),
648 token::NtStmt(stmt) =>
649 visit_clobber(stmt, |stmt| {
650 // See reasoning above.
651 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
653 token::NtPat(pat) => vis.visit_pat(pat),
654 token::NtExpr(expr) => vis.visit_expr(expr),
655 token::NtTy(ty) => vis.visit_ty(ty),
656 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
657 token::NtLifetime(ident) => vis.visit_ident(ident),
658 token::NtLiteral(expr) => vis.visit_expr(expr),
659 token::NtMeta(meta) => vis.visit_meta_item(meta),
660 token::NtPath(path) => vis.visit_path(path),
661 token::NtTT(tt) => vis.visit_tt(tt),
662 token::NtImplItem(item) =>
663 visit_clobber(item, |item| {
664 // See reasoning above.
665 vis.flat_map_impl_item(item)
666 .expect_one("expected visitor to produce exactly one item")
668 token::NtTraitItem(item) =>
669 visit_clobber(item, |item| {
670 // See reasoning above.
671 vis.flat_map_trait_item(item)
672 .expect_one("expected visitor to produce exactly one item")
674 token::NtVis(visib) => vis.visit_vis(visib),
675 token::NtForeignItem(item) =>
676 visit_clobber(item, |item| {
677 // See reasoning above.
678 vis.flat_map_foreign_item(item)
679 .expect_one("expected visitor to produce exactly one item")
684 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
686 IsAsync::Async { closure_id, return_impl_trait_id } => {
687 vis.visit_id(closure_id);
688 vis.visit_id(return_impl_trait_id);
690 IsAsync::NotAsync => {}
694 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
695 let FnDecl { inputs, output, c_variadic: _ } = decl.deref_mut();
696 visit_vec(inputs, |input| vis.visit_arg(input));
698 FunctionRetTy::Default(span) => vis.visit_span(span),
699 FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
703 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
705 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
706 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
710 pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
711 let GenericParam { id, ident, attrs, bounds, kind } = param;
713 vis.visit_ident(ident);
714 visit_thin_attrs(attrs, vis);
715 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
717 GenericParamKind::Lifetime => {}
718 GenericParamKind::Type { default } => {
719 visit_opt(default, |default| vis.visit_ty(default));
721 GenericParamKind::Const { ty } => {
727 pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
728 visit_vec(params, |param| vis.visit_generic_param(param));
731 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
732 vis.visit_ident(ident);
735 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
737 vis.visit_ident(ident);
740 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
741 let Generics { params, where_clause, span } = generics;
742 vis.visit_generic_params(params);
743 vis.visit_where_clause(where_clause);
744 vis.visit_span(span);
747 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
748 let WhereClause { predicates, span } = wc;
749 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
750 vis.visit_span(span);
753 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
755 WherePredicate::BoundPredicate(bp) => {
756 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
757 vis.visit_span(span);
758 vis.visit_generic_params(bound_generic_params);
759 vis.visit_ty(bounded_ty);
760 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
762 WherePredicate::RegionPredicate(rp) => {
763 let WhereRegionPredicate { span, lifetime, bounds } = rp;
764 vis.visit_span(span);
765 noop_visit_lifetime(lifetime, vis);
766 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
768 WherePredicate::EqPredicate(ep) => {
769 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
771 vis.visit_span(span);
772 vis.visit_ty(lhs_ty);
773 vis.visit_ty(rhs_ty);
778 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
780 VariantData::Struct(fields, ..) => visit_vec(fields, |field| vis.visit_struct_field(field)),
781 VariantData::Tuple(fields, id) => {
782 visit_vec(fields, |field| vis.visit_struct_field(field));
785 VariantData::Unit(id) => vis.visit_id(id),
789 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
790 vis.visit_path(path);
791 vis.visit_id(ref_id);
794 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
795 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
796 vis.visit_generic_params(bound_generic_params);
797 vis.visit_trait_ref(trait_ref);
798 vis.visit_span(span);
801 pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
802 let StructField { span, ident, vis, id, ty, attrs } = f;
803 visitor.visit_span(span);
804 visit_opt(ident, |ident| visitor.visit_ident(ident));
805 visitor.visit_vis(vis);
806 visitor.visit_id(id);
807 visitor.visit_ty(ty);
808 visit_attrs(attrs, visitor);
811 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
812 let Field { ident, expr, span, is_shorthand: _, attrs, id } = f;
813 vis.visit_ident(ident);
814 vis.visit_expr(expr);
816 vis.visit_span(span);
817 visit_thin_attrs(attrs, vis);
820 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
824 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
825 let Block { id, stmts, rules: _, span } = block.deref_mut();
827 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
828 vis.visit_span(span);
831 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
833 ItemKind::ExternCrate(_orig_name) => {}
834 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
835 ItemKind::Static(ty, _mut, expr) => {
837 vis.visit_expr(expr);
839 ItemKind::Const(ty, expr) => {
841 vis.visit_expr(expr);
843 ItemKind::Fn(decl, header, generics, body) => {
844 vis.visit_fn_decl(decl);
845 vis.visit_fn_header(header);
846 vis.visit_generics(generics);
847 vis.visit_block(body);
849 ItemKind::Mod(m) => vis.visit_mod(m),
850 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
851 ItemKind::GlobalAsm(_ga) => {}
852 ItemKind::TyAlias(ty, generics) => {
854 vis.visit_generics(generics);
856 ItemKind::OpaqueTy(bounds, generics) => {
857 visit_bounds(bounds, vis);
858 vis.visit_generics(generics);
860 ItemKind::Enum(EnumDef { variants }, generics) => {
861 visit_vec(variants, |variant| vis.visit_variant(variant));
862 vis.visit_generics(generics);
864 ItemKind::Struct(variant_data, generics) |
865 ItemKind::Union(variant_data, generics) => {
866 vis.visit_variant_data(variant_data);
867 vis.visit_generics(generics);
869 ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
870 vis.visit_generics(generics);
871 visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
873 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
875 ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
876 vis.visit_generics(generics);
877 visit_bounds(bounds, vis);
878 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
880 ItemKind::TraitAlias(generics, bounds) => {
881 vis.visit_generics(generics);
882 visit_bounds(bounds, vis);
884 ItemKind::Mac(m) => vis.visit_mac(m),
885 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
889 pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
890 -> SmallVec<[TraitItem; 1]>
892 let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
894 vis.visit_ident(ident);
895 visit_attrs(attrs, vis);
896 vis.visit_generics(generics);
898 TraitItemKind::Const(ty, default) => {
900 visit_opt(default, |default| vis.visit_expr(default));
902 TraitItemKind::Method(sig, body) => {
903 visit_method_sig(sig, vis);
904 visit_opt(body, |body| vis.visit_block(body));
906 TraitItemKind::Type(bounds, default) => {
907 visit_bounds(bounds, vis);
908 visit_opt(default, |default| vis.visit_ty(default));
910 TraitItemKind::Macro(mac) => {
914 vis.visit_span(span);
919 pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
920 -> SmallVec<[ImplItem; 1]>
922 let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
924 visitor.visit_id(id);
925 visitor.visit_ident(ident);
926 visitor.visit_vis(vis);
927 visit_attrs(attrs, visitor);
928 visitor.visit_generics(generics);
930 ImplItemKind::Const(ty, expr) => {
931 visitor.visit_ty(ty);
932 visitor.visit_expr(expr);
934 ImplItemKind::Method(sig, body) => {
935 visit_method_sig(sig, visitor);
936 visitor.visit_block(body);
938 ImplItemKind::TyAlias(ty) => visitor.visit_ty(ty),
939 ImplItemKind::OpaqueTy(bounds) => visit_bounds(bounds, visitor),
940 ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
942 visitor.visit_span(span);
947 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
948 let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
949 vis.visit_asyncness(&mut asyncness.node);
952 pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
953 vis.visit_span(inner);
954 items.flat_map_in_place(|item| vis.flat_map_item(item));
957 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
958 visit_clobber(krate, |Crate { module, attrs, span }| {
960 ident: Ident::invalid(),
963 vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
965 node: ItemKind::Mod(module),
968 let items = vis.flat_map_item(item);
970 let len = items.len();
972 let module = Mod { inner: span, items: vec![], inline: true };
973 Crate { module, attrs: vec![], span }
975 let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
977 ItemKind::Mod(module) => Crate { module, attrs, span },
978 _ => panic!("visitor converted a module to not a module"),
981 panic!("a crate cannot expand to more than one item");
986 // Mutate one item into possibly many items.
987 pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
988 -> SmallVec<[P<Item>; 1]> {
989 let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
990 visitor.visit_ident(ident);
991 visit_attrs(attrs, visitor);
992 visitor.visit_id(id);
993 visitor.visit_item_kind(node);
994 visitor.visit_vis(vis);
995 visitor.visit_span(span);
997 // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
998 // an ICE during resolve... odd!
1003 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
1004 -> SmallVec<[ForeignItem; 1]>
1006 let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
1007 visitor.visit_ident(ident);
1008 visit_attrs(attrs, visitor);
1010 ForeignItemKind::Fn(fdec, generics) => {
1011 visitor.visit_fn_decl(fdec);
1012 visitor.visit_generics(generics);
1014 ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
1015 ForeignItemKind::Ty => {}
1016 ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
1018 visitor.visit_id(id);
1019 visitor.visit_span(span);
1020 visitor.visit_vis(vis);
1025 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1026 let Pat { id, node, span } = pat.deref_mut();
1029 PatKind::Wild | PatKind::Rest => {}
1030 PatKind::Ident(_binding_mode, ident, sub) => {
1031 vis.visit_ident(ident);
1032 visit_opt(sub, |sub| vis.visit_pat(sub));
1034 PatKind::Lit(e) => vis.visit_expr(e),
1035 PatKind::TupleStruct(path, elems) => {
1036 vis.visit_path(path);
1037 visit_vec(elems, |elem| vis.visit_pat(elem));
1039 PatKind::Path(qself, path) => {
1040 vis.visit_qself(qself);
1041 vis.visit_path(path);
1043 PatKind::Struct(path, fields, _etc) => {
1044 vis.visit_path(path);
1046 node: FieldPat { ident, pat, is_shorthand: _, attrs, id },
1049 vis.visit_ident(ident);
1052 visit_thin_attrs(attrs, vis);
1053 vis.visit_span(span);
1056 PatKind::Tuple(elems) => visit_vec(elems, |elem| vis.visit_pat(elem)),
1057 PatKind::Box(inner) => vis.visit_pat(inner),
1058 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1059 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1062 vis.visit_span(span);
1064 PatKind::Slice(elems) => visit_vec(elems, |elem| vis.visit_pat(elem)),
1065 PatKind::Paren(inner) => vis.visit_pat(inner),
1066 PatKind::Mac(mac) => vis.visit_mac(mac),
1068 vis.visit_span(span);
1071 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1073 vis.visit_expr(value);
1076 pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
1078 ExprKind::Box(expr) => vis.visit_expr(expr),
1079 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1080 ExprKind::Repeat(expr, count) => {
1081 vis.visit_expr(expr);
1082 vis.visit_anon_const(count);
1084 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1085 ExprKind::Call(f, args) => {
1087 visit_exprs(args, vis);
1089 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
1090 vis.visit_ident(ident);
1092 visit_opt(args, |args| vis.visit_generic_args(args));
1093 visit_exprs(exprs, vis);
1095 ExprKind::Binary(_binop, lhs, rhs) => {
1096 vis.visit_expr(lhs);
1097 vis.visit_expr(rhs);
1099 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1100 ExprKind::Cast(expr, ty) => {
1101 vis.visit_expr(expr);
1104 ExprKind::Type(expr, ty) => {
1105 vis.visit_expr(expr);
1108 ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
1109 ExprKind::Let(pats, scrutinee) => {
1110 visit_vec(pats, |pat| vis.visit_pat(pat));
1111 vis.visit_expr(scrutinee);
1113 ExprKind::If(cond, tr, fl) => {
1114 vis.visit_expr(cond);
1115 vis.visit_block(tr);
1116 visit_opt(fl, |fl| vis.visit_expr(fl));
1118 ExprKind::While(cond, body, label) => {
1119 vis.visit_expr(cond);
1120 vis.visit_block(body);
1121 visit_opt(label, |label| vis.visit_label(label));
1123 ExprKind::ForLoop(pat, iter, body, label) => {
1125 vis.visit_expr(iter);
1126 vis.visit_block(body);
1127 visit_opt(label, |label| vis.visit_label(label));
1129 ExprKind::Loop(body, label) => {
1130 vis.visit_block(body);
1131 visit_opt(label, |label| vis.visit_label(label));
1133 ExprKind::Match(expr, arms) => {
1134 vis.visit_expr(expr);
1135 visit_vec(arms, |arm| vis.visit_arm(arm));
1137 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1138 vis.visit_asyncness(asyncness);
1139 vis.visit_fn_decl(decl);
1140 vis.visit_expr(body);
1141 vis.visit_span(span);
1143 ExprKind::Block(blk, label) => {
1144 vis.visit_block(blk);
1145 visit_opt(label, |label| vis.visit_label(label));
1147 ExprKind::Async(_capture_by, node_id, body) => {
1148 vis.visit_id(node_id);
1149 vis.visit_block(body);
1151 ExprKind::Await(expr) => vis.visit_expr(expr),
1152 ExprKind::Assign(el, er) => {
1156 ExprKind::AssignOp(_op, el, er) => {
1160 ExprKind::Field(el, ident) => {
1162 vis.visit_ident(ident);
1164 ExprKind::Index(el, er) => {
1168 ExprKind::Range(e1, e2, _lim) => {
1169 visit_opt(e1, |e1| vis.visit_expr(e1));
1170 visit_opt(e2, |e2| vis.visit_expr(e2));
1172 ExprKind::Path(qself, path) => {
1173 vis.visit_qself(qself);
1174 vis.visit_path(path);
1176 ExprKind::Break(label, expr) => {
1177 visit_opt(label, |label| vis.visit_label(label));
1178 visit_opt(expr, |expr| vis.visit_expr(expr));
1180 ExprKind::Continue(label) => {
1181 visit_opt(label, |label| vis.visit_label(label));
1183 ExprKind::Ret(expr) => {
1184 visit_opt(expr, |expr| vis.visit_expr(expr));
1186 ExprKind::InlineAsm(asm) => {
1187 let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
1188 alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
1189 for out in outputs {
1190 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1191 vis.visit_expr(expr);
1193 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1195 ExprKind::Mac(mac) => vis.visit_mac(mac),
1196 ExprKind::Struct(path, fields, expr) => {
1197 vis.visit_path(path);
1198 visit_vec(fields, |field| vis.visit_field(field));
1199 visit_opt(expr, |expr| vis.visit_expr(expr));
1201 ExprKind::Paren(expr) => {
1202 vis.visit_expr(expr);
1204 // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
1206 vis.visit_span(span);
1207 visit_thin_attrs(attrs, vis);
1210 ExprKind::Yield(expr) => {
1211 visit_opt(expr, |expr| vis.visit_expr(expr));
1213 ExprKind::Try(expr) => vis.visit_expr(expr),
1214 ExprKind::TryBlock(body) => vis.visit_block(body),
1215 ExprKind::Lit(_) | ExprKind::Err => {}
1218 vis.visit_span(span);
1219 visit_thin_attrs(attrs, vis);
1222 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1223 Some({ vis.visit_expr(&mut e); e })
1226 pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
1227 -> SmallVec<[Stmt; 1]>
1229 vis.visit_id(&mut id);
1230 vis.visit_span(&mut span);
1231 noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
1232 Stmt { id, node, span }
1236 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
1237 -> SmallVec<[StmtKind; 1]> {
1239 StmtKind::Local(mut local) =>
1240 smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
1241 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1242 StmtKind::Expr(expr) => {
1243 vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
1245 StmtKind::Semi(expr) => {
1246 vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
1248 StmtKind::Mac(mut mac) => {
1249 let (mac_, _semi, attrs) = mac.deref_mut();
1250 vis.visit_mac(mac_);
1251 visit_thin_attrs(attrs, vis);
1252 smallvec![StmtKind::Mac(mac)]
1257 pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
1259 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1260 VisibilityKind::Restricted { path, id } => {
1261 vis.visit_path(path);
1265 vis.visit_span(span);