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};
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 // Methods in this trait have one of three forms:
39 // fn visit_t(&mut self, t: &mut T); // common
40 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
41 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
43 // Any additions to this trait should happen in form of a call to a public
44 // `noop_*` function that only calls out to the visitor again, not other
45 // `noop_*` functions. This is a necessary API workaround to the problem of
46 // not being able to call out to the super default method in an overridden
49 // When writing these methods, it is better to use destructuring like this:
51 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
56 // than to use field access like this:
58 // fn visit_abc(&mut self, abc: &mut ABC) {
59 // visit_a(&mut abc.a);
60 // visit_b(&mut abc.b);
64 // As well as being more concise, the former is explicit about which fields
65 // are skipped. Furthermore, if a new field is added, the destructuring
66 // version will cause a compile error, which is good. In comparison, the
67 // field access version will continue working and it would be easy to
68 // forget to add handling for it.
70 fn visit_crate(&mut self, c: &mut Crate) {
71 noop_visit_crate(c, self)
74 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
75 noop_visit_meta_list_item(list_item, self);
78 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
79 noop_visit_meta_item(meta_item, self);
82 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
83 noop_visit_use_tree(use_tree, self);
86 fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
87 noop_flat_map_foreign_item(ni, self)
90 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
91 noop_flat_map_item(i, self)
94 fn visit_fn_header(&mut self, header: &mut FnHeader) {
95 noop_visit_fn_header(header, self);
98 fn visit_struct_field(&mut self, sf: &mut StructField) {
99 noop_visit_struct_field(sf, self);
102 fn visit_item_kind(&mut self, i: &mut ItemKind) {
103 noop_visit_item_kind(i, self);
106 fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
107 noop_flat_map_trait_item(i, self)
110 fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
111 noop_flat_map_impl_item(i, self)
114 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
115 noop_visit_fn_decl(d, self);
118 fn visit_asyncness(&mut self, a: &mut IsAsync) {
119 noop_visit_asyncness(a, self);
122 fn visit_block(&mut self, b: &mut P<Block>) {
123 noop_visit_block(b, self);
126 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
127 noop_flat_map_stmt(s, self)
130 fn visit_arm(&mut self, a: &mut Arm) {
131 noop_visit_arm(a, self);
134 fn visit_pat(&mut self, p: &mut P<Pat>) {
135 noop_visit_pat(p, self);
138 fn visit_anon_const(&mut self, c: &mut AnonConst) {
139 noop_visit_anon_const(c, self);
142 fn visit_expr(&mut self, e: &mut P<Expr>) {
143 noop_visit_expr(e, self);
146 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
147 noop_filter_map_expr(e, self)
150 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
151 noop_visit_generic_arg(arg, self);
154 fn visit_ty(&mut self, t: &mut P<Ty>) {
155 noop_visit_ty(t, self);
158 fn visit_lifetime(&mut self, l: &mut Lifetime) {
159 noop_visit_lifetime(l, self);
162 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
163 noop_visit_ty_constraint(t, self);
166 fn visit_mod(&mut self, m: &mut Mod) {
167 noop_visit_mod(m, self);
170 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
171 noop_visit_foreign_mod(nm, self);
174 fn visit_variant(&mut self, v: &mut Variant) {
175 noop_visit_variant(v, self);
178 fn visit_ident(&mut self, i: &mut Ident) {
179 noop_visit_ident(i, self);
182 fn visit_path(&mut self, p: &mut Path) {
183 noop_visit_path(p, self);
186 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
187 noop_visit_qself(qs, self);
190 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
191 noop_visit_generic_args(p, self);
194 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
195 noop_visit_angle_bracketed_parameter_data(p, self);
198 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
199 noop_visit_parenthesized_parameter_data(p, self);
202 fn visit_local(&mut self, l: &mut P<Local>) {
203 noop_visit_local(l, self);
206 fn visit_mac(&mut self, _mac: &mut Mac) {
207 panic!("visit_mac disabled by default");
208 // N.B., see note about macros above. If you really want a visitor that
209 // works on macros, use this definition in your trait impl:
210 // mut_visit::noop_visit_mac(_mac, self);
213 fn visit_macro_def(&mut self, def: &mut MacroDef) {
214 noop_visit_macro_def(def, self);
217 fn visit_label(&mut self, label: &mut Label) {
218 noop_visit_label(label, self);
221 fn visit_attribute(&mut self, at: &mut Attribute) {
222 noop_visit_attribute(at, self);
225 fn visit_arg(&mut self, a: &mut Arg) {
226 noop_visit_arg(a, self);
229 fn visit_generics(&mut self, generics: &mut Generics) {
230 noop_visit_generics(generics, self);
233 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
234 noop_visit_trait_ref(tr, self);
237 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
238 noop_visit_poly_trait_ref(p, self);
241 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
242 noop_visit_variant_data(vdata, self);
245 fn visit_generic_param(&mut self, param: &mut GenericParam) {
246 noop_visit_generic_param(param, self);
249 fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
250 noop_visit_generic_params(params, self);
253 fn visit_tt(&mut self, tt: &mut TokenTree) {
254 noop_visit_tt(tt, self);
257 fn visit_tts(&mut self, tts: &mut TokenStream) {
258 noop_visit_tts(tts, self);
261 fn visit_token(&mut self, t: &mut Token) {
262 noop_visit_token(t, self);
265 fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
266 noop_visit_interpolated(nt, self);
269 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
270 noop_visit_param_bound(tpb, self);
273 fn visit_mt(&mut self, mt: &mut MutTy) {
274 noop_visit_mt(mt, self);
277 fn visit_field(&mut self, field: &mut Field) {
278 noop_visit_field(field, self);
281 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
282 noop_visit_where_clause(where_clause, self);
285 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
286 noop_visit_where_predicate(where_predicate, self);
289 fn visit_vis(&mut self, vis: &mut Visibility) {
290 noop_visit_vis(vis, self);
293 fn visit_id(&mut self, _id: &mut NodeId) {
297 fn visit_span(&mut self, _sp: &mut Span) {
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_`
304 /// method. Abort the program if the closure panics.
306 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
307 pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: 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);
312 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
313 .unwrap_or_else(|_| process::abort());
314 ptr::write(t, new_t);
318 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
320 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
326 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
328 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
329 if let Some(elem) = opt {
334 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
335 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
336 visit_vec(attrs, |attr| vis.visit_attribute(attr));
339 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
340 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
341 for attr in attrs.iter_mut() {
342 vis.visit_attribute(attr);
346 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
347 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
348 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
351 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
352 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
353 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
356 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
357 pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
358 vis.visit_fn_header(header);
359 vis.visit_fn_decl(decl);
362 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
363 let UseTree { prefix, kind, span } = use_tree;
364 vis.visit_path(prefix);
366 UseTreeKind::Simple(rename, id1, id2) => {
367 visit_opt(rename, |rename| vis.visit_ident(rename));
371 UseTreeKind::Nested(items) => {
372 for (tree, id) in items {
373 vis.visit_use_tree(tree);
377 UseTreeKind::Glob => {}
379 vis.visit_span(span);
382 pub fn noop_visit_arm<T: MutVisitor>(
383 Arm { attrs, pats, guard, body, span }: &mut Arm,
386 visit_attrs(attrs, vis);
387 visit_vec(pats, |pat| vis.visit_pat(pat));
388 visit_opt(guard, |guard| vis.visit_expr(guard));
389 vis.visit_expr(body);
390 vis.visit_span(span);
393 pub fn noop_visit_ty_constraint<T: MutVisitor>(
394 AssocTyConstraint { id, ident, kind, span }: &mut AssocTyConstraint,
398 vis.visit_ident(ident);
400 AssocTyConstraintKind::Equality { ref mut ty } => {
403 AssocTyConstraintKind::Bound { ref mut bounds } => {
404 visit_bounds(bounds, vis);
407 vis.visit_span(span);
410 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
411 let Ty { id, node, span } = ty.deref_mut();
414 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err |
415 TyKind::Never | TyKind::CVarArgs => {}
416 TyKind::Slice(ty) => vis.visit_ty(ty),
417 TyKind::Ptr(mt) => vis.visit_mt(mt),
418 TyKind::Rptr(lt, mt) => {
419 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
422 TyKind::BareFn(bft) => {
423 let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
424 vis.visit_generic_params(generic_params);
425 vis.visit_fn_decl(decl);
427 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
428 TyKind::Paren(ty) => vis.visit_ty(ty),
429 TyKind::Path(qself, path) => {
430 vis.visit_qself(qself);
431 vis.visit_path(path);
433 TyKind::Array(ty, length) => {
435 vis.visit_anon_const(length);
437 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
438 TyKind::TraitObject(bounds, _syntax) =>
439 visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
440 TyKind::ImplTrait(id, bounds) => {
442 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
444 TyKind::Mac(mac) => vis.visit_mac(mac),
446 vis.visit_span(span);
449 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
450 let ForeignMod { abi: _, items} = foreign_mod;
451 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
454 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
455 let Spanned { node: Variant_ { ident, attrs, id, data, disr_expr }, span } = variant;
456 vis.visit_ident(ident);
457 visit_attrs(attrs, vis);
459 vis.visit_variant_data(data);
460 visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
461 vis.visit_span(span);
464 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
465 vis.visit_span(span);
468 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
469 vis.visit_span(span);
470 for PathSegment { ident, id, args } in segments {
471 vis.visit_ident(ident);
473 visit_opt(args, |args| vis.visit_generic_args(args));
477 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
478 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
480 vis.visit_span(path_span);
484 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
486 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
487 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
491 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
493 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
494 GenericArg::Type(ty) => vis.visit_ty(ty),
495 GenericArg::Const(ct) => vis.visit_anon_const(ct),
499 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
501 let AngleBracketedArgs { args, constraints, span } = data;
502 visit_vec(args, |arg| vis.visit_generic_arg(arg));
503 visit_vec(constraints, |constraint| vis.visit_ty_constraint(constraint));
504 vis.visit_span(span);
507 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
509 let ParenthesizedArgs { inputs, output, span } = args;
510 visit_vec(inputs, |input| vis.visit_ty(input));
511 visit_opt(output, |output| vis.visit_ty(output));
512 vis.visit_span(span);
515 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
516 let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
519 visit_opt(ty, |ty| vis.visit_ty(ty));
520 visit_opt(init, |init| vis.visit_expr(init));
521 vis.visit_span(span);
522 visit_thin_attrs(attrs, vis);
525 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
526 let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
527 vis.visit_path(path);
528 vis.visit_tts(tokens);
529 vis.visit_span(span);
532 pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
533 let Mac_ { path, delim: _, tts } = node;
534 vis.visit_path(path);
536 vis.visit_span(span);
539 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
540 let MacroDef { tokens, legacy: _ } = macro_def;
541 vis.visit_tts(tokens);
544 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
546 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
547 NestedMetaItem::Literal(_lit) => {}
551 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
552 let MetaItem { path: _, node, span } = mi;
554 MetaItemKind::Word => {}
555 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
556 MetaItemKind::NameValue(_s) => {}
558 vis.visit_span(span);
561 pub fn noop_visit_arg<T: MutVisitor>(Arg { attrs, id, pat, span, ty }: &mut Arg, vis: &mut T) {
563 visit_thin_attrs(attrs, vis);
565 vis.visit_span(span);
569 pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
571 TokenTree::Token(token) => {
572 vis.visit_token(token);
574 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
575 vis.visit_span(open);
576 vis.visit_span(close);
582 pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
583 visit_opt(tts, |tts| {
584 let tts = Lrc::make_mut(tts);
585 visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
589 // Apply ident visitor if it's an ident, apply other visits to interpolated nodes.
590 // In practice the ident part is not actually used by specific visitors right now,
591 // but there's a test below checking that it works.
592 pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
593 let Token { kind, span } = t;
595 token::Ident(name, _) | token::Lifetime(name) => {
596 let mut ident = Ident::new(*name, *span);
597 vis.visit_ident(&mut ident);
600 return; // avoid visiting the span for the second time
602 token::Interpolated(nt) => {
603 let mut nt = Lrc::make_mut(nt);
604 vis.visit_interpolated(&mut nt);
608 vis.visit_span(span);
611 /// Apply visitor to elements of interpolated nodes.
613 // N.B., this can occur only when applying a visitor to partially expanded
614 // code, where parsed pieces have gotten implanted ito *other* macro
615 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
617 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
618 // etc. allow the visitor to return *multiple* items; this is a problem for the
619 // nodes here, because they insist on having exactly one piece. One solution
620 // would be to mangle the MutVisitor trait to include one-to-many and
621 // one-to-one versions of these entry points, but that would probably confuse a
622 // lot of people and help very few. Instead, I'm just going to put in dynamic
623 // checks. I think the performance impact of this will be pretty much
624 // nonexistent. The danger is that someone will apply a MutVisitor to a
625 // partially expanded node, and will be confused by the fact that their
626 // "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
627 // nodes. Hopefully they'll wind up reading this comment, and doing something
630 // BTW, design choice: I considered just changing the type of, e.g., NtItem to
631 // contain multiple items, but decided against it when I looked at
632 // parse_item_or_view_item and tried to figure out what I would do with
633 // multiple items there....
634 pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
636 token::NtItem(item) =>
637 visit_clobber(item, |item| {
638 // This is probably okay, because the only visitors likely to
639 // peek inside interpolated nodes will be renamings/markings,
640 // which map single items to single items.
641 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
643 token::NtBlock(block) => vis.visit_block(block),
644 token::NtStmt(stmt) =>
645 visit_clobber(stmt, |stmt| {
646 // See reasoning above.
647 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
649 token::NtPat(pat) => vis.visit_pat(pat),
650 token::NtExpr(expr) => vis.visit_expr(expr),
651 token::NtTy(ty) => vis.visit_ty(ty),
652 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
653 token::NtLifetime(ident) => vis.visit_ident(ident),
654 token::NtLiteral(expr) => vis.visit_expr(expr),
655 token::NtMeta(meta) => vis.visit_meta_item(meta),
656 token::NtPath(path) => vis.visit_path(path),
657 token::NtTT(tt) => vis.visit_tt(tt),
658 token::NtImplItem(item) =>
659 visit_clobber(item, |item| {
660 // See reasoning above.
661 vis.flat_map_impl_item(item)
662 .expect_one("expected visitor to produce exactly one item")
664 token::NtTraitItem(item) =>
665 visit_clobber(item, |item| {
666 // See reasoning above.
667 vis.flat_map_trait_item(item)
668 .expect_one("expected visitor to produce exactly one item")
670 token::NtVis(visib) => vis.visit_vis(visib),
671 token::NtForeignItem(item) =>
672 visit_clobber(item, |item| {
673 // See reasoning above.
674 vis.flat_map_foreign_item(item)
675 .expect_one("expected visitor to produce exactly one item")
680 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
682 IsAsync::Async { closure_id, return_impl_trait_id } => {
683 vis.visit_id(closure_id);
684 vis.visit_id(return_impl_trait_id);
686 IsAsync::NotAsync => {}
690 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
691 let FnDecl { inputs, output, c_variadic: _ } = decl.deref_mut();
692 visit_vec(inputs, |input| vis.visit_arg(input));
694 FunctionRetTy::Default(span) => vis.visit_span(span),
695 FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
699 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
701 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
702 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
706 pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
707 let GenericParam { id, ident, attrs, bounds, kind } = param;
709 vis.visit_ident(ident);
710 visit_thin_attrs(attrs, vis);
711 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
713 GenericParamKind::Lifetime => {}
714 GenericParamKind::Type { default } => {
715 visit_opt(default, |default| vis.visit_ty(default));
717 GenericParamKind::Const { ty } => {
723 pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
724 visit_vec(params, |param| vis.visit_generic_param(param));
727 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
728 vis.visit_ident(ident);
731 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
733 vis.visit_ident(ident);
736 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
737 let Generics { params, where_clause, span } = generics;
738 vis.visit_generic_params(params);
739 vis.visit_where_clause(where_clause);
740 vis.visit_span(span);
743 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
744 let WhereClause { predicates, span } = wc;
745 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
746 vis.visit_span(span);
749 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
751 WherePredicate::BoundPredicate(bp) => {
752 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
753 vis.visit_span(span);
754 vis.visit_generic_params(bound_generic_params);
755 vis.visit_ty(bounded_ty);
756 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
758 WherePredicate::RegionPredicate(rp) => {
759 let WhereRegionPredicate { span, lifetime, bounds } = rp;
760 vis.visit_span(span);
761 noop_visit_lifetime(lifetime, vis);
762 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
764 WherePredicate::EqPredicate(ep) => {
765 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
767 vis.visit_span(span);
768 vis.visit_ty(lhs_ty);
769 vis.visit_ty(rhs_ty);
774 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
776 VariantData::Struct(fields, ..) => visit_vec(fields, |field| vis.visit_struct_field(field)),
777 VariantData::Tuple(fields, id) => {
778 visit_vec(fields, |field| vis.visit_struct_field(field));
781 VariantData::Unit(id) => vis.visit_id(id),
785 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
786 vis.visit_path(path);
787 vis.visit_id(ref_id);
790 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
791 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
792 vis.visit_generic_params(bound_generic_params);
793 vis.visit_trait_ref(trait_ref);
794 vis.visit_span(span);
797 pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
798 let StructField { span, ident, vis, id, ty, attrs } = f;
799 visitor.visit_span(span);
800 visit_opt(ident, |ident| visitor.visit_ident(ident));
801 visitor.visit_vis(vis);
802 visitor.visit_id(id);
803 visitor.visit_ty(ty);
804 visit_attrs(attrs, visitor);
807 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
808 let Field { ident, expr, span, is_shorthand: _, attrs } = f;
809 vis.visit_ident(ident);
810 vis.visit_expr(expr);
811 vis.visit_span(span);
812 visit_thin_attrs(attrs, vis);
815 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
819 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
820 let Block { id, stmts, rules: _, span } = block.deref_mut();
822 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
823 vis.visit_span(span);
826 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
828 ItemKind::ExternCrate(_orig_name) => {}
829 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
830 ItemKind::Static(ty, _mut, expr) => {
832 vis.visit_expr(expr);
834 ItemKind::Const(ty, expr) => {
836 vis.visit_expr(expr);
838 ItemKind::Fn(decl, header, generics, body) => {
839 vis.visit_fn_decl(decl);
840 vis.visit_fn_header(header);
841 vis.visit_generics(generics);
842 vis.visit_block(body);
844 ItemKind::Mod(m) => vis.visit_mod(m),
845 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
846 ItemKind::GlobalAsm(_ga) => {}
847 ItemKind::Ty(ty, generics) => {
849 vis.visit_generics(generics);
851 ItemKind::Existential(bounds, generics) => {
852 visit_bounds(bounds, vis);
853 vis.visit_generics(generics);
855 ItemKind::Enum(EnumDef { variants }, generics) => {
856 visit_vec(variants, |variant| vis.visit_variant(variant));
857 vis.visit_generics(generics);
859 ItemKind::Struct(variant_data, generics) |
860 ItemKind::Union(variant_data, generics) => {
861 vis.visit_variant_data(variant_data);
862 vis.visit_generics(generics);
864 ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
865 vis.visit_generics(generics);
866 visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
868 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
870 ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
871 vis.visit_generics(generics);
872 visit_bounds(bounds, vis);
873 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
875 ItemKind::TraitAlias(generics, bounds) => {
876 vis.visit_generics(generics);
877 visit_bounds(bounds, vis);
879 ItemKind::Mac(m) => vis.visit_mac(m),
880 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
884 pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
885 -> SmallVec<[TraitItem; 1]>
887 let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
889 vis.visit_ident(ident);
890 visit_attrs(attrs, vis);
891 vis.visit_generics(generics);
893 TraitItemKind::Const(ty, default) => {
895 visit_opt(default, |default| vis.visit_expr(default));
897 TraitItemKind::Method(sig, body) => {
898 visit_method_sig(sig, vis);
899 visit_opt(body, |body| vis.visit_block(body));
901 TraitItemKind::Type(bounds, default) => {
902 visit_bounds(bounds, vis);
903 visit_opt(default, |default| vis.visit_ty(default));
905 TraitItemKind::Macro(mac) => {
909 vis.visit_span(span);
914 pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
915 -> SmallVec<[ImplItem; 1]>
917 let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
919 visitor.visit_id(id);
920 visitor.visit_ident(ident);
921 visitor.visit_vis(vis);
922 visit_attrs(attrs, visitor);
923 visitor.visit_generics(generics);
925 ImplItemKind::Const(ty, expr) => {
926 visitor.visit_ty(ty);
927 visitor.visit_expr(expr);
929 ImplItemKind::Method(sig, body) => {
930 visit_method_sig(sig, visitor);
931 visitor.visit_block(body);
933 ImplItemKind::Type(ty) => visitor.visit_ty(ty),
934 ImplItemKind::Existential(bounds) => visit_bounds(bounds, visitor),
935 ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
937 visitor.visit_span(span);
942 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
943 let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
944 vis.visit_asyncness(&mut asyncness.node);
947 pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
948 vis.visit_span(inner);
949 items.flat_map_in_place(|item| vis.flat_map_item(item));
952 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
953 visit_clobber(krate, |Crate { module, attrs, span }| {
955 ident: Ident::invalid(),
958 vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
960 node: ItemKind::Mod(module),
963 let items = vis.flat_map_item(item);
965 let len = items.len();
967 let module = Mod { inner: span, items: vec![], inline: true };
968 Crate { module, attrs: vec![], span }
970 let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
972 ItemKind::Mod(module) => Crate { module, attrs, span },
973 _ => panic!("visitor converted a module to not a module"),
976 panic!("a crate cannot expand to more than one item");
981 // Mutate one item into possibly many items.
982 pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
983 -> SmallVec<[P<Item>; 1]> {
984 let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
985 visitor.visit_ident(ident);
986 visit_attrs(attrs, visitor);
987 visitor.visit_id(id);
988 visitor.visit_item_kind(node);
989 visitor.visit_vis(vis);
990 visitor.visit_span(span);
992 // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
993 // an ICE during resolve... odd!
998 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
999 -> SmallVec<[ForeignItem; 1]>
1001 let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
1002 visitor.visit_ident(ident);
1003 visit_attrs(attrs, visitor);
1005 ForeignItemKind::Fn(fdec, generics) => {
1006 visitor.visit_fn_decl(fdec);
1007 visitor.visit_generics(generics);
1009 ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
1010 ForeignItemKind::Ty => {}
1011 ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
1013 visitor.visit_id(id);
1014 visitor.visit_span(span);
1015 visitor.visit_vis(vis);
1020 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1021 let Pat { id, node, span } = pat.deref_mut();
1024 PatKind::Wild | PatKind::Rest => {}
1025 PatKind::Ident(_binding_mode, ident, sub) => {
1026 vis.visit_ident(ident);
1027 visit_opt(sub, |sub| vis.visit_pat(sub));
1029 PatKind::Lit(e) => vis.visit_expr(e),
1030 PatKind::TupleStruct(path, elems) => {
1031 vis.visit_path(path);
1032 visit_vec(elems, |elem| vis.visit_pat(elem));
1034 PatKind::Path(qself, path) => {
1035 vis.visit_qself(qself);
1036 vis.visit_path(path);
1038 PatKind::Struct(path, fields, _etc) => {
1039 vis.visit_path(path);
1040 for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
1041 vis.visit_ident(ident);
1043 visit_thin_attrs(attrs, vis);
1044 vis.visit_span(span);
1047 PatKind::Tuple(elems) => visit_vec(elems, |elem| vis.visit_pat(elem)),
1048 PatKind::Box(inner) => vis.visit_pat(inner),
1049 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1050 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1053 vis.visit_span(span);
1055 PatKind::Slice(elems) => visit_vec(elems, |elem| vis.visit_pat(elem)),
1056 PatKind::Paren(inner) => vis.visit_pat(inner),
1057 PatKind::Mac(mac) => vis.visit_mac(mac),
1059 vis.visit_span(span);
1062 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1064 vis.visit_expr(value);
1067 pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
1069 ExprKind::Box(expr) => vis.visit_expr(expr),
1070 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1071 ExprKind::Repeat(expr, count) => {
1072 vis.visit_expr(expr);
1073 vis.visit_anon_const(count);
1075 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1076 ExprKind::Call(f, args) => {
1078 visit_exprs(args, vis);
1080 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
1081 vis.visit_ident(ident);
1083 visit_opt(args, |args| vis.visit_generic_args(args));
1084 visit_exprs(exprs, vis);
1086 ExprKind::Binary(_binop, lhs, rhs) => {
1087 vis.visit_expr(lhs);
1088 vis.visit_expr(rhs);
1090 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1091 ExprKind::Cast(expr, ty) => {
1092 vis.visit_expr(expr);
1095 ExprKind::Type(expr, ty) => {
1096 vis.visit_expr(expr);
1099 ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
1100 ExprKind::Let(pats, scrutinee) => {
1101 visit_vec(pats, |pat| vis.visit_pat(pat));
1102 vis.visit_expr(scrutinee);
1104 ExprKind::If(cond, tr, fl) => {
1105 vis.visit_expr(cond);
1106 vis.visit_block(tr);
1107 visit_opt(fl, |fl| vis.visit_expr(fl));
1109 ExprKind::While(cond, body, label) => {
1110 vis.visit_expr(cond);
1111 vis.visit_block(body);
1112 visit_opt(label, |label| vis.visit_label(label));
1114 ExprKind::ForLoop(pat, iter, body, label) => {
1116 vis.visit_expr(iter);
1117 vis.visit_block(body);
1118 visit_opt(label, |label| vis.visit_label(label));
1120 ExprKind::Loop(body, label) => {
1121 vis.visit_block(body);
1122 visit_opt(label, |label| vis.visit_label(label));
1124 ExprKind::Match(expr, arms) => {
1125 vis.visit_expr(expr);
1126 visit_vec(arms, |arm| vis.visit_arm(arm));
1128 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1129 vis.visit_asyncness(asyncness);
1130 vis.visit_fn_decl(decl);
1131 vis.visit_expr(body);
1132 vis.visit_span(span);
1134 ExprKind::Block(blk, label) => {
1135 vis.visit_block(blk);
1136 visit_opt(label, |label| vis.visit_label(label));
1138 ExprKind::Async(_capture_by, node_id, body) => {
1139 vis.visit_id(node_id);
1140 vis.visit_block(body);
1142 ExprKind::Await(_origin, expr) => vis.visit_expr(expr),
1143 ExprKind::Assign(el, er) => {
1147 ExprKind::AssignOp(_op, el, er) => {
1151 ExprKind::Field(el, ident) => {
1153 vis.visit_ident(ident);
1155 ExprKind::Index(el, er) => {
1159 ExprKind::Range(e1, e2, _lim) => {
1160 visit_opt(e1, |e1| vis.visit_expr(e1));
1161 visit_opt(e2, |e2| vis.visit_expr(e2));
1163 ExprKind::Path(qself, path) => {
1164 vis.visit_qself(qself);
1165 vis.visit_path(path);
1167 ExprKind::Break(label, expr) => {
1168 visit_opt(label, |label| vis.visit_label(label));
1169 visit_opt(expr, |expr| vis.visit_expr(expr));
1171 ExprKind::Continue(label) => {
1172 visit_opt(label, |label| vis.visit_label(label));
1174 ExprKind::Ret(expr) => {
1175 visit_opt(expr, |expr| vis.visit_expr(expr));
1177 ExprKind::InlineAsm(asm) => {
1178 let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
1179 alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
1180 for out in outputs {
1181 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1182 vis.visit_expr(expr);
1184 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1186 ExprKind::Mac(mac) => vis.visit_mac(mac),
1187 ExprKind::Struct(path, fields, expr) => {
1188 vis.visit_path(path);
1189 visit_vec(fields, |field| vis.visit_field(field));
1190 visit_opt(expr, |expr| vis.visit_expr(expr));
1192 ExprKind::Paren(expr) => {
1193 vis.visit_expr(expr);
1195 // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
1197 vis.visit_span(span);
1198 visit_thin_attrs(attrs, vis);
1201 ExprKind::Yield(expr) => {
1202 visit_opt(expr, |expr| vis.visit_expr(expr));
1204 ExprKind::Try(expr) => vis.visit_expr(expr),
1205 ExprKind::TryBlock(body) => vis.visit_block(body),
1206 ExprKind::Lit(_) | ExprKind::Err => {}
1209 vis.visit_span(span);
1210 visit_thin_attrs(attrs, vis);
1213 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1214 Some({ vis.visit_expr(&mut e); e })
1217 pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
1218 -> SmallVec<[Stmt; 1]>
1220 vis.visit_id(&mut id);
1221 vis.visit_span(&mut span);
1222 noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
1223 Stmt { id, node, span }
1227 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
1228 -> SmallVec<[StmtKind; 1]> {
1230 StmtKind::Local(mut local) =>
1231 smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
1232 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1233 StmtKind::Expr(expr) => {
1234 vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
1236 StmtKind::Semi(expr) => {
1237 vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
1239 StmtKind::Mac(mut mac) => {
1240 let (mac_, _semi, attrs) = mac.deref_mut();
1241 vis.visit_mac(mac_);
1242 visit_thin_attrs(attrs, vis);
1243 smallvec![StmtKind::Mac(mac)]
1248 pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
1250 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1251 VisibilityKind::Restricted { path, id } => {
1252 vis.visit_path(path);
1256 vis.visit_span(span);
1261 use crate::ast::{self, Ident};
1262 use crate::util::parser_testing::{string_to_crate, matches_codepattern};
1263 use crate::print::pprust;
1264 use crate::mut_visit;
1265 use crate::with_default_globals;
1268 // this version doesn't care about getting comments or docstrings in.
1269 fn fake_print_crate(s: &mut pprust::State<'_>,
1270 krate: &ast::Crate) {
1271 s.print_mod(&krate.module, &krate.attrs)
1274 // change every identifier to "zz"
1275 struct ToZzIdentMutVisitor;
1277 impl MutVisitor for ToZzIdentMutVisitor {
1278 fn visit_ident(&mut self, ident: &mut ast::Ident) {
1279 *ident = Ident::from_str("zz");
1281 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1282 mut_visit::noop_visit_mac(mac, self)
1286 // maybe add to expand.rs...
1287 macro_rules! assert_pred {
1288 ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
1290 let pred_val = $pred;
1293 if !(pred_val(&a_val, &b_val)) {
1294 panic!("expected args satisfying {}, got {} and {}",
1295 $predname, a_val, b_val);
1301 // make sure idents get transformed everywhere
1302 #[test] fn ident_transformation () {
1303 with_default_globals(|| {
1304 let mut zz_visitor = ToZzIdentMutVisitor;
1305 let mut krate = string_to_crate(
1306 "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
1307 zz_visitor.visit_crate(&mut krate);
1309 matches_codepattern,
1310 "matches_codepattern",
1311 pprust::to_string(|s| fake_print_crate(s, &krate)),
1312 "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
1316 // even inside macro defs....
1317 #[test] fn ident_transformation_in_defs () {
1318 with_default_globals(|| {
1319 let mut zz_visitor = ToZzIdentMutVisitor;
1320 let mut krate = string_to_crate(
1321 "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
1322 (g $(d $d $e)+))} ".to_string());
1323 zz_visitor.visit_crate(&mut krate);
1325 matches_codepattern,
1326 "matches_codepattern",
1327 pprust::to_string(|s| fake_print_crate(s, &krate)),
1328 "macro_rules! zz{(zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+))}".to_string());