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};
14 use crate::symbol::keywords;
16 use crate::tokenstream::*;
17 use crate::util::map_in_place::MapInPlace;
19 use smallvec::{smallvec, Array, SmallVec};
22 use rustc_data_structures::sync::Lrc;
23 use std::ops::DerefMut;
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_guard(&mut self, g: &mut Guard) {
135 noop_visit_guard(g, self);
138 fn visit_pat(&mut self, p: &mut P<Pat>) {
139 noop_visit_pat(p, self);
142 fn visit_anon_const(&mut self, c: &mut AnonConst) {
143 noop_visit_anon_const(c, self);
146 fn visit_expr(&mut self, e: &mut P<Expr>) {
147 noop_visit_expr(e, self);
150 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
151 noop_filter_map_expr(e, self)
154 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
155 noop_visit_generic_arg(arg, self);
158 fn visit_ty(&mut self, t: &mut P<Ty>) {
159 noop_visit_ty(t, self);
162 fn visit_lifetime(&mut self, l: &mut Lifetime) {
163 noop_visit_lifetime(l, self);
166 fn visit_ty_binding(&mut self, t: &mut TypeBinding) {
167 noop_visit_ty_binding(t, self);
170 fn visit_mod(&mut self, m: &mut Mod) {
171 noop_visit_mod(m, self);
174 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
175 noop_visit_foreign_mod(nm, self);
178 fn visit_variant(&mut self, v: &mut Variant) {
179 noop_visit_variant(v, self);
182 fn visit_ident(&mut self, i: &mut Ident) {
183 noop_visit_ident(i, self);
186 fn visit_path(&mut self, p: &mut Path) {
187 noop_visit_path(p, self);
190 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
191 noop_visit_qself(qs, self);
194 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
195 noop_visit_generic_args(p, self);
198 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
199 noop_visit_angle_bracketed_parameter_data(p, self);
202 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
203 noop_visit_parenthesized_parameter_data(p, self);
206 fn visit_local(&mut self, l: &mut P<Local>) {
207 noop_visit_local(l, self);
210 fn visit_mac(&mut self, _mac: &mut Mac) {
211 panic!("visit_mac disabled by default");
212 // N.B., see note about macros above. If you really want a visitor that
213 // works on macros, use this definition in your trait impl:
214 // mut_visit::noop_visit_mac(_mac, self);
217 fn visit_macro_def(&mut self, def: &mut MacroDef) {
218 noop_visit_macro_def(def, self);
221 fn visit_label(&mut self, label: &mut Label) {
222 noop_visit_label(label, self);
225 fn visit_attribute(&mut self, at: &mut Attribute) {
226 noop_visit_attribute(at, self);
229 fn visit_arg(&mut self, a: &mut Arg) {
230 noop_visit_arg(a, self);
233 fn visit_generics(&mut self, generics: &mut Generics) {
234 noop_visit_generics(generics, self);
237 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
238 noop_visit_trait_ref(tr, self);
241 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
242 noop_visit_poly_trait_ref(p, self);
245 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
246 noop_visit_variant_data(vdata, self);
249 fn visit_generic_param(&mut self, param: &mut GenericParam) {
250 noop_visit_generic_param(param, self);
253 fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
254 noop_visit_generic_params(params, self);
257 fn visit_tt(&mut self, tt: &mut TokenTree) {
258 noop_visit_tt(tt, self);
261 fn visit_tts(&mut self, tts: &mut TokenStream) {
262 noop_visit_tts(tts, self);
265 fn visit_token(&mut self, t: &mut Token) {
266 noop_visit_token(t, self);
269 fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
270 noop_visit_interpolated(nt, self);
273 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
274 noop_visit_param_bound(tpb, self);
277 fn visit_mt(&mut self, mt: &mut MutTy) {
278 noop_visit_mt(mt, self);
281 fn visit_field(&mut self, field: &mut Field) {
282 noop_visit_field(field, self);
285 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
286 noop_visit_where_clause(where_clause, self);
289 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
290 noop_visit_where_predicate(where_predicate, self);
293 fn visit_vis(&mut self, vis: &mut Visibility) {
294 noop_visit_vis(vis, self);
297 fn visit_id(&mut self, _id: &mut NodeId) {
301 fn visit_span(&mut self, _sp: &mut Span) {
306 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
307 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
310 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
311 pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
312 unsafe { std::ptr::write(t, f(std::ptr::read(t))); }
315 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
317 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
323 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
325 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
326 if let Some(elem) = opt {
331 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
332 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
333 visit_vec(attrs, |attr| vis.visit_attribute(attr));
336 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
337 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
338 for attr in attrs.iter_mut() {
339 vis.visit_attribute(attr);
343 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
344 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
345 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
348 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
349 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
350 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
353 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
354 pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
355 vis.visit_fn_header(header);
356 vis.visit_fn_decl(decl);
359 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
360 let UseTree { prefix, kind, span } = use_tree;
361 vis.visit_path(prefix);
363 UseTreeKind::Simple(rename, id1, id2) => {
364 visit_opt(rename, |rename| vis.visit_ident(rename));
368 UseTreeKind::Nested(items) => {
369 for (tree, id) in items {
370 vis.visit_use_tree(tree);
374 UseTreeKind::Glob => {}
376 vis.visit_span(span);
379 pub fn noop_visit_arm<T: MutVisitor>(Arm { attrs, pats, guard, body }: &mut Arm, vis: &mut T) {
380 visit_attrs(attrs, vis);
381 visit_vec(pats, |pat| vis.visit_pat(pat));
382 visit_opt(guard, |guard| vis.visit_guard(guard));
383 vis.visit_expr(body);
386 pub fn noop_visit_guard<T: MutVisitor>(g: &mut Guard, vis: &mut T) {
388 Guard::If(e) => vis.visit_expr(e),
392 pub fn noop_visit_ty_binding<T: MutVisitor>(TypeBinding { id, ident, ty, span }: &mut TypeBinding,
395 vis.visit_ident(ident);
397 vis.visit_span(span);
400 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
401 let Ty { id, node, span } = ty.deref_mut();
404 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never => {}
405 TyKind::Slice(ty) => vis.visit_ty(ty),
406 TyKind::Ptr(mt) => vis.visit_mt(mt),
407 TyKind::Rptr(lt, mt) => {
408 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
411 TyKind::BareFn(bft) => {
412 let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
413 vis.visit_generic_params(generic_params);
414 vis.visit_fn_decl(decl);
416 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
417 TyKind::Paren(ty) => vis.visit_ty(ty),
418 TyKind::Path(qself, path) => {
419 vis.visit_qself(qself);
420 vis.visit_path(path);
422 TyKind::Array(ty, length) => {
424 vis.visit_anon_const(length);
426 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
427 TyKind::TraitObject(bounds, _syntax) =>
428 visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
429 TyKind::ImplTrait(id, bounds) => {
431 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
433 TyKind::Mac(mac) => vis.visit_mac(mac),
435 vis.visit_span(span);
438 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
439 let ForeignMod { abi: _, items} = foreign_mod;
440 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
443 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
444 let Spanned { node: Variant_ { ident, attrs, data, disr_expr }, span } = variant;
445 vis.visit_ident(ident);
446 visit_attrs(attrs, vis);
447 vis.visit_variant_data(data);
448 visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
449 vis.visit_span(span);
452 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
453 vis.visit_span(span);
456 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
457 vis.visit_span(span);
458 for PathSegment { ident, id, args } in segments {
459 vis.visit_ident(ident);
461 visit_opt(args, |args| vis.visit_generic_args(args));
465 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
466 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
468 vis.visit_span(path_span);
472 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
474 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
475 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
479 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
481 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
482 GenericArg::Type(ty) => vis.visit_ty(ty),
483 GenericArg::Const(ct) => vis.visit_anon_const(ct),
487 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
489 let AngleBracketedArgs { args, bindings, span } = data;
490 visit_vec(args, |arg| vis.visit_generic_arg(arg));
491 visit_vec(bindings, |binding| vis.visit_ty_binding(binding));
492 vis.visit_span(span);
495 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
497 let ParenthesizedArgs { inputs, output, span } = args;
498 visit_vec(inputs, |input| vis.visit_ty(input));
499 visit_opt(output, |output| vis.visit_ty(output));
500 vis.visit_span(span);
503 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
504 let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
507 visit_opt(ty, |ty| vis.visit_ty(ty));
508 visit_opt(init, |init| vis.visit_expr(init));
509 vis.visit_span(span);
510 visit_thin_attrs(attrs, vis);
513 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
514 let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
515 vis.visit_path(path);
516 vis.visit_tts(tokens);
517 vis.visit_span(span);
520 pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
521 let Mac_ { path, delim: _, tts } = node;
522 vis.visit_path(path);
524 vis.visit_span(span);
527 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
528 let MacroDef { tokens, legacy: _ } = macro_def;
529 vis.visit_tts(tokens);
532 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
533 let Spanned { node, span } = li;
535 NestedMetaItemKind::MetaItem(mi) => vis.visit_meta_item(mi),
536 NestedMetaItemKind::Literal(_lit) => {}
538 vis.visit_span(span);
541 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
542 let MetaItem { ident: _, node, span } = mi;
544 MetaItemKind::Word => {}
545 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
546 MetaItemKind::NameValue(_s) => {}
548 vis.visit_span(span);
551 pub fn noop_visit_arg<T: MutVisitor>(Arg { id, pat, ty }: &mut Arg, vis: &mut T) {
557 pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
559 TokenTree::Token(span, tok) => {
560 vis.visit_span(span);
561 vis.visit_token(tok);
563 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
564 vis.visit_span(open);
565 vis.visit_span(close);
571 pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
572 visit_opt(tts, |tts| {
573 let tts = Lrc::make_mut(tts);
574 visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
578 // apply ident visitor if it's an ident, apply other visits to interpolated nodes
579 pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
581 token::Ident(id, _is_raw) => vis.visit_ident(id),
582 token::Lifetime(id) => vis.visit_ident(id),
583 token::Interpolated(nt) => {
584 let mut nt = Lrc::make_mut(nt);
585 vis.visit_interpolated(&mut nt);
591 /// Apply visitor to elements of interpolated nodes.
593 // N.B., this can occur only when applying a visitor to partially expanded
594 // code, where parsed pieces have gotten implanted ito *other* macro
595 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
597 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
598 // etc. allow the visitor to return *multiple* items; this is a problem for the
599 // nodes here, because they insist on having exactly one piece. One solution
600 // would be to mangle the MutVisitor trait to include one-to-many and
601 // one-to-one versions of these entry points, but that would probably confuse a
602 // lot of people and help very few. Instead, I'm just going to put in dynamic
603 // checks. I think the performance impact of this will be pretty much
604 // nonexistent. The danger is that someone will apply a MutVisitor to a
605 // partially expanded node, and will be confused by the fact that their
606 // "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
607 // nodes. Hopefully they'll wind up reading this comment, and doing something
610 // BTW, design choice: I considered just changing the type of, e.g., NtItem to
611 // contain multiple items, but decided against it when I looked at
612 // parse_item_or_view_item and tried to figure out what I would do with
613 // multiple items there....
614 pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
616 token::NtItem(item) =>
617 visit_clobber(item, |item| {
618 // This is probably okay, because the only visitors likely to
619 // peek inside interpolated nodes will be renamings/markings,
620 // which map single items to single items.
621 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
623 token::NtBlock(block) => vis.visit_block(block),
624 token::NtStmt(stmt) =>
625 visit_clobber(stmt, |stmt| {
626 // See reasoning above.
627 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
629 token::NtPat(pat) => vis.visit_pat(pat),
630 token::NtExpr(expr) => vis.visit_expr(expr),
631 token::NtTy(ty) => vis.visit_ty(ty),
632 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
633 token::NtLifetime(ident) => vis.visit_ident(ident),
634 token::NtLiteral(expr) => vis.visit_expr(expr),
635 token::NtMeta(meta) => vis.visit_meta_item(meta),
636 token::NtPath(path) => vis.visit_path(path),
637 token::NtTT(tt) => vis.visit_tt(tt),
638 token::NtArm(arm) => vis.visit_arm(arm),
639 token::NtImplItem(item) =>
640 visit_clobber(item, |item| {
641 // See reasoning above.
642 vis.flat_map_impl_item(item)
643 .expect_one("expected visitor to produce exactly one item")
645 token::NtTraitItem(item) =>
646 visit_clobber(item, |item| {
647 // See reasoning above.
648 vis.flat_map_trait_item(item)
649 .expect_one("expected visitor to produce exactly one item")
651 token::NtGenerics(generics) => vis.visit_generics(generics),
652 token::NtWhereClause(where_clause) => vis.visit_where_clause(where_clause),
653 token::NtArg(arg) => vis.visit_arg(arg),
654 token::NtVis(visib) => vis.visit_vis(visib),
655 token::NtForeignItem(item) =>
656 visit_clobber(item, |item| {
657 // See reasoning above.
658 vis.flat_map_foreign_item(item)
659 .expect_one("expected visitor to produce exactly one item")
664 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
666 IsAsync::Async { closure_id, return_impl_trait_id } => {
667 vis.visit_id(closure_id);
668 vis.visit_id(return_impl_trait_id);
670 IsAsync::NotAsync => {}
674 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
675 let FnDecl { inputs, output, variadic: _ } = decl.deref_mut();
676 visit_vec(inputs, |input| vis.visit_arg(input));
678 FunctionRetTy::Default(span) => vis.visit_span(span),
679 FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
683 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
685 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
686 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
690 pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
691 let GenericParam { id, ident, attrs, bounds, kind } = param;
693 vis.visit_ident(ident);
694 visit_thin_attrs(attrs, vis);
695 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
697 GenericParamKind::Lifetime => {}
698 GenericParamKind::Type { default } => {
699 visit_opt(default, |default| vis.visit_ty(default));
701 GenericParamKind::Const { ty } => {
707 pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
708 visit_vec(params, |param| vis.visit_generic_param(param));
711 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
712 vis.visit_ident(ident);
715 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
717 vis.visit_ident(ident);
720 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
721 let Generics { params, where_clause, span } = generics;
722 vis.visit_generic_params(params);
723 vis.visit_where_clause(where_clause);
724 vis.visit_span(span);
727 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
728 let WhereClause { id, predicates, span } = wc;
730 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
731 vis.visit_span(span);
734 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
736 WherePredicate::BoundPredicate(bp) => {
737 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
738 vis.visit_span(span);
739 vis.visit_generic_params(bound_generic_params);
740 vis.visit_ty(bounded_ty);
741 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
743 WherePredicate::RegionPredicate(rp) => {
744 let WhereRegionPredicate { span, lifetime, bounds } = rp;
745 vis.visit_span(span);
746 noop_visit_lifetime(lifetime, vis);
747 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
749 WherePredicate::EqPredicate(ep) => {
750 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
752 vis.visit_span(span);
753 vis.visit_ty(lhs_ty);
754 vis.visit_ty(rhs_ty);
759 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
761 VariantData::Struct(fields, id) |
762 VariantData::Tuple(fields, id) => {
763 visit_vec(fields, |field| vis.visit_struct_field(field));
766 VariantData::Unit(id) => vis.visit_id(id),
770 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
771 vis.visit_path(path);
772 vis.visit_id(ref_id);
775 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
776 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
777 vis.visit_generic_params(bound_generic_params);
778 vis.visit_trait_ref(trait_ref);
779 vis.visit_span(span);
782 pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
783 let StructField { span, ident, vis, id, ty, attrs } = f;
784 visitor.visit_span(span);
785 visit_opt(ident, |ident| visitor.visit_ident(ident));
786 visitor.visit_vis(vis);
787 visitor.visit_id(id);
788 visitor.visit_ty(ty);
789 visit_attrs(attrs, visitor);
792 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
793 let Field { ident, expr, span, is_shorthand: _, attrs } = f;
794 vis.visit_ident(ident);
795 vis.visit_expr(expr);
796 vis.visit_span(span);
797 visit_thin_attrs(attrs, vis);
800 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
804 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
805 let Block { id, stmts, rules: _, span } = block.deref_mut();
807 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
808 vis.visit_span(span);
811 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
813 ItemKind::ExternCrate(_orig_name) => {}
814 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
815 ItemKind::Static(ty, _mut, expr) => {
817 vis.visit_expr(expr);
819 ItemKind::Const(ty, expr) => {
821 vis.visit_expr(expr);
823 ItemKind::Fn(decl, header, generics, body) => {
824 vis.visit_fn_decl(decl);
825 vis.visit_fn_header(header);
826 vis.visit_generics(generics);
827 vis.visit_block(body);
829 ItemKind::Mod(m) => vis.visit_mod(m),
830 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
831 ItemKind::GlobalAsm(_ga) => {}
832 ItemKind::Ty(ty, generics) => {
834 vis.visit_generics(generics);
836 ItemKind::Existential(bounds, generics) => {
837 visit_bounds(bounds, vis);
838 vis.visit_generics(generics);
840 ItemKind::Enum(EnumDef { variants }, generics) => {
841 visit_vec(variants, |variant| vis.visit_variant(variant));
842 vis.visit_generics(generics);
844 ItemKind::Struct(variant_data, generics) |
845 ItemKind::Union(variant_data, generics) => {
846 vis.visit_variant_data(variant_data);
847 vis.visit_generics(generics);
849 ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
850 vis.visit_generics(generics);
851 visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
853 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
855 ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
856 vis.visit_generics(generics);
857 visit_bounds(bounds, vis);
858 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
860 ItemKind::TraitAlias(generics, bounds) => {
861 vis.visit_generics(generics);
862 visit_bounds(bounds, vis);
864 ItemKind::Mac(m) => vis.visit_mac(m),
865 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
869 pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
870 -> SmallVec<[TraitItem; 1]>
872 let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
874 vis.visit_ident(ident);
875 visit_attrs(attrs, vis);
876 vis.visit_generics(generics);
878 TraitItemKind::Const(ty, default) => {
880 visit_opt(default, |default| vis.visit_expr(default));
882 TraitItemKind::Method(sig, body) => {
883 visit_method_sig(sig, vis);
884 visit_opt(body, |body| vis.visit_block(body));
886 TraitItemKind::Type(bounds, default) => {
887 visit_bounds(bounds, vis);
888 visit_opt(default, |default| vis.visit_ty(default));
890 TraitItemKind::Macro(mac) => {
894 vis.visit_span(span);
899 pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
900 -> SmallVec<[ImplItem; 1]>
902 let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
904 visitor.visit_id(id);
905 visitor.visit_ident(ident);
906 visitor.visit_vis(vis);
907 visit_attrs(attrs, visitor);
908 visitor.visit_generics(generics);
910 ImplItemKind::Const(ty, expr) => {
911 visitor.visit_ty(ty);
912 visitor.visit_expr(expr);
914 ImplItemKind::Method(sig, body) => {
915 visit_method_sig(sig, visitor);
916 visitor.visit_block(body);
918 ImplItemKind::Type(ty) => visitor.visit_ty(ty),
919 ImplItemKind::Existential(bounds) => visit_bounds(bounds, visitor),
920 ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
922 visitor.visit_span(span);
927 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
928 let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
929 vis.visit_asyncness(asyncness);
932 pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
933 vis.visit_span(inner);
934 items.flat_map_in_place(|item| vis.flat_map_item(item));
937 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
938 visit_clobber(krate, |Crate { module, attrs, span }| {
940 ident: keywords::Invalid.ident(),
943 vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
945 node: ItemKind::Mod(module),
948 let items = vis.flat_map_item(item);
950 let len = items.len();
952 let module = Mod { inner: span, items: vec![], inline: true };
953 Crate { module, attrs: vec![], span }
955 let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
957 ItemKind::Mod(module) => Crate { module, attrs, span },
958 _ => panic!("visitor converted a module to not a module"),
961 panic!("a crate cannot expand to more than one item");
966 // Mutate one item into possibly many items.
967 pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
968 -> SmallVec<[P<Item>; 1]> {
969 let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
970 visitor.visit_ident(ident);
971 visit_attrs(attrs, visitor);
972 visitor.visit_id(id);
973 visitor.visit_item_kind(node);
974 visitor.visit_vis(vis);
975 visitor.visit_span(span);
977 // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
978 // an ICE during resolve... odd!
983 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
984 -> SmallVec<[ForeignItem; 1]>
986 let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
987 visitor.visit_ident(ident);
988 visit_attrs(attrs, visitor);
990 ForeignItemKind::Fn(fdec, generics) => {
991 visitor.visit_fn_decl(fdec);
992 visitor.visit_generics(generics);
994 ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
995 ForeignItemKind::Ty => {}
996 ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
998 visitor.visit_id(id);
999 visitor.visit_span(span);
1000 visitor.visit_vis(vis);
1005 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1006 let Pat { id, node, span } = pat.deref_mut();
1010 PatKind::Ident(_binding_mode, ident, sub) => {
1011 vis.visit_ident(ident);
1012 visit_opt(sub, |sub| vis.visit_pat(sub));
1014 PatKind::Lit(e) => vis.visit_expr(e),
1015 PatKind::TupleStruct(path, pats, _ddpos) => {
1016 vis.visit_path(path);
1017 visit_vec(pats, |pat| vis.visit_pat(pat));
1019 PatKind::Path(qself, path) => {
1020 vis.visit_qself(qself);
1021 vis.visit_path(path);
1023 PatKind::Struct(path, fields, _etc) => {
1024 vis.visit_path(path);
1025 for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
1026 vis.visit_ident(ident);
1028 visit_thin_attrs(attrs, vis);
1029 vis.visit_span(span);
1032 PatKind::Tuple(elts, _ddpos) => visit_vec(elts, |elt| vis.visit_pat(elt)),
1033 PatKind::Box(inner) => vis.visit_pat(inner),
1034 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1035 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1038 vis.visit_span(span);
1040 PatKind::Slice(before, slice, after) => {
1041 visit_vec(before, |pat| vis.visit_pat(pat));
1042 visit_opt(slice, |slice| vis.visit_pat(slice));
1043 visit_vec(after, |pat| vis.visit_pat(pat));
1045 PatKind::Paren(inner) => vis.visit_pat(inner),
1046 PatKind::Mac(mac) => vis.visit_mac(mac),
1048 vis.visit_span(span);
1051 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1053 vis.visit_expr(value);
1056 pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
1058 ExprKind::Box(expr) => vis.visit_expr(expr),
1059 ExprKind::ObsoleteInPlace(a, b) => {
1063 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1064 ExprKind::Repeat(expr, count) => {
1065 vis.visit_expr(expr);
1066 vis.visit_anon_const(count);
1068 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1069 ExprKind::Call(f, args) => {
1071 visit_exprs(args, vis);
1073 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
1074 vis.visit_ident(ident);
1076 visit_opt(args, |args| vis.visit_generic_args(args));
1077 visit_exprs(exprs, vis);
1079 ExprKind::Binary(_binop, lhs, rhs) => {
1080 vis.visit_expr(lhs);
1081 vis.visit_expr(rhs);
1083 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1084 ExprKind::Lit(_lit) => {}
1085 ExprKind::Cast(expr, ty) => {
1086 vis.visit_expr(expr);
1089 ExprKind::Type(expr, ty) => {
1090 vis.visit_expr(expr);
1093 ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
1094 ExprKind::If(cond, tr, fl) => {
1095 vis.visit_expr(cond);
1096 vis.visit_block(tr);
1097 visit_opt(fl, |fl| vis.visit_expr(fl));
1099 ExprKind::IfLet(pats, expr, tr, fl) => {
1100 visit_vec(pats, |pat| vis.visit_pat(pat));
1101 vis.visit_expr(expr);
1102 vis.visit_block(tr);
1103 visit_opt(fl, |fl| vis.visit_expr(fl));
1105 ExprKind::While(cond, body, label) => {
1106 vis.visit_expr(cond);
1107 vis.visit_block(body);
1108 visit_opt(label, |label| vis.visit_label(label));
1110 ExprKind::WhileLet(pats, expr, body, label) => {
1111 visit_vec(pats, |pat| vis.visit_pat(pat));
1112 vis.visit_expr(expr);
1113 vis.visit_block(body);
1114 visit_opt(label, |label| vis.visit_label(label));
1116 ExprKind::ForLoop(pat, iter, body, label) => {
1118 vis.visit_expr(iter);
1119 vis.visit_block(body);
1120 visit_opt(label, |label| vis.visit_label(label));
1122 ExprKind::Loop(body, label) => {
1123 vis.visit_block(body);
1124 visit_opt(label, |label| vis.visit_label(label));
1126 ExprKind::Match(expr, arms) => {
1127 vis.visit_expr(expr);
1128 visit_vec(arms, |arm| vis.visit_arm(arm));
1130 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1131 vis.visit_asyncness(asyncness);
1132 vis.visit_fn_decl(decl);
1133 vis.visit_expr(body);
1134 vis.visit_span(span);
1136 ExprKind::Block(blk, label) => {
1137 vis.visit_block(blk);
1138 visit_opt(label, |label| vis.visit_label(label));
1140 ExprKind::Async(_capture_by, node_id, body) => {
1141 vis.visit_id(node_id);
1142 vis.visit_block(body);
1144 ExprKind::Assign(el, er) => {
1148 ExprKind::AssignOp(_op, el, er) => {
1152 ExprKind::Field(el, ident) => {
1154 vis.visit_ident(ident);
1156 ExprKind::Index(el, er) => {
1160 ExprKind::Range(e1, e2, _lim) => {
1161 visit_opt(e1, |e1| vis.visit_expr(e1));
1162 visit_opt(e2, |e2| vis.visit_expr(e2));
1164 ExprKind::Path(qself, path) => {
1165 vis.visit_qself(qself);
1166 vis.visit_path(path);
1168 ExprKind::Break(label, expr) => {
1169 visit_opt(label, |label| vis.visit_label(label));
1170 visit_opt(expr, |expr| vis.visit_expr(expr));
1172 ExprKind::Continue(label) => {
1173 visit_opt(label, |label| vis.visit_label(label));
1175 ExprKind::Ret(expr) => {
1176 visit_opt(expr, |expr| vis.visit_expr(expr));
1178 ExprKind::InlineAsm(asm) => {
1179 let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
1180 alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
1181 for out in outputs {
1182 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1183 vis.visit_expr(expr);
1185 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1187 ExprKind::Mac(mac) => vis.visit_mac(mac),
1188 ExprKind::Struct(path, fields, expr) => {
1189 vis.visit_path(path);
1190 visit_vec(fields, |field| vis.visit_field(field));
1191 visit_opt(expr, |expr| vis.visit_expr(expr));
1193 ExprKind::Paren(expr) => {
1194 vis.visit_expr(expr);
1196 // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
1198 vis.visit_span(span);
1199 visit_thin_attrs(attrs, vis);
1202 ExprKind::Yield(expr) => {
1203 visit_opt(expr, |expr| vis.visit_expr(expr));
1205 ExprKind::Try(expr) => vis.visit_expr(expr),
1206 ExprKind::TryBlock(body) => vis.visit_block(body),
1210 vis.visit_span(span);
1211 visit_thin_attrs(attrs, vis);
1214 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1215 Some({ vis.visit_expr(&mut e); e })
1218 pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
1219 -> SmallVec<[Stmt; 1]>
1221 vis.visit_id(&mut id);
1222 vis.visit_span(&mut span);
1223 noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
1224 Stmt { id, node, span }
1228 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
1229 -> SmallVec<[StmtKind; 1]> {
1231 StmtKind::Local(mut local) =>
1232 smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
1233 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1234 StmtKind::Expr(expr) => {
1235 vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
1237 StmtKind::Semi(expr) => {
1238 vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
1240 StmtKind::Mac(mut mac) => {
1241 let (mac_, _semi, attrs) = mac.deref_mut();
1242 vis.visit_mac(mac_);
1243 visit_thin_attrs(attrs, vis);
1244 smallvec![StmtKind::Mac(mac)]
1249 pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
1251 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1252 VisibilityKind::Restricted { path, id } => {
1253 vis.visit_path(path);
1257 vis.visit_span(span);
1263 use crate::ast::{self, Ident};
1264 use crate::util::parser_testing::{string_to_crate, matches_codepattern};
1265 use crate::print::pprust;
1266 use crate::mut_visit;
1267 use crate::with_globals;
1270 // this version doesn't care about getting comments or docstrings in.
1271 fn fake_print_crate(s: &mut pprust::State<'_>,
1272 krate: &ast::Crate) -> io::Result<()> {
1273 s.print_mod(&krate.module, &krate.attrs)
1276 // change every identifier to "zz"
1277 struct ToZzIdentMutVisitor;
1279 impl MutVisitor for ToZzIdentMutVisitor {
1280 fn visit_ident(&mut self, ident: &mut ast::Ident) {
1281 *ident = Ident::from_str("zz");
1283 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1284 mut_visit::noop_visit_mac(mac, self)
1288 // maybe add to expand.rs...
1289 macro_rules! assert_pred {
1290 ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
1292 let pred_val = $pred;
1295 if !(pred_val(&a_val, &b_val)) {
1296 panic!("expected args satisfying {}, got {} and {}",
1297 $predname, a_val, b_val);
1303 // make sure idents get transformed everywhere
1304 #[test] fn ident_transformation () {
1306 let mut zz_visitor = ToZzIdentMutVisitor;
1307 let mut krate = string_to_crate(
1308 "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
1309 zz_visitor.visit_crate(&mut krate);
1311 matches_codepattern,
1312 "matches_codepattern",
1313 pprust::to_string(|s| fake_print_crate(s, &krate)),
1314 "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
1318 // even inside macro defs....
1319 #[test] fn ident_transformation_in_defs () {
1321 let mut zz_visitor = ToZzIdentMutVisitor;
1322 let mut krate = string_to_crate(
1323 "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
1324 (g $(d $d $e)+))} ".to_string());
1325 zz_visitor.visit_crate(&mut krate);
1327 matches_codepattern,
1328 "matches_codepattern",
1329 pprust::to_string(|s| fake_print_crate(s, &krate)),
1330 "macro_rules! zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());