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;
24 use std::{panic, process, ptr};
26 pub trait ExpectOne<A: Array> {
27 fn expect_one(self, err: &'static str) -> A::Item;
30 impl<A: Array> ExpectOne<A> for SmallVec<A> {
31 fn expect_one(self, err: &'static str) -> A::Item {
32 assert!(self.len() == 1, err);
33 self.into_iter().next().unwrap()
37 pub trait MutVisitor: Sized {
38 // Methods in this trait have one of three forms:
40 // fn visit_t(&mut self, t: &mut T); // common
41 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
42 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
44 // Any additions to this trait should happen in form of a call to a public
45 // `noop_*` function that only calls out to the visitor again, not other
46 // `noop_*` functions. This is a necessary API workaround to the problem of
47 // not being able to call out to the super default method in an overridden
50 // When writing these methods, it is better to use destructuring like this:
52 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
57 // than to use field access like this:
59 // fn visit_abc(&mut self, abc: &mut ABC) {
60 // visit_a(&mut abc.a);
61 // visit_b(&mut abc.b);
65 // As well as being more concise, the former is explicit about which fields
66 // are skipped. Furthermore, if a new field is added, the destructuring
67 // version will cause a compile error, which is good. In comparison, the
68 // field access version will continue working and it would be easy to
69 // forget to add handling for it.
71 fn visit_crate(&mut self, c: &mut Crate) {
72 noop_visit_crate(c, self)
75 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
76 noop_visit_meta_list_item(list_item, self);
79 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
80 noop_visit_meta_item(meta_item, self);
83 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
84 noop_visit_use_tree(use_tree, self);
87 fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
88 noop_flat_map_foreign_item(ni, self)
91 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
92 noop_flat_map_item(i, self)
95 fn visit_fn_header(&mut self, header: &mut FnHeader) {
96 noop_visit_fn_header(header, self);
99 fn visit_struct_field(&mut self, sf: &mut StructField) {
100 noop_visit_struct_field(sf, self);
103 fn visit_item_kind(&mut self, i: &mut ItemKind) {
104 noop_visit_item_kind(i, self);
107 fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
108 noop_flat_map_trait_item(i, self)
111 fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
112 noop_flat_map_impl_item(i, self)
115 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
116 noop_visit_fn_decl(d, self);
119 fn visit_asyncness(&mut self, a: &mut IsAsync) {
120 noop_visit_asyncness(a, self);
123 fn visit_block(&mut self, b: &mut P<Block>) {
124 noop_visit_block(b, self);
127 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
128 noop_flat_map_stmt(s, self)
131 fn visit_arm(&mut self, a: &mut Arm) {
132 noop_visit_arm(a, self);
135 fn visit_guard(&mut self, g: &mut Guard) {
136 noop_visit_guard(g, self);
139 fn visit_pat(&mut self, p: &mut P<Pat>) {
140 noop_visit_pat(p, self);
143 fn visit_anon_const(&mut self, c: &mut AnonConst) {
144 noop_visit_anon_const(c, self);
147 fn visit_expr(&mut self, e: &mut P<Expr>) {
148 noop_visit_expr(e, self);
151 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
152 noop_filter_map_expr(e, self)
155 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
156 noop_visit_generic_arg(arg, self);
159 fn visit_ty(&mut self, t: &mut P<Ty>) {
160 noop_visit_ty(t, self);
163 fn visit_lifetime(&mut self, l: &mut Lifetime) {
164 noop_visit_lifetime(l, self);
167 fn visit_ty_binding(&mut self, t: &mut TypeBinding) {
168 noop_visit_ty_binding(t, self);
171 fn visit_mod(&mut self, m: &mut Mod) {
172 noop_visit_mod(m, self);
175 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
176 noop_visit_foreign_mod(nm, self);
179 fn visit_variant(&mut self, v: &mut Variant) {
180 noop_visit_variant(v, self);
183 fn visit_ident(&mut self, i: &mut Ident) {
184 noop_visit_ident(i, self);
187 fn visit_path(&mut self, p: &mut Path) {
188 noop_visit_path(p, self);
191 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
192 noop_visit_qself(qs, self);
195 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
196 noop_visit_generic_args(p, self);
199 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
200 noop_visit_angle_bracketed_parameter_data(p, self);
203 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
204 noop_visit_parenthesized_parameter_data(p, self);
207 fn visit_local(&mut self, l: &mut P<Local>) {
208 noop_visit_local(l, self);
211 fn visit_mac(&mut self, _mac: &mut Mac) {
212 panic!("visit_mac disabled by default");
213 // N.B., see note about macros above. If you really want a visitor that
214 // works on macros, use this definition in your trait impl:
215 // mut_visit::noop_visit_mac(_mac, self);
218 fn visit_macro_def(&mut self, def: &mut MacroDef) {
219 noop_visit_macro_def(def, self);
222 fn visit_label(&mut self, label: &mut Label) {
223 noop_visit_label(label, self);
226 fn visit_attribute(&mut self, at: &mut Attribute) {
227 noop_visit_attribute(at, self);
230 fn visit_arg(&mut self, a: &mut Arg) {
231 noop_visit_arg(a, self);
234 fn visit_generics(&mut self, generics: &mut Generics) {
235 noop_visit_generics(generics, self);
238 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
239 noop_visit_trait_ref(tr, self);
242 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
243 noop_visit_poly_trait_ref(p, self);
246 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
247 noop_visit_variant_data(vdata, self);
250 fn visit_generic_param(&mut self, param: &mut GenericParam) {
251 noop_visit_generic_param(param, self);
254 fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
255 noop_visit_generic_params(params, self);
258 fn visit_tt(&mut self, tt: &mut TokenTree) {
259 noop_visit_tt(tt, self);
262 fn visit_tts(&mut self, tts: &mut TokenStream) {
263 noop_visit_tts(tts, self);
266 fn visit_token(&mut self, t: &mut Token) {
267 noop_visit_token(t, self);
270 fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
271 noop_visit_interpolated(nt, self);
274 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
275 noop_visit_param_bound(tpb, self);
278 fn visit_mt(&mut self, mt: &mut MutTy) {
279 noop_visit_mt(mt, self);
282 fn visit_field(&mut self, field: &mut Field) {
283 noop_visit_field(field, self);
286 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
287 noop_visit_where_clause(where_clause, self);
290 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
291 noop_visit_where_predicate(where_predicate, self);
294 fn visit_vis(&mut self, vis: &mut Visibility) {
295 noop_visit_vis(vis, self);
298 fn visit_id(&mut self, _id: &mut NodeId) {
302 fn visit_span(&mut self, _sp: &mut Span) {
307 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
308 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
309 /// method. Abort the program if the closure panics.
311 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
312 pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
314 // Safe because `t` is used in a read-only fashion by `read()` before
315 // being overwritten by `write()`.
316 let old_t = ptr::read(t);
317 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
318 .unwrap_or_else(|_| process::abort());
319 ptr::write(t, new_t);
323 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
325 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
331 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
333 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
334 if let Some(elem) = opt {
339 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
340 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
341 visit_vec(attrs, |attr| vis.visit_attribute(attr));
344 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
345 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
346 for attr in attrs.iter_mut() {
347 vis.visit_attribute(attr);
351 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
352 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
353 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
356 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
357 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
358 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
361 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
362 pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
363 vis.visit_fn_header(header);
364 vis.visit_fn_decl(decl);
367 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
368 let UseTree { prefix, kind, span } = use_tree;
369 vis.visit_path(prefix);
371 UseTreeKind::Simple(rename, id1, id2) => {
372 visit_opt(rename, |rename| vis.visit_ident(rename));
376 UseTreeKind::Nested(items) => {
377 for (tree, id) in items {
378 vis.visit_use_tree(tree);
382 UseTreeKind::Glob => {}
384 vis.visit_span(span);
387 pub fn noop_visit_arm<T: MutVisitor>(Arm { attrs, pats, guard, body }: &mut Arm, vis: &mut T) {
388 visit_attrs(attrs, vis);
389 visit_vec(pats, |pat| vis.visit_pat(pat));
390 visit_opt(guard, |guard| vis.visit_guard(guard));
391 vis.visit_expr(body);
394 pub fn noop_visit_guard<T: MutVisitor>(g: &mut Guard, vis: &mut T) {
396 Guard::If(e) => vis.visit_expr(e),
400 pub fn noop_visit_ty_binding<T: MutVisitor>(TypeBinding { id, ident, ty, span }: &mut TypeBinding,
403 vis.visit_ident(ident);
405 vis.visit_span(span);
408 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
409 let Ty { id, node, span } = ty.deref_mut();
412 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err |
413 TyKind::Never | TyKind::CVarArgs => {}
414 TyKind::Slice(ty) => vis.visit_ty(ty),
415 TyKind::Ptr(mt) => vis.visit_mt(mt),
416 TyKind::Rptr(lt, mt) => {
417 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
420 TyKind::BareFn(bft) => {
421 let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
422 vis.visit_generic_params(generic_params);
423 vis.visit_fn_decl(decl);
425 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
426 TyKind::Paren(ty) => vis.visit_ty(ty),
427 TyKind::Path(qself, path) => {
428 vis.visit_qself(qself);
429 vis.visit_path(path);
431 TyKind::Array(ty, length) => {
433 vis.visit_anon_const(length);
435 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
436 TyKind::TraitObject(bounds, _syntax) =>
437 visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
438 TyKind::ImplTrait(id, bounds) => {
440 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
442 TyKind::Mac(mac) => vis.visit_mac(mac),
444 vis.visit_span(span);
447 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
448 let ForeignMod { abi: _, items} = foreign_mod;
449 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
452 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
453 let Spanned { node: Variant_ { ident, attrs, data, disr_expr }, span } = variant;
454 vis.visit_ident(ident);
455 visit_attrs(attrs, vis);
456 vis.visit_variant_data(data);
457 visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
458 vis.visit_span(span);
461 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
462 vis.visit_span(span);
465 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
466 vis.visit_span(span);
467 for PathSegment { ident, id, args } in segments {
468 vis.visit_ident(ident);
470 visit_opt(args, |args| vis.visit_generic_args(args));
474 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
475 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
477 vis.visit_span(path_span);
481 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
483 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
484 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
488 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
490 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
491 GenericArg::Type(ty) => vis.visit_ty(ty),
492 GenericArg::Const(ct) => vis.visit_anon_const(ct),
496 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
498 let AngleBracketedArgs { args, bindings, span } = data;
499 visit_vec(args, |arg| vis.visit_generic_arg(arg));
500 visit_vec(bindings, |binding| vis.visit_ty_binding(binding));
501 vis.visit_span(span);
504 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
506 let ParenthesizedArgs { inputs, output, span } = args;
507 visit_vec(inputs, |input| vis.visit_ty(input));
508 visit_opt(output, |output| vis.visit_ty(output));
509 vis.visit_span(span);
512 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
513 let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
516 visit_opt(ty, |ty| vis.visit_ty(ty));
517 visit_opt(init, |init| vis.visit_expr(init));
518 vis.visit_span(span);
519 visit_thin_attrs(attrs, vis);
522 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
523 let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
524 vis.visit_path(path);
525 vis.visit_tts(tokens);
526 vis.visit_span(span);
529 pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
530 let Mac_ { path, delim: _, tts } = node;
531 vis.visit_path(path);
533 vis.visit_span(span);
536 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
537 let MacroDef { tokens, legacy: _ } = macro_def;
538 vis.visit_tts(tokens);
541 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
543 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
544 NestedMetaItem::Literal(_lit) => {}
548 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
549 let MetaItem { path: _, node, span } = mi;
551 MetaItemKind::Word => {}
552 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
553 MetaItemKind::NameValue(_s) => {}
555 vis.visit_span(span);
558 pub fn noop_visit_arg<T: MutVisitor>(Arg { id, pat, ty }: &mut Arg, vis: &mut T) {
564 pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
566 TokenTree::Token(span, tok) => {
567 vis.visit_span(span);
568 vis.visit_token(tok);
570 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
571 vis.visit_span(open);
572 vis.visit_span(close);
578 pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
579 visit_opt(tts, |tts| {
580 let tts = Lrc::make_mut(tts);
581 visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
585 // apply ident visitor if it's an ident, apply other visits to interpolated nodes
586 pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
588 token::Ident(id, _is_raw) => vis.visit_ident(id),
589 token::Lifetime(id) => vis.visit_ident(id),
590 token::Interpolated(nt) => {
591 let mut nt = Lrc::make_mut(nt);
592 vis.visit_interpolated(&mut nt);
598 /// Apply visitor to elements of interpolated nodes.
600 // N.B., this can occur only when applying a visitor to partially expanded
601 // code, where parsed pieces have gotten implanted ito *other* macro
602 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
604 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
605 // etc. allow the visitor to return *multiple* items; this is a problem for the
606 // nodes here, because they insist on having exactly one piece. One solution
607 // would be to mangle the MutVisitor trait to include one-to-many and
608 // one-to-one versions of these entry points, but that would probably confuse a
609 // lot of people and help very few. Instead, I'm just going to put in dynamic
610 // checks. I think the performance impact of this will be pretty much
611 // nonexistent. The danger is that someone will apply a MutVisitor to a
612 // partially expanded node, and will be confused by the fact that their
613 // "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
614 // nodes. Hopefully they'll wind up reading this comment, and doing something
617 // BTW, design choice: I considered just changing the type of, e.g., NtItem to
618 // contain multiple items, but decided against it when I looked at
619 // parse_item_or_view_item and tried to figure out what I would do with
620 // multiple items there....
621 pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
623 token::NtItem(item) =>
624 visit_clobber(item, |item| {
625 // This is probably okay, because the only visitors likely to
626 // peek inside interpolated nodes will be renamings/markings,
627 // which map single items to single items.
628 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
630 token::NtBlock(block) => vis.visit_block(block),
631 token::NtStmt(stmt) =>
632 visit_clobber(stmt, |stmt| {
633 // See reasoning above.
634 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
636 token::NtPat(pat) => vis.visit_pat(pat),
637 token::NtExpr(expr) => vis.visit_expr(expr),
638 token::NtTy(ty) => vis.visit_ty(ty),
639 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
640 token::NtLifetime(ident) => vis.visit_ident(ident),
641 token::NtLiteral(expr) => vis.visit_expr(expr),
642 token::NtMeta(meta) => vis.visit_meta_item(meta),
643 token::NtPath(path) => vis.visit_path(path),
644 token::NtTT(tt) => vis.visit_tt(tt),
645 token::NtArm(arm) => vis.visit_arm(arm),
646 token::NtImplItem(item) =>
647 visit_clobber(item, |item| {
648 // See reasoning above.
649 vis.flat_map_impl_item(item)
650 .expect_one("expected visitor to produce exactly one item")
652 token::NtTraitItem(item) =>
653 visit_clobber(item, |item| {
654 // See reasoning above.
655 vis.flat_map_trait_item(item)
656 .expect_one("expected visitor to produce exactly one item")
658 token::NtGenerics(generics) => vis.visit_generics(generics),
659 token::NtWhereClause(where_clause) => vis.visit_where_clause(where_clause),
660 token::NtArg(arg) => vis.visit_arg(arg),
661 token::NtVis(visib) => vis.visit_vis(visib),
662 token::NtForeignItem(item) =>
663 visit_clobber(item, |item| {
664 // See reasoning above.
665 vis.flat_map_foreign_item(item)
666 .expect_one("expected visitor to produce exactly one item")
671 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
673 IsAsync::Async { closure_id, return_impl_trait_id } => {
674 vis.visit_id(closure_id);
675 vis.visit_id(return_impl_trait_id);
677 IsAsync::NotAsync => {}
681 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
682 let FnDecl { inputs, output, c_variadic: _ } = decl.deref_mut();
683 visit_vec(inputs, |input| vis.visit_arg(input));
685 FunctionRetTy::Default(span) => vis.visit_span(span),
686 FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
690 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
692 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
693 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
697 pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
698 let GenericParam { id, ident, attrs, bounds, kind } = param;
700 vis.visit_ident(ident);
701 visit_thin_attrs(attrs, vis);
702 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
704 GenericParamKind::Lifetime => {}
705 GenericParamKind::Type { default } => {
706 visit_opt(default, |default| vis.visit_ty(default));
708 GenericParamKind::Const { ty } => {
714 pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
715 visit_vec(params, |param| vis.visit_generic_param(param));
718 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
719 vis.visit_ident(ident);
722 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
724 vis.visit_ident(ident);
727 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
728 let Generics { params, where_clause, span } = generics;
729 vis.visit_generic_params(params);
730 vis.visit_where_clause(where_clause);
731 vis.visit_span(span);
734 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
735 let WhereClause { id, predicates, span } = wc;
737 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
738 vis.visit_span(span);
741 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
743 WherePredicate::BoundPredicate(bp) => {
744 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
745 vis.visit_span(span);
746 vis.visit_generic_params(bound_generic_params);
747 vis.visit_ty(bounded_ty);
748 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
750 WherePredicate::RegionPredicate(rp) => {
751 let WhereRegionPredicate { span, lifetime, bounds } = rp;
752 vis.visit_span(span);
753 noop_visit_lifetime(lifetime, vis);
754 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
756 WherePredicate::EqPredicate(ep) => {
757 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
759 vis.visit_span(span);
760 vis.visit_ty(lhs_ty);
761 vis.visit_ty(rhs_ty);
766 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
768 VariantData::Struct(fields, id, _) |
769 VariantData::Tuple(fields, id) => {
770 visit_vec(fields, |field| vis.visit_struct_field(field));
773 VariantData::Unit(id) => vis.visit_id(id),
777 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
778 vis.visit_path(path);
779 vis.visit_id(ref_id);
782 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
783 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
784 vis.visit_generic_params(bound_generic_params);
785 vis.visit_trait_ref(trait_ref);
786 vis.visit_span(span);
789 pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
790 let StructField { span, ident, vis, id, ty, attrs } = f;
791 visitor.visit_span(span);
792 visit_opt(ident, |ident| visitor.visit_ident(ident));
793 visitor.visit_vis(vis);
794 visitor.visit_id(id);
795 visitor.visit_ty(ty);
796 visit_attrs(attrs, visitor);
799 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
800 let Field { ident, expr, span, is_shorthand: _, attrs } = f;
801 vis.visit_ident(ident);
802 vis.visit_expr(expr);
803 vis.visit_span(span);
804 visit_thin_attrs(attrs, vis);
807 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
811 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
812 let Block { id, stmts, rules: _, span } = block.deref_mut();
814 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
815 vis.visit_span(span);
818 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
820 ItemKind::ExternCrate(_orig_name) => {}
821 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
822 ItemKind::Static(ty, _mut, expr) => {
824 vis.visit_expr(expr);
826 ItemKind::Const(ty, expr) => {
828 vis.visit_expr(expr);
830 ItemKind::Fn(decl, header, generics, body) => {
831 vis.visit_fn_decl(decl);
832 vis.visit_fn_header(header);
833 vis.visit_generics(generics);
834 vis.visit_block(body);
836 ItemKind::Mod(m) => vis.visit_mod(m),
837 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
838 ItemKind::GlobalAsm(_ga) => {}
839 ItemKind::Ty(ty, generics) => {
841 vis.visit_generics(generics);
843 ItemKind::Existential(bounds, generics) => {
844 visit_bounds(bounds, vis);
845 vis.visit_generics(generics);
847 ItemKind::Enum(EnumDef { variants }, generics) => {
848 visit_vec(variants, |variant| vis.visit_variant(variant));
849 vis.visit_generics(generics);
851 ItemKind::Struct(variant_data, generics) |
852 ItemKind::Union(variant_data, generics) => {
853 vis.visit_variant_data(variant_data);
854 vis.visit_generics(generics);
856 ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
857 vis.visit_generics(generics);
858 visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
860 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
862 ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
863 vis.visit_generics(generics);
864 visit_bounds(bounds, vis);
865 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
867 ItemKind::TraitAlias(generics, bounds) => {
868 vis.visit_generics(generics);
869 visit_bounds(bounds, vis);
871 ItemKind::Mac(m) => vis.visit_mac(m),
872 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
876 pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
877 -> SmallVec<[TraitItem; 1]>
879 let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
881 vis.visit_ident(ident);
882 visit_attrs(attrs, vis);
883 vis.visit_generics(generics);
885 TraitItemKind::Const(ty, default) => {
887 visit_opt(default, |default| vis.visit_expr(default));
889 TraitItemKind::Method(sig, body) => {
890 visit_method_sig(sig, vis);
891 visit_opt(body, |body| vis.visit_block(body));
893 TraitItemKind::Type(bounds, default) => {
894 visit_bounds(bounds, vis);
895 visit_opt(default, |default| vis.visit_ty(default));
897 TraitItemKind::Macro(mac) => {
901 vis.visit_span(span);
906 pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
907 -> SmallVec<[ImplItem; 1]>
909 let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
911 visitor.visit_id(id);
912 visitor.visit_ident(ident);
913 visitor.visit_vis(vis);
914 visit_attrs(attrs, visitor);
915 visitor.visit_generics(generics);
917 ImplItemKind::Const(ty, expr) => {
918 visitor.visit_ty(ty);
919 visitor.visit_expr(expr);
921 ImplItemKind::Method(sig, body) => {
922 visit_method_sig(sig, visitor);
923 visitor.visit_block(body);
925 ImplItemKind::Type(ty) => visitor.visit_ty(ty),
926 ImplItemKind::Existential(bounds) => visit_bounds(bounds, visitor),
927 ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
929 visitor.visit_span(span);
934 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
935 let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
936 vis.visit_asyncness(&mut asyncness.node);
939 pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
940 vis.visit_span(inner);
941 items.flat_map_in_place(|item| vis.flat_map_item(item));
944 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
945 visit_clobber(krate, |Crate { module, attrs, span }| {
947 ident: keywords::Invalid.ident(),
950 vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
952 node: ItemKind::Mod(module),
955 let items = vis.flat_map_item(item);
957 let len = items.len();
959 let module = Mod { inner: span, items: vec![], inline: true };
960 Crate { module, attrs: vec![], span }
962 let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
964 ItemKind::Mod(module) => Crate { module, attrs, span },
965 _ => panic!("visitor converted a module to not a module"),
968 panic!("a crate cannot expand to more than one item");
973 // Mutate one item into possibly many items.
974 pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
975 -> SmallVec<[P<Item>; 1]> {
976 let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
977 visitor.visit_ident(ident);
978 visit_attrs(attrs, visitor);
979 visitor.visit_id(id);
980 visitor.visit_item_kind(node);
981 visitor.visit_vis(vis);
982 visitor.visit_span(span);
984 // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
985 // an ICE during resolve... odd!
990 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
991 -> SmallVec<[ForeignItem; 1]>
993 let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
994 visitor.visit_ident(ident);
995 visit_attrs(attrs, visitor);
997 ForeignItemKind::Fn(fdec, generics) => {
998 visitor.visit_fn_decl(fdec);
999 visitor.visit_generics(generics);
1001 ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
1002 ForeignItemKind::Ty => {}
1003 ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
1005 visitor.visit_id(id);
1006 visitor.visit_span(span);
1007 visitor.visit_vis(vis);
1012 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1013 let Pat { id, node, span } = pat.deref_mut();
1017 PatKind::Ident(_binding_mode, ident, sub) => {
1018 vis.visit_ident(ident);
1019 visit_opt(sub, |sub| vis.visit_pat(sub));
1021 PatKind::Lit(e) => vis.visit_expr(e),
1022 PatKind::TupleStruct(path, pats, _ddpos) => {
1023 vis.visit_path(path);
1024 visit_vec(pats, |pat| vis.visit_pat(pat));
1026 PatKind::Path(qself, path) => {
1027 vis.visit_qself(qself);
1028 vis.visit_path(path);
1030 PatKind::Struct(path, fields, _etc) => {
1031 vis.visit_path(path);
1032 for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
1033 vis.visit_ident(ident);
1035 visit_thin_attrs(attrs, vis);
1036 vis.visit_span(span);
1039 PatKind::Tuple(elts, _ddpos) => visit_vec(elts, |elt| vis.visit_pat(elt)),
1040 PatKind::Box(inner) => vis.visit_pat(inner),
1041 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1042 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1045 vis.visit_span(span);
1047 PatKind::Slice(before, slice, after) => {
1048 visit_vec(before, |pat| vis.visit_pat(pat));
1049 visit_opt(slice, |slice| vis.visit_pat(slice));
1050 visit_vec(after, |pat| vis.visit_pat(pat));
1052 PatKind::Paren(inner) => vis.visit_pat(inner),
1053 PatKind::Mac(mac) => vis.visit_mac(mac),
1055 vis.visit_span(span);
1058 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1060 vis.visit_expr(value);
1063 pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
1065 ExprKind::Box(expr) => vis.visit_expr(expr),
1066 ExprKind::ObsoleteInPlace(a, b) => {
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::Lit(_lit) => {}
1092 ExprKind::Cast(expr, ty) => {
1093 vis.visit_expr(expr);
1096 ExprKind::Type(expr, ty) => {
1097 vis.visit_expr(expr);
1100 ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
1101 ExprKind::If(cond, tr, fl) => {
1102 vis.visit_expr(cond);
1103 vis.visit_block(tr);
1104 visit_opt(fl, |fl| vis.visit_expr(fl));
1106 ExprKind::IfLet(pats, expr, tr, fl) => {
1107 visit_vec(pats, |pat| vis.visit_pat(pat));
1108 vis.visit_expr(expr);
1109 vis.visit_block(tr);
1110 visit_opt(fl, |fl| vis.visit_expr(fl));
1112 ExprKind::While(cond, body, label) => {
1113 vis.visit_expr(cond);
1114 vis.visit_block(body);
1115 visit_opt(label, |label| vis.visit_label(label));
1117 ExprKind::WhileLet(pats, expr, body, label) => {
1118 visit_vec(pats, |pat| vis.visit_pat(pat));
1119 vis.visit_expr(expr);
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::Assign(el, er) => {
1155 ExprKind::AssignOp(_op, el, er) => {
1159 ExprKind::Field(el, ident) => {
1161 vis.visit_ident(ident);
1163 ExprKind::Index(el, er) => {
1167 ExprKind::Range(e1, e2, _lim) => {
1168 visit_opt(e1, |e1| vis.visit_expr(e1));
1169 visit_opt(e2, |e2| vis.visit_expr(e2));
1171 ExprKind::Path(qself, path) => {
1172 vis.visit_qself(qself);
1173 vis.visit_path(path);
1175 ExprKind::Break(label, expr) => {
1176 visit_opt(label, |label| vis.visit_label(label));
1177 visit_opt(expr, |expr| vis.visit_expr(expr));
1179 ExprKind::Continue(label) => {
1180 visit_opt(label, |label| vis.visit_label(label));
1182 ExprKind::Ret(expr) => {
1183 visit_opt(expr, |expr| vis.visit_expr(expr));
1185 ExprKind::InlineAsm(asm) => {
1186 let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
1187 alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
1188 for out in outputs {
1189 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1190 vis.visit_expr(expr);
1192 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1194 ExprKind::Mac(mac) => vis.visit_mac(mac),
1195 ExprKind::Struct(path, fields, expr) => {
1196 vis.visit_path(path);
1197 visit_vec(fields, |field| vis.visit_field(field));
1198 visit_opt(expr, |expr| vis.visit_expr(expr));
1200 ExprKind::Paren(expr) => {
1201 vis.visit_expr(expr);
1203 // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
1205 vis.visit_span(span);
1206 visit_thin_attrs(attrs, vis);
1209 ExprKind::Yield(expr) => {
1210 visit_opt(expr, |expr| vis.visit_expr(expr));
1212 ExprKind::Try(expr) => vis.visit_expr(expr),
1213 ExprKind::TryBlock(body) => vis.visit_block(body),
1217 vis.visit_span(span);
1218 visit_thin_attrs(attrs, vis);
1221 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1222 Some({ vis.visit_expr(&mut e); e })
1225 pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
1226 -> SmallVec<[Stmt; 1]>
1228 vis.visit_id(&mut id);
1229 vis.visit_span(&mut span);
1230 noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
1231 Stmt { id, node, span }
1235 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
1236 -> SmallVec<[StmtKind; 1]> {
1238 StmtKind::Local(mut local) =>
1239 smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
1240 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1241 StmtKind::Expr(expr) => {
1242 vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
1244 StmtKind::Semi(expr) => {
1245 vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
1247 StmtKind::Mac(mut mac) => {
1248 let (mac_, _semi, attrs) = mac.deref_mut();
1249 vis.visit_mac(mac_);
1250 visit_thin_attrs(attrs, vis);
1251 smallvec![StmtKind::Mac(mac)]
1256 pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
1258 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1259 VisibilityKind::Restricted { path, id } => {
1260 vis.visit_path(path);
1264 vis.visit_span(span);
1270 use crate::ast::{self, Ident};
1271 use crate::util::parser_testing::{string_to_crate, matches_codepattern};
1272 use crate::print::pprust;
1273 use crate::mut_visit;
1274 use crate::with_globals;
1277 // this version doesn't care about getting comments or docstrings in.
1278 fn fake_print_crate(s: &mut pprust::State<'_>,
1279 krate: &ast::Crate) -> io::Result<()> {
1280 s.print_mod(&krate.module, &krate.attrs)
1283 // change every identifier to "zz"
1284 struct ToZzIdentMutVisitor;
1286 impl MutVisitor for ToZzIdentMutVisitor {
1287 fn visit_ident(&mut self, ident: &mut ast::Ident) {
1288 *ident = Ident::from_str("zz");
1290 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1291 mut_visit::noop_visit_mac(mac, self)
1295 // maybe add to expand.rs...
1296 macro_rules! assert_pred {
1297 ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
1299 let pred_val = $pred;
1302 if !(pred_val(&a_val, &b_val)) {
1303 panic!("expected args satisfying {}, got {} and {}",
1304 $predname, a_val, b_val);
1310 // make sure idents get transformed everywhere
1311 #[test] fn ident_transformation () {
1313 let mut zz_visitor = ToZzIdentMutVisitor;
1314 let mut krate = string_to_crate(
1315 "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
1316 zz_visitor.visit_crate(&mut krate);
1318 matches_codepattern,
1319 "matches_codepattern",
1320 pprust::to_string(|s| fake_print_crate(s, &krate)),
1321 "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
1325 // even inside macro defs....
1326 #[test] fn ident_transformation_in_defs () {
1328 let mut zz_visitor = ToZzIdentMutVisitor;
1329 let mut krate = string_to_crate(
1330 "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
1331 (g $(d $d $e)+))} ".to_string());
1332 zz_visitor.visit_crate(&mut krate);
1334 matches_codepattern,
1335 "matches_codepattern",
1336 pprust::to_string(|s| fake_print_crate(s, &krate)),
1337 "macro_rules! zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());