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.
4 //!
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.
9
10 use crate::ast::*;
11 use crate::ptr::P;
12 use crate::token::{self, Token};
13 use crate::tokenstream::*;
14
15 use rustc_data_structures::map_in_place::MapInPlace;
16 use rustc_data_structures::sync::Lrc;
17 use rustc_span::source_map::Spanned;
18 use rustc_span::symbol::Ident;
19 use rustc_span::Span;
20
21 use smallvec::{smallvec, Array, SmallVec};
22 use std::ops::DerefMut;
23 use std::{panic, process, ptr};
24
25 pub trait ExpectOne<A: Array> {
expect_one(self, err: &'static str) -> A::Item26 fn expect_one(self, err: &'static str) -> A::Item;
27 }
28
29 impl<A: Array> ExpectOne<A> for SmallVec<A> {
expect_one(self, err: &'static str) -> A::Item30 fn expect_one(self, err: &'static str) -> A::Item {
31 assert!(self.len() == 1, "{}", err);
32 self.into_iter().next().unwrap()
33 }
34 }
35
36 pub trait MutVisitor: Sized {
37 /// Mutable token visiting only exists for the `macro_rules` token marker and should not be
38 /// used otherwise. Token visitor would be entirely separate from the regular visitor if
39 /// the marker didn't have to visit AST fragments in nonterminal tokens.
40 const VISIT_TOKENS: bool = false;
41
42 // Methods in this trait have one of three forms:
43 //
44 // fn visit_t(&mut self, t: &mut T); // common
45 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
46 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
47 //
48 // Any additions to this trait should happen in form of a call to a public
49 // `noop_*` function that only calls out to the visitor again, not other
50 // `noop_*` functions. This is a necessary API workaround to the problem of
51 // not being able to call out to the super default method in an overridden
52 // default method.
53 //
54 // When writing these methods, it is better to use destructuring like this:
55 //
56 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
57 // visit_a(a);
58 // visit_b(b);
59 // }
60 //
61 // than to use field access like this:
62 //
63 // fn visit_abc(&mut self, abc: &mut ABC) {
64 // visit_a(&mut abc.a);
65 // visit_b(&mut abc.b);
66 // // ignore abc.c
67 // }
68 //
69 // As well as being more concise, the former is explicit about which fields
70 // are skipped. Furthermore, if a new field is added, the destructuring
71 // version will cause a compile error, which is good. In comparison, the
72 // field access version will continue working and it would be easy to
73 // forget to add handling for it.
74
visit_crate(&mut self, c: &mut Crate)75 fn visit_crate(&mut self, c: &mut Crate) {
76 noop_visit_crate(c, self)
77 }
78
visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem)79 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
80 noop_visit_meta_list_item(list_item, self);
81 }
82
visit_meta_item(&mut self, meta_item: &mut MetaItem)83 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
84 noop_visit_meta_item(meta_item, self);
85 }
86
visit_use_tree(&mut self, use_tree: &mut UseTree)87 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
88 noop_visit_use_tree(use_tree, self);
89 }
90
flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]>91 fn flat_map_foreign_item(&mut self, ni: P<ForeignItem>) -> SmallVec<[P<ForeignItem>; 1]> {
92 noop_flat_map_foreign_item(ni, self)
93 }
94
flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]>95 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
96 noop_flat_map_item(i, self)
97 }
98
visit_fn_header(&mut self, header: &mut FnHeader)99 fn visit_fn_header(&mut self, header: &mut FnHeader) {
100 noop_visit_fn_header(header, self);
101 }
102
flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]>103 fn flat_map_field_def(&mut self, fd: FieldDef) -> SmallVec<[FieldDef; 1]> {
104 noop_flat_map_field_def(fd, self)
105 }
106
visit_item_kind(&mut self, i: &mut ItemKind)107 fn visit_item_kind(&mut self, i: &mut ItemKind) {
108 noop_visit_item_kind(i, self);
109 }
110
flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]>111 fn flat_map_trait_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
112 noop_flat_map_assoc_item(i, self)
113 }
114
flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]>115 fn flat_map_impl_item(&mut self, i: P<AssocItem>) -> SmallVec<[P<AssocItem>; 1]> {
116 noop_flat_map_assoc_item(i, self)
117 }
118
visit_fn_decl(&mut self, d: &mut P<FnDecl>)119 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
120 noop_visit_fn_decl(d, self);
121 }
122
visit_asyncness(&mut self, a: &mut Async)123 fn visit_asyncness(&mut self, a: &mut Async) {
124 noop_visit_asyncness(a, self);
125 }
126
visit_block(&mut self, b: &mut P<Block>)127 fn visit_block(&mut self, b: &mut P<Block>) {
128 noop_visit_block(b, self);
129 }
130
flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]>131 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
132 noop_flat_map_stmt(s, self)
133 }
134
flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]>135 fn flat_map_arm(&mut self, arm: Arm) -> SmallVec<[Arm; 1]> {
136 noop_flat_map_arm(arm, self)
137 }
138
visit_pat(&mut self, p: &mut P<Pat>)139 fn visit_pat(&mut self, p: &mut P<Pat>) {
140 noop_visit_pat(p, self);
141 }
142
visit_anon_const(&mut self, c: &mut AnonConst)143 fn visit_anon_const(&mut self, c: &mut AnonConst) {
144 noop_visit_anon_const(c, self);
145 }
146
visit_expr(&mut self, e: &mut P<Expr>)147 fn visit_expr(&mut self, e: &mut P<Expr>) {
148 noop_visit_expr(e, self);
149 }
150
filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>>151 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
152 noop_filter_map_expr(e, self)
153 }
154
visit_generic_arg(&mut self, arg: &mut GenericArg)155 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
156 noop_visit_generic_arg(arg, self);
157 }
158
visit_ty(&mut self, t: &mut P<Ty>)159 fn visit_ty(&mut self, t: &mut P<Ty>) {
160 noop_visit_ty(t, self);
161 }
162
visit_lifetime(&mut self, l: &mut Lifetime)163 fn visit_lifetime(&mut self, l: &mut Lifetime) {
164 noop_visit_lifetime(l, self);
165 }
166
visit_ty_constraint(&mut self, t: &mut AssocTyConstraint)167 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
168 noop_visit_ty_constraint(t, self);
169 }
170
visit_foreign_mod(&mut self, nm: &mut ForeignMod)171 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
172 noop_visit_foreign_mod(nm, self);
173 }
174
flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]>175 fn flat_map_variant(&mut self, v: Variant) -> SmallVec<[Variant; 1]> {
176 noop_flat_map_variant(v, self)
177 }
178
visit_ident(&mut self, i: &mut Ident)179 fn visit_ident(&mut self, i: &mut Ident) {
180 noop_visit_ident(i, self);
181 }
182
visit_path(&mut self, p: &mut Path)183 fn visit_path(&mut self, p: &mut Path) {
184 noop_visit_path(p, self);
185 }
186
visit_qself(&mut self, qs: &mut Option<QSelf>)187 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
188 noop_visit_qself(qs, self);
189 }
190
visit_generic_args(&mut self, p: &mut GenericArgs)191 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
192 noop_visit_generic_args(p, self);
193 }
194
visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs)195 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
196 noop_visit_angle_bracketed_parameter_data(p, self);
197 }
198
visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs)199 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
200 noop_visit_parenthesized_parameter_data(p, self);
201 }
202
visit_local(&mut self, l: &mut P<Local>)203 fn visit_local(&mut self, l: &mut P<Local>) {
204 noop_visit_local(l, self);
205 }
206
visit_mac_call(&mut self, mac: &mut MacCall)207 fn visit_mac_call(&mut self, mac: &mut MacCall) {
208 noop_visit_mac(mac, self);
209 }
210
visit_macro_def(&mut self, def: &mut MacroDef)211 fn visit_macro_def(&mut self, def: &mut MacroDef) {
212 noop_visit_macro_def(def, self);
213 }
214
visit_label(&mut self, label: &mut Label)215 fn visit_label(&mut self, label: &mut Label) {
216 noop_visit_label(label, self);
217 }
218
visit_attribute(&mut self, at: &mut Attribute)219 fn visit_attribute(&mut self, at: &mut Attribute) {
220 noop_visit_attribute(at, self);
221 }
222
flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]>223 fn flat_map_param(&mut self, param: Param) -> SmallVec<[Param; 1]> {
224 noop_flat_map_param(param, self)
225 }
226
visit_generics(&mut self, generics: &mut Generics)227 fn visit_generics(&mut self, generics: &mut Generics) {
228 noop_visit_generics(generics, self);
229 }
230
visit_trait_ref(&mut self, tr: &mut TraitRef)231 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
232 noop_visit_trait_ref(tr, self);
233 }
234
visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef)235 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
236 noop_visit_poly_trait_ref(p, self);
237 }
238
visit_variant_data(&mut self, vdata: &mut VariantData)239 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
240 noop_visit_variant_data(vdata, self);
241 }
242
flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]>243 fn flat_map_generic_param(&mut self, param: GenericParam) -> SmallVec<[GenericParam; 1]> {
244 noop_flat_map_generic_param(param, self)
245 }
246
visit_param_bound(&mut self, tpb: &mut GenericBound)247 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
248 noop_visit_param_bound(tpb, self);
249 }
250
visit_mt(&mut self, mt: &mut MutTy)251 fn visit_mt(&mut self, mt: &mut MutTy) {
252 noop_visit_mt(mt, self);
253 }
254
flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]>255 fn flat_map_expr_field(&mut self, f: ExprField) -> SmallVec<[ExprField; 1]> {
256 noop_flat_map_expr_field(f, self)
257 }
258
visit_where_clause(&mut self, where_clause: &mut WhereClause)259 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
260 noop_visit_where_clause(where_clause, self);
261 }
262
visit_where_predicate(&mut self, where_predicate: &mut WherePredicate)263 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
264 noop_visit_where_predicate(where_predicate, self);
265 }
266
visit_vis(&mut self, vis: &mut Visibility)267 fn visit_vis(&mut self, vis: &mut Visibility) {
268 noop_visit_vis(vis, self);
269 }
270
visit_id(&mut self, _id: &mut NodeId)271 fn visit_id(&mut self, _id: &mut NodeId) {
272 // Do nothing.
273 }
274
visit_span(&mut self, _sp: &mut Span)275 fn visit_span(&mut self, _sp: &mut Span) {
276 // Do nothing.
277 }
278
flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]>279 fn flat_map_pat_field(&mut self, fp: PatField) -> SmallVec<[PatField; 1]> {
280 noop_flat_map_pat_field(fp, self)
281 }
282 }
283
284 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
285 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
286 /// method. Abort the program if the closure panics.
287 //
288 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T,289 pub fn visit_clobber<T, F>(t: &mut T, f: F)
290 where
291 F: FnOnce(T) -> T,
292 {
293 unsafe {
294 // Safe because `t` is used in a read-only fashion by `read()` before
295 // being overwritten by `write()`.
296 let old_t = ptr::read(t);
297 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
298 .unwrap_or_else(|_| process::abort());
299 ptr::write(t, new_t);
300 }
301 }
302
303 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
304 #[inline]
visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T),305 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
306 where
307 F: FnMut(&mut T),
308 {
309 for elem in elems {
310 visit_elem(elem);
311 }
312 }
313
314 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
315 #[inline]
visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T),316 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
317 where
318 F: FnMut(&mut T),
319 {
320 if let Some(elem) = opt {
321 visit_elem(elem);
322 }
323 }
324
325 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T)326 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
327 visit_vec(attrs, |attr| vis.visit_attribute(attr));
328 }
329
330 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T)331 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
332 for attr in attrs.iter_mut() {
333 vis.visit_attribute(attr);
334 }
335 }
336
337 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T)338 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
339 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
340 }
341
342 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T)343 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
344 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
345 }
346
347 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
348 pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
349 vis.visit_fn_header(header);
350 vis.visit_fn_decl(decl);
351 vis.visit_span(span);
352 }
353
354 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T)355 pub fn visit_mac_args<T: MutVisitor>(args: &mut MacArgs, vis: &mut T) {
356 match args {
357 MacArgs::Empty => {}
358 MacArgs::Delimited(dspan, _delim, tokens) => {
359 visit_delim_span(dspan, vis);
360 visit_tts(tokens, vis);
361 }
362 MacArgs::Eq(eq_span, token) => {
363 vis.visit_span(eq_span);
364 if T::VISIT_TOKENS {
365 visit_token(token, vis);
366 } else {
367 // The value in `#[key = VALUE]` must be visited as an expression for backward
368 // compatibility, so that macros can be expanded in that position.
369 match &mut token.kind {
370 token::Interpolated(nt) => match Lrc::make_mut(nt) {
371 token::NtExpr(expr) => vis.visit_expr(expr),
372 t => panic!("unexpected token in key-value attribute: {:?}", t),
373 },
374 t => panic!("unexpected token in key-value attribute: {:?}", t),
375 }
376 }
377 }
378 }
379 }
380
visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T)381 pub fn visit_delim_span<T: MutVisitor>(dspan: &mut DelimSpan, vis: &mut T) {
382 vis.visit_span(&mut dspan.open);
383 vis.visit_span(&mut dspan.close);
384 }
385
noop_flat_map_pat_field<T: MutVisitor>( mut fp: PatField, vis: &mut T, ) -> SmallVec<[PatField; 1]>386 pub fn noop_flat_map_pat_field<T: MutVisitor>(
387 mut fp: PatField,
388 vis: &mut T,
389 ) -> SmallVec<[PatField; 1]> {
390 let PatField { attrs, id, ident, is_placeholder: _, is_shorthand: _, pat, span } = &mut fp;
391 vis.visit_id(id);
392 vis.visit_ident(ident);
393 vis.visit_pat(pat);
394 vis.visit_span(span);
395 visit_thin_attrs(attrs, vis);
396 smallvec![fp]
397 }
398
noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T)399 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
400 let UseTree { prefix, kind, span } = use_tree;
401 vis.visit_path(prefix);
402 match kind {
403 UseTreeKind::Simple(rename, id1, id2) => {
404 visit_opt(rename, |rename| vis.visit_ident(rename));
405 vis.visit_id(id1);
406 vis.visit_id(id2);
407 }
408 UseTreeKind::Nested(items) => {
409 for (tree, id) in items {
410 vis.visit_use_tree(tree);
411 vis.visit_id(id);
412 }
413 }
414 UseTreeKind::Glob => {}
415 }
416 vis.visit_span(span);
417 }
418
noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]>419 pub fn noop_flat_map_arm<T: MutVisitor>(mut arm: Arm, vis: &mut T) -> SmallVec<[Arm; 1]> {
420 let Arm { attrs, pat, guard, body, span, id, is_placeholder: _ } = &mut arm;
421 visit_thin_attrs(attrs, vis);
422 vis.visit_id(id);
423 vis.visit_pat(pat);
424 visit_opt(guard, |guard| vis.visit_expr(guard));
425 vis.visit_expr(body);
426 vis.visit_span(span);
427 smallvec![arm]
428 }
429
430 pub fn noop_visit_ty_constraint<T: MutVisitor>(
431 AssocTyConstraint { id, ident, gen_args, kind, span }: &mut AssocTyConstraint,
432 vis: &mut T,
433 ) {
434 vis.visit_id(id);
435 vis.visit_ident(ident);
436 if let Some(ref mut gen_args) = gen_args {
437 vis.visit_generic_args(gen_args);
438 }
439 match kind {
440 AssocTyConstraintKind::Equality { ref mut ty } => {
441 vis.visit_ty(ty);
442 }
443 AssocTyConstraintKind::Bound { ref mut bounds } => {
444 visit_bounds(bounds, vis);
445 }
446 }
447 vis.visit_span(span);
448 }
449
noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T)450 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
451 let Ty { id, kind, span, tokens } = ty.deref_mut();
452 vis.visit_id(id);
453 match kind {
454 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never | TyKind::CVarArgs => {}
455 TyKind::Slice(ty) => vis.visit_ty(ty),
456 TyKind::Ptr(mt) => vis.visit_mt(mt),
457 TyKind::Rptr(lt, mt) => {
458 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
459 vis.visit_mt(mt);
460 }
461 TyKind::BareFn(bft) => {
462 let BareFnTy { unsafety, ext: _, generic_params, decl } = bft.deref_mut();
463 visit_unsafety(unsafety, vis);
464 generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
465 vis.visit_fn_decl(decl);
466 }
467 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
468 TyKind::Paren(ty) => vis.visit_ty(ty),
469 TyKind::Path(qself, path) => {
470 vis.visit_qself(qself);
471 vis.visit_path(path);
472 }
473 TyKind::Array(ty, length) => {
474 vis.visit_ty(ty);
475 vis.visit_anon_const(length);
476 }
477 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
478 TyKind::TraitObject(bounds, _syntax) => {
479 visit_vec(bounds, |bound| vis.visit_param_bound(bound))
480 }
481 TyKind::ImplTrait(id, bounds) => {
482 vis.visit_id(id);
483 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
484 }
485 TyKind::MacCall(mac) => vis.visit_mac_call(mac),
486 }
487 vis.visit_span(span);
488 visit_lazy_tts(tokens, vis);
489 }
490
noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T)491 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
492 let ForeignMod { unsafety, abi: _, items } = foreign_mod;
493 visit_unsafety(unsafety, vis);
494 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
495 }
496
noop_flat_map_variant<T: MutVisitor>( mut variant: Variant, visitor: &mut T, ) -> SmallVec<[Variant; 1]>497 pub fn noop_flat_map_variant<T: MutVisitor>(
498 mut variant: Variant,
499 visitor: &mut T,
500 ) -> SmallVec<[Variant; 1]> {
501 let Variant { ident, vis, attrs, id, data, disr_expr, span, is_placeholder: _ } = &mut variant;
502 visitor.visit_ident(ident);
503 visitor.visit_vis(vis);
504 visit_thin_attrs(attrs, visitor);
505 visitor.visit_id(id);
506 visitor.visit_variant_data(data);
507 visit_opt(disr_expr, |disr_expr| visitor.visit_anon_const(disr_expr));
508 visitor.visit_span(span);
509 smallvec![variant]
510 }
511
512 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
513 vis.visit_span(span);
514 }
515
516 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
517 vis.visit_span(span);
518 for PathSegment { ident, id, args } in segments {
519 vis.visit_ident(ident);
520 vis.visit_id(id);
521 visit_opt(args, |args| vis.visit_generic_args(args));
522 }
523 visit_lazy_tts(tokens, vis);
524 }
525
noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T)526 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
527 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
528 vis.visit_ty(ty);
529 vis.visit_span(path_span);
530 })
531 }
532
noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T)533 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
534 match generic_args {
535 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
536 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
537 }
538 }
539
noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T)540 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
541 match arg {
542 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
543 GenericArg::Type(ty) => vis.visit_ty(ty),
544 GenericArg::Const(ct) => vis.visit_anon_const(ct),
545 }
546 }
547
noop_visit_angle_bracketed_parameter_data<T: MutVisitor>( data: &mut AngleBracketedArgs, vis: &mut T, )548 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
549 data: &mut AngleBracketedArgs,
550 vis: &mut T,
551 ) {
552 let AngleBracketedArgs { args, span } = data;
553 visit_vec(args, |arg| match arg {
554 AngleBracketedArg::Arg(arg) => vis.visit_generic_arg(arg),
555 AngleBracketedArg::Constraint(constraint) => vis.visit_ty_constraint(constraint),
556 });
557 vis.visit_span(span);
558 }
559
noop_visit_parenthesized_parameter_data<T: MutVisitor>( args: &mut ParenthesizedArgs, vis: &mut T, )560 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
561 args: &mut ParenthesizedArgs,
562 vis: &mut T,
563 ) {
564 let ParenthesizedArgs { inputs, output, span, .. } = args;
565 visit_vec(inputs, |input| vis.visit_ty(input));
566 noop_visit_fn_ret_ty(output, vis);
567 vis.visit_span(span);
568 }
569
noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T)570 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
571 let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
572 vis.visit_id(id);
573 vis.visit_pat(pat);
574 visit_opt(ty, |ty| vis.visit_ty(ty));
575 match kind {
576 LocalKind::Decl => {}
577 LocalKind::Init(init) => {
578 vis.visit_expr(init);
579 }
580 LocalKind::InitElse(init, els) => {
581 vis.visit_expr(init);
582 vis.visit_block(els);
583 }
584 }
585 vis.visit_span(span);
586 visit_thin_attrs(attrs, vis);
587 visit_lazy_tts(tokens, vis);
588 }
589
noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T)590 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
591 let Attribute { kind, id: _, style: _, span } = attr;
592 match kind {
593 AttrKind::Normal(AttrItem { path, args, tokens }, attr_tokens) => {
594 vis.visit_path(path);
595 visit_mac_args(args, vis);
596 visit_lazy_tts(tokens, vis);
597 visit_lazy_tts(attr_tokens, vis);
598 }
599 AttrKind::DocComment(..) => {}
600 }
601 vis.visit_span(span);
602 }
603
noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T)604 pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
605 let MacCall { path, args, prior_type_ascription: _ } = mac;
606 vis.visit_path(path);
607 visit_mac_args(args, vis);
608 }
609
noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T)610 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
611 let MacroDef { body, macro_rules: _ } = macro_def;
612 visit_mac_args(body, vis);
613 }
614
noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T)615 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
616 match li {
617 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
618 NestedMetaItem::Literal(_lit) => {}
619 }
620 }
621
noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T)622 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
623 let MetaItem { path: _, kind, span } = mi;
624 match kind {
625 MetaItemKind::Word => {}
626 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
627 MetaItemKind::NameValue(_s) => {}
628 }
629 vis.visit_span(span);
630 }
631
noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]>632 pub fn noop_flat_map_param<T: MutVisitor>(mut param: Param, vis: &mut T) -> SmallVec<[Param; 1]> {
633 let Param { attrs, id, pat, span, ty, is_placeholder: _ } = &mut param;
634 vis.visit_id(id);
635 visit_thin_attrs(attrs, vis);
636 vis.visit_pat(pat);
637 vis.visit_span(span);
638 vis.visit_ty(ty);
639 smallvec![param]
640 }
641
642 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T)643 pub fn visit_attr_annotated_tt<T: MutVisitor>(tt: &mut AttrAnnotatedTokenTree, vis: &mut T) {
644 match tt {
645 AttrAnnotatedTokenTree::Token(token) => {
646 visit_token(token, vis);
647 }
648 AttrAnnotatedTokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
649 vis.visit_span(open);
650 vis.visit_span(close);
651 visit_attr_annotated_tts(tts, vis);
652 }
653 AttrAnnotatedTokenTree::Attributes(data) => {
654 for attr in &mut *data.attrs {
655 match &mut attr.kind {
656 AttrKind::Normal(_, attr_tokens) => {
657 visit_lazy_tts(attr_tokens, vis);
658 }
659 AttrKind::DocComment(..) => {
660 vis.visit_span(&mut attr.span);
661 }
662 }
663 }
664 visit_lazy_tts_opt_mut(Some(&mut data.tokens), vis);
665 }
666 }
667 }
668
669 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T)670 pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
671 match tt {
672 TokenTree::Token(token) => {
673 visit_token(token, vis);
674 }
675 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
676 vis.visit_span(open);
677 vis.visit_span(close);
678 visit_tts(tts, vis);
679 }
680 }
681 }
682
683 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T)684 pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
685 if T::VISIT_TOKENS && !tts.is_empty() {
686 let tts = Lrc::make_mut(tts);
687 visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis));
688 }
689 }
690
visit_attr_annotated_tts<T: MutVisitor>( AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream, vis: &mut T, )691 pub fn visit_attr_annotated_tts<T: MutVisitor>(
692 AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream,
693 vis: &mut T,
694 ) {
695 if T::VISIT_TOKENS && !tts.is_empty() {
696 let tts = Lrc::make_mut(tts);
697 visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis));
698 }
699 }
700
visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T)701 pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) {
702 if T::VISIT_TOKENS {
703 if let Some(lazy_tts) = lazy_tts {
704 let mut tts = lazy_tts.create_token_stream();
705 visit_attr_annotated_tts(&mut tts, vis);
706 *lazy_tts = LazyTokenStream::new(tts);
707 }
708 }
709 }
710
visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T)711 pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyTokenStream>, vis: &mut T) {
712 visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
713 }
714
715 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
716 // Applies ident visitor if it's an ident; applies other visits to interpolated nodes.
717 // In practice the ident part is not actually used by specific visitors right now,
718 // but there's a test below checking that it works.
visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T)719 pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
720 let Token { kind, span } = t;
721 match kind {
722 token::Ident(name, _) | token::Lifetime(name) => {
723 let mut ident = Ident::new(*name, *span);
724 vis.visit_ident(&mut ident);
725 *name = ident.name;
726 *span = ident.span;
727 return; // Avoid visiting the span for the second time.
728 }
729 token::Interpolated(nt) => {
730 let mut nt = Lrc::make_mut(nt);
731 visit_interpolated(&mut nt, vis);
732 }
733 _ => {}
734 }
735 vis.visit_span(span);
736 }
737
738 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
739 /// Applies the visitor to elements of interpolated nodes.
740 //
741 // N.B., this can occur only when applying a visitor to partially expanded
742 // code, where parsed pieces have gotten implanted ito *other* macro
743 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
744 //
745 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
746 // etc., allow the visitor to return *multiple* items; this is a problem for the
747 // nodes here, because they insist on having exactly one piece. One solution
748 // would be to mangle the MutVisitor trait to include one-to-many and
749 // one-to-one versions of these entry points, but that would probably confuse a
750 // lot of people and help very few. Instead, I'm just going to put in dynamic
751 // checks. I think the performance impact of this will be pretty much
752 // nonexistent. The danger is that someone will apply a `MutVisitor` to a
753 // partially expanded node, and will be confused by the fact that their
754 // `flat_map_item` or `flat_map_stmt` isn't getting called on `NtItem` or `NtStmt`
755 // nodes. Hopefully they'll wind up reading this comment, and doing something
756 // appropriate.
757 //
758 // BTW, design choice: I considered just changing the type of, e.g., `NtItem` to
759 // contain multiple items, but decided against it when I looked at
760 // `parse_item_or_view_item` and tried to figure out what I would do with
761 // multiple items there....
visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T)762 pub fn visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
763 match nt {
764 token::NtItem(item) => visit_clobber(item, |item| {
765 // This is probably okay, because the only visitors likely to
766 // peek inside interpolated nodes will be renamings/markings,
767 // which map single items to single items.
768 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
769 }),
770 token::NtBlock(block) => vis.visit_block(block),
771 token::NtStmt(stmt) => visit_clobber(stmt, |stmt| {
772 // See reasoning above.
773 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
774 }),
775 token::NtPat(pat) => vis.visit_pat(pat),
776 token::NtExpr(expr) => vis.visit_expr(expr),
777 token::NtTy(ty) => vis.visit_ty(ty),
778 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
779 token::NtLifetime(ident) => vis.visit_ident(ident),
780 token::NtLiteral(expr) => vis.visit_expr(expr),
781 token::NtMeta(item) => {
782 let AttrItem { path, args, tokens } = item.deref_mut();
783 vis.visit_path(path);
784 visit_mac_args(args, vis);
785 visit_lazy_tts(tokens, vis);
786 }
787 token::NtPath(path) => vis.visit_path(path),
788 token::NtTT(tt) => visit_tt(tt, vis),
789 token::NtVis(visib) => vis.visit_vis(visib),
790 }
791 }
792
793 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T)794 pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
795 match defaultness {
796 Defaultness::Default(span) => vis.visit_span(span),
797 Defaultness::Final => {}
798 }
799 }
800
801 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T)802 pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
803 match unsafety {
804 Unsafe::Yes(span) => vis.visit_span(span),
805 Unsafe::No => {}
806 }
807 }
808
809 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T)810 pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
811 match polarity {
812 ImplPolarity::Positive => {}
813 ImplPolarity::Negative(span) => vis.visit_span(span),
814 }
815 }
816
817 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T)818 pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
819 match constness {
820 Const::Yes(span) => vis.visit_span(span),
821 Const::No => {}
822 }
823 }
824
noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T)825 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut Async, vis: &mut T) {
826 match asyncness {
827 Async::Yes { span: _, closure_id, return_impl_trait_id } => {
828 vis.visit_id(closure_id);
829 vis.visit_id(return_impl_trait_id);
830 }
831 Async::No => {}
832 }
833 }
834
noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T)835 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
836 let FnDecl { inputs, output } = decl.deref_mut();
837 inputs.flat_map_in_place(|param| vis.flat_map_param(param));
838 noop_visit_fn_ret_ty(output, vis);
839 }
840
noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T)841 pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
842 match fn_ret_ty {
843 FnRetTy::Default(span) => vis.visit_span(span),
844 FnRetTy::Ty(ty) => vis.visit_ty(ty),
845 }
846 }
847
noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T)848 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
849 match pb {
850 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
851 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
852 }
853 }
854
noop_flat_map_generic_param<T: MutVisitor>( mut param: GenericParam, vis: &mut T, ) -> SmallVec<[GenericParam; 1]>855 pub fn noop_flat_map_generic_param<T: MutVisitor>(
856 mut param: GenericParam,
857 vis: &mut T,
858 ) -> SmallVec<[GenericParam; 1]> {
859 let GenericParam { id, ident, attrs, bounds, kind, is_placeholder: _ } = &mut param;
860 vis.visit_id(id);
861 vis.visit_ident(ident);
862 visit_thin_attrs(attrs, vis);
863 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
864 match kind {
865 GenericParamKind::Lifetime => {}
866 GenericParamKind::Type { default } => {
867 visit_opt(default, |default| vis.visit_ty(default));
868 }
869 GenericParamKind::Const { ty, kw_span: _, default } => {
870 vis.visit_ty(ty);
871 visit_opt(default, |default| vis.visit_anon_const(default));
872 }
873 }
874 smallvec![param]
875 }
876
877 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
878 vis.visit_ident(ident);
879 }
880
881 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
882 vis.visit_id(id);
883 vis.visit_ident(ident);
884 }
885
noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T)886 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
887 let Generics { params, where_clause, span } = generics;
888 params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
889 vis.visit_where_clause(where_clause);
890 vis.visit_span(span);
891 }
892
noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T)893 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
894 let WhereClause { has_where_token: _, predicates, span } = wc;
895 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
896 vis.visit_span(span);
897 }
898
noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T)899 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
900 match pred {
901 WherePredicate::BoundPredicate(bp) => {
902 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
903 vis.visit_span(span);
904 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
905 vis.visit_ty(bounded_ty);
906 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
907 }
908 WherePredicate::RegionPredicate(rp) => {
909 let WhereRegionPredicate { span, lifetime, bounds } = rp;
910 vis.visit_span(span);
911 noop_visit_lifetime(lifetime, vis);
912 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
913 }
914 WherePredicate::EqPredicate(ep) => {
915 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
916 vis.visit_id(id);
917 vis.visit_span(span);
918 vis.visit_ty(lhs_ty);
919 vis.visit_ty(rhs_ty);
920 }
921 }
922 }
923
noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T)924 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
925 match vdata {
926 VariantData::Struct(fields, ..) => {
927 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
928 }
929 VariantData::Tuple(fields, id) => {
930 fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
931 vis.visit_id(id);
932 }
933 VariantData::Unit(id) => vis.visit_id(id),
934 }
935 }
936
937 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
938 vis.visit_path(path);
939 vis.visit_id(ref_id);
940 }
941
noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T)942 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
943 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
944 bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
945 vis.visit_trait_ref(trait_ref);
946 vis.visit_span(span);
947 }
948
noop_flat_map_field_def<T: MutVisitor>( mut fd: FieldDef, visitor: &mut T, ) -> SmallVec<[FieldDef; 1]>949 pub fn noop_flat_map_field_def<T: MutVisitor>(
950 mut fd: FieldDef,
951 visitor: &mut T,
952 ) -> SmallVec<[FieldDef; 1]> {
953 let FieldDef { span, ident, vis, id, ty, attrs, is_placeholder: _ } = &mut fd;
954 visitor.visit_span(span);
955 visit_opt(ident, |ident| visitor.visit_ident(ident));
956 visitor.visit_vis(vis);
957 visitor.visit_id(id);
958 visitor.visit_ty(ty);
959 visit_thin_attrs(attrs, visitor);
960 smallvec![fd]
961 }
962
noop_flat_map_expr_field<T: MutVisitor>( mut f: ExprField, vis: &mut T, ) -> SmallVec<[ExprField; 1]>963 pub fn noop_flat_map_expr_field<T: MutVisitor>(
964 mut f: ExprField,
965 vis: &mut T,
966 ) -> SmallVec<[ExprField; 1]> {
967 let ExprField { ident, expr, span, is_shorthand: _, attrs, id, is_placeholder: _ } = &mut f;
968 vis.visit_ident(ident);
969 vis.visit_expr(expr);
970 vis.visit_id(id);
971 vis.visit_span(span);
972 visit_thin_attrs(attrs, vis);
973 smallvec![f]
974 }
975
976 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
977 vis.visit_ty(ty);
978 }
979
noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T)980 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
981 let Block { id, stmts, rules: _, span, tokens, could_be_bare_literal: _ } = block.deref_mut();
982 vis.visit_id(id);
983 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
984 vis.visit_span(span);
985 visit_lazy_tts(tokens, vis);
986 }
987
noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T)988 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
989 match kind {
990 ItemKind::ExternCrate(_orig_name) => {}
991 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
992 ItemKind::Static(ty, _, expr) => {
993 vis.visit_ty(ty);
994 visit_opt(expr, |expr| vis.visit_expr(expr));
995 }
996 ItemKind::Const(defaultness, ty, expr) => {
997 visit_defaultness(defaultness, vis);
998 vis.visit_ty(ty);
999 visit_opt(expr, |expr| vis.visit_expr(expr));
1000 }
1001 ItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1002 visit_defaultness(defaultness, vis);
1003 visit_fn_sig(sig, vis);
1004 vis.visit_generics(generics);
1005 visit_opt(body, |body| vis.visit_block(body));
1006 }
1007 ItemKind::Mod(unsafety, mod_kind) => {
1008 visit_unsafety(unsafety, vis);
1009 match mod_kind {
1010 ModKind::Loaded(items, _inline, inner_span) => {
1011 vis.visit_span(inner_span);
1012 items.flat_map_in_place(|item| vis.flat_map_item(item));
1013 }
1014 ModKind::Unloaded => {}
1015 }
1016 }
1017 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
1018 ItemKind::GlobalAsm(asm) => noop_visit_inline_asm(asm, vis),
1019 ItemKind::TyAlias(box TyAlias { defaultness, generics, bounds, ty }) => {
1020 visit_defaultness(defaultness, vis);
1021 vis.visit_generics(generics);
1022 visit_bounds(bounds, vis);
1023 visit_opt(ty, |ty| vis.visit_ty(ty));
1024 }
1025 ItemKind::Enum(EnumDef { variants }, generics) => {
1026 variants.flat_map_in_place(|variant| vis.flat_map_variant(variant));
1027 vis.visit_generics(generics);
1028 }
1029 ItemKind::Struct(variant_data, generics) | ItemKind::Union(variant_data, generics) => {
1030 vis.visit_variant_data(variant_data);
1031 vis.visit_generics(generics);
1032 }
1033 ItemKind::Impl(box Impl {
1034 defaultness,
1035 unsafety,
1036 generics,
1037 constness,
1038 polarity,
1039 of_trait,
1040 self_ty,
1041 items,
1042 }) => {
1043 visit_defaultness(defaultness, vis);
1044 visit_unsafety(unsafety, vis);
1045 vis.visit_generics(generics);
1046 visit_constness(constness, vis);
1047 visit_polarity(polarity, vis);
1048 visit_opt(of_trait, |trait_ref| vis.visit_trait_ref(trait_ref));
1049 vis.visit_ty(self_ty);
1050 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
1051 }
1052 ItemKind::Trait(box Trait { unsafety, is_auto: _, generics, bounds, items }) => {
1053 visit_unsafety(unsafety, vis);
1054 vis.visit_generics(generics);
1055 visit_bounds(bounds, vis);
1056 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
1057 }
1058 ItemKind::TraitAlias(generics, bounds) => {
1059 vis.visit_generics(generics);
1060 visit_bounds(bounds, vis);
1061 }
1062 ItemKind::MacCall(m) => vis.visit_mac_call(m),
1063 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
1064 }
1065 }
1066
noop_flat_map_assoc_item<T: MutVisitor>( mut item: P<AssocItem>, visitor: &mut T, ) -> SmallVec<[P<AssocItem>; 1]>1067 pub fn noop_flat_map_assoc_item<T: MutVisitor>(
1068 mut item: P<AssocItem>,
1069 visitor: &mut T,
1070 ) -> SmallVec<[P<AssocItem>; 1]> {
1071 let Item { id, ident, vis, attrs, kind, span, tokens } = item.deref_mut();
1072 visitor.visit_id(id);
1073 visitor.visit_ident(ident);
1074 visitor.visit_vis(vis);
1075 visit_attrs(attrs, visitor);
1076 match kind {
1077 AssocItemKind::Const(defaultness, ty, expr) => {
1078 visit_defaultness(defaultness, visitor);
1079 visitor.visit_ty(ty);
1080 visit_opt(expr, |expr| visitor.visit_expr(expr));
1081 }
1082 AssocItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1083 visit_defaultness(defaultness, visitor);
1084 visitor.visit_generics(generics);
1085 visit_fn_sig(sig, visitor);
1086 visit_opt(body, |body| visitor.visit_block(body));
1087 }
1088 AssocItemKind::TyAlias(box TyAlias { defaultness, generics, bounds, ty }) => {
1089 visit_defaultness(defaultness, visitor);
1090 visitor.visit_generics(generics);
1091 visit_bounds(bounds, visitor);
1092 visit_opt(ty, |ty| visitor.visit_ty(ty));
1093 }
1094 AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1095 }
1096 visitor.visit_span(span);
1097 visit_lazy_tts(tokens, visitor);
1098 smallvec![item]
1099 }
1100
noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T)1101 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
1102 let FnHeader { unsafety, asyncness, constness, ext: _ } = header;
1103 visit_constness(constness, vis);
1104 vis.visit_asyncness(asyncness);
1105 visit_unsafety(unsafety, vis);
1106 }
1107
1108 // FIXME: Avoid visiting the crate as a `Mod` item, flat map only the inner items if possible,
1109 // or make crate visiting first class if necessary.
noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T)1110 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
1111 visit_clobber(krate, |Crate { attrs, items, span }| {
1112 let item_vis =
1113 Visibility { kind: VisibilityKind::Public, span: span.shrink_to_lo(), tokens: None };
1114 let item = P(Item {
1115 ident: Ident::empty(),
1116 attrs,
1117 id: DUMMY_NODE_ID,
1118 vis: item_vis,
1119 span,
1120 kind: ItemKind::Mod(Unsafe::No, ModKind::Loaded(items, Inline::Yes, span)),
1121 tokens: None,
1122 });
1123 let items = vis.flat_map_item(item);
1124
1125 let len = items.len();
1126 if len == 0 {
1127 Crate { attrs: vec![], items: vec![], span }
1128 } else if len == 1 {
1129 let Item { attrs, span, kind, .. } = items.into_iter().next().unwrap().into_inner();
1130 match kind {
1131 ItemKind::Mod(_, ModKind::Loaded(items, ..)) => Crate { attrs, items, span },
1132 _ => panic!("visitor converted a module to not a module"),
1133 }
1134 } else {
1135 panic!("a crate cannot expand to more than one item");
1136 }
1137 });
1138 }
1139
1140 // Mutates one item into possibly many items.
noop_flat_map_item<T: MutVisitor>( mut item: P<Item>, visitor: &mut T, ) -> SmallVec<[P<Item>; 1]>1141 pub fn noop_flat_map_item<T: MutVisitor>(
1142 mut item: P<Item>,
1143 visitor: &mut T,
1144 ) -> SmallVec<[P<Item>; 1]> {
1145 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1146 visitor.visit_ident(ident);
1147 visit_attrs(attrs, visitor);
1148 visitor.visit_id(id);
1149 visitor.visit_item_kind(kind);
1150 visitor.visit_vis(vis);
1151 visitor.visit_span(span);
1152 visit_lazy_tts(tokens, visitor);
1153
1154 smallvec![item]
1155 }
1156
noop_flat_map_foreign_item<T: MutVisitor>( mut item: P<ForeignItem>, visitor: &mut T, ) -> SmallVec<[P<ForeignItem>; 1]>1157 pub fn noop_flat_map_foreign_item<T: MutVisitor>(
1158 mut item: P<ForeignItem>,
1159 visitor: &mut T,
1160 ) -> SmallVec<[P<ForeignItem>; 1]> {
1161 let Item { ident, attrs, id, kind, vis, span, tokens } = item.deref_mut();
1162 visitor.visit_id(id);
1163 visitor.visit_ident(ident);
1164 visitor.visit_vis(vis);
1165 visit_attrs(attrs, visitor);
1166 match kind {
1167 ForeignItemKind::Static(ty, _, expr) => {
1168 visitor.visit_ty(ty);
1169 visit_opt(expr, |expr| visitor.visit_expr(expr));
1170 }
1171 ForeignItemKind::Fn(box Fn { defaultness, generics, sig, body }) => {
1172 visit_defaultness(defaultness, visitor);
1173 visitor.visit_generics(generics);
1174 visit_fn_sig(sig, visitor);
1175 visit_opt(body, |body| visitor.visit_block(body));
1176 }
1177 ForeignItemKind::TyAlias(box TyAlias { defaultness, generics, bounds, ty }) => {
1178 visit_defaultness(defaultness, visitor);
1179 visitor.visit_generics(generics);
1180 visit_bounds(bounds, visitor);
1181 visit_opt(ty, |ty| visitor.visit_ty(ty));
1182 }
1183 ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
1184 }
1185 visitor.visit_span(span);
1186 visit_lazy_tts(tokens, visitor);
1187 smallvec![item]
1188 }
1189
noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T)1190 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1191 let Pat { id, kind, span, tokens } = pat.deref_mut();
1192 vis.visit_id(id);
1193 match kind {
1194 PatKind::Wild | PatKind::Rest => {}
1195 PatKind::Ident(_binding_mode, ident, sub) => {
1196 vis.visit_ident(ident);
1197 visit_opt(sub, |sub| vis.visit_pat(sub));
1198 }
1199 PatKind::Lit(e) => vis.visit_expr(e),
1200 PatKind::TupleStruct(qself, path, elems) => {
1201 vis.visit_qself(qself);
1202 vis.visit_path(path);
1203 visit_vec(elems, |elem| vis.visit_pat(elem));
1204 }
1205 PatKind::Path(qself, path) => {
1206 vis.visit_qself(qself);
1207 vis.visit_path(path);
1208 }
1209 PatKind::Struct(qself, path, fields, _etc) => {
1210 vis.visit_qself(qself);
1211 vis.visit_path(path);
1212 fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
1213 }
1214 PatKind::Box(inner) => vis.visit_pat(inner),
1215 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1216 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1217 visit_opt(e1, |e| vis.visit_expr(e));
1218 visit_opt(e2, |e| vis.visit_expr(e));
1219 vis.visit_span(span);
1220 }
1221 PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
1222 visit_vec(elems, |elem| vis.visit_pat(elem))
1223 }
1224 PatKind::Paren(inner) => vis.visit_pat(inner),
1225 PatKind::MacCall(mac) => vis.visit_mac_call(mac),
1226 }
1227 vis.visit_span(span);
1228 visit_lazy_tts(tokens, vis);
1229 }
1230
1231 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1232 vis.visit_id(id);
1233 vis.visit_expr(value);
1234 }
1235
noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T)1236 fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
1237 for (op, _) in &mut asm.operands {
1238 match op {
1239 InlineAsmOperand::In { expr, .. }
1240 | InlineAsmOperand::Out { expr: Some(expr), .. }
1241 | InlineAsmOperand::InOut { expr, .. }
1242 | InlineAsmOperand::Sym { expr, .. } => vis.visit_expr(expr),
1243 InlineAsmOperand::Out { expr: None, .. } => {}
1244 InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
1245 vis.visit_expr(in_expr);
1246 if let Some(out_expr) = out_expr {
1247 vis.visit_expr(out_expr);
1248 }
1249 }
1250 InlineAsmOperand::Const { anon_const, .. } => vis.visit_anon_const(anon_const),
1251 }
1252 }
1253 }
1254
1255 pub fn noop_visit_expr<T: MutVisitor>(
1256 Expr { kind, id, span, attrs, tokens }: &mut Expr,
1257 vis: &mut T,
1258 ) {
1259 match kind {
1260 ExprKind::Box(expr) => vis.visit_expr(expr),
1261 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1262 ExprKind::ConstBlock(anon_const) => {
1263 vis.visit_anon_const(anon_const);
1264 }
1265 ExprKind::Repeat(expr, count) => {
1266 vis.visit_expr(expr);
1267 vis.visit_anon_const(count);
1268 }
1269 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1270 ExprKind::Call(f, args) => {
1271 vis.visit_expr(f);
1272 visit_exprs(args, vis);
1273 }
1274 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs, span) => {
1275 vis.visit_ident(ident);
1276 vis.visit_id(id);
1277 visit_opt(args, |args| vis.visit_generic_args(args));
1278 visit_exprs(exprs, vis);
1279 vis.visit_span(span);
1280 }
1281 ExprKind::Binary(_binop, lhs, rhs) => {
1282 vis.visit_expr(lhs);
1283 vis.visit_expr(rhs);
1284 }
1285 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1286 ExprKind::Cast(expr, ty) => {
1287 vis.visit_expr(expr);
1288 vis.visit_ty(ty);
1289 }
1290 ExprKind::Type(expr, ty) => {
1291 vis.visit_expr(expr);
1292 vis.visit_ty(ty);
1293 }
1294 ExprKind::AddrOf(_, _, ohs) => vis.visit_expr(ohs),
1295 ExprKind::Let(pat, scrutinee, _) => {
1296 vis.visit_pat(pat);
1297 vis.visit_expr(scrutinee);
1298 }
1299 ExprKind::If(cond, tr, fl) => {
1300 vis.visit_expr(cond);
1301 vis.visit_block(tr);
1302 visit_opt(fl, |fl| vis.visit_expr(fl));
1303 }
1304 ExprKind::While(cond, body, label) => {
1305 vis.visit_expr(cond);
1306 vis.visit_block(body);
1307 visit_opt(label, |label| vis.visit_label(label));
1308 }
1309 ExprKind::ForLoop(pat, iter, body, label) => {
1310 vis.visit_pat(pat);
1311 vis.visit_expr(iter);
1312 vis.visit_block(body);
1313 visit_opt(label, |label| vis.visit_label(label));
1314 }
1315 ExprKind::Loop(body, label) => {
1316 vis.visit_block(body);
1317 visit_opt(label, |label| vis.visit_label(label));
1318 }
1319 ExprKind::Match(expr, arms) => {
1320 vis.visit_expr(expr);
1321 arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
1322 }
1323 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1324 vis.visit_asyncness(asyncness);
1325 vis.visit_fn_decl(decl);
1326 vis.visit_expr(body);
1327 vis.visit_span(span);
1328 }
1329 ExprKind::Block(blk, label) => {
1330 vis.visit_block(blk);
1331 visit_opt(label, |label| vis.visit_label(label));
1332 }
1333 ExprKind::Async(_capture_by, node_id, body) => {
1334 vis.visit_id(node_id);
1335 vis.visit_block(body);
1336 }
1337 ExprKind::Await(expr) => vis.visit_expr(expr),
1338 ExprKind::Assign(el, er, _) => {
1339 vis.visit_expr(el);
1340 vis.visit_expr(er);
1341 }
1342 ExprKind::AssignOp(_op, el, er) => {
1343 vis.visit_expr(el);
1344 vis.visit_expr(er);
1345 }
1346 ExprKind::Field(el, ident) => {
1347 vis.visit_expr(el);
1348 vis.visit_ident(ident);
1349 }
1350 ExprKind::Index(el, er) => {
1351 vis.visit_expr(el);
1352 vis.visit_expr(er);
1353 }
1354 ExprKind::Range(e1, e2, _lim) => {
1355 visit_opt(e1, |e1| vis.visit_expr(e1));
1356 visit_opt(e2, |e2| vis.visit_expr(e2));
1357 }
1358 ExprKind::Underscore => {}
1359 ExprKind::Path(qself, path) => {
1360 vis.visit_qself(qself);
1361 vis.visit_path(path);
1362 }
1363 ExprKind::Break(label, expr) => {
1364 visit_opt(label, |label| vis.visit_label(label));
1365 visit_opt(expr, |expr| vis.visit_expr(expr));
1366 }
1367 ExprKind::Continue(label) => {
1368 visit_opt(label, |label| vis.visit_label(label));
1369 }
1370 ExprKind::Ret(expr) => {
1371 visit_opt(expr, |expr| vis.visit_expr(expr));
1372 }
1373 ExprKind::InlineAsm(asm) => noop_visit_inline_asm(asm, vis),
1374 ExprKind::LlvmInlineAsm(asm) => {
1375 let LlvmInlineAsm {
1376 asm: _,
1377 asm_str_style: _,
1378 outputs,
1379 inputs,
1380 clobbers: _,
1381 volatile: _,
1382 alignstack: _,
1383 dialect: _,
1384 } = asm.deref_mut();
1385 for out in outputs {
1386 let LlvmInlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1387 vis.visit_expr(expr);
1388 }
1389 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1390 }
1391 ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
1392 ExprKind::Struct(se) => {
1393 let StructExpr { qself, path, fields, rest } = se.deref_mut();
1394 vis.visit_qself(qself);
1395 vis.visit_path(path);
1396 fields.flat_map_in_place(|field| vis.flat_map_expr_field(field));
1397 match rest {
1398 StructRest::Base(expr) => vis.visit_expr(expr),
1399 StructRest::Rest(_span) => {}
1400 StructRest::None => {}
1401 }
1402 }
1403 ExprKind::Paren(expr) => {
1404 vis.visit_expr(expr);
1405 }
1406 ExprKind::Yield(expr) => {
1407 visit_opt(expr, |expr| vis.visit_expr(expr));
1408 }
1409 ExprKind::Try(expr) => vis.visit_expr(expr),
1410 ExprKind::TryBlock(body) => vis.visit_block(body),
1411 ExprKind::Lit(_) | ExprKind::Err => {}
1412 }
1413 vis.visit_id(id);
1414 vis.visit_span(span);
1415 visit_thin_attrs(attrs, vis);
1416 visit_lazy_tts(tokens, vis);
1417 }
1418
noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>>1419 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1420 Some({
1421 vis.visit_expr(&mut e);
1422 e
1423 })
1424 }
1425
1426 pub fn noop_flat_map_stmt<T: MutVisitor>(
1427 Stmt { kind, mut span, mut id }: Stmt,
1428 vis: &mut T,
1429 ) -> SmallVec<[Stmt; 1]> {
1430 vis.visit_id(&mut id);
1431 vis.visit_span(&mut span);
1432 let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
1433 .into_iter()
1434 .map(|kind| Stmt { id, kind, span })
1435 .collect();
1436 if stmts.len() > 1 {
1437 panic!(
1438 "cloning statement `NodeId`s is prohibited by default, \
1439 the visitor should implement custom statement visiting"
1440 );
1441 }
1442 stmts
1443 }
1444
noop_flat_map_stmt_kind<T: MutVisitor>( kind: StmtKind, vis: &mut T, ) -> SmallVec<[StmtKind; 1]>1445 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
1446 kind: StmtKind,
1447 vis: &mut T,
1448 ) -> SmallVec<[StmtKind; 1]> {
1449 match kind {
1450 StmtKind::Local(mut local) => smallvec![StmtKind::Local({
1451 vis.visit_local(&mut local);
1452 local
1453 })],
1454 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1455 StmtKind::Expr(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect(),
1456 StmtKind::Semi(expr) => vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect(),
1457 StmtKind::Empty => smallvec![StmtKind::Empty],
1458 StmtKind::MacCall(mut mac) => {
1459 let MacCallStmt { mac: mac_, style: _, attrs, tokens } = mac.deref_mut();
1460 vis.visit_mac_call(mac_);
1461 visit_thin_attrs(attrs, vis);
1462 visit_lazy_tts(tokens, vis);
1463 smallvec![StmtKind::MacCall(mac)]
1464 }
1465 }
1466 }
1467
noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T)1468 pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
1469 match &mut visibility.kind {
1470 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1471 VisibilityKind::Restricted { path, id } => {
1472 vis.visit_path(path);
1473 vis.visit_id(id);
1474 }
1475 }
1476 vis.visit_span(&mut visibility.span);
1477 }
1478