rustc_ast_pretty/pprust/state/
item.rs

1use ast::StaticItem;
2use itertools::{Itertools, Position};
3use rustc_ast::{self as ast, ModKind, TraitAlias};
4use rustc_span::Ident;
5
6use crate::pp::BoxMarker;
7use crate::pp::Breaks::Inconsistent;
8use crate::pprust::state::fixup::FixupContext;
9use crate::pprust::state::{AnnNode, INDENT_UNIT, PrintState, State};
10
11enum DelegationKind<'a> {
12    Single,
13    List(&'a [(Ident, Option<Ident>)]),
14    Glob,
15}
16
17fn visibility_qualified(vis: &ast::Visibility, s: &str) -> String {
18    format!("{}{}", State::to_string(|s| s.print_visibility(vis)), s)
19}
20
21impl<'a> State<'a> {
22    fn print_foreign_mod(&mut self, nmod: &ast::ForeignMod, attrs: &[ast::Attribute]) {
23        self.print_inner_attributes(attrs);
24        for item in &nmod.items {
25            self.print_foreign_item(item);
26        }
27    }
28
29    pub(crate) fn print_foreign_item(&mut self, item: &ast::ForeignItem) {
30        let ast::Item { id, span, ref attrs, ref kind, ref vis, tokens: _ } = *item;
31        self.ann.pre(self, AnnNode::SubItem(id));
32        self.hardbreak_if_not_bol();
33        self.maybe_print_comment(span.lo());
34        self.print_outer_attributes(attrs);
35        match kind {
36            ast::ForeignItemKind::Fn(func) => {
37                self.print_fn_full(vis, attrs, &*func);
38            }
39            ast::ForeignItemKind::Static(box ast::StaticItem {
40                ident,
41                ty,
42                mutability,
43                expr,
44                safety,
45                define_opaque,
46            }) => self.print_item_const(
47                *ident,
48                Some(*mutability),
49                &ast::Generics::default(),
50                ty,
51                expr.as_deref(),
52                vis,
53                *safety,
54                ast::Defaultness::Final,
55                define_opaque.as_deref(),
56            ),
57            ast::ForeignItemKind::TyAlias(box ast::TyAlias {
58                defaultness,
59                ident,
60                generics,
61                after_where_clause,
62                bounds,
63                ty,
64            }) => {
65                self.print_associated_type(
66                    *ident,
67                    generics,
68                    after_where_clause,
69                    bounds,
70                    ty.as_deref(),
71                    vis,
72                    *defaultness,
73                );
74            }
75            ast::ForeignItemKind::MacCall(m) => {
76                self.print_mac(m);
77                if m.args.need_semicolon() {
78                    self.word(";");
79                }
80            }
81        }
82        self.ann.post(self, AnnNode::SubItem(id))
83    }
84
85    fn print_item_const(
86        &mut self,
87        ident: Ident,
88        mutbl: Option<ast::Mutability>,
89        generics: &ast::Generics,
90        ty: &ast::Ty,
91        body: Option<&ast::Expr>,
92        vis: &ast::Visibility,
93        safety: ast::Safety,
94        defaultness: ast::Defaultness,
95        define_opaque: Option<&[(ast::NodeId, ast::Path)]>,
96    ) {
97        self.print_define_opaques(define_opaque);
98        let (cb, ib) = self.head("");
99        self.print_visibility(vis);
100        self.print_safety(safety);
101        self.print_defaultness(defaultness);
102        let leading = match mutbl {
103            None => "const",
104            Some(ast::Mutability::Not) => "static",
105            Some(ast::Mutability::Mut) => "static mut",
106        };
107        self.word_space(leading);
108        self.print_ident(ident);
109        self.print_generic_params(&generics.params);
110        self.word_space(":");
111        self.print_type(ty);
112        if body.is_some() {
113            self.space();
114        }
115        self.end(ib);
116        if let Some(body) = body {
117            self.word_space("=");
118            self.print_expr(body, FixupContext::default());
119        }
120        self.print_where_clause(&generics.where_clause);
121        self.word(";");
122        self.end(cb);
123    }
124
125    fn print_associated_type(
126        &mut self,
127        ident: Ident,
128        generics: &ast::Generics,
129        after_where_clause: &ast::WhereClause,
130        bounds: &ast::GenericBounds,
131        ty: Option<&ast::Ty>,
132        vis: &ast::Visibility,
133        defaultness: ast::Defaultness,
134    ) {
135        let (cb, ib) = self.head("");
136        self.print_visibility(vis);
137        self.print_defaultness(defaultness);
138        self.word_space("type");
139        self.print_ident(ident);
140        self.print_generic_params(&generics.params);
141        if !bounds.is_empty() {
142            self.word_nbsp(":");
143            self.print_type_bounds(bounds);
144        }
145        self.print_where_clause(&generics.where_clause);
146        if let Some(ty) = ty {
147            self.space();
148            self.word_space("=");
149            self.print_type(ty);
150        }
151        self.print_where_clause(&after_where_clause);
152        self.word(";");
153        self.end(ib);
154        self.end(cb);
155    }
156
157    /// Pretty-prints an item.
158    pub(crate) fn print_item(&mut self, item: &ast::Item) {
159        if self.is_sdylib_interface && item.span.is_dummy() {
160            // Do not print prelude for interface files.
161            return;
162        }
163        self.hardbreak_if_not_bol();
164        self.maybe_print_comment(item.span.lo());
165        self.print_outer_attributes(&item.attrs);
166        self.ann.pre(self, AnnNode::Item(item));
167        match &item.kind {
168            ast::ItemKind::ExternCrate(orig_name, ident) => {
169                let (cb, ib) = self.head(visibility_qualified(&item.vis, "extern crate"));
170                if let &Some(orig_name) = orig_name {
171                    self.print_name(orig_name);
172                    self.space();
173                    self.word("as");
174                    self.space();
175                }
176                self.print_ident(*ident);
177                self.word(";");
178                self.end(ib);
179                self.end(cb);
180            }
181            ast::ItemKind::Use(tree) => {
182                self.print_visibility(&item.vis);
183                self.word_nbsp("use");
184                self.print_use_tree(tree);
185                self.word(";");
186            }
187            ast::ItemKind::Static(box StaticItem {
188                ident,
189                ty,
190                safety,
191                mutability: mutbl,
192                expr: body,
193                define_opaque,
194            }) => {
195                self.print_safety(*safety);
196                self.print_item_const(
197                    *ident,
198                    Some(*mutbl),
199                    &ast::Generics::default(),
200                    ty,
201                    body.as_deref(),
202                    &item.vis,
203                    ast::Safety::Default,
204                    ast::Defaultness::Final,
205                    define_opaque.as_deref(),
206                );
207            }
208            ast::ItemKind::Const(box ast::ConstItem {
209                defaultness,
210                ident,
211                generics,
212                ty,
213                rhs,
214                define_opaque,
215            }) => {
216                self.print_item_const(
217                    *ident,
218                    None,
219                    generics,
220                    ty,
221                    rhs.as_ref().map(|ct| ct.expr()),
222                    &item.vis,
223                    ast::Safety::Default,
224                    *defaultness,
225                    define_opaque.as_deref(),
226                );
227            }
228            ast::ItemKind::Fn(func) => {
229                self.print_fn_full(&item.vis, &item.attrs, &*func);
230            }
231            ast::ItemKind::Mod(safety, ident, mod_kind) => {
232                let (cb, ib) = self.head(Self::to_string(|s| {
233                    s.print_visibility(&item.vis);
234                    s.print_safety(*safety);
235                    s.word("mod");
236                }));
237                self.print_ident(*ident);
238
239                match mod_kind {
240                    ModKind::Loaded(items, ..) => {
241                        self.nbsp();
242                        self.bopen(ib);
243                        self.print_inner_attributes(&item.attrs);
244                        for item in items {
245                            self.print_item(item);
246                        }
247                        let empty = item.attrs.is_empty() && items.is_empty();
248                        self.bclose(item.span, empty, cb);
249                    }
250                    ModKind::Unloaded => {
251                        self.word(";");
252                        self.end(ib);
253                        self.end(cb);
254                    }
255                }
256            }
257            ast::ItemKind::ForeignMod(nmod) => {
258                let (cb, ib) = self.head(Self::to_string(|s| {
259                    s.print_safety(nmod.safety);
260                    s.word("extern");
261                }));
262                if let Some(abi) = nmod.abi {
263                    self.print_token_literal(abi.as_token_lit(), abi.span);
264                    self.nbsp();
265                }
266                self.bopen(ib);
267                self.print_foreign_mod(nmod, &item.attrs);
268                let empty = item.attrs.is_empty() && nmod.items.is_empty();
269                self.bclose(item.span, empty, cb);
270            }
271            ast::ItemKind::GlobalAsm(asm) => {
272                // FIXME: Print `builtin # global_asm` once macro `global_asm` uses `builtin_syntax`.
273                let (cb, ib) = self.head(visibility_qualified(&item.vis, "global_asm!"));
274                self.print_inline_asm(asm);
275                self.word(";");
276                self.end(ib);
277                self.end(cb);
278            }
279            ast::ItemKind::TyAlias(box ast::TyAlias {
280                defaultness,
281                ident,
282                generics,
283                after_where_clause,
284                bounds,
285                ty,
286            }) => {
287                self.print_associated_type(
288                    *ident,
289                    generics,
290                    after_where_clause,
291                    bounds,
292                    ty.as_deref(),
293                    &item.vis,
294                    *defaultness,
295                );
296            }
297            ast::ItemKind::Enum(ident, generics, enum_definition) => {
298                self.print_enum_def(enum_definition, generics, *ident, item.span, &item.vis);
299            }
300            ast::ItemKind::Struct(ident, generics, struct_def) => {
301                let (cb, ib) = self.head(visibility_qualified(&item.vis, "struct"));
302                self.print_struct(struct_def, generics, *ident, item.span, true, cb, ib);
303            }
304            ast::ItemKind::Union(ident, generics, struct_def) => {
305                let (cb, ib) = self.head(visibility_qualified(&item.vis, "union"));
306                self.print_struct(struct_def, generics, *ident, item.span, true, cb, ib);
307            }
308            ast::ItemKind::Impl(ast::Impl { generics, of_trait, self_ty, items, constness }) => {
309                let (cb, ib) = self.head("");
310                self.print_visibility(&item.vis);
311
312                let impl_generics = |this: &mut Self| {
313                    this.word("impl");
314
315                    if generics.params.is_empty() {
316                        this.nbsp();
317                    } else {
318                        this.print_generic_params(&generics.params);
319                        this.space();
320                    }
321                };
322
323                if let Some(box of_trait) = of_trait {
324                    let ast::TraitImplHeader { defaultness, safety, polarity, ref trait_ref } =
325                        *of_trait;
326                    self.print_defaultness(defaultness);
327                    self.print_safety(safety);
328                    impl_generics(self);
329                    self.print_constness(*constness);
330                    if let ast::ImplPolarity::Negative(_) = polarity {
331                        self.word("!");
332                    }
333                    self.print_trait_ref(trait_ref);
334                    self.space();
335                    self.word_space("for");
336                } else {
337                    self.print_constness(*constness);
338                    impl_generics(self);
339                }
340
341                self.print_type(self_ty);
342                self.print_where_clause(&generics.where_clause);
343
344                self.space();
345                self.bopen(ib);
346                self.print_inner_attributes(&item.attrs);
347                for impl_item in items {
348                    self.print_assoc_item(impl_item);
349                }
350                let empty = item.attrs.is_empty() && items.is_empty();
351                self.bclose(item.span, empty, cb);
352            }
353            ast::ItemKind::Trait(box ast::Trait {
354                constness,
355                safety,
356                is_auto,
357                ident,
358                generics,
359                bounds,
360                items,
361            }) => {
362                let (cb, ib) = self.head("");
363                self.print_visibility(&item.vis);
364                self.print_constness(*constness);
365                self.print_safety(*safety);
366                self.print_is_auto(*is_auto);
367                self.word_nbsp("trait");
368                self.print_ident(*ident);
369                self.print_generic_params(&generics.params);
370                if !bounds.is_empty() {
371                    self.word_nbsp(":");
372                    self.print_type_bounds(bounds);
373                }
374                self.print_where_clause(&generics.where_clause);
375                self.word(" ");
376                self.bopen(ib);
377                self.print_inner_attributes(&item.attrs);
378                for trait_item in items {
379                    self.print_assoc_item(trait_item);
380                }
381                let empty = item.attrs.is_empty() && items.is_empty();
382                self.bclose(item.span, empty, cb);
383            }
384            ast::ItemKind::TraitAlias(box TraitAlias { constness, ident, generics, bounds }) => {
385                let (cb, ib) = self.head("");
386                self.print_visibility(&item.vis);
387                self.print_constness(*constness);
388                self.word_nbsp("trait");
389                self.print_ident(*ident);
390                self.print_generic_params(&generics.params);
391                self.nbsp();
392                if !bounds.is_empty() {
393                    self.word_nbsp("=");
394                    self.print_type_bounds(bounds);
395                }
396                self.print_where_clause(&generics.where_clause);
397                self.word(";");
398                self.end(ib);
399                self.end(cb);
400            }
401            ast::ItemKind::MacCall(mac) => {
402                self.print_mac(mac);
403                if mac.args.need_semicolon() {
404                    self.word(";");
405                }
406            }
407            ast::ItemKind::MacroDef(ident, macro_def) => {
408                self.print_mac_def(macro_def, &ident, item.span, |state| {
409                    state.print_visibility(&item.vis)
410                });
411            }
412            ast::ItemKind::Delegation(deleg) => self.print_delegation(
413                &item.attrs,
414                &item.vis,
415                &deleg.qself,
416                &deleg.path,
417                DelegationKind::Single,
418                &deleg.body,
419            ),
420            ast::ItemKind::DelegationMac(deleg) => self.print_delegation(
421                &item.attrs,
422                &item.vis,
423                &deleg.qself,
424                &deleg.prefix,
425                deleg.suffixes.as_ref().map_or(DelegationKind::Glob, |s| DelegationKind::List(s)),
426                &deleg.body,
427            ),
428        }
429        self.ann.post(self, AnnNode::Item(item))
430    }
431
432    fn print_enum_def(
433        &mut self,
434        enum_definition: &ast::EnumDef,
435        generics: &ast::Generics,
436        ident: Ident,
437        span: rustc_span::Span,
438        visibility: &ast::Visibility,
439    ) {
440        let (cb, ib) = self.head(visibility_qualified(visibility, "enum"));
441        self.print_ident(ident);
442        self.print_generic_params(&generics.params);
443        self.print_where_clause(&generics.where_clause);
444        self.space();
445        self.bopen(ib);
446        for v in enum_definition.variants.iter() {
447            self.space_if_not_bol();
448            self.maybe_print_comment(v.span.lo());
449            self.print_outer_attributes(&v.attrs);
450            let ib = self.ibox(0);
451            self.print_variant(v);
452            self.word(",");
453            self.end(ib);
454            self.maybe_print_trailing_comment(v.span, None);
455        }
456        let empty = enum_definition.variants.is_empty();
457        self.bclose(span, empty, cb)
458    }
459
460    pub(crate) fn print_visibility(&mut self, vis: &ast::Visibility) {
461        match &vis.kind {
462            ast::VisibilityKind::Public => self.word_nbsp("pub"),
463            ast::VisibilityKind::Restricted { path, shorthand, .. } => {
464                let path = Self::to_string(|s| s.print_path(path, false, 0));
465                if *shorthand && (path == "crate" || path == "self" || path == "super") {
466                    self.word_nbsp(format!("pub({path})"))
467                } else {
468                    self.word_nbsp(format!("pub(in {path})"))
469                }
470            }
471            ast::VisibilityKind::Inherited => {}
472        }
473    }
474
475    fn print_defaultness(&mut self, defaultness: ast::Defaultness) {
476        if let ast::Defaultness::Default(_) = defaultness {
477            self.word_nbsp("default");
478        }
479    }
480
481    fn print_struct(
482        &mut self,
483        struct_def: &ast::VariantData,
484        generics: &ast::Generics,
485        ident: Ident,
486        span: rustc_span::Span,
487        print_finalizer: bool,
488        cb: BoxMarker,
489        ib: BoxMarker,
490    ) {
491        self.print_ident(ident);
492        self.print_generic_params(&generics.params);
493        match &struct_def {
494            ast::VariantData::Tuple(..) | ast::VariantData::Unit(..) => {
495                if let ast::VariantData::Tuple(..) = struct_def {
496                    self.popen();
497                    self.commasep(Inconsistent, struct_def.fields(), |s, field| {
498                        s.maybe_print_comment(field.span.lo());
499                        s.print_outer_attributes(&field.attrs);
500                        s.print_visibility(&field.vis);
501                        s.print_type(&field.ty)
502                    });
503                    self.pclose();
504                }
505                self.print_where_clause(&generics.where_clause);
506                if print_finalizer {
507                    self.word(";");
508                }
509                self.end(ib);
510                self.end(cb);
511            }
512            ast::VariantData::Struct { fields, .. } => {
513                self.print_where_clause(&generics.where_clause);
514                self.nbsp();
515                self.bopen(ib);
516
517                let empty = fields.is_empty();
518                if !empty {
519                    self.hardbreak_if_not_bol();
520
521                    for field in fields {
522                        self.hardbreak_if_not_bol();
523                        self.maybe_print_comment(field.span.lo());
524                        self.print_outer_attributes(&field.attrs);
525                        self.print_visibility(&field.vis);
526                        self.print_ident(field.ident.unwrap());
527                        self.word_nbsp(":");
528                        self.print_type(&field.ty);
529                        self.word(",");
530                    }
531                }
532
533                self.bclose(span, empty, cb);
534            }
535        }
536    }
537
538    pub(crate) fn print_variant(&mut self, v: &ast::Variant) {
539        let (cb, ib) = self.head("");
540        self.print_visibility(&v.vis);
541        let generics = ast::Generics::default();
542        self.print_struct(&v.data, &generics, v.ident, v.span, false, cb, ib);
543        if let Some(d) = &v.disr_expr {
544            self.space();
545            self.word_space("=");
546            self.print_expr(&d.value, FixupContext::default())
547        }
548    }
549
550    pub(crate) fn print_assoc_item(&mut self, item: &ast::AssocItem) {
551        let ast::Item { id, span, ref attrs, ref kind, ref vis, tokens: _ } = *item;
552        self.ann.pre(self, AnnNode::SubItem(id));
553        self.hardbreak_if_not_bol();
554        self.maybe_print_comment(span.lo());
555        self.print_outer_attributes(attrs);
556        match kind {
557            ast::AssocItemKind::Fn(func) => {
558                self.print_fn_full(vis, attrs, &*func);
559            }
560            ast::AssocItemKind::Const(box ast::ConstItem {
561                defaultness,
562                ident,
563                generics,
564                ty,
565                rhs,
566                define_opaque,
567            }) => {
568                self.print_item_const(
569                    *ident,
570                    None,
571                    generics,
572                    ty,
573                    rhs.as_ref().map(|ct| ct.expr()),
574                    vis,
575                    ast::Safety::Default,
576                    *defaultness,
577                    define_opaque.as_deref(),
578                );
579            }
580            ast::AssocItemKind::Type(box ast::TyAlias {
581                defaultness,
582                ident,
583                generics,
584                after_where_clause,
585                bounds,
586                ty,
587            }) => {
588                self.print_associated_type(
589                    *ident,
590                    generics,
591                    after_where_clause,
592                    bounds,
593                    ty.as_deref(),
594                    vis,
595                    *defaultness,
596                );
597            }
598            ast::AssocItemKind::MacCall(m) => {
599                self.print_mac(m);
600                if m.args.need_semicolon() {
601                    self.word(";");
602                }
603            }
604            ast::AssocItemKind::Delegation(deleg) => self.print_delegation(
605                &item.attrs,
606                vis,
607                &deleg.qself,
608                &deleg.path,
609                DelegationKind::Single,
610                &deleg.body,
611            ),
612            ast::AssocItemKind::DelegationMac(deleg) => self.print_delegation(
613                &item.attrs,
614                vis,
615                &deleg.qself,
616                &deleg.prefix,
617                deleg.suffixes.as_ref().map_or(DelegationKind::Glob, |s| DelegationKind::List(s)),
618                &deleg.body,
619            ),
620        }
621        self.ann.post(self, AnnNode::SubItem(id))
622    }
623
624    fn print_delegation(
625        &mut self,
626        attrs: &[ast::Attribute],
627        vis: &ast::Visibility,
628        qself: &Option<Box<ast::QSelf>>,
629        path: &ast::Path,
630        kind: DelegationKind<'_>,
631        body: &Option<Box<ast::Block>>,
632    ) {
633        let body_cb_ib = body.as_ref().map(|body| (body, self.head("")));
634        self.print_visibility(vis);
635        self.word_nbsp("reuse");
636
637        if let Some(qself) = qself {
638            self.print_qpath(path, qself, false);
639        } else {
640            self.print_path(path, false, 0);
641        }
642        match kind {
643            DelegationKind::Single => {}
644            DelegationKind::List(suffixes) => {
645                self.word("::");
646                self.word("{");
647                for (i, (ident, rename)) in suffixes.iter().enumerate() {
648                    self.print_ident(*ident);
649                    if let Some(rename) = rename {
650                        self.nbsp();
651                        self.word_nbsp("as");
652                        self.print_ident(*rename);
653                    }
654                    if i != suffixes.len() - 1 {
655                        self.word_space(",");
656                    }
657                }
658                self.word("}");
659            }
660            DelegationKind::Glob => {
661                self.word("::");
662                self.word("*");
663            }
664        }
665        if let Some((body, (cb, ib))) = body_cb_ib {
666            self.nbsp();
667            self.print_block_with_attrs(body, attrs, cb, ib);
668        } else {
669            self.word(";");
670        }
671    }
672
673    fn print_fn_full(&mut self, vis: &ast::Visibility, attrs: &[ast::Attribute], func: &ast::Fn) {
674        let ast::Fn { defaultness, ident, generics, sig, contract, body, define_opaque } = func;
675
676        self.print_define_opaques(define_opaque.as_deref());
677
678        let body_cb_ib = body.as_ref().map(|body| (body, self.head("")));
679
680        self.print_visibility(vis);
681        self.print_defaultness(*defaultness);
682        self.print_fn(&sig.decl, sig.header, Some(*ident), generics);
683        if let Some(contract) = &contract {
684            self.nbsp();
685            self.print_contract(contract);
686        }
687        if let Some((body, (cb, ib))) = body_cb_ib {
688            if self.is_sdylib_interface {
689                self.word(";");
690                self.end(ib); // end inner head-block
691                self.end(cb); // end outer head-block
692                return;
693            }
694
695            self.nbsp();
696            self.print_block_with_attrs(body, attrs, cb, ib);
697        } else {
698            self.word(";");
699        }
700    }
701
702    fn print_define_opaques(&mut self, define_opaque: Option<&[(ast::NodeId, ast::Path)]>) {
703        if let Some(define_opaque) = define_opaque {
704            self.word("#[define_opaque(");
705            for (i, (_, path)) in define_opaque.iter().enumerate() {
706                if i != 0 {
707                    self.word_space(",");
708                }
709
710                self.print_path(path, false, 0);
711            }
712            self.word(")]");
713        }
714        self.hardbreak_if_not_bol();
715    }
716
717    fn print_contract(&mut self, contract: &ast::FnContract) {
718        if let Some(pred) = &contract.requires {
719            self.word("rustc_requires");
720            self.popen();
721            self.print_expr(pred, FixupContext::default());
722            self.pclose();
723        }
724        if let Some(pred) = &contract.ensures {
725            self.word("rustc_ensures");
726            self.popen();
727            self.print_expr(pred, FixupContext::default());
728            self.pclose();
729        }
730    }
731
732    pub(crate) fn print_fn(
733        &mut self,
734        decl: &ast::FnDecl,
735        header: ast::FnHeader,
736        ident: Option<Ident>,
737        generics: &ast::Generics,
738    ) {
739        self.print_fn_header_info(header);
740        if let Some(ident) = ident {
741            self.nbsp();
742            self.print_ident(ident);
743        }
744        self.print_generic_params(&generics.params);
745        self.print_fn_params_and_ret(decl, false);
746        self.print_where_clause(&generics.where_clause);
747    }
748
749    pub(crate) fn print_fn_params_and_ret(&mut self, decl: &ast::FnDecl, is_closure: bool) {
750        let (open, close) = if is_closure { ("|", "|") } else { ("(", ")") };
751        self.word(open);
752        self.commasep(Inconsistent, &decl.inputs, |s, param| s.print_param(param, is_closure));
753        self.word(close);
754        self.print_fn_ret_ty(&decl.output)
755    }
756
757    fn print_where_clause(&mut self, where_clause: &ast::WhereClause) {
758        let ast::WhereClause { has_where_token, ref predicates, span: _ } = *where_clause;
759        if predicates.is_empty() && !has_where_token {
760            return;
761        }
762
763        self.space();
764        self.word_space("where");
765
766        for (i, predicate) in predicates.iter().enumerate() {
767            if i != 0 {
768                self.word_space(",");
769            }
770
771            self.print_where_predicate(predicate);
772        }
773    }
774
775    pub fn print_where_predicate(&mut self, predicate: &ast::WherePredicate) {
776        let ast::WherePredicate { attrs, kind, id: _, span: _, is_placeholder: _ } = predicate;
777        self.print_outer_attributes(attrs);
778        match kind {
779            ast::WherePredicateKind::BoundPredicate(where_bound_predicate) => {
780                self.print_where_bound_predicate(where_bound_predicate);
781            }
782            ast::WherePredicateKind::RegionPredicate(ast::WhereRegionPredicate {
783                lifetime,
784                bounds,
785                ..
786            }) => {
787                self.print_lifetime(*lifetime);
788                self.word(":");
789                if !bounds.is_empty() {
790                    self.nbsp();
791                    self.print_lifetime_bounds(bounds);
792                }
793            }
794            ast::WherePredicateKind::EqPredicate(ast::WhereEqPredicate {
795                lhs_ty, rhs_ty, ..
796            }) => {
797                self.print_type(lhs_ty);
798                self.space();
799                self.word_space("=");
800                self.print_type(rhs_ty);
801            }
802        }
803    }
804
805    pub(crate) fn print_where_bound_predicate(
806        &mut self,
807        where_bound_predicate: &ast::WhereBoundPredicate,
808    ) {
809        self.print_formal_generic_params(&where_bound_predicate.bound_generic_params);
810        self.print_type(&where_bound_predicate.bounded_ty);
811        self.word(":");
812        if !where_bound_predicate.bounds.is_empty() {
813            self.nbsp();
814            self.print_type_bounds(&where_bound_predicate.bounds);
815        }
816    }
817
818    fn print_use_tree(&mut self, tree: &ast::UseTree) {
819        match &tree.kind {
820            ast::UseTreeKind::Simple(rename) => {
821                self.print_path(&tree.prefix, false, 0);
822                if let &Some(rename) = rename {
823                    self.nbsp();
824                    self.word_nbsp("as");
825                    self.print_ident(rename);
826                }
827            }
828            ast::UseTreeKind::Glob => {
829                if !tree.prefix.segments.is_empty() {
830                    self.print_path(&tree.prefix, false, 0);
831                    self.word("::");
832                }
833                self.word("*");
834            }
835            ast::UseTreeKind::Nested { items, .. } => {
836                if !tree.prefix.segments.is_empty() {
837                    self.print_path(&tree.prefix, false, 0);
838                    self.word("::");
839                }
840                if items.is_empty() {
841                    self.word("{}");
842                } else if let [(item, _)] = items.as_slice() {
843                    self.print_use_tree(item);
844                } else {
845                    let cb = self.cbox(INDENT_UNIT);
846                    self.word("{");
847                    self.zerobreak();
848                    let ib = self.ibox(0);
849                    for (pos, use_tree) in items.iter().with_position() {
850                        let is_last = matches!(pos, Position::Last | Position::Only);
851                        self.print_use_tree(&use_tree.0);
852                        if !is_last {
853                            self.word(",");
854                            if let ast::UseTreeKind::Nested { .. } = use_tree.0.kind {
855                                self.hardbreak();
856                            } else {
857                                self.space();
858                            }
859                        }
860                    }
861                    self.end(ib);
862                    self.trailing_comma();
863                    self.offset(-INDENT_UNIT);
864                    self.word("}");
865                    self.end(cb);
866                }
867            }
868        }
869    }
870}