charon_driver/translate/
translate_closures.rs

1//! In rust, closures behave like ADTs that implement the FnOnce/FnMut/Fn traits automatically.
2//!
3//! Here we convert closures to a struct containing the closure's state (upvars), along with
4//! matching trait impls and fun decls (e.g. a Fn closure will have a trait impl for Fn, FnMut and
5//! FnOnce, along with 3 matching method implementations for call, call_mut and call_once).
6//!
7//! For example, given the following Rust code:
8//! ```rust
9//! pub fn test_closure_capture<T: Clone>() {
10//!     let mut v = vec![];
11//!     let mut add = |x: &u32| v.push(*x);
12//!     add(&0);
13//!     add(&1);
14//! }
15//! ```
16//!
17//! We generate the equivalent desugared code:
18//! ```rust
19//! struct {test_closure_capture::closure#0}<'a, T: Clone> (&'a mut Vec<u32>);
20//!
21//! // The 'a comes from captured variables, the 'b comes from the closure higher-kinded signature.
22//! impl<'a, 'b, T: Clone> FnMut<(&'b u32,)> for {test_closure_capture::closure#0}<'a, T> {
23//!     fn call_mut<'c>(&'c mut self, arg: (&'b u32,)) {
24//!         self.0.push(*arg.0);
25//!     }
26//! }
27//!
28//! impl<'a, 'b, T: Clone> FnOnce<(&'b u32,)> for {test_closure_capture::closure#0}<'a, T> {
29//!     type Output = ();
30//!     ...
31//! }
32//!
33//! pub fn test_closure_capture<T: Clone>() {
34//!     let mut v = vec![];
35//!     let mut add = {test_closure_capture::closure#0} (&mut v);
36//!     state.call_mut(&0);
37//!     state.call_mut(&1);
38//! }
39//! ```
40
41use itertools::Itertools;
42use std::mem;
43
44use super::translate_crate::TransItemSourceKind;
45use super::translate_ctx::*;
46use charon_lib::ast::ullbc_ast_utils::BodyBuilder;
47use charon_lib::ast::*;
48use charon_lib::ids::IndexVec;
49use charon_lib::ullbc_ast::*;
50
51pub fn translate_closure_kind(kind: &hax::ClosureKind) -> ClosureKind {
52    match kind {
53        hax::ClosureKind::Fn => ClosureKind::Fn,
54        hax::ClosureKind::FnMut => ClosureKind::FnMut,
55        hax::ClosureKind::FnOnce => ClosureKind::FnOnce,
56    }
57}
58
59/// References to closure items are subtle because there are three sources of lifetimes on top of
60/// the normal generics: the upvars, the higher-kindedness of the closure itself, and the
61/// late-bound generics of the `call`/`call_mut` methods. One must be careful to choose the right
62/// method from these.
63impl ItemTransCtx<'_, '_> {
64    /// Translate a reference to a closure item that takes late-bound lifetimes. The binder binds
65    /// the late-bound lifetimes of the closure itself, if it is higher-kinded.
66    fn translate_closure_bound_ref_with_late_bound(
67        &mut self,
68        span: Span,
69        closure: &hax::ClosureArgs,
70        kind: TransItemSourceKind,
71    ) -> Result<RegionBinder<DeclRef<ItemId>>, Error> {
72        if !matches!(
73            kind,
74            TransItemSourceKind::TraitImpl(..) | TransItemSourceKind::ClosureAsFnCast
75        ) {
76            raise_error!(
77                self,
78                span,
79                "Called `translate_closure_bound_ref_with_late_bound` on a `{kind:?}`; \
80                use `translate_closure_ref_with_upvars` \
81                or `translate_closure_bound_ref_with_method_bound` instead"
82            )
83        }
84        let dref: DeclRef<ItemId> = self.translate_item(span, &closure.item, kind)?;
85        self.translate_region_binder(span, &closure.fn_sig, |ctx, _| {
86            let mut dref = dref.move_under_binder();
87            // The regions for these item kinds have the fn late bound regions at the end.
88            for (a, b) in dref.generics.regions.iter_mut().rev().zip(
89                ctx.innermost_binder()
90                    .params
91                    .identity_args()
92                    .regions
93                    .into_iter()
94                    .rev(),
95            ) {
96                *a = b;
97            }
98            Ok(dref)
99        })
100    }
101
102    /// Translate a reference to a closure item that takes late-bound lifetimes and method
103    /// lifetimes. The binder binds the late-bound lifetimes of the `call`/`call_mut` method
104    /// (specified by `target_kind`).
105    fn translate_closure_bound_ref_with_method_bound(
106        &mut self,
107        span: Span,
108        closure: &hax::ClosureArgs,
109        kind: TransItemSourceKind,
110        target_kind: ClosureKind,
111    ) -> Result<RegionBinder<DeclRef<ItemId>>, Error> {
112        if !matches!(kind, TransItemSourceKind::ClosureMethod(..)) {
113            raise_error!(
114                self,
115                span,
116                "Called `translate_closure_bound_ref_with_method_bound` on a `{kind:?}`; \
117                use `translate_closure_ref_with_upvars` \
118                or `translate_closure_bound_ref_with_late_bound` instead"
119            )
120        }
121        let dref: DeclRef<ItemId> = self.translate_item(span, &closure.item, kind)?;
122        let mut dref = dref.move_under_binder();
123        let mut regions = IndexMap::new();
124        match target_kind {
125            ClosureKind::FnOnce => {}
126            ClosureKind::FnMut | ClosureKind::Fn => {
127                let rid = regions.push_with(|index| RegionParam { index, name: None });
128                *dref.generics.regions.iter_mut().last().unwrap() =
129                    Region::Var(DeBruijnVar::new_at_zero(rid));
130            }
131        }
132        Ok(RegionBinder {
133            regions,
134            skip_binder: dref,
135        })
136    }
137}
138
139impl ItemTransCtx<'_, '_> {
140    /// Translate a reference to the closure ADT.
141    pub fn translate_closure_type_ref(
142        &mut self,
143        span: Span,
144        closure: &hax::ClosureArgs,
145    ) -> Result<TypeDeclRef, Error> {
146        self.translate_item(span, &closure.item, TransItemSourceKind::Type)
147    }
148
149    /// For stateless closures, translate a function reference to the top-level function that
150    /// executes the closure code without taking the state as parameter.If you want to instantiate
151    /// the binder, use the lifetimes from `self.closure_late_regions`.
152    pub fn translate_stateless_closure_as_fn_ref(
153        &mut self,
154        span: Span,
155        closure: &hax::ClosureArgs,
156    ) -> Result<RegionBinder<FunDeclRef>, Error> {
157        let kind = TransItemSourceKind::ClosureAsFnCast;
158        let bound_dref = self.translate_closure_bound_ref_with_late_bound(span, closure, kind)?;
159        Ok(bound_dref.map(|dref| dref.try_into().unwrap()))
160    }
161
162    /// Translate a reference to the chosen closure impl. The resulting value needs lifetime
163    /// arguments for late-bound lifetimes. If you want to instantiate the binder, use the
164    /// lifetimes from `self.closure_late_regions`.
165    pub fn translate_closure_bound_impl_ref(
166        &mut self,
167        span: Span,
168        closure: &hax::ClosureArgs,
169        target_kind: ClosureKind,
170    ) -> Result<RegionBinder<TraitImplRef>, Error> {
171        let kind = TransItemSourceKind::TraitImpl(TraitImplSource::Closure(target_kind));
172        let bound_dref = self.translate_closure_bound_ref_with_late_bound(span, closure, kind)?;
173        Ok(bound_dref.map(|dref| dref.try_into().unwrap()))
174    }
175
176    /// Translate a reference to the chosen closure impl.
177    pub fn translate_closure_impl_ref(
178        &mut self,
179        span: Span,
180        closure: &hax::ClosureArgs,
181        target_kind: ClosureKind,
182    ) -> Result<TraitImplRef, Error> {
183        self.translate_item(
184            span,
185            &closure.item,
186            TransItemSourceKind::TraitImpl(TraitImplSource::Closure(target_kind)),
187        )
188    }
189
190    pub fn translate_closure_info(
191        &mut self,
192        span: Span,
193        args: &hax::ClosureArgs,
194    ) -> Result<ClosureInfo, Error> {
195        use ClosureKind::*;
196        let kind = translate_closure_kind(&args.kind);
197
198        let fn_once_impl = self.translate_closure_bound_impl_ref(span, args, FnOnce)?;
199        let fn_mut_impl = if matches!(kind, FnMut | Fn) {
200            Some(self.translate_closure_bound_impl_ref(span, args, FnMut)?)
201        } else {
202            None
203        };
204        let fn_impl = if matches!(kind, Fn) {
205            Some(self.translate_closure_bound_impl_ref(span, args, Fn)?)
206        } else {
207            None
208        };
209        let signature = self.translate_poly_fun_sig(span, &args.fn_sig)?;
210        Ok(ClosureInfo {
211            kind,
212            fn_once_impl,
213            fn_mut_impl,
214            fn_impl,
215            signature,
216        })
217    }
218
219    pub fn get_closure_state_ty(
220        &mut self,
221        span: Span,
222        args: &hax::ClosureArgs,
223    ) -> Result<Ty, Error> {
224        let tref = self.translate_closure_type_ref(span, args)?;
225        Ok(TyKind::Adt(tref).into_ty())
226    }
227
228    /// Translate the types of the captured variables. Should be called only in
229    /// `translate_item_generics`. If you need these types, fetch them in
230    /// `outermost_binder().closure_upvar_tys`.
231    pub fn translate_closure_upvar_tys(
232        &mut self,
233        span: Span,
234        args: &hax::ClosureArgs,
235    ) -> Result<IndexVec<FieldId, Ty>, Error> {
236        args.upvar_tys
237            .iter()
238            .map(|ty| self.translate_ty(span, ty))
239            .try_collect()
240    }
241
242    pub fn translate_closure_adt(
243        &mut self,
244        span: Span,
245        _args: &hax::ClosureArgs,
246    ) -> Result<TypeDeclKind, Error> {
247        let fields: IndexVec<FieldId, Field> = self
248            .the_only_binder()
249            .closure_upvar_tys
250            .as_ref()
251            .unwrap()
252            .iter()
253            .cloned()
254            .map(|ty| Field {
255                span,
256                attr_info: AttrInfo::dummy_private(),
257                name: None,
258                ty: ty,
259            })
260            .collect();
261        Ok(TypeDeclKind::Struct(fields))
262    }
263
264    /// Given an item that is a closure, generate the signature of the
265    /// `call_once`/`call_mut`/`call` method (depending on `target_kind`).
266    fn translate_closure_method_sig(
267        &mut self,
268        def: &hax::FullDef,
269        span: Span,
270        args: &hax::ClosureArgs,
271        target_kind: ClosureKind,
272    ) -> Result<RegionBinder<FunSig>, Error> {
273        let signature = &args.fn_sig;
274        trace!(
275            "signature of closure {:?}:\n{:?}",
276            def.def_id(),
277            signature.value,
278        );
279
280        let mut bound_regions = IndexMap::new();
281        let mut fun_sig = self
282            .translate_fun_sig(span, signature.hax_skip_binder_ref())?
283            .move_under_binder();
284        let state_ty = self.get_closure_state_ty(span, args)?.move_under_binder();
285
286        // Depending on the kind of the closure generated, add a reference
287        let state_ty = match target_kind {
288            ClosureKind::FnOnce => state_ty,
289            ClosureKind::Fn | ClosureKind::FnMut => {
290                let rid = bound_regions.push_with(|index| RegionParam { index, name: None });
291                let r = Region::Var(DeBruijnVar::new_at_zero(rid));
292                let mutability = if target_kind == ClosureKind::Fn {
293                    RefKind::Shared
294                } else {
295                    RefKind::Mut
296                };
297                TyKind::Ref(r, state_ty, mutability).into_ty()
298            }
299        };
300
301        // The types that the closure takes as input.
302        let input_tys: Vec<Ty> = mem::take(&mut fun_sig.inputs);
303        // The method takes `self` and the closure inputs as a tuple.
304        fun_sig.inputs = vec![state_ty, Ty::mk_tuple(input_tys)];
305
306        Ok(RegionBinder {
307            regions: bound_regions,
308            skip_binder: fun_sig,
309        })
310    }
311
312    fn translate_closure_method_body(
313        &mut self,
314        span: Span,
315        def: &hax::FullDef,
316        target_kind: ClosureKind,
317        args: &hax::ClosureArgs,
318        signature: &FunSig,
319    ) -> Result<Body, Error> {
320        use ClosureKind::*;
321        let closure_kind = translate_closure_kind(&args.kind);
322        Ok(match (target_kind, closure_kind) {
323            (Fn, Fn) | (FnMut, FnMut) | (FnOnce, FnOnce) => {
324                // Translate the function's body normally
325                let mut body = self.translate_def_body(span, def);
326                // The body is translated as if the locals are: ret value, state, arg-1,
327                // ..., arg-N, rest...
328                // However, there is only one argument with the tupled closure arguments;
329                // we must thus shift all locals with index >=2 by 1, and add a new local
330                // for the tupled arg, giving us: ret value, state, args, arg-1, ...,
331                // arg-N, rest...
332                // We then add N statements of the form `locals[N+3] := move locals[2].N`,
333                // to destructure the arguments.
334                let Body::Unstructured(GExprBody {
335                    locals,
336                    body: blocks,
337                    ..
338                }) = &mut body
339                else {
340                    return Ok(body);
341                };
342
343                // The (Arg1, Arg2, ..) type.
344                let tupled_ty = &signature.inputs[1];
345
346                blocks.dyn_visit_mut(|local: &mut LocalId| {
347                    if local.index() >= 2 {
348                        *local += 1;
349                    }
350                });
351
352                let mut old_locals = mem::take(&mut locals.locals).into_iter();
353                locals.arg_count = 2;
354                locals.locals.push(old_locals.next().unwrap()); // ret
355                locals.locals.push(old_locals.next().unwrap()); // state
356                let tupled_arg = locals.new_var(Some("tupled_args".to_string()), tupled_ty.clone());
357                locals.locals.extend(old_locals.map(|mut l| {
358                    l.index += 1;
359                    l
360                }));
361
362                let untupled_args = tupled_ty.as_tuple().unwrap();
363                let closure_arg_count = untupled_args.elem_count();
364                let new_stts = untupled_args.iter().cloned().enumerate().map(|(i, ty)| {
365                    let nth_field = tupled_arg.clone().project(
366                        ProjectionElem::Field(
367                            FieldProjKind::Tuple(closure_arg_count),
368                            FieldId::new(i),
369                        ),
370                        ty,
371                    );
372                    let local_id = LocalId::new(i + 3);
373                    Statement::new(
374                        span,
375                        StatementKind::Assign(
376                            locals.place_for_var(local_id),
377                            Rvalue::Use(Operand::Move(nth_field)),
378                        ),
379                    )
380                });
381                blocks[BlockId::ZERO].statements.splice(0..0, new_stts);
382
383                body
384            }
385            // Target translation:
386            //
387            // fn call_once(state: Self, args: Args) -> Output {
388            //   let temp_ref = &[mut] state;
389            //   let ret = self.call[_mut](temp, args);
390            //   drop state;
391            //   return ret;
392            // }
393            //
394            (FnOnce, Fn | FnMut) => {
395                // Hax (via rustc) gives us the MIR to do this.
396                let Some(body) = def.this.closure_once_shim(self.hax_state()) else {
397                    panic!("missing shim for closure")
398                };
399                self.translate_body(span, body, &def.source_text)
400            }
401            // Target translation:
402            //
403            // fn call_mut(state: &mut Self, args: Args) -> Output {
404            //   let reborrow = &*state;
405            //   self.call(reborrow, args)
406            // }
407            (FnMut, Fn) => {
408                let fun_id: FunDeclId = self.register_item(
409                    span,
410                    def.this(),
411                    TransItemSourceKind::ClosureMethod(closure_kind),
412                );
413                let impl_ref = self.translate_closure_impl_ref(span, args, closure_kind)?;
414                // TODO: make a trait call to avoid needing to concatenate things ourselves.
415                // TODO: can we ask hax for the trait ref?
416                let fn_op = FnOperand::Regular(FnPtr::new(
417                    fun_id.into(),
418                    impl_ref.generics.concat(&GenericArgs {
419                        regions: vec![self.translate_erased_region()].into(),
420                        ..GenericArgs::empty()
421                    }),
422                ));
423
424                let mut builder = BodyBuilder::new(span, 2);
425
426                let output = builder.new_var(None, signature.output.clone());
427                let state = builder.new_var(Some("state".to_string()), signature.inputs[0].clone());
428                let args = builder.new_var(Some("args".to_string()), signature.inputs[1].clone());
429                let deref_state = state.deref();
430                let reborrow_ty = TyKind::Ref(
431                    self.translate_erased_region(),
432                    deref_state.ty.clone(),
433                    RefKind::Shared,
434                )
435                .into_ty();
436                let reborrow = builder.new_var(None, reborrow_ty);
437
438                builder.push_statement(StatementKind::Assign(
439                    reborrow.clone(),
440                    Rvalue::Ref {
441                        place: deref_state,
442                        kind: BorrowKind::Shared,
443                        // The state must be Sized, hence `()` as ptr-metadata
444                        ptr_metadata: Operand::mk_const_unit(),
445                    },
446                ));
447
448                builder.call(Call {
449                    func: fn_op,
450                    args: vec![Operand::Move(reborrow), Operand::Move(args)],
451                    dest: output,
452                });
453
454                Body::Unstructured(builder.build())
455            }
456            (Fn, FnOnce) | (Fn, FnMut) | (FnMut, FnOnce) => {
457                panic!(
458                    "Can't make a closure body for a more restrictive kind \
459                    than the closure kind"
460                )
461            }
462        })
463    }
464
465    /// Given an item that is a closure, generate the `call_once`/`call_mut`/`call` method
466    /// (depending on `target_kind`).
467    #[tracing::instrument(skip(self, item_meta))]
468    pub fn translate_closure_method(
469        mut self,
470        def_id: FunDeclId,
471        item_meta: ItemMeta,
472        def: &hax::FullDef,
473        target_kind: ClosureKind,
474    ) -> Result<FunDecl, Error> {
475        let span = item_meta.span;
476        let hax::FullDefKind::Closure {
477            args,
478            fn_once_impl,
479            fn_mut_impl,
480            fn_impl,
481            ..
482        } = &def.kind
483        else {
484            unreachable!()
485        };
486
487        // Hax gives us trait-related information for the impl we're building.
488        let vimpl = match target_kind {
489            ClosureKind::FnOnce => fn_once_impl,
490            ClosureKind::FnMut => fn_mut_impl.as_ref().unwrap(),
491            ClosureKind::Fn => fn_impl.as_ref().unwrap(),
492        };
493        let implemented_trait = self.translate_trait_predicate(span, &vimpl.trait_pred)?;
494
495        let impl_ref = self.translate_closure_impl_ref(span, args, target_kind)?;
496        let src = ItemSource::TraitImpl {
497            impl_ref,
498            trait_ref: implemented_trait,
499            item_name: TraitItemName(target_kind.method_name().into()),
500            reuses_default: false,
501        };
502
503        // Translate the function signature
504        let bound_sig = self.translate_closure_method_sig(def, span, args, target_kind)?;
505        // We give it the lifetime parameter we had prepared for that purpose.
506        let signature = bound_sig.apply(
507            self.the_only_binder()
508                .closure_call_method_region
509                .iter()
510                .map(|r| Region::Var(DeBruijnVar::new_at_zero(*r)))
511                .collect(),
512        );
513
514        let body = if item_meta.opacity.with_private_contents().is_opaque() {
515            Body::Opaque
516        } else {
517            self.translate_closure_method_body(span, def, target_kind, args, &signature)?
518        };
519
520        Ok(FunDecl {
521            def_id,
522            item_meta,
523            generics: self.into_generics(),
524            signature,
525            src,
526            is_global_initializer: None,
527            body,
528        })
529    }
530
531    #[tracing::instrument(skip(self, item_meta))]
532    pub fn translate_closure_trait_impl(
533        mut self,
534        def_id: TraitImplId,
535        item_meta: ItemMeta,
536        def: &hax::FullDef,
537        target_kind: ClosureKind,
538    ) -> Result<TraitImpl, Error> {
539        let span = item_meta.span;
540        let hax::FullDefKind::Closure {
541            args,
542            fn_once_impl,
543            fn_mut_impl,
544            fn_impl,
545            ..
546        } = def.kind()
547        else {
548            unreachable!()
549        };
550
551        // Hax gives us trait-related information for the impl we're building.
552        let vimpl = match target_kind {
553            ClosureKind::FnOnce => fn_once_impl,
554            ClosureKind::FnMut => fn_mut_impl.as_ref().unwrap(),
555            ClosureKind::Fn => fn_impl.as_ref().unwrap(),
556        };
557        let mut timpl = self.translate_virtual_trait_impl(def_id, item_meta, vimpl)?;
558
559        // Construct the `call_*` method reference.
560        let call_fn_name = TraitItemName(target_kind.method_name().into());
561        let call_fn_binder = {
562            let kind = TransItemSourceKind::ClosureMethod(target_kind);
563            let bound_method_ref: RegionBinder<DeclRef<ItemId>> =
564                self.translate_closure_bound_ref_with_method_bound(span, args, kind, target_kind)?;
565            let params = GenericParams {
566                regions: bound_method_ref.regions,
567                ..GenericParams::empty()
568            };
569            let fn_decl_ref: FunDeclRef = bound_method_ref.skip_binder.try_into().unwrap();
570            Binder::new(
571                BinderKind::TraitMethod(timpl.impl_trait.id, call_fn_name),
572                params,
573                fn_decl_ref,
574            )
575        };
576        timpl.methods.push((call_fn_name, call_fn_binder));
577
578        Ok(timpl)
579    }
580
581    /// Given an item that is a non-capturing closure, generate the equivalent function,
582    /// by removing the state from the parameters and untupling the arguments.
583    #[tracing::instrument(skip(self, item_meta))]
584    pub fn translate_stateless_closure_as_fn(
585        mut self,
586        def_id: FunDeclId,
587        item_meta: ItemMeta,
588        def: &hax::FullDef,
589    ) -> Result<FunDecl, Error> {
590        let span = item_meta.span;
591        let hax::FullDefKind::Closure { args: closure, .. } = &def.kind else {
592            unreachable!()
593        };
594
595        trace!("About to translate closure as fn:\n{:?}", def.def_id());
596
597        assert!(
598            closure.upvar_tys.is_empty(),
599            "Only stateless closures can be translated as functions"
600        );
601
602        // Translate the function signature
603        let signature = self.translate_fun_sig(span, closure.fn_sig.hax_skip_binder_ref())?;
604        let state_ty = self.get_closure_state_ty(span, closure)?;
605
606        let body = if item_meta.opacity.with_private_contents().is_opaque() {
607            Body::Opaque
608        } else {
609            // Target translation:
610            //
611            // fn call_fn(arg0: Args[0], ..., argN: Args[N]) -> Output {
612            //   let closure: Closure = {};
613            //   let args = (arg0, ..., argN);
614            //   closure.call(args)
615            // }
616            let fun_id: FunDeclId = self.register_item(
617                span,
618                def.this(),
619                TransItemSourceKind::ClosureMethod(ClosureKind::FnOnce),
620            );
621            let impl_ref = self.translate_closure_impl_ref(span, closure, ClosureKind::FnOnce)?;
622            let fn_op = FnOperand::Regular(FnPtr::new(fun_id.into(), impl_ref.generics.clone()));
623
624            let mut builder = BodyBuilder::new(span, signature.inputs.len());
625
626            let output = builder.new_var(None, signature.output.clone());
627            let args: Vec<Place> = signature
628                .inputs
629                .iter()
630                .enumerate()
631                .map(|(i, ty)| builder.new_var(Some(format!("arg{}", i + 1)), ty.clone()))
632                .collect();
633            let args_tupled_ty = Ty::mk_tuple(signature.inputs.clone());
634            let args_tupled = builder.new_var(Some("args".to_string()), args_tupled_ty.clone());
635            let state = builder.new_var(Some("state".to_string()), state_ty.clone());
636
637            builder.push_statement(StatementKind::Assign(
638                args_tupled.clone(),
639                Rvalue::Aggregate(
640                    AggregateKind::Adt(args_tupled_ty.as_adt().unwrap().clone(), None, None),
641                    args.into_iter().map(Operand::Move).collect(),
642                ),
643            ));
644
645            let state_ty_adt = state_ty.as_adt().unwrap();
646            builder.push_statement(StatementKind::Assign(
647                state.clone(),
648                Rvalue::Aggregate(AggregateKind::Adt(state_ty_adt.clone(), None, None), vec![]),
649            ));
650
651            builder.call(Call {
652                func: fn_op,
653                args: vec![Operand::Move(state), Operand::Move(args_tupled)],
654                dest: output,
655            });
656
657            Body::Unstructured(builder.build())
658        };
659
660        Ok(FunDecl {
661            def_id,
662            item_meta,
663            generics: self.into_generics(),
664            signature,
665            src: ItemSource::TopLevel,
666            is_global_initializer: None,
667            body,
668        })
669    }
670}
charon_driver/translate/translate_closures.rs

charon_driver/translate/
translate_closures.rs
