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 crate::hax;
42use itertools::Itertools;
43use std::mem;
44
45use super::translate_crate::TransItemSourceKind;
46use super::translate_ctx::*;
47use charon_lib::ast::ullbc_ast_utils::BodyBuilder;
48use charon_lib::ast::*;
49use charon_lib::ids::IndexVec;
50use charon_lib::ullbc_ast::*;
51
52pub fn translate_closure_kind(kind: &hax::ClosureKind) -> ClosureKind {
53    match kind {
54        hax::ClosureKind::Fn => ClosureKind::Fn,
55        hax::ClosureKind::FnMut => ClosureKind::FnMut,
56        hax::ClosureKind::FnOnce => ClosureKind::FnOnce,
57    }
58}
59
60/// References to closure items are subtle because there are three sources of lifetimes on top of
61/// the normal generics: the upvars, the higher-kindedness of the closure itself, and the
62/// late-bound generics of the `call`/`call_mut` methods. One must be careful to choose the right
63/// method from these.
64impl ItemTransCtx<'_, '_> {
65    /// Translate a reference to a closure item that takes late-bound lifetimes. The binder binds
66    /// the late-bound lifetimes of the closure itself, if it is higher-kinded.
67    fn translate_closure_bound_ref_with_late_bound(
68        &mut self,
69        span: Span,
70        closure: &hax::ClosureArgs,
71        kind: TransItemSourceKind,
72    ) -> Result<RegionBinder<DeclRef<ItemId>>, Error> {
73        if !matches!(
74            kind,
75            TransItemSourceKind::TraitImpl(..) | TransItemSourceKind::ClosureAsFnCast
76        ) {
77            raise_error!(
78                self,
79                span,
80                "Called `translate_closure_bound_ref_with_late_bound` on a `{kind:?}`; \
81                use `translate_closure_ref_with_upvars` \
82                or `translate_closure_bound_ref_with_method_bound` instead"
83            )
84        }
85        let dref: DeclRef<ItemId> = self.translate_item(span, &closure.item, kind)?;
86        self.translate_region_binder(span, &closure.fn_sig, |ctx, _| {
87            let mut dref = dref.move_under_binder();
88            // The regions for these item kinds have the fn late bound regions at the end.
89            for (a, b) in dref.generics.regions.iter_mut().rev().zip(
90                ctx.innermost_binder()
91                    .params
92                    .identity_args()
93                    .regions
94                    .into_iter()
95                    .rev(),
96            ) {
97                *a = b;
98            }
99            Ok(dref)
100        })
101    }
102
103    /// Translate a reference to a closure item that takes late-bound lifetimes and method
104    /// lifetimes. The binder binds the late-bound lifetimes of the `call`/`call_mut` method
105    /// (specified by `target_kind`).
106    fn translate_closure_bound_ref_with_method_bound(
107        &mut self,
108        span: Span,
109        closure: &hax::ClosureArgs,
110        kind: TransItemSourceKind,
111        target_kind: ClosureKind,
112    ) -> Result<RegionBinder<DeclRef<ItemId>>, Error> {
113        if !matches!(kind, TransItemSourceKind::ClosureMethod(..)) {
114            raise_error!(
115                self,
116                span,
117                "Called `translate_closure_bound_ref_with_method_bound` on a `{kind:?}`; \
118                use `translate_closure_ref_with_upvars` \
119                or `translate_closure_bound_ref_with_late_bound` instead"
120            )
121        }
122        let dref: DeclRef<ItemId> = self.translate_item(span, &closure.item, kind)?;
123        let mut dref = dref.move_under_binder();
124        let mut regions = IndexVec::new();
125        match target_kind {
126            ClosureKind::FnOnce => {}
127            ClosureKind::FnMut | ClosureKind::Fn => {
128                let rid = regions.push_with(|index| RegionParam::new(index, None));
129                *dref.generics.regions.iter_mut().last().unwrap() =
130                    Region::Var(DeBruijnVar::new_at_zero(rid));
131            }
132        }
133        Ok(RegionBinder {
134            regions,
135            skip_binder: dref,
136        })
137    }
138}
139
140impl ItemTransCtx<'_, '_> {
141    /// Translate a reference to the closure ADT.
142    pub fn translate_closure_type_ref(
143        &mut self,
144        span: Span,
145        closure: &hax::ClosureArgs,
146    ) -> Result<TypeDeclRef, Error> {
147        self.translate_item(span, &closure.item, TransItemSourceKind::Type)
148    }
149
150    /// For stateless closures, translate a function reference to the top-level function that
151    /// executes the closure code without taking the state as parameter.If you want to instantiate
152    /// the binder, use the lifetimes from `self.closure_late_regions`.
153    pub fn translate_stateless_closure_as_fn_ref(
154        &mut self,
155        span: Span,
156        closure: &hax::ClosureArgs,
157    ) -> Result<RegionBinder<FunDeclRef>, Error> {
158        let kind = TransItemSourceKind::ClosureAsFnCast;
159        let bound_dref = self.translate_closure_bound_ref_with_late_bound(span, closure, kind)?;
160        Ok(bound_dref.map(|dref| dref.try_into().unwrap()))
161    }
162
163    /// Translate a reference to the chosen closure impl. The resulting value needs lifetime
164    /// arguments for late-bound lifetimes. If you want to instantiate the binder, use the
165    /// lifetimes from `self.closure_late_regions`.
166    pub fn translate_closure_bound_impl_ref(
167        &mut self,
168        span: Span,
169        closure: &hax::ClosureArgs,
170        target_kind: ClosureKind,
171    ) -> Result<RegionBinder<TraitImplRef>, Error> {
172        let kind = TransItemSourceKind::TraitImpl(TraitImplSource::Closure(target_kind));
173        let bound_dref = self.translate_closure_bound_ref_with_late_bound(span, closure, kind)?;
174        Ok(bound_dref.map(|dref| dref.try_into().unwrap()))
175    }
176
177    /// Translate a reference to the chosen closure impl.
178    pub fn translate_closure_impl_ref(
179        &mut self,
180        span: Span,
181        closure: &hax::ClosureArgs,
182        target_kind: ClosureKind,
183    ) -> Result<TraitImplRef, Error> {
184        self.translate_item(
185            span,
186            &closure.item,
187            TransItemSourceKind::TraitImpl(TraitImplSource::Closure(target_kind)),
188        )
189    }
190
191    pub fn translate_closure_info(
192        &mut self,
193        span: Span,
194        args: &hax::ClosureArgs,
195    ) -> Result<ClosureInfo, Error> {
196        use ClosureKind::*;
197        let kind = translate_closure_kind(&args.kind);
198
199        let fn_once_impl = self.translate_closure_bound_impl_ref(span, args, FnOnce)?;
200        let fn_mut_impl = if matches!(kind, FnMut | Fn) {
201            Some(self.translate_closure_bound_impl_ref(span, args, FnMut)?)
202        } else {
203            None
204        };
205        let fn_impl = if matches!(kind, Fn) {
206            Some(self.translate_closure_bound_impl_ref(span, args, Fn)?)
207        } else {
208            None
209        };
210        let signature = self.translate_poly_fun_sig(span, &args.fn_sig)?;
211        Ok(ClosureInfo {
212            kind,
213            fn_once_impl,
214            fn_mut_impl,
215            fn_impl,
216            signature,
217        })
218    }
219
220    pub fn get_closure_state_ty(
221        &mut self,
222        span: Span,
223        args: &hax::ClosureArgs,
224    ) -> Result<Ty, Error> {
225        let tref = self.translate_closure_type_ref(span, args)?;
226        Ok(TyKind::Adt(tref).into_ty())
227    }
228
229    /// Translate the types of the captured variables. Should be called only in
230    /// `translate_item_generics`. If you need these types, fetch them in
231    /// `outermost_binder().closure_upvar_tys`.
232    pub fn translate_closure_upvar_tys(
233        &mut self,
234        span: Span,
235        args: &hax::ClosureArgs,
236    ) -> Result<IndexVec<FieldId, Ty>, Error> {
237        args.upvar_tys
238            .iter()
239            .map(|ty| self.translate_ty(span, ty))
240            .try_collect()
241    }
242
243    pub fn translate_closure_adt(
244        &mut self,
245        span: Span,
246        _args: &hax::ClosureArgs,
247    ) -> Result<TypeDeclKind, Error> {
248        let fields: IndexVec<FieldId, Field> = self
249            .the_only_binder()
250            .closure_upvar_tys
251            .as_ref()
252            .unwrap()
253            .iter()
254            .cloned()
255            .map(|ty| Field {
256                span,
257                attr_info: AttrInfo::dummy_private(),
258                name: None,
259                ty,
260            })
261            .collect();
262        Ok(TypeDeclKind::Struct(fields))
263    }
264
265    /// Given an item that is a closure, generate the signature of the
266    /// `call_once`/`call_mut`/`call` method (depending on `target_kind`).
267    fn translate_closure_method_sig(
268        &mut self,
269        def: &hax::FullDef,
270        span: Span,
271        args: &hax::ClosureArgs,
272        target_kind: ClosureKind,
273    ) -> Result<RegionBinder<FunSig>, Error> {
274        let signature = &args.fn_sig;
275        trace!(
276            "signature of closure {:?}:\n{:?}",
277            def.def_id(),
278            signature.value,
279        );
280
281        let mut bound_regions = IndexVec::new();
282        let mut fun_sig = self
283            .translate_fun_sig(span, signature.hax_skip_binder_ref())?
284            .move_under_binder();
285        let state_ty = self.get_closure_state_ty(span, args)?.move_under_binder();
286
287        // Depending on the kind of the closure generated, add a reference
288        let state_ty = match target_kind {
289            ClosureKind::FnOnce => state_ty,
290            ClosureKind::Fn | ClosureKind::FnMut => {
291                let rid = bound_regions.push_with(|index| RegionParam::new(index, None));
292                let r = Region::Var(DeBruijnVar::new_at_zero(rid));
293                let mutability = if target_kind == ClosureKind::Fn {
294                    RefKind::Shared
295                } else {
296                    RefKind::Mut
297                };
298                TyKind::Ref(r, state_ty, mutability).into_ty()
299            }
300        };
301
302        // The types that the closure takes as input.
303        let input_tys: Vec<Ty> = mem::take(&mut fun_sig.inputs);
304        // The method takes `self` and the closure inputs as a tuple.
305        fun_sig.inputs = vec![state_ty, Ty::mk_tuple(input_tys)];
306
307        Ok(RegionBinder {
308            regions: bound_regions,
309            skip_binder: fun_sig,
310        })
311    }
312
313    fn translate_closure_method_body(
314        &mut self,
315        span: Span,
316        def: &hax::FullDef,
317        target_kind: ClosureKind,
318        args: &hax::ClosureArgs,
319        signature: &FunSig,
320    ) -> Result<Body, Error> {
321        use ClosureKind::*;
322        let closure_kind = translate_closure_kind(&args.kind);
323        Ok(match (target_kind, closure_kind) {
324            (Fn, Fn) | (FnMut, FnMut) | (FnOnce, FnOnce) => {
325                // Translate the function's body normally
326                let mut body = self.translate_def_body(span, def);
327                // The body is translated as if the locals are: ret value, state, arg-1,
328                // ..., arg-N, rest...
329                // However, there is only one argument with the tupled closure arguments;
330                // we must thus shift all locals with index >=2 by 1, and add a new local
331                // for the tupled arg, giving us: ret value, state, args, arg-1, ...,
332                // arg-N, rest...
333                // We then add N statements of the form `locals[N+3] := move locals[2].N`,
334                // to destructure the arguments.
335                let Body::Unstructured(GExprBody {
336                    locals,
337                    body: blocks,
338                    ..
339                }) = &mut body
340                else {
341                    return Ok(body);
342                };
343
344                // The (Arg1, Arg2, ..) type.
345                let tupled_ty = &signature.inputs[1];
346
347                blocks.dyn_visit_mut(|local: &mut LocalId| {
348                    if local.index() >= 2 {
349                        *local += 1;
350                    }
351                });
352
353                let mut old_locals = mem::take(&mut locals.locals).into_iter();
354                locals.arg_count = 2;
355                locals.locals.push(old_locals.next().unwrap()); // ret
356                locals.locals.push(old_locals.next().unwrap()); // state
357                let tupled_arg = locals.new_var(Some("tupled_args".to_string()), tupled_ty.clone());
358                locals.locals.extend(old_locals.map(|mut l| {
359                    l.index += 1;
360                    l
361                }));
362
363                let untupled_args = tupled_ty.as_tuple().unwrap();
364                let closure_arg_count = untupled_args.len();
365                let new_stts = untupled_args.iter().cloned().enumerate().map(|(i, ty)| {
366                    let nth_field = tupled_arg.clone().project(
367                        ProjectionElem::Field(
368                            FieldProjKind::Tuple(closure_arg_count),
369                            FieldId::new(i),
370                        ),
371                        ty,
372                    );
373                    let local_id = LocalId::new(i + 3);
374                    Statement::new(
375                        span,
376                        StatementKind::Assign(
377                            locals.place_for_var(local_id),
378                            Rvalue::Use(Operand::Move(nth_field)),
379                        ),
380                    )
381                });
382                blocks[BlockId::ZERO].statements.splice(0..0, new_stts);
383
384                body
385            }
386            // Target translation:
387            //
388            // fn call_once(state: Self, args: Args) -> Output {
389            //   let temp_ref = &[mut] state;
390            //   let ret = self.call[_mut](temp, args);
391            //   drop state;
392            //   return ret;
393            // }
394            //
395            (FnOnce, Fn | FnMut) => {
396                // Hax (via rustc) gives us the MIR to do this.
397                let Some(body) = def.this.closure_once_shim(self.hax_state()) else {
398                    panic!("missing shim for closure")
399                };
400                self.translate_body(span, body, &def.source_text)
401            }
402            // Target translation:
403            //
404            // fn call_mut(state: &mut Self, args: Args) -> Output {
405            //   let reborrow = &*state;
406            //   self.call(reborrow, args)
407            // }
408            (FnMut, Fn) => {
409                let fun_id: FunDeclId = self.register_item(
410                    span,
411                    def.this(),
412                    TransItemSourceKind::ClosureMethod(closure_kind),
413                );
414                let impl_ref = self.translate_closure_impl_ref(span, args, closure_kind)?;
415                // TODO: make a trait call to avoid needing to concatenate things ourselves.
416                // TODO: can we ask hax for the trait ref?
417                let fn_op = FnOperand::Regular(FnPtr::new(
418                    fun_id.into(),
419                    impl_ref.generics.concat(&GenericArgs {
420                        regions: vec![self.translate_erased_region()].into(),
421                        ..GenericArgs::empty()
422                    }),
423                ));
424
425                let mut builder = BodyBuilder::new(span, 2);
426
427                let output = builder.new_var(None, signature.output.clone());
428                let state = builder.new_var(Some("state".to_string()), signature.inputs[0].clone());
429                let args = builder.new_var(Some("args".to_string()), signature.inputs[1].clone());
430                let deref_state = state.deref();
431                let reborrow_ty = TyKind::Ref(
432                    self.translate_erased_region(),
433                    deref_state.ty.clone(),
434                    RefKind::Shared,
435                )
436                .into_ty();
437                let reborrow = builder.new_var(None, reborrow_ty);
438
439                builder.push_statement(StatementKind::Assign(
440                    reborrow.clone(),
441                    Rvalue::Ref {
442                        place: deref_state,
443                        kind: BorrowKind::Shared,
444                        // The state must be Sized, hence `()` as ptr-metadata
445                        ptr_metadata: Operand::mk_const_unit(),
446                    },
447                ));
448
449                builder.call(Call {
450                    func: fn_op,
451                    args: vec![Operand::Move(reborrow), Operand::Move(args)],
452                    dest: output,
453                });
454
455                Body::Unstructured(builder.build())
456            }
457            (Fn, FnOnce) | (Fn, FnMut) | (FnMut, FnOnce) => {
458                panic!(
459                    "Can't make a closure body for a more restrictive kind \
460                    than the closure kind"
461                )
462            }
463        })
464    }
465
466    /// Given an item that is a closure, generate the `call_once`/`call_mut`/`call` method
467    /// (depending on `target_kind`).
468    #[tracing::instrument(skip(self, item_meta))]
469    pub fn translate_closure_method(
470        mut self,
471        def_id: FunDeclId,
472        item_meta: ItemMeta,
473        def: &hax::FullDef,
474        target_kind: ClosureKind,
475    ) -> Result<FunDecl, Error> {
476        let span = item_meta.span;
477        let hax::FullDefKind::Closure {
478            args,
479            fn_once_impl,
480            fn_mut_impl,
481            fn_impl,
482            ..
483        } = &def.kind
484        else {
485            unreachable!()
486        };
487
488        // Hax gives us trait-related information for the impl we're building.
489        let vimpl = match target_kind {
490            ClosureKind::FnOnce => fn_once_impl,
491            ClosureKind::FnMut => fn_mut_impl.as_ref().unwrap(),
492            ClosureKind::Fn => fn_impl.as_ref().unwrap(),
493        };
494        let implemented_trait = self.translate_trait_predicate(span, &vimpl.trait_pred)?;
495
496        let impl_ref = self.translate_closure_impl_ref(span, args, target_kind)?;
497        let src = ItemSource::TraitImpl {
498            impl_ref,
499            trait_ref: implemented_trait,
500            item_name: TraitItemName(target_kind.method_name().into()),
501            reuses_default: false,
502        };
503
504        // Translate the function signature
505        let bound_sig = self.translate_closure_method_sig(def, span, args, target_kind)?;
506        // We give it the lifetime parameter we had prepared for that purpose.
507        let signature = bound_sig.apply(
508            self.the_only_binder()
509                .closure_call_method_region
510                .iter()
511                .map(|r| Region::Var(DeBruijnVar::new_at_zero(*r)))
512                .collect(),
513        );
514
515        let body = if item_meta.opacity.with_private_contents().is_opaque() {
516            Body::Opaque
517        } else {
518            self.translate_closure_method_body(span, def, target_kind, args, &signature)?
519        };
520
521        Ok(FunDecl {
522            def_id,
523            item_meta,
524            generics: self.into_generics(),
525            signature,
526            src,
527            is_global_initializer: None,
528            body,
529        })
530    }
531
532    #[tracing::instrument(skip(self, item_meta))]
533    pub fn translate_closure_trait_impl(
534        mut self,
535        def_id: TraitImplId,
536        item_meta: ItemMeta,
537        def: &hax::FullDef,
538        target_kind: ClosureKind,
539    ) -> Result<TraitImpl, Error> {
540        let span = item_meta.span;
541        let hax::FullDefKind::Closure {
542            args,
543            fn_once_impl,
544            fn_mut_impl,
545            fn_impl,
546            ..
547        } = def.kind()
548        else {
549            unreachable!()
550        };
551
552        // Hax gives us trait-related information for the impl we're building.
553        let vimpl = match target_kind {
554            ClosureKind::FnOnce => fn_once_impl,
555            ClosureKind::FnMut => fn_mut_impl.as_ref().unwrap(),
556            ClosureKind::Fn => fn_impl.as_ref().unwrap(),
557        };
558        let mut timpl = self.translate_virtual_trait_impl(def_id, item_meta, vimpl)?;
559
560        if self.monomorphize() {
561            return Ok(timpl);
562        }
563
564        // Construct the `call_*` method reference.
565        let call_fn_name = TraitItemName(target_kind.method_name().into());
566        let call_fn_binder = {
567            let kind = TransItemSourceKind::ClosureMethod(target_kind);
568            let bound_method_ref: RegionBinder<DeclRef<ItemId>> =
569                self.translate_closure_bound_ref_with_method_bound(span, args, kind, target_kind)?;
570            let params = GenericParams {
571                regions: bound_method_ref.regions,
572                ..GenericParams::empty()
573            };
574            let fn_decl_ref: FunDeclRef = bound_method_ref.skip_binder.try_into().unwrap();
575            Binder::new(
576                BinderKind::TraitMethod(timpl.impl_trait.id, call_fn_name),
577                params,
578                fn_decl_ref,
579            )
580        };
581        timpl.methods.push((call_fn_name, call_fn_binder));
582
583        Ok(timpl)
584    }
585
586    /// Given an item that is a non-capturing closure, generate the equivalent function,
587    /// by removing the state from the parameters and untupling the arguments.
588    #[tracing::instrument(skip(self, item_meta))]
589    pub fn translate_stateless_closure_as_fn(
590        mut self,
591        def_id: FunDeclId,
592        item_meta: ItemMeta,
593        def: &hax::FullDef,
594    ) -> Result<FunDecl, Error> {
595        let span = item_meta.span;
596        let hax::FullDefKind::Closure { args: closure, .. } = &def.kind else {
597            unreachable!()
598        };
599
600        trace!("About to translate closure as fn:\n{:?}", def.def_id());
601
602        assert!(
603            closure.upvar_tys.is_empty(),
604            "Only stateless closures can be translated as functions"
605        );
606
607        // Translate the function signature
608        let signature = self.translate_fun_sig(span, closure.fn_sig.hax_skip_binder_ref())?;
609        let state_ty = self.get_closure_state_ty(span, closure)?;
610
611        let body = if item_meta.opacity.with_private_contents().is_opaque() {
612            Body::Opaque
613        } else {
614            // Target translation:
615            //
616            // fn call_fn(arg0: Args[0], ..., argN: Args[N]) -> Output {
617            //   let closure: Closure = {};
618            //   let args = (arg0, ..., argN);
619            //   closure.call(args)
620            // }
621            let fun_id: FunDeclId = self.register_item(
622                span,
623                def.this(),
624                TransItemSourceKind::ClosureMethod(ClosureKind::FnOnce),
625            );
626            let impl_ref = self.translate_closure_impl_ref(span, closure, ClosureKind::FnOnce)?;
627            let fn_op = FnOperand::Regular(FnPtr::new(fun_id.into(), impl_ref.generics.clone()));
628
629            let mut builder = BodyBuilder::new(span, signature.inputs.len());
630
631            let output = builder.new_var(None, signature.output.clone());
632            let args: Vec<Place> = signature
633                .inputs
634                .iter()
635                .enumerate()
636                .map(|(i, ty)| builder.new_var(Some(format!("arg{}", i + 1)), ty.clone()))
637                .collect();
638            let args_tupled_ty = Ty::mk_tuple(signature.inputs.clone());
639            let args_tupled = builder.new_var(Some("args".to_string()), args_tupled_ty.clone());
640            let state = builder.new_var(Some("state".to_string()), state_ty.clone());
641
642            builder.push_statement(StatementKind::Assign(
643                args_tupled.clone(),
644                Rvalue::Aggregate(
645                    AggregateKind::Adt(args_tupled_ty.as_adt().unwrap().clone(), None, None),
646                    args.into_iter().map(Operand::Move).collect(),
647                ),
648            ));
649
650            let state_ty_adt = state_ty.as_adt().unwrap();
651            builder.push_statement(StatementKind::Assign(
652                state.clone(),
653                Rvalue::Aggregate(AggregateKind::Adt(state_ty_adt.clone(), None, None), vec![]),
654            ));
655
656            builder.call(Call {
657                func: fn_op,
658                args: vec![Operand::Move(state), Operand::Move(args_tupled)],
659                dest: output,
660            });
661
662            Body::Unstructured(builder.build())
663        };
664
665        Ok(FunDecl {
666            def_id,
667            item_meta,
668            generics: self.into_generics(),
669            signature,
670            src: ItemSource::TopLevel,
671            is_global_initializer: None,
672            body,
673        })
674    }
675}
charon_driver/translate/translate_closures.rs

charon_driver/translate/
translate_closures.rs
