-
Notifications
You must be signed in to change notification settings - Fork 182
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #494 from Aaron1011/feature/fn-once
Add FnOnce trait, and provide impl for Function type
- Loading branch information
Showing
11 changed files
with
361 additions
and
25 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,90 @@ | ||
| use crate::clauses::ClauseBuilder; | ||
| use crate::infer::instantiate::IntoBindersAndValue; | ||
| use crate::rust_ir::WellKnownTrait; | ||
| use crate::{Interner, RustIrDatabase, TraitRef}; | ||
| use chalk_ir::{ | ||
| AliasTy, ApplicationTy, Binders, Floundered, Normalize, ProjectionTy, Substitution, TraitId, | ||
| Ty, TyData, TypeName, VariableKinds, | ||
| }; | ||
|
|
||
| /// Handles clauses for FnOnce/FnMut/Fn. | ||
| /// If `self_ty` is a function, we push a clause of the form | ||
| /// `fn(A1, A2, ..., AN) -> O: FnTrait<(A1, A2, ..., AN)>`, where `FnTrait` | ||
| /// is the trait corresponding to `trait_id` (FnOnce/FnMut/Fn) | ||
| /// | ||
| /// If `trait_id` is `FnOnce`, we also push a clause for the output type of the form: | ||
| /// `Normalize(<fn(A) -> B as FnOnce<(A,)>>::Output -> B)` | ||
| /// We do not add the usual `Implemented(fn(A) -> b as FnOnce<(A,)>` clause | ||
| /// as a condition, since we already called `push_fact` with it | ||
| pub fn add_fn_trait_program_clauses<I: Interner>( | ||
| db: &dyn RustIrDatabase<I>, | ||
| builder: &mut ClauseBuilder<'_, I>, | ||
| trait_id: TraitId<I>, | ||
| self_ty: Ty<I>, | ||
| ) -> Result<(), Floundered> { | ||
| let interner = db.interner(); | ||
| match self_ty.data(interner) { | ||
| TyData::Function(fn_val) => { | ||
| let (binders, orig_sub) = fn_val.into_binders_and_value(interner); | ||
| let bound_ref = Binders::new(VariableKinds::from(interner, binders), orig_sub); | ||
| builder.push_binders(&bound_ref, |builder, orig_sub| { | ||
| // The last parameter represents the function return type | ||
| let (arg_sub, fn_output_ty) = orig_sub | ||
| .parameters(interner) | ||
| .split_at(orig_sub.len(interner) - 1); | ||
| let arg_sub = Substitution::from(interner, arg_sub); | ||
| let fn_output_ty = fn_output_ty[0].assert_ty_ref(interner); | ||
|
|
||
| // We are constructing a reference to `FnOnce<Args>`, where | ||
| // `Args` is a tuple of the function's argument types | ||
| let tupled = Ty::new( | ||
| interner, | ||
| TyData::Apply(ApplicationTy { | ||
| name: TypeName::Tuple(arg_sub.len(interner)), | ||
| substitution: arg_sub.clone(), | ||
| }), | ||
| ); | ||
|
|
||
| let tupled_sub = Substitution::from(interner, vec![self_ty.clone(), tupled]); | ||
| // Given a function type `fn(A1, A2, ..., AN)`, construct a `TraitRef` | ||
| // of the form `fn(A1, A2, ..., AN): FnOnce<(A1, A2, ..., AN)>` | ||
| let new_trait_ref = TraitRef { | ||
| trait_id, | ||
| substitution: tupled_sub.clone(), | ||
| }; | ||
|
|
||
| builder.push_fact(new_trait_ref.clone()); | ||
|
|
||
| if let Some(WellKnownTrait::FnOnce) = db.trait_datum(trait_id).well_known { | ||
| //The `Output` type is defined on the `FnOnce` | ||
| let fn_once = db.trait_datum(trait_id); | ||
| assert_eq!(fn_once.well_known, Some(WellKnownTrait::FnOnce)); | ||
| let assoc_types = &fn_once.associated_ty_ids; | ||
| assert_eq!( | ||
| assoc_types.len(), | ||
| 1, | ||
| "FnOnce trait should have exactly one associated type, found {:?}", | ||
| assoc_types | ||
| ); | ||
|
|
||
| // Construct `Normalize(<fn(A) -> B as FnOnce<(A,)>>::Output -> B)` | ||
| let assoc_output_ty = assoc_types[0]; | ||
| let proj_ty = ProjectionTy { | ||
| associated_ty_id: assoc_output_ty, | ||
| substitution: tupled_sub, | ||
| }; | ||
| let normalize = Normalize { | ||
| alias: AliasTy::Projection(proj_ty), | ||
| ty: fn_output_ty.clone(), | ||
| }; | ||
|
|
||
| builder.push_fact(normalize); | ||
| } | ||
| }); | ||
| Ok(()) | ||
| } | ||
| // Function traits are non-enumerable | ||
| TyData::InferenceVar(..) | TyData::Alias(..) => Err(Floundered), | ||
| _ => Ok(()), | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.