1 use rustc_hir::{Movability, Mutability};
2 use rustc_infer::{infer::InferCtxt, traits::query::NoSolution};
3 use rustc_middle::ty::{self, Ty, TyCtxt};
5 // Calculates the constituent types of a type for `auto trait` purposes.
7 // For types with an "existential" binder, i.e. generator witnesses, we also
8 // instantiate the binder with placeholders eagerly.
9 pub(super) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
10 infcx: &InferCtxt<'tcx>,
12 ) -> Result<Vec<Ty<'tcx>>, NoSolution> {
23 | ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
25 | ty::Char => Ok(vec![]),
31 | ty::Alias(ty::Projection, ..)
33 | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
35 ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
37 ty::RawPtr(ty::TypeAndMut { ty: element_ty, .. }) | ty::Ref(_, element_ty, _) => {
41 ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![element_ty]),
43 ty::Tuple(ref tys) => {
44 // (T1, ..., Tn) -- meets any bound that all of T1...Tn meet
45 Ok(tys.iter().collect())
48 ty::Closure(_, ref substs) => Ok(vec![substs.as_closure().tupled_upvars_ty()]),
50 ty::Generator(_, ref substs, _) => {
51 let generator_substs = substs.as_generator();
52 Ok(vec![generator_substs.tupled_upvars_ty(), generator_substs.witness()])
55 ty::GeneratorWitness(types) => {
56 Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
59 // For `PhantomData<T>`, we pass `T`.
60 ty::Adt(def, substs) if def.is_phantom_data() => Ok(vec![substs.type_at(0)]),
62 ty::Adt(def, substs) => Ok(def.all_fields().map(|f| f.ty(tcx, substs)).collect()),
64 ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
65 // We can resolve the `impl Trait` to its concrete type,
66 // which enforces a DAG between the functions requiring
67 // the auto trait bounds in question.
68 Ok(vec![tcx.bound_type_of(def_id).subst(tcx, substs)])
73 pub(super) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
74 infcx: &InferCtxt<'tcx>,
76 ) -> Result<Vec<Ty<'tcx>>, NoSolution> {
78 ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
89 | ty::GeneratorWitness(..)
93 | ty::Dynamic(_, _, ty::DynStar)
94 | ty::Error(_) => Ok(vec![]),
102 | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
106 | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
108 ty::Tuple(tys) => Ok(tys.to_vec()),
110 ty::Adt(def, substs) => {
111 let sized_crit = def.sized_constraint(infcx.tcx);
115 .map(|ty| sized_crit.rebind(*ty).subst(infcx.tcx, substs))
121 pub(super) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
122 infcx: &InferCtxt<'tcx>,
124 ) -> Result<Vec<Ty<'tcx>>, NoSolution> {
126 ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
129 | ty::Error(_) => Ok(vec![]),
131 // Implementations are provided in core
139 | ty::Ref(_, _, Mutability::Not)
140 | ty::Array(..) => Err(NoSolution),
145 | ty::Generator(_, _, Movability::Static)
147 | ty::Ref(_, _, Mutability::Mut)
151 | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
155 | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
157 ty::Tuple(tys) => Ok(tys.to_vec()),
159 ty::Closure(_, substs) => Ok(vec![substs.as_closure().tupled_upvars_ty()]),
161 ty::Generator(_, substs, Movability::Movable) => {
162 if infcx.tcx.features().generator_clone {
163 let generator = substs.as_generator();
164 Ok(vec![generator.tupled_upvars_ty(), generator.witness()])
170 ty::GeneratorWitness(types) => {
171 Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
176 pub(crate) fn extract_tupled_inputs_and_output_from_callable<'tcx>(
179 goal_kind: ty::ClosureKind,
180 ) -> Result<Option<ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>)>>, NoSolution> {
181 match *self_ty.kind() {
182 ty::FnDef(def_id, substs) => Ok(Some(
183 tcx.bound_fn_sig(def_id)
185 .map_bound(|sig| (tcx.mk_tup(sig.inputs().iter()), sig.output())),
188 Ok(Some(sig.map_bound(|sig| (tcx.mk_tup(sig.inputs().iter()), sig.output()))))
190 ty::Closure(_, substs) => {
191 let closure_substs = substs.as_closure();
192 match closure_substs.kind_ty().to_opt_closure_kind() {
193 Some(closure_kind) if closure_kind.extends(goal_kind) => {}
194 None => return Ok(None),
195 _ => return Err(NoSolution),
197 Ok(Some(closure_substs.sig().map_bound(|sig| (sig.inputs()[0], sig.output()))))
211 | ty::Dynamic(_, _, _)
212 | ty::Generator(_, _, _)
213 | ty::GeneratorWitness(_)
221 | ty::Error(_) => Err(NoSolution),