1 use crate::ty::subst::{GenericArg, GenericArgKind};
2 use crate::ty::{self, InferConst, Ty, TypeFlags};
6 pub struct FlagComputation {
9 // see `TyS::outer_exclusive_binder` for details
10 pub outer_exclusive_binder: ty::DebruijnIndex,
13 impl FlagComputation {
14 fn new() -> FlagComputation {
15 FlagComputation { flags: TypeFlags::empty(), outer_exclusive_binder: ty::INNERMOST }
18 #[allow(rustc::usage_of_ty_tykind)]
19 pub fn for_kind(kind: &ty::TyKind<'_>) -> FlagComputation {
20 let mut result = FlagComputation::new();
21 result.add_kind(kind);
25 pub fn for_predicate(binder: ty::Binder<ty::PredicateKind<'_>>) -> FlagComputation {
26 let mut result = FlagComputation::new();
27 result.add_predicate(binder);
31 pub fn for_const(c: &ty::Const<'_>) -> TypeFlags {
32 let mut result = FlagComputation::new();
37 fn add_flags(&mut self, flags: TypeFlags) {
38 self.flags = self.flags | flags;
41 /// indicates that `self` refers to something at binding level `binder`
42 fn add_bound_var(&mut self, binder: ty::DebruijnIndex) {
43 let exclusive_binder = binder.shifted_in(1);
44 self.add_exclusive_binder(exclusive_binder);
47 /// indicates that `self` refers to something *inside* binding
48 /// level `binder` -- not bound by `binder`, but bound by the next
49 /// binder internal to it
50 fn add_exclusive_binder(&mut self, exclusive_binder: ty::DebruijnIndex) {
51 self.outer_exclusive_binder = self.outer_exclusive_binder.max(exclusive_binder);
54 /// Adds the flags/depth from a set of types that appear within the current type, but within a
56 fn bound_computation<T, F>(&mut self, value: ty::Binder<T>, f: F)
58 F: FnOnce(&mut Self, T),
60 let mut computation = FlagComputation::new();
62 f(&mut computation, value.skip_binder());
64 self.add_flags(computation.flags);
66 // The types that contributed to `computation` occurred within
67 // a region binder, so subtract one from the region depth
68 // within when adding the depth to `self`.
69 let outer_exclusive_binder = computation.outer_exclusive_binder;
70 if outer_exclusive_binder > ty::INNERMOST {
71 self.add_exclusive_binder(outer_exclusive_binder.shifted_out(1));
72 } // otherwise, this binder captures nothing
75 #[allow(rustc::usage_of_ty_tykind)]
76 fn add_kind(&mut self, kind: &ty::TyKind<'_>) {
85 | &ty::Foreign(..) => {}
87 &ty::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
90 self.add_flags(TypeFlags::HAS_TY_PARAM);
91 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
94 &ty::Generator(_, ref substs, _) => {
95 let substs = substs.as_generator();
96 let should_remove_further_specializable =
97 !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
98 self.add_substs(substs.parent_substs());
99 if should_remove_further_specializable {
100 self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE;
103 self.add_ty(substs.resume_ty());
104 self.add_ty(substs.return_ty());
105 self.add_ty(substs.witness());
106 self.add_ty(substs.yield_ty());
107 self.add_ty(substs.tupled_upvars_ty());
110 &ty::GeneratorWitness(ts) => {
111 self.bound_computation(ts, |flags, ts| flags.add_tys(ts));
114 &ty::Closure(_, substs) => {
115 let substs = substs.as_closure();
116 let should_remove_further_specializable =
117 !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
118 self.add_substs(substs.parent_substs());
119 if should_remove_further_specializable {
120 self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE;
123 self.add_ty(substs.sig_as_fn_ptr_ty());
124 self.add_ty(substs.kind_ty());
125 self.add_ty(substs.tupled_upvars_ty());
128 &ty::Bound(debruijn, _) => {
129 self.add_bound_var(debruijn);
132 &ty::Placeholder(..) => {
133 self.add_flags(TypeFlags::HAS_TY_PLACEHOLDER);
134 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
137 &ty::Infer(infer) => {
138 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
140 ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_) => {}
142 ty::TyVar(_) | ty::IntVar(_) | ty::FloatVar(_) => {
143 self.add_flags(TypeFlags::HAS_TY_INFER)
148 &ty::Adt(_, substs) => {
149 self.add_substs(substs);
152 &ty::Projection(data) => {
153 self.add_flags(TypeFlags::HAS_TY_PROJECTION);
154 self.add_projection_ty(data);
157 &ty::Opaque(_, substs) => {
158 self.add_flags(TypeFlags::HAS_TY_OPAQUE);
159 self.add_substs(substs);
162 &ty::Dynamic(obj, r) => {
163 for predicate in obj.iter() {
164 self.bound_computation(predicate, |computation, predicate| match predicate {
165 ty::ExistentialPredicate::Trait(tr) => computation.add_substs(tr.substs),
166 ty::ExistentialPredicate::Projection(p) => {
167 computation.add_existential_projection(&p);
169 ty::ExistentialPredicate::AutoTrait(_) => {}
176 &ty::Array(tt, len) => {
181 &ty::Slice(tt) => self.add_ty(tt),
183 &ty::RawPtr(ref m) => {
187 &ty::Ref(r, ty, _) => {
192 &ty::Tuple(ref substs) => {
193 self.add_substs(substs);
196 &ty::FnDef(_, substs) => {
197 self.add_substs(substs);
200 &ty::FnPtr(fn_sig) => self.bound_computation(fn_sig, |computation, fn_sig| {
201 computation.add_tys(fn_sig.inputs());
202 computation.add_ty(fn_sig.output());
207 fn add_predicate(&mut self, binder: ty::Binder<ty::PredicateKind<'_>>) {
208 self.bound_computation(binder, |computation, atom| computation.add_predicate_atom(atom));
211 fn add_predicate_atom(&mut self, atom: ty::PredicateKind<'_>) {
213 ty::PredicateKind::Trait(trait_pred, _constness) => {
214 self.add_substs(trait_pred.trait_ref.substs);
216 ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => {
220 ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty, region)) => {
222 self.add_region(region);
224 ty::PredicateKind::Subtype(ty::SubtypePredicate { a_is_expected: _, a, b }) => {
228 ty::PredicateKind::Projection(ty::ProjectionPredicate { projection_ty, ty }) => {
229 self.add_projection_ty(projection_ty);
232 ty::PredicateKind::WellFormed(arg) => {
233 self.add_substs(slice::from_ref(&arg));
235 ty::PredicateKind::ObjectSafe(_def_id) => {}
236 ty::PredicateKind::ClosureKind(_def_id, substs, _kind) => {
237 self.add_substs(substs);
239 ty::PredicateKind::ConstEvaluatable(_def_id, substs) => {
240 self.add_substs(substs);
242 ty::PredicateKind::ConstEquate(expected, found) => {
243 self.add_const(expected);
244 self.add_const(found);
246 ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
252 fn add_ty(&mut self, ty: Ty<'_>) {
253 self.add_flags(ty.flags());
254 self.add_exclusive_binder(ty.outer_exclusive_binder);
257 fn add_tys(&mut self, tys: &[Ty<'_>]) {
263 fn add_region(&mut self, r: ty::Region<'_>) {
264 self.add_flags(r.type_flags());
265 if let ty::ReLateBound(debruijn, _) = *r {
266 self.add_bound_var(debruijn);
270 fn add_const(&mut self, c: &ty::Const<'_>) {
273 ty::ConstKind::Unevaluated(unevaluated) => self.add_unevaluated_const(unevaluated),
274 ty::ConstKind::Infer(infer) => {
275 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
277 InferConst::Fresh(_) => {}
278 InferConst::Var(_) => self.add_flags(TypeFlags::HAS_CT_INFER),
281 ty::ConstKind::Bound(debruijn, _) => {
282 self.add_bound_var(debruijn);
284 ty::ConstKind::Param(_) => {
285 self.add_flags(TypeFlags::HAS_CT_PARAM);
286 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
288 ty::ConstKind::Placeholder(_) => {
289 self.add_flags(TypeFlags::HAS_CT_PLACEHOLDER);
290 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
292 ty::ConstKind::Value(_) => {}
293 ty::ConstKind::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
297 fn add_unevaluated_const(&mut self, ct: ty::Unevaluated<'tcx>) {
298 self.add_substs(ct.substs);
299 self.add_flags(TypeFlags::HAS_CT_PROJECTION);
302 fn add_existential_projection(&mut self, projection: &ty::ExistentialProjection<'_>) {
303 self.add_substs(projection.substs);
304 self.add_ty(projection.ty);
307 fn add_projection_ty(&mut self, projection_ty: ty::ProjectionTy<'_>) {
308 self.add_substs(projection_ty.substs);
311 fn add_substs(&mut self, substs: &[GenericArg<'_>]) {
313 match kind.unpack() {
314 GenericArgKind::Type(ty) => self.add_ty(ty),
315 GenericArgKind::Lifetime(lt) => self.add_region(lt),
316 GenericArgKind::Const(ct) => self.add_const(ct),