1 use crate::ty::subst::{GenericArg, GenericArgKind};
2 use crate::ty::{self, InferConst, Ty, TypeFlags};
6 pub struct FlagComputation {
9 /// see `Ty::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 for bv in value.bound_vars() {
64 ty::BoundVariableKind::Ty(_) => {
65 computation.flags |= TypeFlags::HAS_TY_LATE_BOUND;
67 ty::BoundVariableKind::Region(_) => {
68 computation.flags |= TypeFlags::HAS_RE_LATE_BOUND;
70 ty::BoundVariableKind::Const => {
71 computation.flags |= TypeFlags::HAS_CT_LATE_BOUND;
76 f(&mut computation, value.skip_binder());
78 self.add_flags(computation.flags);
80 // The types that contributed to `computation` occurred within
81 // a region binder, so subtract one from the region depth
82 // within when adding the depth to `self`.
83 let outer_exclusive_binder = computation.outer_exclusive_binder;
84 if outer_exclusive_binder > ty::INNERMOST {
85 self.add_exclusive_binder(outer_exclusive_binder.shifted_out(1));
86 } // otherwise, this binder captures nothing
89 #[allow(rustc::usage_of_ty_tykind)]
90 fn add_kind(&mut self, kind: &ty::TyKind<'_>) {
99 | &ty::Foreign(..) => {}
101 &ty::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
104 self.add_flags(TypeFlags::HAS_TY_PARAM);
105 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
108 ty::Generator(_, substs, _) => {
109 let substs = substs.as_generator();
110 let should_remove_further_specializable =
111 !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
112 self.add_substs(substs.parent_substs());
113 if should_remove_further_specializable {
114 self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE;
117 self.add_ty(substs.resume_ty());
118 self.add_ty(substs.return_ty());
119 self.add_ty(substs.witness());
120 self.add_ty(substs.yield_ty());
121 self.add_ty(substs.tupled_upvars_ty());
124 &ty::GeneratorWitness(ts) => {
125 self.bound_computation(ts, |flags, ts| flags.add_tys(ts));
128 &ty::Closure(_, substs) => {
129 let substs = substs.as_closure();
130 let should_remove_further_specializable =
131 !self.flags.contains(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
132 self.add_substs(substs.parent_substs());
133 if should_remove_further_specializable {
134 self.flags -= TypeFlags::STILL_FURTHER_SPECIALIZABLE;
137 self.add_ty(substs.sig_as_fn_ptr_ty());
138 self.add_ty(substs.kind_ty());
139 self.add_ty(substs.tupled_upvars_ty());
142 &ty::Bound(debruijn, _) => {
143 self.add_bound_var(debruijn);
144 self.add_flags(TypeFlags::HAS_TY_LATE_BOUND);
147 &ty::Placeholder(..) => {
148 self.add_flags(TypeFlags::HAS_TY_PLACEHOLDER);
149 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
152 &ty::Infer(infer) => {
153 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
155 ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_) => {
156 self.add_flags(TypeFlags::HAS_TY_FRESH)
159 ty::TyVar(_) | ty::IntVar(_) | ty::FloatVar(_) => {
160 self.add_flags(TypeFlags::HAS_TY_INFER)
165 &ty::Adt(_, substs) => {
166 self.add_substs(substs);
169 &ty::Alias(ty::Projection, data) => {
170 self.add_flags(TypeFlags::HAS_TY_PROJECTION);
171 self.add_projection_ty(data);
174 &ty::Alias(ty::Opaque, ty::AliasTy { substs, .. }) => {
175 self.add_flags(TypeFlags::HAS_TY_OPAQUE);
176 self.add_substs(substs);
179 &ty::Dynamic(obj, r, _) => {
180 for predicate in obj.iter() {
181 self.bound_computation(predicate, |computation, predicate| match predicate {
182 ty::ExistentialPredicate::Trait(tr) => computation.add_substs(tr.substs),
183 ty::ExistentialPredicate::Projection(p) => {
184 computation.add_existential_projection(&p);
186 ty::ExistentialPredicate::AutoTrait(_) => {}
193 &ty::Array(tt, len) => {
198 &ty::Slice(tt) => self.add_ty(tt),
204 &ty::Ref(r, ty, _) => {
209 &ty::Tuple(types) => {
213 &ty::FnDef(_, substs) => {
214 self.add_substs(substs);
217 &ty::FnPtr(fn_sig) => self.bound_computation(fn_sig, |computation, fn_sig| {
218 computation.add_tys(fn_sig.inputs());
219 computation.add_ty(fn_sig.output());
224 fn add_predicate(&mut self, binder: ty::Binder<'_, ty::PredicateKind<'_>>) {
225 self.bound_computation(binder, |computation, atom| computation.add_predicate_atom(atom));
228 fn add_predicate_atom(&mut self, atom: ty::PredicateKind<'_>) {
230 ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) => {
231 self.add_substs(trait_pred.trait_ref.substs);
233 ty::PredicateKind::Clause(ty::Clause::RegionOutlives(ty::OutlivesPredicate(a, b))) => {
237 ty::PredicateKind::Clause(ty::Clause::TypeOutlives(ty::OutlivesPredicate(
242 self.add_region(region);
244 ty::PredicateKind::Subtype(ty::SubtypePredicate { a_is_expected: _, a, b }) => {
248 ty::PredicateKind::Coerce(ty::CoercePredicate { a, b }) => {
252 ty::PredicateKind::Clause(ty::Clause::Projection(ty::ProjectionPredicate {
256 self.add_projection_ty(projection_ty);
257 match term.unpack() {
258 ty::TermKind::Ty(ty) => self.add_ty(ty),
259 ty::TermKind::Const(c) => self.add_const(c),
262 ty::PredicateKind::WellFormed(arg) => {
263 self.add_substs(slice::from_ref(&arg));
265 ty::PredicateKind::ObjectSafe(_def_id) => {}
266 ty::PredicateKind::ClosureKind(_def_id, substs, _kind) => {
267 self.add_substs(substs);
269 ty::PredicateKind::ConstEvaluatable(uv) => {
272 ty::PredicateKind::ConstEquate(expected, found) => {
273 self.add_const(expected);
274 self.add_const(found);
276 ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
279 ty::PredicateKind::Ambiguous => {}
283 fn add_ty(&mut self, ty: Ty<'_>) {
284 self.add_flags(ty.flags());
285 self.add_exclusive_binder(ty.outer_exclusive_binder());
288 fn add_tys(&mut self, tys: &[Ty<'_>]) {
294 fn add_region(&mut self, r: ty::Region<'_>) {
295 self.add_flags(r.type_flags());
296 if let ty::ReLateBound(debruijn, _) = *r {
297 self.add_bound_var(debruijn);
301 fn add_const(&mut self, c: ty::Const<'_>) {
304 ty::ConstKind::Unevaluated(uv) => {
305 self.add_substs(uv.substs);
306 self.add_flags(TypeFlags::HAS_CT_PROJECTION);
308 ty::ConstKind::Infer(infer) => {
309 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
311 InferConst::Fresh(_) => self.add_flags(TypeFlags::HAS_CT_FRESH),
312 InferConst::Var(_) => self.add_flags(TypeFlags::HAS_CT_INFER),
315 ty::ConstKind::Bound(debruijn, _) => {
316 self.add_bound_var(debruijn);
317 self.add_flags(TypeFlags::HAS_CT_LATE_BOUND);
319 ty::ConstKind::Param(_) => {
320 self.add_flags(TypeFlags::HAS_CT_PARAM);
321 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
323 ty::ConstKind::Placeholder(_) => {
324 self.add_flags(TypeFlags::HAS_CT_PLACEHOLDER);
325 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
327 ty::ConstKind::Value(_) => {}
328 ty::ConstKind::Expr(e) => {
331 Expr::Binop(_, l, r) => {
335 Expr::UnOp(_, v) => self.add_const(v),
336 Expr::FunctionCall(f, args) => {
342 Expr::Cast(_, c, t) => {
348 ty::ConstKind::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
352 fn add_existential_projection(&mut self, projection: &ty::ExistentialProjection<'_>) {
353 self.add_substs(projection.substs);
354 match projection.term.unpack() {
355 ty::TermKind::Ty(ty) => self.add_ty(ty),
356 ty::TermKind::Const(ct) => self.add_const(ct),
360 fn add_projection_ty(&mut self, projection_ty: ty::AliasTy<'_>) {
361 self.add_substs(projection_ty.substs);
364 fn add_substs(&mut self, substs: &[GenericArg<'_>]) {
366 match kind.unpack() {
367 GenericArgKind::Type(ty) => self.add_ty(ty),
368 GenericArgKind::Lifetime(lt) => self.add_region(lt),
369 GenericArgKind::Const(ct) => self.add_const(ct),