1 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
3 use crate::ty::subst::{Subst, SubstsRef};
5 use rustc_data_structures::fx::FxHashMap;
7 use rustc_hir::def_id::DefId;
8 use rustc_span::symbol::Symbol;
11 use super::{EarlyBoundRegion, InstantiatedPredicates, ParamConst, ParamTy, Predicate, TyCtxt};
13 #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
14 pub enum GenericParamDefKind {
18 object_lifetime_default: ObjectLifetimeDefault,
19 synthetic: Option<hir::SyntheticTyParamKind>,
26 impl GenericParamDefKind {
27 pub fn descr(&self) -> &'static str {
29 GenericParamDefKind::Lifetime => "lifetime",
30 GenericParamDefKind::Type { .. } => "type",
31 GenericParamDefKind::Const { .. } => "constant",
34 pub fn to_ord(&self, tcx: TyCtxt<'_>) -> ast::ParamKindOrd {
36 GenericParamDefKind::Lifetime => ast::ParamKindOrd::Lifetime,
37 GenericParamDefKind::Type { .. } => ast::ParamKindOrd::Type,
38 GenericParamDefKind::Const { .. } => {
39 ast::ParamKindOrd::Const { unordered: tcx.features().const_generics }
45 #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
46 pub struct GenericParamDef {
51 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
52 /// on generic parameter `'a`/`T`, asserts data behind the parameter
53 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
54 pub pure_wrt_drop: bool,
56 pub kind: GenericParamDefKind,
59 impl GenericParamDef {
60 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
61 if let GenericParamDefKind::Lifetime = self.kind {
62 ty::EarlyBoundRegion { def_id: self.def_id, index: self.index, name: self.name }
64 bug!("cannot convert a non-lifetime parameter def to an early bound region")
70 pub struct GenericParamCount {
76 /// Information about the formal type/lifetime parameters associated
77 /// with an item or method. Analogous to `hir::Generics`.
79 /// The ordering of parameters is the same as in `Subst` (excluding child generics):
80 /// `Self` (optionally), `Lifetime` params..., `Type` params...
81 #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
83 pub parent: Option<DefId>,
84 pub parent_count: usize,
85 pub params: Vec<GenericParamDef>,
87 /// Reverse map to the `index` field of each `GenericParamDef`.
88 #[stable_hasher(ignore)]
89 pub param_def_id_to_index: FxHashMap<DefId, u32>,
92 pub has_late_bound_regions: Option<Span>,
96 pub fn count(&self) -> usize {
97 self.parent_count + self.params.len()
100 pub fn own_counts(&self) -> GenericParamCount {
101 // We could cache this as a property of `GenericParamCount`, but
102 // the aim is to refactor this away entirely eventually and the
103 // presence of this method will be a constant reminder.
104 let mut own_counts = GenericParamCount::default();
106 for param in &self.params {
108 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
109 GenericParamDefKind::Type { .. } => own_counts.types += 1,
110 GenericParamDefKind::Const { .. } => own_counts.consts += 1,
117 pub fn own_defaults(&self) -> GenericParamCount {
118 let mut own_defaults = GenericParamCount::default();
120 for param in &self.params {
122 GenericParamDefKind::Lifetime => (),
123 GenericParamDefKind::Type { has_default, .. }
124 | GenericParamDefKind::Const { has_default } => {
125 own_defaults.types += has_default as usize;
133 pub fn requires_monomorphization(&self, tcx: TyCtxt<'tcx>) -> bool {
134 if self.own_requires_monomorphization() {
138 if let Some(parent_def_id) = self.parent {
139 let parent = tcx.generics_of(parent_def_id);
140 parent.requires_monomorphization(tcx)
146 pub fn own_requires_monomorphization(&self) -> bool {
147 for param in &self.params {
149 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
152 GenericParamDefKind::Lifetime => {}
158 /// Returns the `GenericParamDef` with the given index.
159 pub fn param_at(&'tcx self, param_index: usize, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
160 if let Some(index) = param_index.checked_sub(self.parent_count) {
163 tcx.generics_of(self.parent.expect("parent_count > 0 but no parent?"))
164 .param_at(param_index, tcx)
168 /// Returns the `GenericParamDef` associated with this `EarlyBoundRegion`.
171 param: &EarlyBoundRegion,
173 ) -> &'tcx GenericParamDef {
174 let param = self.param_at(param.index as usize, tcx);
176 GenericParamDefKind::Lifetime => param,
177 _ => bug!("expected lifetime parameter, but found another generic parameter"),
181 /// Returns the `GenericParamDef` associated with this `ParamTy`.
182 pub fn type_param(&'tcx self, param: &ParamTy, tcx: TyCtxt<'tcx>) -> &'tcx GenericParamDef {
183 let param = self.param_at(param.index as usize, tcx);
185 GenericParamDefKind::Type { .. } => param,
186 _ => bug!("expected type parameter, but found another generic parameter"),
190 /// Returns the `GenericParamDef` associated with this `ParamConst`.
191 pub fn const_param(&'tcx self, param: &ParamConst, tcx: TyCtxt<'tcx>) -> &GenericParamDef {
192 let param = self.param_at(param.index as usize, tcx);
194 GenericParamDefKind::Const { .. } => param,
195 _ => bug!("expected const parameter, but found another generic parameter"),
200 /// Bounds on generics.
201 #[derive(Copy, Clone, Default, Debug, TyEncodable, TyDecodable, HashStable)]
202 pub struct GenericPredicates<'tcx> {
203 pub parent: Option<DefId>,
204 pub predicates: &'tcx [(Predicate<'tcx>, Span)],
207 impl<'tcx> GenericPredicates<'tcx> {
211 substs: SubstsRef<'tcx>,
212 ) -> InstantiatedPredicates<'tcx> {
213 let mut instantiated = InstantiatedPredicates::empty();
214 self.instantiate_into(tcx, &mut instantiated, substs);
218 pub fn instantiate_own(
221 substs: SubstsRef<'tcx>,
222 ) -> InstantiatedPredicates<'tcx> {
223 InstantiatedPredicates {
224 predicates: self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)).collect(),
225 spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
232 instantiated: &mut InstantiatedPredicates<'tcx>,
233 substs: SubstsRef<'tcx>,
235 if let Some(def_id) = self.parent {
236 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
238 instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p.subst(tcx, substs)));
239 instantiated.spans.extend(self.predicates.iter().map(|(_, sp)| *sp));
242 pub fn instantiate_identity(&self, tcx: TyCtxt<'tcx>) -> InstantiatedPredicates<'tcx> {
243 let mut instantiated = InstantiatedPredicates::empty();
244 self.instantiate_identity_into(tcx, &mut instantiated);
248 fn instantiate_identity_into(
251 instantiated: &mut InstantiatedPredicates<'tcx>,
253 if let Some(def_id) = self.parent {
254 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
256 instantiated.predicates.extend(self.predicates.iter().map(|(p, _)| p));
257 instantiated.spans.extend(self.predicates.iter().map(|(_, s)| s));