crates/hir_ty/src/chalk_ext.rs

   1 //! Various extensions traits for Chalk types.
   2
   3 use chalk_ir::{FloatTy, IntTy, Mutability, Scalar, UintTy};
   4 use hir_def::{
   5     builtin_type::{BuiltinFloat, BuiltinInt, BuiltinType, BuiltinUint},
   6     type_ref::Rawness,
   7     AssocContainerId, FunctionId, GenericDefId, HasModule, Lookup, TraitId,
   8 };
   9
  10 use crate::{
  11     db::HirDatabase, from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id,
  12     from_placeholder_idx, to_chalk_trait_id, AdtId, AliasEq, AliasTy, Binders, CallableDefId,
  13     CallableSig, FnPointer, ImplTraitId, Interner, Lifetime, ProjectionTy, QuantifiedWhereClause,
  14     Substitution, TraitRef, Ty, TyBuilder, TyKind, WhereClause,
  15 };
  16
  17 pub trait TyExt {
  18     fn is_unit(&self) -> bool;
  19     fn is_never(&self) -> bool;
  20     fn is_unknown(&self) -> bool;
  21
  22     fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)>;
  23     fn as_builtin(&self) -> Option<BuiltinType>;
  24     fn as_tuple(&self) -> Option<&Substitution>;
  25     fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId>;
  26     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)>;
  27     fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)>;
  28     fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId>;
  29
  30     fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId>;
  31     fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig>;
  32
  33     fn strip_references(&self) -> &Ty;
  34
  35     /// If this is a `dyn Trait`, returns that trait.
  36     fn dyn_trait(&self) -> Option<TraitId>;
  37
  38     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>>;
  39     fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId>;
  40
  41     /// FIXME: Get rid of this, it's not a good abstraction
  42     fn equals_ctor(&self, other: &Ty) -> bool;
  43 }
  44
  45 impl TyExt for Ty {
  46     fn is_unit(&self) -> bool {
  47         matches!(self.kind(&Interner), TyKind::Tuple(0, _))
  48     }
  49
  50     fn is_never(&self) -> bool {
  51         matches!(self.kind(&Interner), TyKind::Never)
  52     }
  53
  54     fn is_unknown(&self) -> bool {
  55         matches!(self.kind(&Interner), TyKind::Error)
  56     }
  57
  58     fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)> {
  59         match self.kind(&Interner) {
  60             TyKind::Adt(AdtId(adt), parameters) => Some((*adt, parameters)),
  61             _ => None,
  62         }
  63     }
  64
  65     fn as_builtin(&self) -> Option<BuiltinType> {
  66         match self.kind(&Interner) {
  67             TyKind::Str => Some(BuiltinType::Str),
  68             TyKind::Scalar(Scalar::Bool) => Some(BuiltinType::Bool),
  69             TyKind::Scalar(Scalar::Char) => Some(BuiltinType::Char),
  70             TyKind::Scalar(Scalar::Float(fty)) => Some(BuiltinType::Float(match fty {
  71                 FloatTy::F64 => BuiltinFloat::F64,
  72                 FloatTy::F32 => BuiltinFloat::F32,
  73             })),
  74             TyKind::Scalar(Scalar::Int(ity)) => Some(BuiltinType::Int(match ity {
  75                 IntTy::Isize => BuiltinInt::Isize,
  76                 IntTy::I8 => BuiltinInt::I8,
  77                 IntTy::I16 => BuiltinInt::I16,
  78                 IntTy::I32 => BuiltinInt::I32,
  79                 IntTy::I64 => BuiltinInt::I64,
  80                 IntTy::I128 => BuiltinInt::I128,
  81             })),
  82             TyKind::Scalar(Scalar::Uint(ity)) => Some(BuiltinType::Uint(match ity {
  83                 UintTy::Usize => BuiltinUint::Usize,
  84                 UintTy::U8 => BuiltinUint::U8,
  85                 UintTy::U16 => BuiltinUint::U16,
  86                 UintTy::U32 => BuiltinUint::U32,
  87                 UintTy::U64 => BuiltinUint::U64,
  88                 UintTy::U128 => BuiltinUint::U128,
  89             })),
  90             _ => None,
  91         }
  92     }
  93
  94     fn as_tuple(&self) -> Option<&Substitution> {
  95         match self.kind(&Interner) {
  96             TyKind::Tuple(_, substs) => Some(substs),
  97             _ => None,
  98         }
  99     }
 100
 101     fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
 102         if let Some(CallableDefId::FunctionId(func)) = self.callable_def(db) {
 103             Some(func)
 104         } else {
 105             None
 106         }
 107     }
 108     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)> {
 109         match self.kind(&Interner) {
 110             TyKind::Ref(mutability, lifetime, ty) => Some((ty, lifetime.clone(), *mutability)),
 111             _ => None,
 112         }
 113     }
 114
 115     fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)> {
 116         match self.kind(&Interner) {
 117             TyKind::Ref(mutability, _, ty) => Some((ty, Rawness::Ref, *mutability)),
 118             TyKind::Raw(mutability, ty) => Some((ty, Rawness::RawPtr, *mutability)),
 119             _ => None,
 120         }
 121     }
 122
 123     fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
 124         match *self.kind(&Interner) {
 125             TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
 126             TyKind::FnDef(callable, ..) => {
 127                 Some(db.lookup_intern_callable_def(callable.into()).into())
 128             }
 129             TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
 130             TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
 131             _ => None,
 132         }
 133     }
 134
 135     fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId> {
 136         match self.kind(&Interner) {
 137             &TyKind::FnDef(def, ..) => Some(db.lookup_intern_callable_def(def.into())),
 138             _ => None,
 139         }
 140     }
 141
 142     fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
 143         match self.kind(&Interner) {
 144             TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
 145             TyKind::FnDef(def, parameters) => {
 146                 let callable_def = db.lookup_intern_callable_def((*def).into());
 147                 let sig = db.callable_item_signature(callable_def);
 148                 Some(sig.substitute(&Interner, &parameters))
 149             }
 150             TyKind::Closure(.., substs) => {
 151                 let sig_param = substs.at(&Interner, 0).assert_ty_ref(&Interner);
 152                 sig_param.callable_sig(db)
 153             }
 154             _ => None,
 155         }
 156     }
 157
 158     fn dyn_trait(&self) -> Option<TraitId> {
 159         let trait_ref = match self.kind(&Interner) {
 160             TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
 161                 match b.skip_binders() {
 162                     WhereClause::Implemented(trait_ref) => Some(trait_ref),
 163                     _ => None,
 164                 }
 165             }),
 166             _ => None,
 167         }?;
 168         Some(from_chalk_trait_id(trait_ref.trait_id))
 169     }
 170
 171     fn strip_references(&self) -> &Ty {
 172         let mut t: &Ty = self;
 173         while let TyKind::Ref(_mutability, _lifetime, ty) = t.kind(&Interner) {
 174             t = ty;
 175         }
 176         t
 177     }
 178
 179     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
 180         match self.kind(&Interner) {
 181             TyKind::OpaqueType(opaque_ty_id, ..) => {
 182                 match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
 183                     ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
 184                         let krate = def.module(db.upcast()).krate();
 185                         if let Some(future_trait) = db
 186                             .lang_item(krate, "future_trait".into())
 187                             .and_then(|item| item.as_trait())
 188                         {
 189                             // This is only used by type walking.
 190                             // Parameters will be walked outside, and projection predicate is not used.
 191                             // So just provide the Future trait.
 192                             let impl_bound = Binders::empty(
 193                                 &Interner,
 194                                 WhereClause::Implemented(TraitRef {
 195                                     trait_id: to_chalk_trait_id(future_trait),
 196                                     substitution: Substitution::empty(&Interner),
 197                                 }),
 198                             );
 199                             Some(vec![impl_bound])
 200                         } else {
 201                             None
 202                         }
 203                     }
 204                     ImplTraitId::ReturnTypeImplTrait(..) => None,
 205                 }
 206             }
 207             TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
 208                 let predicates = match db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into())
 209                 {
 210                     ImplTraitId::ReturnTypeImplTrait(func, idx) => {
 211                         db.return_type_impl_traits(func).map(|it| {
 212                             let data = (*it)
 213                                 .as_ref()
 214                                 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
 215                             data.substitute(&Interner, &opaque_ty.substitution)
 216                         })
 217                     }
 218                     // It always has an parameter for Future::Output type.
 219                     ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
 220                 };
 221
 222                 predicates.map(|it| it.into_value_and_skipped_binders().0)
 223             }
 224             TyKind::Placeholder(idx) => {
 225                 let id = from_placeholder_idx(db, *idx);
 226                 let generic_params = db.generic_params(id.parent);
 227                 let param_data = &generic_params.types[id.local_id];
 228                 match param_data.provenance {
 229                     hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
 230                         let substs = TyBuilder::type_params_subst(db, id.parent);
 231                         let predicates = db
 232                             .generic_predicates(id.parent)
 233                             .into_iter()
 234                             .map(|pred| pred.clone().substitute(&Interner, &substs))
 235                             .filter(|wc| match &wc.skip_binders() {
 236                                 WhereClause::Implemented(tr) => {
 237                                     &tr.self_type_parameter(&Interner) == self
 238                                 }
 239                                 WhereClause::AliasEq(AliasEq {
 240                                     alias: AliasTy::Projection(proj),
 241                                     ty: _,
 242                                 }) => &proj.self_type_parameter(&Interner) == self,
 243                                 _ => false,
 244                             })
 245                             .collect::<Vec<_>>();
 246
 247                         Some(predicates)
 248                     }
 249                     _ => None,
 250                 }
 251             }
 252             _ => None,
 253         }
 254     }
 255
 256     fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
 257         match self.kind(&Interner) {
 258             TyKind::AssociatedType(id, ..) => {
 259                 match from_assoc_type_id(*id).lookup(db.upcast()).container {
 260                     AssocContainerId::TraitId(trait_id) => Some(trait_id),
 261                     _ => None,
 262                 }
 263             }
 264             TyKind::Alias(AliasTy::Projection(projection_ty)) => {
 265                 match from_assoc_type_id(projection_ty.associated_ty_id)
 266                     .lookup(db.upcast())
 267                     .container
 268                 {
 269                     AssocContainerId::TraitId(trait_id) => Some(trait_id),
 270                     _ => None,
 271                 }
 272             }
 273             _ => None,
 274         }
 275     }
 276
 277     fn equals_ctor(&self, other: &Ty) -> bool {
 278         match (self.kind(&Interner), other.kind(&Interner)) {
 279             (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
 280             (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_, _), TyKind::Array(_, _)) => {
 281                 true
 282             }
 283             (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
 284             (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
 285             (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
 286                 ty_id == ty_id2
 287             }
 288             (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
 289             (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
 290             (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
 291             | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
 292                 mutability == mutability2
 293             }
 294             (
 295                 TyKind::Function(FnPointer { num_binders, sig, .. }),
 296                 TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
 297             ) => num_binders == num_binders2 && sig == sig2,
 298             (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
 299                 cardinality == cardinality2
 300             }
 301             (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
 302             (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
 303             _ => false,
 304         }
 305     }
 306 }
 307
 308 pub trait ProjectionTyExt {
 309     fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef;
 310     fn trait_(&self, db: &dyn HirDatabase) -> TraitId;
 311 }
 312
 313 impl ProjectionTyExt for ProjectionTy {
 314     fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef {
 315         TraitRef {
 316             trait_id: to_chalk_trait_id(self.trait_(db)),
 317             substitution: self.substitution.clone(),
 318         }
 319     }
 320
 321     fn trait_(&self, db: &dyn HirDatabase) -> TraitId {
 322         match from_assoc_type_id(self.associated_ty_id).lookup(db.upcast()).container {
 323             AssocContainerId::TraitId(it) => it,
 324             _ => panic!("projection ty without parent trait"),
 325         }
 326     }
 327 }
 328
 329 pub trait TraitRefExt {
 330     fn hir_trait_id(&self) -> TraitId;
 331 }
 332
 333 impl TraitRefExt for TraitRef {
 334     fn hir_trait_id(&self) -> TraitId {
 335         from_chalk_trait_id(self.trait_id)
 336     }
 337 }