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     generics::TypeOrConstParamData,
   7     type_ref::Rawness,
   8     FunctionId, GenericDefId, HasModule, ItemContainerId, Lookup, TraitId,
   9 };
  10 use syntax::SmolStr;
  11
  12 use crate::{
  13     db::HirDatabase, from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id,
  14     from_placeholder_idx, to_chalk_trait_id, AdtId, AliasEq, AliasTy, Binders, CallableDefId,
  15     CallableSig, FnPointer, ImplTraitId, Interner, Lifetime, ProjectionTy, QuantifiedWhereClause,
  16     Substitution, TraitRef, Ty, TyBuilder, TyKind, WhereClause,
  17 };
  18
  19 pub trait TyExt {
  20     fn is_unit(&self) -> bool;
  21     fn is_never(&self) -> bool;
  22     fn is_unknown(&self) -> bool;
  23     fn is_ty_var(&self) -> bool;
  24
  25     fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)>;
  26     fn as_builtin(&self) -> Option<BuiltinType>;
  27     fn as_tuple(&self) -> Option<&Substitution>;
  28     fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId>;
  29     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)>;
  30     fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)>;
  31     fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId>;
  32
  33     fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId>;
  34     fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig>;
  35
  36     fn strip_references(&self) -> &Ty;
  37
  38     /// If this is a `dyn Trait`, returns that trait.
  39     fn dyn_trait(&self) -> Option<TraitId>;
  40
  41     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>>;
  42     fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId>;
  43
  44     /// FIXME: Get rid of this, it's not a good abstraction
  45     fn equals_ctor(&self, other: &Ty) -> bool;
  46 }
  47
  48 impl TyExt for Ty {
  49     fn is_unit(&self) -> bool {
  50         matches!(self.kind(Interner), TyKind::Tuple(0, _))
  51     }
  52
  53     fn is_never(&self) -> bool {
  54         matches!(self.kind(Interner), TyKind::Never)
  55     }
  56
  57     fn is_unknown(&self) -> bool {
  58         matches!(self.kind(Interner), TyKind::Error)
  59     }
  60
  61     fn is_ty_var(&self) -> bool {
  62         matches!(self.kind(Interner), TyKind::InferenceVar(_, _))
  63     }
  64
  65     fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)> {
  66         match self.kind(Interner) {
  67             TyKind::Adt(AdtId(adt), parameters) => Some((*adt, parameters)),
  68             _ => None,
  69         }
  70     }
  71
  72     fn as_builtin(&self) -> Option<BuiltinType> {
  73         match self.kind(Interner) {
  74             TyKind::Str => Some(BuiltinType::Str),
  75             TyKind::Scalar(Scalar::Bool) => Some(BuiltinType::Bool),
  76             TyKind::Scalar(Scalar::Char) => Some(BuiltinType::Char),
  77             TyKind::Scalar(Scalar::Float(fty)) => Some(BuiltinType::Float(match fty {
  78                 FloatTy::F64 => BuiltinFloat::F64,
  79                 FloatTy::F32 => BuiltinFloat::F32,
  80             })),
  81             TyKind::Scalar(Scalar::Int(ity)) => Some(BuiltinType::Int(match ity {
  82                 IntTy::Isize => BuiltinInt::Isize,
  83                 IntTy::I8 => BuiltinInt::I8,
  84                 IntTy::I16 => BuiltinInt::I16,
  85                 IntTy::I32 => BuiltinInt::I32,
  86                 IntTy::I64 => BuiltinInt::I64,
  87                 IntTy::I128 => BuiltinInt::I128,
  88             })),
  89             TyKind::Scalar(Scalar::Uint(ity)) => Some(BuiltinType::Uint(match ity {
  90                 UintTy::Usize => BuiltinUint::Usize,
  91                 UintTy::U8 => BuiltinUint::U8,
  92                 UintTy::U16 => BuiltinUint::U16,
  93                 UintTy::U32 => BuiltinUint::U32,
  94                 UintTy::U64 => BuiltinUint::U64,
  95                 UintTy::U128 => BuiltinUint::U128,
  96             })),
  97             _ => None,
  98         }
  99     }
 100
 101     fn as_tuple(&self) -> Option<&Substitution> {
 102         match self.kind(Interner) {
 103             TyKind::Tuple(_, substs) => Some(substs),
 104             _ => None,
 105         }
 106     }
 107
 108     fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
 109         match self.callable_def(db) {
 110             Some(CallableDefId::FunctionId(func)) => Some(func),
 111             Some(CallableDefId::StructId(_) | CallableDefId::EnumVariantId(_)) | None => None,
 112         }
 113     }
 114     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)> {
 115         match self.kind(Interner) {
 116             TyKind::Ref(mutability, lifetime, ty) => Some((ty, lifetime.clone(), *mutability)),
 117             _ => None,
 118         }
 119     }
 120
 121     fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)> {
 122         match self.kind(Interner) {
 123             TyKind::Ref(mutability, _, ty) => Some((ty, Rawness::Ref, *mutability)),
 124             TyKind::Raw(mutability, ty) => Some((ty, Rawness::RawPtr, *mutability)),
 125             _ => None,
 126         }
 127     }
 128
 129     fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
 130         match *self.kind(Interner) {
 131             TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
 132             TyKind::FnDef(callable, ..) => {
 133                 Some(db.lookup_intern_callable_def(callable.into()).into())
 134             }
 135             TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
 136             TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
 137             _ => None,
 138         }
 139     }
 140
 141     fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId> {
 142         match self.kind(Interner) {
 143             &TyKind::FnDef(def, ..) => Some(db.lookup_intern_callable_def(def.into())),
 144             _ => None,
 145         }
 146     }
 147
 148     fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
 149         match self.kind(Interner) {
 150             TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
 151             TyKind::FnDef(def, parameters) => {
 152                 let callable_def = db.lookup_intern_callable_def((*def).into());
 153                 let sig = db.callable_item_signature(callable_def);
 154                 Some(sig.substitute(Interner, &parameters))
 155             }
 156             TyKind::Closure(.., substs) => {
 157                 let sig_param = substs.at(Interner, 0).assert_ty_ref(Interner);
 158                 sig_param.callable_sig(db)
 159             }
 160             _ => None,
 161         }
 162     }
 163
 164     fn dyn_trait(&self) -> Option<TraitId> {
 165         let trait_ref = match self.kind(Interner) {
 166             TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
 167                 match b.skip_binders() {
 168                     WhereClause::Implemented(trait_ref) => Some(trait_ref),
 169                     _ => None,
 170                 }
 171             }),
 172             _ => None,
 173         }?;
 174         Some(from_chalk_trait_id(trait_ref.trait_id))
 175     }
 176
 177     fn strip_references(&self) -> &Ty {
 178         let mut t: &Ty = self;
 179         while let TyKind::Ref(_mutability, _lifetime, ty) = t.kind(Interner) {
 180             t = ty;
 181         }
 182         t
 183     }
 184
 185     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
 186         match self.kind(Interner) {
 187             TyKind::OpaqueType(opaque_ty_id, subst) => {
 188                 match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
 189                     ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
 190                         let krate = def.module(db.upcast()).krate();
 191                         if let Some(future_trait) = db
 192                             .lang_item(krate, SmolStr::new_inline("future_trait"))
 193                             .and_then(|item| item.as_trait())
 194                         {
 195                             // This is only used by type walking.
 196                             // Parameters will be walked outside, and projection predicate is not used.
 197                             // So just provide the Future trait.
 198                             let impl_bound = Binders::empty(
 199                                 Interner,
 200                                 WhereClause::Implemented(TraitRef {
 201                                     trait_id: to_chalk_trait_id(future_trait),
 202                                     substitution: Substitution::empty(Interner),
 203                                 }),
 204                             );
 205                             Some(vec![impl_bound])
 206                         } else {
 207                             None
 208                         }
 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, &subst).into_value_and_skipped_binders().0
 216                         })
 217                     }
 218                 }
 219             }
 220             TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
 221                 let predicates = match db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into())
 222                 {
 223                     ImplTraitId::ReturnTypeImplTrait(func, idx) => {
 224                         db.return_type_impl_traits(func).map(|it| {
 225                             let data = (*it)
 226                                 .as_ref()
 227                                 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
 228                             data.substitute(Interner, &opaque_ty.substitution)
 229                         })
 230                     }
 231                     // It always has an parameter for Future::Output type.
 232                     ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
 233                 };
 234
 235                 predicates.map(|it| it.into_value_and_skipped_binders().0)
 236             }
 237             TyKind::Placeholder(idx) => {
 238                 let id = from_placeholder_idx(db, *idx);
 239                 let generic_params = db.generic_params(id.parent);
 240                 let param_data = &generic_params.type_or_consts[id.local_id];
 241                 match param_data {
 242                     TypeOrConstParamData::TypeParamData(p) => match p.provenance {
 243                         hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
 244                             let substs = TyBuilder::placeholder_subst(db, id.parent);
 245                             let predicates = db
 246                                 .generic_predicates(id.parent)
 247                                 .iter()
 248                                 .map(|pred| pred.clone().substitute(Interner, &substs))
 249                                 .filter(|wc| match &wc.skip_binders() {
 250                                     WhereClause::Implemented(tr) => {
 251                                         &tr.self_type_parameter(Interner) == self
 252                                     }
 253                                     WhereClause::AliasEq(AliasEq {
 254                                         alias: AliasTy::Projection(proj),
 255                                         ty: _,
 256                                     }) => &proj.self_type_parameter(Interner) == self,
 257                                     _ => false,
 258                                 })
 259                                 .collect::<Vec<_>>();
 260
 261                             Some(predicates)
 262                         }
 263                         _ => None,
 264                     },
 265                     _ => None,
 266                 }
 267             }
 268             _ => None,
 269         }
 270     }
 271
 272     fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
 273         match self.kind(Interner) {
 274             TyKind::AssociatedType(id, ..) => {
 275                 match from_assoc_type_id(*id).lookup(db.upcast()).container {
 276                     ItemContainerId::TraitId(trait_id) => Some(trait_id),
 277                     _ => None,
 278                 }
 279             }
 280             TyKind::Alias(AliasTy::Projection(projection_ty)) => {
 281                 match from_assoc_type_id(projection_ty.associated_ty_id)
 282                     .lookup(db.upcast())
 283                     .container
 284                 {
 285                     ItemContainerId::TraitId(trait_id) => Some(trait_id),
 286                     _ => None,
 287                 }
 288             }
 289             _ => None,
 290         }
 291     }
 292
 293     fn equals_ctor(&self, other: &Ty) -> bool {
 294         match (self.kind(Interner), other.kind(Interner)) {
 295             (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
 296             (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_, _), TyKind::Array(_, _)) => {
 297                 true
 298             }
 299             (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
 300             (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
 301             (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
 302                 ty_id == ty_id2
 303             }
 304             (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
 305             (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
 306             (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
 307             | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
 308                 mutability == mutability2
 309             }
 310             (
 311                 TyKind::Function(FnPointer { num_binders, sig, .. }),
 312                 TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
 313             ) => num_binders == num_binders2 && sig == sig2,
 314             (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
 315                 cardinality == cardinality2
 316             }
 317             (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
 318             (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
 319             _ => false,
 320         }
 321     }
 322 }
 323
 324 pub trait ProjectionTyExt {
 325     fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef;
 326     fn trait_(&self, db: &dyn HirDatabase) -> TraitId;
 327 }
 328
 329 impl ProjectionTyExt for ProjectionTy {
 330     fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef {
 331         TraitRef {
 332             trait_id: to_chalk_trait_id(self.trait_(db)),
 333             substitution: self.substitution.clone(),
 334         }
 335     }
 336
 337     fn trait_(&self, db: &dyn HirDatabase) -> TraitId {
 338         match from_assoc_type_id(self.associated_ty_id).lookup(db.upcast()).container {
 339             ItemContainerId::TraitId(it) => it,
 340             _ => panic!("projection ty without parent trait"),
 341         }
 342     }
 343 }
 344
 345 pub trait TraitRefExt {
 346     fn hir_trait_id(&self) -> TraitId;
 347 }
 348
 349 impl TraitRefExt for TraitRef {
 350     fn hir_trait_id(&self) -> TraitId {
 351         from_chalk_trait_id(self.trait_id)
 352     }
 353 }