aboutsummaryrefslogtreecommitdiff
path: root/crates/hir_ty/src/lib.rs
blob: c3ec123522cb17241d6d53f55a9ad9a8e9eed290 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
//! The type system. We currently use this to infer types for completion, hover
//! information and various assists.
#[allow(unused)]
macro_rules! eprintln {
    ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
}

mod autoderef;
pub mod primitive;
pub mod traits;
pub mod method_resolution;
mod op;
mod lower;
pub(crate) mod infer;
pub(crate) mod utils;
mod chalk_cast;
mod chalk_ext;
mod builder;
mod walk;
mod types;

pub mod display;
pub mod db;
pub mod diagnostics;

#[cfg(test)]
mod tests;
#[cfg(test)]
mod test_db;

use std::sync::Arc;

use itertools::Itertools;

use base_db::salsa;
use hir_def::{
    expr::ExprId, type_ref::Rawness, AssocContainerId, FunctionId, GenericDefId, HasModule,
    LifetimeParamId, Lookup, TraitId, TypeAliasId, TypeParamId,
};

use crate::{db::HirDatabase, display::HirDisplay, utils::generics};

pub use autoderef::autoderef;
pub use builder::TyBuilder;
pub use chalk_ext::{ProjectionTyExt, TyExt};
pub use infer::{could_unify, InferenceResult, InferenceVar};
pub use lower::{
    associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
    TyDefId, TyLoweringContext, ValueTyDefId,
};
pub use traits::{chalk::Interner, TraitEnvironment};
pub use types::*;
pub use walk::TypeWalk;

pub use chalk_ir::{
    cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
};

pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
pub type FnDefId = chalk_ir::FnDefId<Interner>;
pub type ClosureId = chalk_ir::ClosureId<Interner>;
pub type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
pub type PlaceholderIndex = chalk_ir::PlaceholderIndex;

pub type VariableKind = chalk_ir::VariableKind<Interner>;
pub type VariableKinds = chalk_ir::VariableKinds<Interner>;
pub type CanonicalVarKinds = chalk_ir::CanonicalVarKinds<Interner>;

pub type Lifetime = chalk_ir::Lifetime<Interner>;
pub type LifetimeData = chalk_ir::LifetimeData<Interner>;
pub type LifetimeOutlives = chalk_ir::LifetimeOutlives<Interner>;

pub type ChalkTraitId = chalk_ir::TraitId<Interner>;

pub type FnSig = chalk_ir::FnSig<Interner>;

// FIXME: get rid of this
pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution {
    Substitution::intern(s.interned()[..std::cmp::min(s.len(&Interner), n)].into())
}

/// Return an index of a parameter in the generic type parameter list by it's id.
pub fn param_idx(db: &dyn HirDatabase, id: TypeParamId) -> Option<usize> {
    generics(db.upcast(), id.parent).param_idx(id)
}

pub fn wrap_empty_binders<T>(value: T) -> Binders<T>
where
    T: TypeWalk,
{
    Binders::empty(&Interner, value.shifted_in_from(DebruijnIndex::ONE))
}

pub fn make_only_type_binders<T>(num_vars: usize, value: T) -> Binders<T> {
    Binders::new(
        VariableKinds::from_iter(
            &Interner,
            std::iter::repeat(chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General))
                .take(num_vars),
        ),
        value,
    )
}

impl TraitRef {
    pub fn hir_trait_id(&self) -> TraitId {
        from_chalk_trait_id(self.trait_id)
    }
}

impl<T> Canonical<T> {
    pub fn new(value: T, kinds: impl IntoIterator<Item = TyVariableKind>) -> Self {
        let kinds = kinds.into_iter().map(|tk| {
            chalk_ir::CanonicalVarKind::new(
                chalk_ir::VariableKind::Ty(tk),
                chalk_ir::UniverseIndex::ROOT,
            )
        });
        Self { value, binders: chalk_ir::CanonicalVarKinds::from_iter(&Interner, kinds) }
    }
}

/// A function signature as seen by type inference: Several parameter types and
/// one return type.
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct CallableSig {
    params_and_return: Arc<[Ty]>,
    is_varargs: bool,
}

/// A polymorphic function signature.
pub type PolyFnSig = Binders<CallableSig>;

impl CallableSig {
    pub fn from_params_and_return(mut params: Vec<Ty>, ret: Ty, is_varargs: bool) -> CallableSig {
        params.push(ret);
        CallableSig { params_and_return: params.into(), is_varargs }
    }

    pub fn from_fn_ptr(fn_ptr: &FnPointer) -> CallableSig {
        CallableSig {
            // FIXME: what to do about lifetime params? -> return PolyFnSig
            params_and_return: fn_ptr
                .substitution
                .clone()
                .shifted_out_to(DebruijnIndex::ONE)
                .expect("unexpected lifetime vars in fn ptr")
                .0
                .interned()
                .iter()
                .map(|arg| arg.assert_ty_ref(&Interner).clone())
                .collect(),
            is_varargs: fn_ptr.sig.variadic,
        }
    }

    pub fn params(&self) -> &[Ty] {
        &self.params_and_return[0..self.params_and_return.len() - 1]
    }

    pub fn ret(&self) -> &Ty {
        &self.params_and_return[self.params_and_return.len() - 1]
    }
}

impl Ty {
    pub fn as_reference(&self) -> Option<(&Ty, Mutability)> {
        match self.kind(&Interner) {
            TyKind::Ref(mutability, ty) => Some((ty, *mutability)),
            _ => None,
        }
    }

    pub fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)> {
        match self.kind(&Interner) {
            TyKind::Ref(mutability, ty) => Some((ty, Rawness::Ref, *mutability)),
            TyKind::Raw(mutability, ty) => Some((ty, Rawness::RawPtr, *mutability)),
            _ => None,
        }
    }

    pub fn strip_references(&self) -> &Ty {
        let mut t: &Ty = self;

        while let TyKind::Ref(_mutability, ty) = t.kind(&Interner) {
            t = ty;
        }

        t
    }

    pub fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)> {
        match self.kind(&Interner) {
            TyKind::Adt(AdtId(adt), parameters) => Some((*adt, parameters)),
            _ => None,
        }
    }

    pub fn as_tuple(&self) -> Option<&Substitution> {
        match self.kind(&Interner) {
            TyKind::Tuple(_, substs) => Some(substs),
            _ => None,
        }
    }

    pub fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
        match *self.kind(&Interner) {
            TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
            TyKind::FnDef(callable, ..) => {
                Some(db.lookup_intern_callable_def(callable.into()).into())
            }
            TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
            TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
            _ => None,
        }
    }

    pub fn is_never(&self) -> bool {
        matches!(self.kind(&Interner), TyKind::Never)
    }

    pub fn is_unknown(&self) -> bool {
        matches!(self.kind(&Interner), TyKind::Error)
    }

    pub fn equals_ctor(&self, other: &Ty) -> bool {
        match (self.kind(&Interner), other.kind(&Interner)) {
            (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
            (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_), TyKind::Array(_)) => true,
            (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
            (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
            (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
                ty_id == ty_id2
            }
            (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
            (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
            (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
            | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
                mutability == mutability2
            }
            (
                TyKind::Function(FnPointer { num_binders, sig, .. }),
                TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
            ) => num_binders == num_binders2 && sig == sig2,
            (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
                cardinality == cardinality2
            }
            (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
            (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
            _ => false,
        }
    }

    /// If this is a `dyn Trait` type, this returns the `Trait` part.
    fn dyn_trait_ref(&self) -> Option<&TraitRef> {
        match self.kind(&Interner) {
            TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
                match b.skip_binders() {
                    WhereClause::Implemented(trait_ref) => Some(trait_ref),
                    _ => None,
                }
            }),
            _ => None,
        }
    }

    /// If this is a `dyn Trait`, returns that trait.
    pub fn dyn_trait(&self) -> Option<TraitId> {
        self.dyn_trait_ref().map(|it| it.trait_id).map(from_chalk_trait_id)
    }

    fn builtin_deref(&self) -> Option<Ty> {
        match self.kind(&Interner) {
            TyKind::Ref(.., ty) => Some(ty.clone()),
            TyKind::Raw(.., ty) => Some(ty.clone()),
            _ => None,
        }
    }

    pub fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId> {
        match self.kind(&Interner) {
            &TyKind::FnDef(def, ..) => Some(db.lookup_intern_callable_def(def.into())),
            _ => None,
        }
    }

    pub fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
        if let Some(CallableDefId::FunctionId(func)) = self.callable_def(db) {
            Some(func)
        } else {
            None
        }
    }

    pub fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
        match self.kind(&Interner) {
            TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
            TyKind::FnDef(def, parameters) => {
                let callable_def = db.lookup_intern_callable_def((*def).into());
                let sig = db.callable_item_signature(callable_def);
                Some(sig.substitute(&Interner, &parameters))
            }
            TyKind::Closure(.., substs) => {
                let sig_param = substs.at(&Interner, 0).assert_ty_ref(&Interner);
                sig_param.callable_sig(db)
            }
            _ => None,
        }
    }

    /// Returns the type parameters of this type if it has some (i.e. is an ADT
    /// or function); so if `self` is `Option<u32>`, this returns the `u32`.
    pub fn substs(&self) -> Option<&Substitution> {
        match self.kind(&Interner) {
            TyKind::Adt(_, substs)
            | TyKind::FnDef(_, substs)
            | TyKind::Tuple(_, substs)
            | TyKind::OpaqueType(_, substs)
            | TyKind::AssociatedType(_, substs)
            | TyKind::Closure(.., substs) => Some(substs),
            TyKind::Function(FnPointer { substitution: substs, .. }) => Some(&substs.0),
            _ => None,
        }
    }

    fn substs_mut(&mut self) -> Option<&mut Substitution> {
        match self.interned_mut() {
            TyKind::Adt(_, substs)
            | TyKind::FnDef(_, substs)
            | TyKind::Tuple(_, substs)
            | TyKind::OpaqueType(_, substs)
            | TyKind::AssociatedType(_, substs)
            | TyKind::Closure(.., substs) => Some(substs),
            TyKind::Function(FnPointer { substitution: substs, .. }) => Some(&mut substs.0),
            _ => None,
        }
    }

    pub fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
        match self.kind(&Interner) {
            TyKind::OpaqueType(opaque_ty_id, ..) => {
                match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
                    ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
                        let krate = def.module(db.upcast()).krate();
                        if let Some(future_trait) = db
                            .lang_item(krate, "future_trait".into())
                            .and_then(|item| item.as_trait())
                        {
                            // This is only used by type walking.
                            // Parameters will be walked outside, and projection predicate is not used.
                            // So just provide the Future trait.
                            let impl_bound = Binders::empty(
                                &Interner,
                                WhereClause::Implemented(TraitRef {
                                    trait_id: to_chalk_trait_id(future_trait),
                                    substitution: Substitution::empty(&Interner),
                                }),
                            );
                            Some(vec![impl_bound])
                        } else {
                            None
                        }
                    }
                    ImplTraitId::ReturnTypeImplTrait(..) => None,
                }
            }
            TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
                let predicates = match db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into())
                {
                    ImplTraitId::ReturnTypeImplTrait(func, idx) => {
                        db.return_type_impl_traits(func).map(|it| {
                            let data = (*it)
                                .as_ref()
                                .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
                            data.substitute(&Interner, &opaque_ty.substitution)
                        })
                    }
                    // It always has an parameter for Future::Output type.
                    ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
                };

                predicates.map(|it| it.into_value_and_skipped_binders().0)
            }
            TyKind::Placeholder(idx) => {
                let id = from_placeholder_idx(db, *idx);
                let generic_params = db.generic_params(id.parent);
                let param_data = &generic_params.types[id.local_id];
                match param_data.provenance {
                    hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
                        let substs = TyBuilder::type_params_subst(db, id.parent);
                        let predicates = db
                            .generic_predicates(id.parent)
                            .into_iter()
                            .map(|pred| pred.clone().substitute(&Interner, &substs))
                            .filter(|wc| match &wc.skip_binders() {
                                WhereClause::Implemented(tr) => {
                                    tr.self_type_parameter(&Interner) == self
                                }
                                WhereClause::AliasEq(AliasEq {
                                    alias: AliasTy::Projection(proj),
                                    ty: _,
                                }) => proj.self_type_parameter(&Interner) == self,
                                _ => false,
                            })
                            .collect_vec();

                        Some(predicates)
                    }
                    _ => None,
                }
            }
            _ => None,
        }
    }

    pub fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
        match self.kind(&Interner) {
            TyKind::AssociatedType(id, ..) => {
                match from_assoc_type_id(*id).lookup(db.upcast()).container {
                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
                    _ => None,
                }
            }
            TyKind::Alias(AliasTy::Projection(projection_ty)) => {
                match from_assoc_type_id(projection_ty.associated_ty_id)
                    .lookup(db.upcast())
                    .container
                {
                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
                    _ => None,
                }
            }
            _ => None,
        }
    }
}

#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
pub enum ImplTraitId {
    ReturnTypeImplTrait(hir_def::FunctionId, u16),
    AsyncBlockTypeImplTrait(hir_def::DefWithBodyId, ExprId),
}

#[derive(Clone, PartialEq, Eq, Debug, Hash)]
pub struct ReturnTypeImplTraits {
    pub(crate) impl_traits: Vec<ReturnTypeImplTrait>,
}

#[derive(Clone, PartialEq, Eq, Debug, Hash)]
pub(crate) struct ReturnTypeImplTrait {
    pub(crate) bounds: Binders<Vec<QuantifiedWhereClause>>,
}

pub fn to_foreign_def_id(id: TypeAliasId) -> ForeignDefId {
    chalk_ir::ForeignDefId(salsa::InternKey::as_intern_id(&id))
}

pub fn from_foreign_def_id(id: ForeignDefId) -> TypeAliasId {
    salsa::InternKey::from_intern_id(id.0)
}

pub fn to_assoc_type_id(id: TypeAliasId) -> AssocTypeId {
    chalk_ir::AssocTypeId(salsa::InternKey::as_intern_id(&id))
}

pub fn from_assoc_type_id(id: AssocTypeId) -> TypeAliasId {
    salsa::InternKey::from_intern_id(id.0)
}

pub fn from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> TypeParamId {
    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
    db.lookup_intern_type_param_id(interned_id)
}

pub fn to_placeholder_idx(db: &dyn HirDatabase, id: TypeParamId) -> PlaceholderIndex {
    let interned_id = db.intern_type_param_id(id);
    PlaceholderIndex {
        ui: chalk_ir::UniverseIndex::ROOT,
        idx: salsa::InternKey::as_intern_id(&interned_id).as_usize(),
    }
}

pub fn lt_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> LifetimeParamId {
    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
    db.lookup_intern_lifetime_param_id(interned_id)
}

pub fn to_chalk_trait_id(id: TraitId) -> ChalkTraitId {
    chalk_ir::TraitId(salsa::InternKey::as_intern_id(&id))
}

pub fn from_chalk_trait_id(id: ChalkTraitId) -> TraitId {
    salsa::InternKey::from_intern_id(id.0)
}