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f9f354fc XL |
1 | //! Contains the logic to lower rustc types into Chalk types |
2 | //! | |
3 | //! In many cases there is a 1:1 relationship between a rustc type and a Chalk type. | |
4 | //! For example, a `SubstsRef` maps almost directly to a `Substitution`. In some | |
5 | //! other cases, such as `Param`s, there is no Chalk type, so we have to handle | |
6 | //! accordingly. | |
7 | //! | |
8 | //! ## `Ty` lowering | |
9 | //! Much of the `Ty` lowering is 1:1 with Chalk. (Or will be eventually). A | |
10 | //! helpful table for what types lower to what can be found in the | |
11 | //! [Chalk book](http://rust-lang.github.io/chalk/book/types/rust_types.html). | |
12 | //! The most notable difference lies with `Param`s. To convert from rustc to | |
13 | //! Chalk, we eagerly and deeply convert `Param`s to placeholders (in goals) or | |
14 | //! bound variables (for clause generation through functions in `db`). | |
15 | //! | |
16 | //! ## `Region` lowering | |
17 | //! Regions are handled in rustc and Chalk is quite differently. In rustc, there | |
18 | //! is a difference between "early bound" and "late bound" regions, where only | |
19 | //! the late bound regions have a `DebruijnIndex`. Moreover, in Chalk all | |
20 | //! regions (Lifetimes) have an associated index. In rustc, only `BrAnon`s have | |
21 | //! an index, whereas `BrNamed` don't. In order to lower regions to Chalk, we | |
22 | //! convert all regions into `BrAnon` late-bound regions. | |
23 | //! | |
24 | //! ## `Const` lowering | |
25 | //! Chalk doesn't handle consts currently, so consts are currently lowered to | |
26 | //! an empty tuple. | |
27 | //! | |
28 | //! ## Bound variable collection | |
29 | //! Another difference between rustc and Chalk lies in the handling of binders. | |
30 | //! Chalk requires that we store the bound parameter kinds, whereas rustc does | |
31 | //! not. To lower anything wrapped in a `Binder`, we first deeply find any bound | |
32 | //! variables from the current `Binder`. | |
33 | ||
34 | use rustc_middle::traits::{ | |
f035d41b | 35 | ChalkEnvironmentAndGoal, ChalkEnvironmentClause, ChalkRustInterner as RustInterner, |
f9f354fc XL |
36 | }; |
37 | use rustc_middle::ty::fold::TypeFolder; | |
f035d41b | 38 | use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef}; |
f9f354fc XL |
39 | use rustc_middle::ty::{ |
40 | self, Binder, BoundRegion, Region, RegionKind, Ty, TyCtxt, TyKind, TypeFoldable, TypeVisitor, | |
41 | }; | |
42 | use rustc_span::def_id::DefId; | |
43 | ||
44 | use std::collections::btree_map::{BTreeMap, Entry}; | |
45 | ||
f035d41b XL |
46 | use chalk_ir::fold::shift::Shift; |
47 | ||
f9f354fc XL |
48 | /// Essentially an `Into` with a `&RustInterner` parameter |
49 | crate trait LowerInto<'tcx, T> { | |
50 | /// Lower a rustc construct (e.g., `ty::TraitPredicate`) to a chalk type, consuming `self`. | |
51 | fn lower_into(self, interner: &RustInterner<'tcx>) -> T; | |
52 | } | |
53 | ||
54 | impl<'tcx> LowerInto<'tcx, chalk_ir::Substitution<RustInterner<'tcx>>> for SubstsRef<'tcx> { | |
55 | fn lower_into( | |
56 | self, | |
57 | interner: &RustInterner<'tcx>, | |
58 | ) -> chalk_ir::Substitution<RustInterner<'tcx>> { | |
59 | chalk_ir::Substitution::from(interner, self.iter().map(|s| s.lower_into(interner))) | |
60 | } | |
61 | } | |
62 | ||
63 | impl<'tcx> LowerInto<'tcx, chalk_ir::AliasTy<RustInterner<'tcx>>> for ty::ProjectionTy<'tcx> { | |
64 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::AliasTy<RustInterner<'tcx>> { | |
65 | chalk_ir::AliasTy::Projection(chalk_ir::ProjectionTy { | |
f035d41b | 66 | associated_ty_id: chalk_ir::AssocTypeId(self.item_def_id), |
f9f354fc XL |
67 | substitution: self.substs.lower_into(interner), |
68 | }) | |
69 | } | |
70 | } | |
71 | ||
72 | impl<'tcx> LowerInto<'tcx, chalk_ir::InEnvironment<chalk_ir::Goal<RustInterner<'tcx>>>> | |
73 | for ChalkEnvironmentAndGoal<'tcx> | |
74 | { | |
75 | fn lower_into( | |
76 | self, | |
77 | interner: &RustInterner<'tcx>, | |
78 | ) -> chalk_ir::InEnvironment<chalk_ir::Goal<RustInterner<'tcx>>> { | |
79 | let clauses = self.environment.into_iter().filter_map(|clause| match clause { | |
80 | ChalkEnvironmentClause::Predicate(predicate) => { | |
3dfed10e XL |
81 | // FIXME(chalk): forall |
82 | match predicate.bound_atom(interner.tcx).skip_binder() { | |
83 | ty::PredicateAtom::Trait(predicate, _) => { | |
84 | let predicate = ty::Binder::bind(predicate); | |
f9f354fc | 85 | let (predicate, binders, _named_regions) = |
3dfed10e | 86 | collect_bound_vars(interner, interner.tcx, &predicate); |
f9f354fc XL |
87 | |
88 | Some( | |
f035d41b | 89 | chalk_ir::ProgramClauseData(chalk_ir::Binders::new( |
f9f354fc XL |
90 | binders, |
91 | chalk_ir::ProgramClauseImplication { | |
92 | consequence: chalk_ir::DomainGoal::FromEnv( | |
93 | chalk_ir::FromEnv::Trait( | |
94 | predicate.trait_ref.lower_into(interner), | |
95 | ), | |
96 | ), | |
97 | conditions: chalk_ir::Goals::new(interner), | |
98 | priority: chalk_ir::ClausePriority::High, | |
99 | }, | |
100 | )) | |
101 | .intern(interner), | |
102 | ) | |
103 | } | |
3dfed10e XL |
104 | ty::PredicateAtom::RegionOutlives(predicate) => { |
105 | let predicate = ty::Binder::bind(predicate); | |
f035d41b | 106 | let (predicate, binders, _named_regions) = |
3dfed10e | 107 | collect_bound_vars(interner, interner.tcx, &predicate); |
f035d41b XL |
108 | |
109 | Some( | |
110 | chalk_ir::ProgramClauseData(chalk_ir::Binders::new( | |
111 | binders, | |
112 | chalk_ir::ProgramClauseImplication { | |
113 | consequence: chalk_ir::DomainGoal::Holds( | |
114 | chalk_ir::WhereClause::LifetimeOutlives( | |
115 | chalk_ir::LifetimeOutlives { | |
116 | a: predicate.0.lower_into(interner), | |
117 | b: predicate.1.lower_into(interner), | |
118 | }, | |
119 | ), | |
120 | ), | |
121 | conditions: chalk_ir::Goals::new(interner), | |
122 | priority: chalk_ir::ClausePriority::High, | |
123 | }, | |
124 | )) | |
125 | .intern(interner), | |
126 | ) | |
127 | } | |
128 | // FIXME(chalk): need to add TypeOutlives | |
3dfed10e XL |
129 | ty::PredicateAtom::TypeOutlives(_) => None, |
130 | ty::PredicateAtom::Projection(predicate) => { | |
131 | let predicate = ty::Binder::bind(predicate); | |
f9f354fc | 132 | let (predicate, binders, _named_regions) = |
3dfed10e | 133 | collect_bound_vars(interner, interner.tcx, &predicate); |
f9f354fc XL |
134 | |
135 | Some( | |
f035d41b | 136 | chalk_ir::ProgramClauseData(chalk_ir::Binders::new( |
f9f354fc XL |
137 | binders, |
138 | chalk_ir::ProgramClauseImplication { | |
139 | consequence: chalk_ir::DomainGoal::Holds( | |
140 | chalk_ir::WhereClause::AliasEq( | |
141 | predicate.lower_into(interner), | |
142 | ), | |
143 | ), | |
144 | conditions: chalk_ir::Goals::new(interner), | |
145 | priority: chalk_ir::ClausePriority::High, | |
146 | }, | |
147 | )) | |
148 | .intern(interner), | |
149 | ) | |
150 | } | |
3dfed10e XL |
151 | ty::PredicateAtom::WellFormed(..) |
152 | | ty::PredicateAtom::ObjectSafe(..) | |
153 | | ty::PredicateAtom::ClosureKind(..) | |
154 | | ty::PredicateAtom::Subtype(..) | |
155 | | ty::PredicateAtom::ConstEvaluatable(..) | |
156 | | ty::PredicateAtom::ConstEquate(..) => { | |
f9f354fc XL |
157 | bug!("unexpected predicate {}", predicate) |
158 | } | |
159 | } | |
160 | } | |
161 | ChalkEnvironmentClause::TypeFromEnv(ty) => Some( | |
f035d41b XL |
162 | chalk_ir::ProgramClauseData(chalk_ir::Binders::new( |
163 | chalk_ir::VariableKinds::new(interner), | |
164 | chalk_ir::ProgramClauseImplication { | |
165 | consequence: chalk_ir::DomainGoal::FromEnv(chalk_ir::FromEnv::Ty( | |
166 | ty.lower_into(interner).shifted_in(interner), | |
167 | )), | |
168 | conditions: chalk_ir::Goals::new(interner), | |
169 | priority: chalk_ir::ClausePriority::High, | |
170 | }, | |
171 | )) | |
f9f354fc XL |
172 | .intern(interner), |
173 | ), | |
174 | }); | |
175 | ||
176 | let goal: chalk_ir::GoalData<RustInterner<'tcx>> = self.goal.lower_into(&interner); | |
177 | chalk_ir::InEnvironment { | |
178 | environment: chalk_ir::Environment { | |
179 | clauses: chalk_ir::ProgramClauses::from(&interner, clauses), | |
180 | }, | |
181 | goal: goal.intern(&interner), | |
182 | } | |
183 | } | |
184 | } | |
185 | ||
186 | impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predicate<'tcx> { | |
187 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::GoalData<RustInterner<'tcx>> { | |
3dfed10e XL |
188 | // FIXME(chalk): forall |
189 | match self.bound_atom(interner.tcx).skip_binder() { | |
190 | ty::PredicateAtom::Trait(predicate, _) => { | |
191 | ty::Binder::bind(predicate).lower_into(interner) | |
192 | } | |
193 | ty::PredicateAtom::RegionOutlives(predicate) => { | |
194 | let predicate = ty::Binder::bind(predicate); | |
f035d41b | 195 | let (predicate, binders, _named_regions) = |
3dfed10e | 196 | collect_bound_vars(interner, interner.tcx, &predicate); |
f035d41b XL |
197 | |
198 | chalk_ir::GoalData::Quantified( | |
199 | chalk_ir::QuantifierKind::ForAll, | |
200 | chalk_ir::Binders::new( | |
201 | binders, | |
202 | chalk_ir::GoalData::DomainGoal(chalk_ir::DomainGoal::Holds( | |
203 | chalk_ir::WhereClause::LifetimeOutlives(chalk_ir::LifetimeOutlives { | |
204 | a: predicate.0.lower_into(interner), | |
205 | b: predicate.1.lower_into(interner), | |
206 | }), | |
207 | )) | |
208 | .intern(interner), | |
209 | ), | |
210 | ) | |
f9f354fc | 211 | } |
f035d41b | 212 | // FIXME(chalk): TypeOutlives |
3dfed10e | 213 | ty::PredicateAtom::TypeOutlives(_predicate) => { |
f9f354fc XL |
214 | chalk_ir::GoalData::All(chalk_ir::Goals::new(interner)) |
215 | } | |
3dfed10e XL |
216 | ty::PredicateAtom::Projection(predicate) => { |
217 | ty::Binder::bind(predicate).lower_into(interner) | |
218 | } | |
219 | ty::PredicateAtom::WellFormed(arg) => match arg.unpack() { | |
f035d41b XL |
220 | GenericArgKind::Type(ty) => match ty.kind { |
221 | // FIXME(chalk): In Chalk, a placeholder is WellFormed if it | |
222 | // `FromEnv`. However, when we "lower" Params, we don't update | |
223 | // the environment. | |
224 | ty::Placeholder(..) => chalk_ir::GoalData::All(chalk_ir::Goals::new(interner)), | |
225 | ||
3dfed10e XL |
226 | _ => { |
227 | let (ty, binders, _named_regions) = | |
228 | collect_bound_vars(interner, interner.tcx, &ty::Binder::bind(ty)); | |
229 | ||
230 | chalk_ir::GoalData::Quantified( | |
231 | chalk_ir::QuantifierKind::ForAll, | |
232 | chalk_ir::Binders::new( | |
233 | binders, | |
234 | chalk_ir::GoalData::DomainGoal(chalk_ir::DomainGoal::WellFormed( | |
235 | chalk_ir::WellFormed::Ty(ty.lower_into(interner)), | |
236 | )) | |
237 | .intern(interner), | |
238 | ), | |
239 | ) | |
240 | } | |
f035d41b XL |
241 | }, |
242 | // FIXME(chalk): handle well formed consts | |
243 | GenericArgKind::Const(..) => { | |
f9f354fc XL |
244 | chalk_ir::GoalData::All(chalk_ir::Goals::new(interner)) |
245 | } | |
f035d41b | 246 | GenericArgKind::Lifetime(lt) => bug!("unexpect well formed predicate: {:?}", lt), |
f9f354fc XL |
247 | }, |
248 | ||
3dfed10e XL |
249 | ty::PredicateAtom::ObjectSafe(t) => chalk_ir::GoalData::DomainGoal( |
250 | chalk_ir::DomainGoal::ObjectSafe(chalk_ir::TraitId(t)), | |
f035d41b XL |
251 | ), |
252 | ||
f9f354fc XL |
253 | // FIXME(chalk): other predicates |
254 | // | |
255 | // We can defer this, but ultimately we'll want to express | |
256 | // some of these in terms of chalk operations. | |
3dfed10e XL |
257 | ty::PredicateAtom::ClosureKind(..) |
258 | | ty::PredicateAtom::Subtype(..) | |
259 | | ty::PredicateAtom::ConstEvaluatable(..) | |
260 | | ty::PredicateAtom::ConstEquate(..) => { | |
f9f354fc XL |
261 | chalk_ir::GoalData::All(chalk_ir::Goals::new(interner)) |
262 | } | |
263 | } | |
264 | } | |
265 | } | |
266 | ||
267 | impl<'tcx> LowerInto<'tcx, chalk_ir::TraitRef<RustInterner<'tcx>>> | |
268 | for rustc_middle::ty::TraitRef<'tcx> | |
269 | { | |
270 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::TraitRef<RustInterner<'tcx>> { | |
271 | chalk_ir::TraitRef { | |
f035d41b | 272 | trait_id: chalk_ir::TraitId(self.def_id), |
f9f354fc XL |
273 | substitution: self.substs.lower_into(interner), |
274 | } | |
275 | } | |
276 | } | |
277 | ||
278 | impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> | |
279 | for ty::PolyTraitPredicate<'tcx> | |
280 | { | |
281 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::GoalData<RustInterner<'tcx>> { | |
282 | let (ty, binders, _named_regions) = collect_bound_vars(interner, interner.tcx, &self); | |
283 | ||
284 | chalk_ir::GoalData::Quantified( | |
285 | chalk_ir::QuantifierKind::ForAll, | |
286 | chalk_ir::Binders::new( | |
287 | binders, | |
288 | chalk_ir::GoalData::DomainGoal(chalk_ir::DomainGoal::Holds( | |
289 | chalk_ir::WhereClause::Implemented(ty.trait_ref.lower_into(interner)), | |
290 | )) | |
291 | .intern(interner), | |
292 | ), | |
293 | ) | |
294 | } | |
295 | } | |
296 | ||
297 | impl<'tcx> LowerInto<'tcx, chalk_ir::AliasEq<RustInterner<'tcx>>> | |
298 | for rustc_middle::ty::ProjectionPredicate<'tcx> | |
299 | { | |
300 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::AliasEq<RustInterner<'tcx>> { | |
301 | chalk_ir::AliasEq { | |
302 | ty: self.ty.lower_into(interner), | |
303 | alias: self.projection_ty.lower_into(interner), | |
304 | } | |
305 | } | |
306 | } | |
307 | ||
308 | impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> | |
309 | for ty::PolyProjectionPredicate<'tcx> | |
310 | { | |
311 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::GoalData<RustInterner<'tcx>> { | |
312 | let (ty, binders, _named_regions) = collect_bound_vars(interner, interner.tcx, &self); | |
313 | ||
314 | chalk_ir::GoalData::Quantified( | |
315 | chalk_ir::QuantifierKind::ForAll, | |
316 | chalk_ir::Binders::new( | |
317 | binders, | |
318 | chalk_ir::GoalData::DomainGoal(chalk_ir::DomainGoal::Holds( | |
319 | chalk_ir::WhereClause::AliasEq(ty.lower_into(interner)), | |
320 | )) | |
321 | .intern(interner), | |
322 | ), | |
323 | ) | |
324 | } | |
325 | } | |
326 | ||
327 | impl<'tcx> LowerInto<'tcx, chalk_ir::Ty<RustInterner<'tcx>>> for Ty<'tcx> { | |
328 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::Ty<RustInterner<'tcx>> { | |
329 | use chalk_ir::TyData; | |
3dfed10e | 330 | use rustc_ast as ast; |
f9f354fc XL |
331 | use TyKind::*; |
332 | ||
333 | let empty = || chalk_ir::Substitution::empty(interner); | |
f035d41b XL |
334 | let struct_ty = |
335 | |def_id| chalk_ir::TypeName::Adt(chalk_ir::AdtId(interner.tcx.adt_def(def_id))); | |
f9f354fc XL |
336 | let apply = |name, substitution| { |
337 | TyData::Apply(chalk_ir::ApplicationTy { name, substitution }).intern(interner) | |
338 | }; | |
339 | let int = |i| apply(chalk_ir::TypeName::Scalar(chalk_ir::Scalar::Int(i)), empty()); | |
340 | let uint = |i| apply(chalk_ir::TypeName::Scalar(chalk_ir::Scalar::Uint(i)), empty()); | |
341 | let float = |f| apply(chalk_ir::TypeName::Scalar(chalk_ir::Scalar::Float(f)), empty()); | |
342 | ||
343 | match self.kind { | |
344 | Bool => apply(chalk_ir::TypeName::Scalar(chalk_ir::Scalar::Bool), empty()), | |
345 | Char => apply(chalk_ir::TypeName::Scalar(chalk_ir::Scalar::Char), empty()), | |
346 | Int(ty) => match ty { | |
347 | ast::IntTy::Isize => int(chalk_ir::IntTy::Isize), | |
348 | ast::IntTy::I8 => int(chalk_ir::IntTy::I8), | |
349 | ast::IntTy::I16 => int(chalk_ir::IntTy::I16), | |
350 | ast::IntTy::I32 => int(chalk_ir::IntTy::I32), | |
351 | ast::IntTy::I64 => int(chalk_ir::IntTy::I64), | |
352 | ast::IntTy::I128 => int(chalk_ir::IntTy::I128), | |
353 | }, | |
354 | Uint(ty) => match ty { | |
355 | ast::UintTy::Usize => uint(chalk_ir::UintTy::Usize), | |
356 | ast::UintTy::U8 => uint(chalk_ir::UintTy::U8), | |
357 | ast::UintTy::U16 => uint(chalk_ir::UintTy::U16), | |
358 | ast::UintTy::U32 => uint(chalk_ir::UintTy::U32), | |
359 | ast::UintTy::U64 => uint(chalk_ir::UintTy::U64), | |
360 | ast::UintTy::U128 => uint(chalk_ir::UintTy::U128), | |
361 | }, | |
362 | Float(ty) => match ty { | |
363 | ast::FloatTy::F32 => float(chalk_ir::FloatTy::F32), | |
364 | ast::FloatTy::F64 => float(chalk_ir::FloatTy::F64), | |
365 | }, | |
f035d41b | 366 | Adt(def, substs) => apply(struct_ty(def.did), substs.lower_into(interner)), |
f9f354fc | 367 | Foreign(_def_id) => unimplemented!(), |
f035d41b XL |
368 | Str => apply(chalk_ir::TypeName::Str, empty()), |
369 | Array(ty, len) => { | |
370 | let value = match len.val { | |
371 | ty::ConstKind::Value(val) => { | |
372 | chalk_ir::ConstValue::Concrete(chalk_ir::ConcreteConst { interned: val }) | |
373 | } | |
374 | ty::ConstKind::Bound(db, bound) => { | |
375 | chalk_ir::ConstValue::BoundVar(chalk_ir::BoundVar::new( | |
376 | chalk_ir::DebruijnIndex::new(db.as_u32()), | |
377 | bound.index(), | |
378 | )) | |
379 | } | |
380 | _ => unimplemented!("Const not implemented. {:?}", len.val), | |
381 | }; | |
382 | apply( | |
383 | chalk_ir::TypeName::Array, | |
384 | chalk_ir::Substitution::from( | |
385 | interner, | |
386 | &[ | |
387 | chalk_ir::GenericArgData::Ty(ty.lower_into(interner)).intern(interner), | |
388 | chalk_ir::GenericArgData::Const( | |
389 | chalk_ir::ConstData { ty: len.ty.lower_into(interner), value } | |
390 | .intern(interner), | |
391 | ) | |
392 | .intern(interner), | |
393 | ], | |
394 | ), | |
395 | ) | |
396 | } | |
f9f354fc | 397 | Slice(ty) => apply( |
f035d41b | 398 | chalk_ir::TypeName::Slice, |
f9f354fc XL |
399 | chalk_ir::Substitution::from1( |
400 | interner, | |
f035d41b | 401 | chalk_ir::GenericArgData::Ty(ty.lower_into(interner)).intern(interner), |
f9f354fc XL |
402 | ), |
403 | ), | |
f035d41b XL |
404 | RawPtr(ptr) => { |
405 | let name = match ptr.mutbl { | |
406 | ast::Mutability::Mut => chalk_ir::TypeName::Raw(chalk_ir::Mutability::Mut), | |
407 | ast::Mutability::Not => chalk_ir::TypeName::Raw(chalk_ir::Mutability::Not), | |
408 | }; | |
409 | apply(name, chalk_ir::Substitution::from1(interner, ptr.ty.lower_into(interner))) | |
410 | } | |
411 | Ref(region, ty, mutability) => { | |
412 | let name = match mutability { | |
413 | ast::Mutability::Mut => chalk_ir::TypeName::Ref(chalk_ir::Mutability::Mut), | |
414 | ast::Mutability::Not => chalk_ir::TypeName::Ref(chalk_ir::Mutability::Not), | |
415 | }; | |
416 | apply( | |
417 | name, | |
418 | chalk_ir::Substitution::from( | |
419 | interner, | |
420 | &[ | |
421 | chalk_ir::GenericArgData::Lifetime(region.lower_into(interner)) | |
422 | .intern(interner), | |
423 | chalk_ir::GenericArgData::Ty(ty.lower_into(interner)).intern(interner), | |
424 | ], | |
425 | ), | |
426 | ) | |
427 | } | |
428 | FnDef(def_id, substs) => apply( | |
429 | chalk_ir::TypeName::FnDef(chalk_ir::FnDefId(def_id)), | |
430 | substs.lower_into(interner), | |
f9f354fc | 431 | ), |
f9f354fc XL |
432 | FnPtr(sig) => { |
433 | let (inputs_and_outputs, binders, _named_regions) = | |
434 | collect_bound_vars(interner, interner.tcx, &sig.inputs_and_output()); | |
435 | TyData::Function(chalk_ir::Fn { | |
436 | num_binders: binders.len(interner), | |
437 | substitution: chalk_ir::Substitution::from( | |
438 | interner, | |
439 | inputs_and_outputs.iter().map(|ty| { | |
f035d41b | 440 | chalk_ir::GenericArgData::Ty(ty.lower_into(interner)).intern(interner) |
f9f354fc XL |
441 | }), |
442 | ), | |
443 | }) | |
444 | .intern(interner) | |
445 | } | |
f035d41b XL |
446 | Dynamic(predicates, region) => TyData::Dyn(chalk_ir::DynTy { |
447 | bounds: predicates.lower_into(interner), | |
448 | lifetime: region.lower_into(interner), | |
449 | }) | |
450 | .intern(interner), | |
451 | Closure(def_id, substs) => apply( | |
452 | chalk_ir::TypeName::Closure(chalk_ir::ClosureId(def_id)), | |
453 | substs.lower_into(interner), | |
454 | ), | |
f9f354fc XL |
455 | Generator(_def_id, _substs, _) => unimplemented!(), |
456 | GeneratorWitness(_) => unimplemented!(), | |
f035d41b | 457 | Never => apply(chalk_ir::TypeName::Never, empty()), |
f9f354fc XL |
458 | Tuple(substs) => { |
459 | apply(chalk_ir::TypeName::Tuple(substs.len()), substs.lower_into(interner)) | |
460 | } | |
461 | Projection(proj) => TyData::Alias(proj.lower_into(interner)).intern(interner), | |
f035d41b XL |
462 | Opaque(def_id, substs) => { |
463 | TyData::Alias(chalk_ir::AliasTy::Opaque(chalk_ir::OpaqueTy { | |
464 | opaque_ty_id: chalk_ir::OpaqueTyId(def_id), | |
465 | substitution: substs.lower_into(interner), | |
466 | })) | |
467 | .intern(interner) | |
468 | } | |
f9f354fc XL |
469 | // This should have been done eagerly prior to this, and all Params |
470 | // should have been substituted to placeholders | |
471 | Param(_) => panic!("Lowering Param when not expected."), | |
472 | Bound(db, bound) => TyData::BoundVar(chalk_ir::BoundVar::new( | |
473 | chalk_ir::DebruijnIndex::new(db.as_u32()), | |
474 | bound.var.index(), | |
475 | )) | |
476 | .intern(interner), | |
477 | Placeholder(_placeholder) => TyData::Placeholder(chalk_ir::PlaceholderIndex { | |
478 | ui: chalk_ir::UniverseIndex { counter: _placeholder.universe.as_usize() }, | |
479 | idx: _placeholder.name.as_usize(), | |
480 | }) | |
481 | .intern(interner), | |
482 | Infer(_infer) => unimplemented!(), | |
f035d41b | 483 | Error(_) => apply(chalk_ir::TypeName::Error, empty()), |
f9f354fc XL |
484 | } |
485 | } | |
486 | } | |
487 | ||
488 | impl<'tcx> LowerInto<'tcx, chalk_ir::Lifetime<RustInterner<'tcx>>> for Region<'tcx> { | |
489 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::Lifetime<RustInterner<'tcx>> { | |
490 | use rustc_middle::ty::RegionKind::*; | |
491 | ||
492 | match self { | |
493 | ReEarlyBound(_) => { | |
494 | panic!("Should have already been substituted."); | |
495 | } | |
496 | ReLateBound(db, br) => match br { | |
497 | ty::BoundRegion::BrAnon(var) => { | |
498 | chalk_ir::LifetimeData::BoundVar(chalk_ir::BoundVar::new( | |
499 | chalk_ir::DebruijnIndex::new(db.as_u32()), | |
500 | *var as usize, | |
501 | )) | |
502 | .intern(interner) | |
503 | } | |
504 | ty::BoundRegion::BrNamed(_def_id, _name) => unimplemented!(), | |
505 | ty::BrEnv => unimplemented!(), | |
506 | }, | |
507 | ReFree(_) => unimplemented!(), | |
f035d41b | 508 | // FIXME(chalk): need to handle ReStatic |
f9f354fc XL |
509 | ReStatic => unimplemented!(), |
510 | ReVar(_) => unimplemented!(), | |
511 | RePlaceholder(placeholder_region) => { | |
512 | chalk_ir::LifetimeData::Placeholder(chalk_ir::PlaceholderIndex { | |
513 | ui: chalk_ir::UniverseIndex { counter: placeholder_region.universe.index() }, | |
514 | idx: 0, | |
515 | }) | |
516 | .intern(interner) | |
517 | } | |
518 | ReEmpty(_) => unimplemented!(), | |
f035d41b | 519 | // FIXME(chalk): need to handle ReErased |
f9f354fc XL |
520 | ReErased => unimplemented!(), |
521 | } | |
522 | } | |
523 | } | |
524 | ||
f035d41b XL |
525 | impl<'tcx> LowerInto<'tcx, chalk_ir::GenericArg<RustInterner<'tcx>>> for GenericArg<'tcx> { |
526 | fn lower_into(self, interner: &RustInterner<'tcx>) -> chalk_ir::GenericArg<RustInterner<'tcx>> { | |
f9f354fc XL |
527 | match self.unpack() { |
528 | ty::subst::GenericArgKind::Type(ty) => { | |
f035d41b | 529 | chalk_ir::GenericArgData::Ty(ty.lower_into(interner)) |
f9f354fc XL |
530 | } |
531 | ty::subst::GenericArgKind::Lifetime(lifetime) => { | |
f035d41b | 532 | chalk_ir::GenericArgData::Lifetime(lifetime.lower_into(interner)) |
f9f354fc | 533 | } |
f035d41b | 534 | ty::subst::GenericArgKind::Const(_) => chalk_ir::GenericArgData::Ty( |
f9f354fc XL |
535 | chalk_ir::TyData::Apply(chalk_ir::ApplicationTy { |
536 | name: chalk_ir::TypeName::Tuple(0), | |
537 | substitution: chalk_ir::Substitution::empty(interner), | |
538 | }) | |
539 | .intern(interner), | |
540 | ), | |
541 | } | |
542 | .intern(interner) | |
543 | } | |
544 | } | |
545 | ||
546 | // We lower into an Option here since there are some predicates which Chalk | |
547 | // doesn't have a representation for yet (as a `WhereClause`), but are so common | |
548 | // that we just are accepting the unsoundness for now. The `Option` will | |
549 | // eventually be removed. | |
550 | impl<'tcx> LowerInto<'tcx, Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>> | |
551 | for ty::Predicate<'tcx> | |
552 | { | |
553 | fn lower_into( | |
554 | self, | |
555 | interner: &RustInterner<'tcx>, | |
556 | ) -> Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>> { | |
3dfed10e XL |
557 | // FIXME(chalk): forall |
558 | match self.bound_atom(interner.tcx).skip_binder() { | |
559 | ty::PredicateAtom::Trait(predicate, _) => { | |
560 | let predicate = ty::Binder::bind(predicate); | |
f9f354fc | 561 | let (predicate, binders, _named_regions) = |
3dfed10e | 562 | collect_bound_vars(interner, interner.tcx, &predicate); |
f9f354fc XL |
563 | |
564 | Some(chalk_ir::Binders::new( | |
565 | binders, | |
566 | chalk_ir::WhereClause::Implemented(predicate.trait_ref.lower_into(interner)), | |
567 | )) | |
568 | } | |
3dfed10e XL |
569 | ty::PredicateAtom::RegionOutlives(predicate) => { |
570 | let predicate = ty::Binder::bind(predicate); | |
f035d41b | 571 | let (predicate, binders, _named_regions) = |
3dfed10e | 572 | collect_bound_vars(interner, interner.tcx, &predicate); |
f035d41b XL |
573 | |
574 | Some(chalk_ir::Binders::new( | |
575 | binders, | |
576 | chalk_ir::WhereClause::LifetimeOutlives(chalk_ir::LifetimeOutlives { | |
577 | a: predicate.0.lower_into(interner), | |
578 | b: predicate.1.lower_into(interner), | |
579 | }), | |
580 | )) | |
581 | } | |
3dfed10e XL |
582 | ty::PredicateAtom::TypeOutlives(_predicate) => None, |
583 | ty::PredicateAtom::Projection(_predicate) => None, | |
584 | ty::PredicateAtom::WellFormed(_ty) => None, | |
585 | ||
586 | ty::PredicateAtom::ObjectSafe(..) | |
587 | | ty::PredicateAtom::ClosureKind(..) | |
588 | | ty::PredicateAtom::Subtype(..) | |
589 | | ty::PredicateAtom::ConstEvaluatable(..) | |
590 | | ty::PredicateAtom::ConstEquate(..) => bug!("unexpected predicate {}", &self), | |
f9f354fc XL |
591 | } |
592 | } | |
593 | } | |
594 | ||
f035d41b XL |
595 | impl<'tcx> LowerInto<'tcx, chalk_ir::Binders<chalk_ir::QuantifiedWhereClauses<RustInterner<'tcx>>>> |
596 | for Binder<&'tcx ty::List<ty::ExistentialPredicate<'tcx>>> | |
597 | { | |
598 | fn lower_into( | |
599 | self, | |
600 | interner: &RustInterner<'tcx>, | |
601 | ) -> chalk_ir::Binders<chalk_ir::QuantifiedWhereClauses<RustInterner<'tcx>>> { | |
602 | let (predicates, binders, _named_regions) = | |
603 | collect_bound_vars(interner, interner.tcx, &self); | |
604 | let where_clauses = predicates.into_iter().map(|predicate| match predicate { | |
605 | ty::ExistentialPredicate::Trait(ty::ExistentialTraitRef { def_id, substs }) => { | |
606 | chalk_ir::Binders::new( | |
607 | chalk_ir::VariableKinds::new(interner), | |
608 | chalk_ir::WhereClause::Implemented(chalk_ir::TraitRef { | |
609 | trait_id: chalk_ir::TraitId(def_id), | |
610 | substitution: substs.lower_into(interner), | |
611 | }), | |
612 | ) | |
613 | } | |
614 | ty::ExistentialPredicate::Projection(_predicate) => unimplemented!(), | |
615 | ty::ExistentialPredicate::AutoTrait(def_id) => chalk_ir::Binders::new( | |
616 | chalk_ir::VariableKinds::new(interner), | |
617 | chalk_ir::WhereClause::Implemented(chalk_ir::TraitRef { | |
618 | trait_id: chalk_ir::TraitId(def_id), | |
619 | substitution: chalk_ir::Substitution::empty(interner), | |
620 | }), | |
621 | ), | |
622 | }); | |
623 | let value = chalk_ir::QuantifiedWhereClauses::from(interner, where_clauses); | |
624 | chalk_ir::Binders::new(binders, value) | |
625 | } | |
626 | } | |
627 | ||
f9f354fc XL |
628 | /// To collect bound vars, we have to do two passes. In the first pass, we |
629 | /// collect all `BoundRegion`s and `ty::Bound`s. In the second pass, we then | |
630 | /// replace `BrNamed` into `BrAnon`. The two separate passes are important, | |
631 | /// since we can only replace `BrNamed` with `BrAnon`s with indices *after* all | |
632 | /// "real" `BrAnon`s. | |
633 | /// | |
634 | /// It's important to note that because of prior substitution, we may have | |
635 | /// late-bound regions, even outside of fn contexts, since this is the best way | |
636 | /// to prep types for chalk lowering. | |
637 | crate fn collect_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>>( | |
638 | interner: &RustInterner<'tcx>, | |
639 | tcx: TyCtxt<'tcx>, | |
640 | ty: &'a Binder<T>, | |
f035d41b | 641 | ) -> (T, chalk_ir::VariableKinds<RustInterner<'tcx>>, BTreeMap<DefId, u32>) { |
f9f354fc | 642 | let mut bound_vars_collector = BoundVarsCollector::new(); |
f035d41b | 643 | ty.as_ref().skip_binder().visit_with(&mut bound_vars_collector); |
f9f354fc XL |
644 | let mut parameters = bound_vars_collector.parameters; |
645 | let named_parameters: BTreeMap<DefId, u32> = bound_vars_collector | |
646 | .named_parameters | |
647 | .into_iter() | |
648 | .enumerate() | |
649 | .map(|(i, def_id)| (def_id, (i + parameters.len()) as u32)) | |
650 | .collect(); | |
651 | ||
652 | let mut bound_var_substitutor = NamedBoundVarSubstitutor::new(tcx, &named_parameters); | |
f035d41b | 653 | let new_ty = ty.as_ref().skip_binder().fold_with(&mut bound_var_substitutor); |
f9f354fc XL |
654 | |
655 | for var in named_parameters.values() { | |
f035d41b | 656 | parameters.insert(*var, chalk_ir::VariableKind::Lifetime); |
f9f354fc XL |
657 | } |
658 | ||
659 | (0..parameters.len()).for_each(|i| { | |
3dfed10e XL |
660 | parameters |
661 | .get(&(i as u32)) | |
662 | .or_else(|| bug!("Skipped bound var index: ty={:?}, parameters={:?}", ty, parameters)); | |
f9f354fc XL |
663 | }); |
664 | ||
f035d41b | 665 | let binders = chalk_ir::VariableKinds::from(interner, parameters.into_iter().map(|(_, v)| v)); |
f9f354fc XL |
666 | |
667 | (new_ty, binders, named_parameters) | |
668 | } | |
669 | ||
f035d41b | 670 | crate struct BoundVarsCollector<'tcx> { |
f9f354fc | 671 | binder_index: ty::DebruijnIndex, |
f035d41b | 672 | crate parameters: BTreeMap<u32, chalk_ir::VariableKind<RustInterner<'tcx>>>, |
f9f354fc XL |
673 | crate named_parameters: Vec<DefId>, |
674 | } | |
675 | ||
f035d41b | 676 | impl<'tcx> BoundVarsCollector<'tcx> { |
f9f354fc XL |
677 | crate fn new() -> Self { |
678 | BoundVarsCollector { | |
679 | binder_index: ty::INNERMOST, | |
680 | parameters: BTreeMap::new(), | |
681 | named_parameters: vec![], | |
682 | } | |
683 | } | |
684 | } | |
685 | ||
f035d41b | 686 | impl<'tcx> TypeVisitor<'tcx> for BoundVarsCollector<'tcx> { |
f9f354fc XL |
687 | fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &Binder<T>) -> bool { |
688 | self.binder_index.shift_in(1); | |
689 | let result = t.super_visit_with(self); | |
690 | self.binder_index.shift_out(1); | |
691 | result | |
692 | } | |
693 | ||
694 | fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { | |
695 | match t.kind { | |
696 | ty::Bound(debruijn, bound_ty) if debruijn == self.binder_index => { | |
697 | match self.parameters.entry(bound_ty.var.as_u32()) { | |
698 | Entry::Vacant(entry) => { | |
f035d41b | 699 | entry.insert(chalk_ir::VariableKind::Ty(chalk_ir::TyKind::General)); |
f9f354fc | 700 | } |
f035d41b XL |
701 | Entry::Occupied(entry) => match entry.get() { |
702 | chalk_ir::VariableKind::Ty(_) => {} | |
703 | _ => panic!(), | |
704 | }, | |
f9f354fc XL |
705 | } |
706 | } | |
707 | ||
708 | _ => (), | |
709 | }; | |
710 | ||
711 | t.super_visit_with(self) | |
712 | } | |
713 | ||
714 | fn visit_region(&mut self, r: Region<'tcx>) -> bool { | |
715 | match r { | |
716 | ty::ReLateBound(index, br) if *index == self.binder_index => match br { | |
717 | ty::BoundRegion::BrNamed(def_id, _name) => { | |
718 | if self.named_parameters.iter().find(|d| *d == def_id).is_none() { | |
719 | self.named_parameters.push(*def_id); | |
720 | } | |
721 | } | |
722 | ||
723 | ty::BoundRegion::BrAnon(var) => match self.parameters.entry(*var) { | |
724 | Entry::Vacant(entry) => { | |
f035d41b | 725 | entry.insert(chalk_ir::VariableKind::Lifetime); |
f9f354fc | 726 | } |
f035d41b XL |
727 | Entry::Occupied(entry) => match entry.get() { |
728 | chalk_ir::VariableKind::Lifetime => {} | |
729 | _ => panic!(), | |
730 | }, | |
f9f354fc XL |
731 | }, |
732 | ||
733 | ty::BrEnv => unimplemented!(), | |
734 | }, | |
735 | ||
736 | ty::ReEarlyBound(_re) => { | |
737 | // FIXME(chalk): jackh726 - I think we should always have already | |
738 | // substituted away `ReEarlyBound`s for `ReLateBound`s, but need to confirm. | |
739 | unimplemented!(); | |
740 | } | |
741 | ||
742 | _ => (), | |
743 | }; | |
744 | ||
745 | r.super_visit_with(self) | |
746 | } | |
747 | } | |
748 | ||
749 | /// This is used to replace `BoundRegion::BrNamed` with `BoundRegion::BrAnon`. | |
750 | /// Note: we assume that we will always have room for more bound vars. (i.e. we | |
751 | /// won't ever hit the `u32` limit in `BrAnon`s). | |
752 | struct NamedBoundVarSubstitutor<'a, 'tcx> { | |
753 | tcx: TyCtxt<'tcx>, | |
754 | binder_index: ty::DebruijnIndex, | |
755 | named_parameters: &'a BTreeMap<DefId, u32>, | |
756 | } | |
757 | ||
758 | impl<'a, 'tcx> NamedBoundVarSubstitutor<'a, 'tcx> { | |
759 | fn new(tcx: TyCtxt<'tcx>, named_parameters: &'a BTreeMap<DefId, u32>) -> Self { | |
760 | NamedBoundVarSubstitutor { tcx, binder_index: ty::INNERMOST, named_parameters } | |
761 | } | |
762 | } | |
763 | ||
764 | impl<'a, 'tcx> TypeFolder<'tcx> for NamedBoundVarSubstitutor<'a, 'tcx> { | |
765 | fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { | |
766 | self.tcx | |
767 | } | |
768 | ||
769 | fn fold_binder<T: TypeFoldable<'tcx>>(&mut self, t: &Binder<T>) -> Binder<T> { | |
770 | self.binder_index.shift_in(1); | |
771 | let result = t.super_fold_with(self); | |
772 | self.binder_index.shift_out(1); | |
773 | result | |
774 | } | |
775 | ||
776 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
777 | t.super_fold_with(self) | |
778 | } | |
779 | ||
780 | fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx> { | |
781 | match r { | |
782 | ty::ReLateBound(index, br) if *index == self.binder_index => match br { | |
783 | ty::BoundRegion::BrNamed(def_id, _name) => { | |
784 | match self.named_parameters.get(def_id) { | |
785 | Some(idx) => { | |
786 | return self.tcx.mk_region(RegionKind::ReLateBound( | |
787 | *index, | |
788 | BoundRegion::BrAnon(*idx), | |
789 | )); | |
790 | } | |
791 | None => panic!("Missing `BrNamed`."), | |
792 | } | |
793 | } | |
794 | ty::BrEnv => unimplemented!(), | |
795 | ty::BoundRegion::BrAnon(_) => {} | |
796 | }, | |
797 | _ => (), | |
798 | }; | |
799 | ||
800 | r.super_fold_with(self) | |
801 | } | |
802 | } | |
803 | ||
804 | /// Used to substitute `Param`s with placeholders. We do this since Chalk | |
805 | /// have a notion of `Param`s. | |
806 | crate struct ParamsSubstitutor<'tcx> { | |
807 | tcx: TyCtxt<'tcx>, | |
808 | binder_index: ty::DebruijnIndex, | |
809 | list: Vec<rustc_middle::ty::ParamTy>, | |
810 | crate params: rustc_data_structures::fx::FxHashMap<usize, rustc_middle::ty::ParamTy>, | |
811 | crate named_regions: BTreeMap<DefId, u32>, | |
812 | } | |
813 | ||
814 | impl<'tcx> ParamsSubstitutor<'tcx> { | |
815 | crate fn new(tcx: TyCtxt<'tcx>) -> Self { | |
816 | ParamsSubstitutor { | |
817 | tcx, | |
818 | binder_index: ty::INNERMOST, | |
819 | list: vec![], | |
820 | params: rustc_data_structures::fx::FxHashMap::default(), | |
821 | named_regions: BTreeMap::default(), | |
822 | } | |
823 | } | |
824 | } | |
825 | ||
826 | impl<'tcx> TypeFolder<'tcx> for ParamsSubstitutor<'tcx> { | |
827 | fn tcx<'b>(&'b self) -> TyCtxt<'tcx> { | |
828 | self.tcx | |
829 | } | |
830 | ||
831 | fn fold_binder<T: TypeFoldable<'tcx>>(&mut self, t: &Binder<T>) -> Binder<T> { | |
832 | self.binder_index.shift_in(1); | |
833 | let result = t.super_fold_with(self); | |
834 | self.binder_index.shift_out(1); | |
835 | result | |
836 | } | |
837 | ||
838 | fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { | |
839 | match t.kind { | |
840 | // FIXME(chalk): currently we convert params to placeholders starting at | |
841 | // index `0`. To support placeholders, we'll actually need to do a | |
842 | // first pass to collect placeholders. Then we can insert params after. | |
843 | ty::Placeholder(_) => unimplemented!(), | |
844 | ty::Param(param) => match self.list.iter().position(|r| r == ¶m) { | |
845 | Some(_idx) => self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType { | |
846 | universe: ty::UniverseIndex::from_usize(0), | |
847 | name: ty::BoundVar::from_usize(_idx), | |
848 | })), | |
849 | None => { | |
850 | self.list.push(param); | |
851 | let idx = self.list.len() - 1; | |
852 | self.params.insert(idx, param); | |
853 | self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType { | |
854 | universe: ty::UniverseIndex::from_usize(0), | |
855 | name: ty::BoundVar::from_usize(idx), | |
856 | })) | |
857 | } | |
858 | }, | |
859 | ||
860 | _ => t.super_fold_with(self), | |
861 | } | |
862 | } | |
863 | ||
864 | fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx> { | |
865 | match r { | |
866 | // FIXME(chalk) - jackh726 - this currently isn't hit in any tests. | |
867 | // This covers any region variables in a goal, right? | |
868 | ty::ReEarlyBound(_re) => match self.named_regions.get(&_re.def_id) { | |
869 | Some(idx) => self.tcx.mk_region(RegionKind::ReLateBound( | |
870 | self.binder_index, | |
871 | BoundRegion::BrAnon(*idx), | |
872 | )), | |
873 | None => { | |
874 | let idx = self.named_regions.len() as u32; | |
875 | self.named_regions.insert(_re.def_id, idx); | |
876 | self.tcx.mk_region(RegionKind::ReLateBound( | |
877 | self.binder_index, | |
878 | BoundRegion::BrAnon(idx), | |
879 | )) | |
880 | } | |
881 | }, | |
882 | ||
883 | _ => r.super_fold_with(self), | |
884 | } | |
885 | } | |
886 | } |