diff options
Diffstat (limited to 'src/tools/rust-analyzer/crates/hir-ty/src/lower.rs')
| -rw-r--r-- | src/tools/rust-analyzer/crates/hir-ty/src/lower.rs | 235 |
1 files changed, 156 insertions, 79 deletions
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs index 532544fee..223d705b1 100644 --- a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs +++ b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs @@ -306,7 +306,7 @@ impl<'a> TyLoweringContext<'a> { // FIXME we're probably doing something wrong here self.impl_trait_counter.set(idx + count_impl_traits(type_ref) as u16); let ( - parent_params, + _parent_params, self_params, list_params, const_params, @@ -319,7 +319,7 @@ impl<'a> TyLoweringContext<'a> { }; TyKind::BoundVar(BoundVar::new( self.in_binders, - idx as usize + parent_params + self_params + list_params + const_params, + idx as usize + self_params + list_params + const_params, )) .intern(Interner) } @@ -499,14 +499,31 @@ impl<'a> TyLoweringContext<'a> { .intern(Interner) } TypeNs::SelfType(impl_id) => { - let generics = generics(self.db.upcast(), impl_id.into()); - let substs = match self.type_param_mode { - ParamLoweringMode::Placeholder => generics.placeholder_subst(self.db), + let def = + self.resolver.generic_def().expect("impl should have generic param scope"); + let generics = generics(self.db.upcast(), def); + + match self.type_param_mode { + ParamLoweringMode::Placeholder => { + // `def` can be either impl itself or item within, and we need impl itself + // now. + let generics = generics.parent_generics().unwrap_or(&generics); + let subst = generics.placeholder_subst(self.db); + self.db.impl_self_ty(impl_id).substitute(Interner, &subst) + } ParamLoweringMode::Variable => { - generics.bound_vars_subst(self.db, self.in_binders) + let starting_from = match def { + GenericDefId::ImplId(_) => 0, + // `def` is an item within impl. We need to substitute `BoundVar`s but + // remember that they are for parent (i.e. impl) generic params so they + // come after our own params. + _ => generics.len_self(), + }; + TyBuilder::impl_self_ty(self.db, impl_id) + .fill_with_bound_vars(self.in_binders, starting_from) + .build() } - }; - self.db.impl_self_ty(impl_id).substitute(Interner, &substs) + } } TypeNs::AdtSelfType(adt) => { let generics = generics(self.db.upcast(), adt.into()); @@ -663,40 +680,31 @@ impl<'a> TyLoweringContext<'a> { fn substs_from_path_segment( &self, segment: PathSegment<'_>, - def_generic: Option<GenericDefId>, + def: Option<GenericDefId>, infer_args: bool, explicit_self_ty: Option<Ty>, ) -> Substitution { + // Remember that the item's own generic args come before its parent's. let mut substs = Vec::new(); - let def_generics = if let Some(def) = def_generic { - generics(self.db.upcast(), def) + let def = if let Some(d) = def { + d } else { return Substitution::empty(Interner); }; + let def_generics = generics(self.db.upcast(), def); let (parent_params, self_params, type_params, const_params, impl_trait_params) = def_generics.provenance_split(); - let total_len = - parent_params + self_params + type_params + const_params + impl_trait_params; + let item_len = self_params + type_params + const_params + impl_trait_params; + let total_len = parent_params + item_len; - let ty_error = GenericArgData::Ty(TyKind::Error.intern(Interner)).intern(Interner); + let ty_error = TyKind::Error.intern(Interner).cast(Interner); let mut def_generic_iter = def_generics.iter_id(); - for _ in 0..parent_params { - if let Some(eid) = def_generic_iter.next() { - match eid { - Either::Left(_) => substs.push(ty_error.clone()), - Either::Right(x) => { - substs.push(unknown_const_as_generic(self.db.const_param_ty(x))) - } - } - } - } - let fill_self_params = || { for x in explicit_self_ty .into_iter() - .map(|x| GenericArgData::Ty(x).intern(Interner)) + .map(|x| x.cast(Interner)) .chain(iter::repeat(ty_error.clone())) .take(self_params) { @@ -757,37 +765,40 @@ impl<'a> TyLoweringContext<'a> { fill_self_params(); } + // These params include those of parent. + let remaining_params: SmallVec<[_; 2]> = def_generic_iter + .map(|eid| match eid { + Either::Left(_) => ty_error.clone(), + Either::Right(x) => unknown_const_as_generic(self.db.const_param_ty(x)), + }) + .collect(); + assert_eq!(remaining_params.len() + substs.len(), total_len); + // handle defaults. In expression or pattern path segments without // explicitly specified type arguments, missing type arguments are inferred // (i.e. defaults aren't used). if !infer_args || had_explicit_args { - if let Some(def_generic) = def_generic { - let defaults = self.db.generic_defaults(def_generic); - assert_eq!(total_len, defaults.len()); - - for default_ty in defaults.iter().skip(substs.len()) { - // each default can depend on the previous parameters - let substs_so_far = Substitution::from_iter(Interner, substs.clone()); - if let Some(_id) = def_generic_iter.next() { - substs.push(default_ty.clone().substitute(Interner, &substs_so_far)); - } - } + let defaults = self.db.generic_defaults(def); + assert_eq!(total_len, defaults.len()); + let parent_from = item_len - substs.len(); + + for (idx, default_ty) in defaults[substs.len()..item_len].iter().enumerate() { + // each default can depend on the previous parameters + let substs_so_far = Substitution::from_iter( + Interner, + substs.iter().cloned().chain(remaining_params[idx..].iter().cloned()), + ); + substs.push(default_ty.clone().substitute(Interner, &substs_so_far)); } - } - // add placeholders for args that were not provided - // FIXME: emit diagnostics in contexts where this is not allowed - for eid in def_generic_iter { - match eid { - Either::Left(_) => substs.push(ty_error.clone()), - Either::Right(x) => { - substs.push(unknown_const_as_generic(self.db.const_param_ty(x))) - } - } + // Keep parent's params as unknown. + let mut remaining_params = remaining_params; + substs.extend(remaining_params.drain(parent_from..)); + } else { + substs.extend(remaining_params); } - // If this assert fails, it means you pushed into subst but didn't call .next() of def_generic_iter - assert_eq!(substs.len(), total_len); + assert_eq!(substs.len(), total_len); Substitution::from_iter(Interner, substs) } @@ -981,10 +992,11 @@ impl<'a> TyLoweringContext<'a> { fn lower_dyn_trait(&self, bounds: &[Interned<TypeBound>]) -> Ty { let self_ty = TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(Interner); - // INVARIANT: The principal trait bound must come first. Others may be in any order but - // should be in the same order for the same set but possibly different order of bounds in - // the input. - // This invariant is used by `TyExt::dyn_trait()` and chalk. + // INVARIANT: The principal trait bound, if present, must come first. Others may be in any + // order but should be in the same order for the same set but possibly different order of + // bounds in the input. + // INVARIANT: If this function returns `DynTy`, there should be at least one trait bound. + // These invariants are utilized by `TyExt::dyn_trait()` and chalk. let bounds = self.with_shifted_in(DebruijnIndex::ONE, |ctx| { let mut bounds: Vec<_> = bounds .iter() @@ -1035,6 +1047,12 @@ impl<'a> TyLoweringContext<'a> { return None; } + if bounds.first().and_then(|b| b.trait_id()).is_none() { + // When there's no trait bound, that's an error. This happens when the trait refs + // are unresolved. + return None; + } + // As multiple occurrences of the same auto traits *are* permitted, we dedulicate the // bounds. We shouldn't have repeated elements besides auto traits at this point. bounds.dedup(); @@ -1046,7 +1064,8 @@ impl<'a> TyLoweringContext<'a> { let bounds = crate::make_single_type_binders(bounds); TyKind::Dyn(DynTy { bounds, lifetime: static_lifetime() }).intern(Interner) } else { - // FIXME: report error (additional non-auto traits or associated type rebound) + // FIXME: report error + // (additional non-auto traits, associated type rebound, or no resolved trait) TyKind::Error.intern(Interner) } } @@ -1139,11 +1158,28 @@ fn named_associated_type_shorthand_candidates<R>( }; match res { - TypeNs::SelfType(impl_id) => search( + TypeNs::SelfType(impl_id) => { // we're _in_ the impl -- the binders get added back later. Correct, // but it would be nice to make this more explicit - db.impl_trait(impl_id)?.into_value_and_skipped_binders().0, - ), + let trait_ref = db.impl_trait(impl_id)?.into_value_and_skipped_binders().0; + + let impl_id_as_generic_def: GenericDefId = impl_id.into(); + if impl_id_as_generic_def != def { + // `trait_ref` contains `BoundVar`s bound by impl's `Binders`, but here we need + // `BoundVar`s from `def`'s point of view. + // FIXME: A `HirDatabase` query may be handy if this process is needed in more + // places. It'd be almost identical as `impl_trait_query` where `resolver` would be + // of `def` instead of `impl_id`. + let starting_idx = generics(db.upcast(), def).len_self(); + let subst = TyBuilder::subst_for_def(db, impl_id, None) + .fill_with_bound_vars(DebruijnIndex::INNERMOST, starting_idx) + .build(); + let trait_ref = subst.apply(trait_ref, Interner); + search(trait_ref) + } else { + search(trait_ref) + } + } TypeNs::GenericParam(param_id) => { let predicates = db.generic_predicates_for_param(def, param_id.into(), assoc_name); let res = predicates.iter().find_map(|pred| match pred.skip_binders().skip_binders() { @@ -1160,10 +1196,18 @@ fn named_associated_type_shorthand_candidates<R>( } // Handle `Self::Type` referring to own associated type in trait definitions if let GenericDefId::TraitId(trait_id) = param_id.parent() { - let generics = generics(db.upcast(), trait_id.into()); - if generics.params.type_or_consts[param_id.local_id()].is_trait_self() { + let trait_generics = generics(db.upcast(), trait_id.into()); + if trait_generics.params.type_or_consts[param_id.local_id()].is_trait_self() { + let def_generics = generics(db.upcast(), def); + let starting_idx = match def { + GenericDefId::TraitId(_) => 0, + // `def` is an item within trait. We need to substitute `BoundVar`s but + // remember that they are for parent (i.e. trait) generic params so they + // come after our own params. + _ => def_generics.len_self(), + }; let trait_ref = TyBuilder::trait_ref(db, trait_id) - .fill_with_bound_vars(DebruijnIndex::INNERMOST, 0) + .fill_with_bound_vars(DebruijnIndex::INNERMOST, starting_idx) .build(); return search(trait_ref); } @@ -1405,6 +1449,7 @@ pub(crate) fn generic_defaults_query( let ctx = TyLoweringContext::new(db, &resolver).with_type_param_mode(ParamLoweringMode::Variable); let generic_params = generics(db.upcast(), def); + let parent_start_idx = generic_params.len_self(); let defaults = generic_params .iter() @@ -1417,19 +1462,17 @@ pub(crate) fn generic_defaults_query( let val = unknown_const_as_generic( db.const_param_ty(ConstParamId::from_unchecked(id)), ); - return crate::make_binders_with_count(db, idx, &generic_params, val); + return make_binders(db, &generic_params, val); } }; let mut ty = p.default.as_ref().map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t)); // Each default can only refer to previous parameters. - // type variable default referring to parameter coming - // after it. This is forbidden (FIXME: report - // diagnostic) - ty = fallback_bound_vars(ty, idx); - let val = GenericArgData::Ty(ty).intern(Interner); - crate::make_binders_with_count(db, idx, &generic_params, val) + // Type variable default referring to parameter coming + // after it is forbidden (FIXME: report diagnostic) + ty = fallback_bound_vars(ty, idx, parent_start_idx); + crate::make_binders(db, &generic_params, ty.cast(Interner)) }) .collect(); @@ -1446,15 +1489,14 @@ pub(crate) fn generic_defaults_recover( // we still need one default per parameter let defaults = generic_params .iter_id() - .enumerate() - .map(|(count, id)| { + .map(|id| { let val = match id { itertools::Either::Left(_) => { GenericArgData::Ty(TyKind::Error.intern(Interner)).intern(Interner) } itertools::Either::Right(id) => unknown_const_as_generic(db.const_param_ty(id)), }; - crate::make_binders_with_count(db, count, &generic_params, val) + crate::make_binders(db, &generic_params, val) }) .collect(); @@ -1633,6 +1675,19 @@ pub enum ValueTyDefId { } impl_from!(FunctionId, StructId, UnionId, EnumVariantId, ConstId, StaticId for ValueTyDefId); +impl ValueTyDefId { + pub(crate) fn to_generic_def_id(self) -> Option<GenericDefId> { + match self { + Self::FunctionId(id) => Some(id.into()), + Self::StructId(id) => Some(id.into()), + Self::UnionId(id) => Some(id.into()), + Self::EnumVariantId(var) => Some(var.into()), + Self::ConstId(id) => Some(id.into()), + Self::StaticId(_) => None, + } + } +} + /// Build the declared type of an item. This depends on the namespace; e.g. for /// `struct Foo(usize)`, we have two types: The type of the struct itself, and /// the constructor function `(usize) -> Foo` which lives in the values @@ -1816,26 +1871,48 @@ pub(crate) fn const_or_path_to_chalk( } } -/// This replaces any 'free' Bound vars in `s` (i.e. those with indices past -/// num_vars_to_keep) by `TyKind::Unknown`. +/// Replaces any 'free' `BoundVar`s in `s` by `TyKind::Error` from the perspective of generic +/// parameter whose index is `param_index`. A `BoundVar` is free when it is or (syntactically) +/// appears after the generic parameter of `param_index`. fn fallback_bound_vars<T: TypeFoldable<Interner> + HasInterner<Interner = Interner>>( s: T, - num_vars_to_keep: usize, + param_index: usize, + parent_start: usize, ) -> T { + // Keep in mind that parent generic parameters, if any, come *after* those of the item in + // question. In the diagrams below, `c*` and `p*` represent generic parameters of the item and + // its parent respectively. + let is_allowed = |index| { + if param_index < parent_start { + // The parameter of `param_index` is one from the item in question. Any parent generic + // parameters or the item's generic parameters that come before `param_index` is + // allowed. + // [c1, .., cj, .., ck, p1, .., pl] where cj is `param_index` + // ^^^^^^ ^^^^^^^^^^ these are allowed + !(param_index..parent_start).contains(&index) + } else { + // The parameter of `param_index` is one from the parent generics. Only parent generic + // parameters that come before `param_index` are allowed. + // [c1, .., ck, p1, .., pj, .., pl] where pj is `param_index` + // ^^^^^^ these are allowed + (parent_start..param_index).contains(&index) + } + }; + crate::fold_free_vars( s, |bound, binders| { - if bound.index >= num_vars_to_keep && bound.debruijn == DebruijnIndex::INNERMOST { - TyKind::Error.intern(Interner) - } else { + if bound.index_if_innermost().map_or(true, is_allowed) { bound.shifted_in_from(binders).to_ty(Interner) + } else { + TyKind::Error.intern(Interner) } }, |ty, bound, binders| { - if bound.index >= num_vars_to_keep && bound.debruijn == DebruijnIndex::INNERMOST { - unknown_const(ty.clone()) - } else { + if bound.index_if_innermost().map_or(true, is_allowed) { bound.shifted_in_from(binders).to_const(Interner, ty) + } else { + unknown_const(ty.clone()) } }, ) |