diff options
Diffstat (limited to '')
-rw-r--r-- | src/tools/rust-analyzer/crates/hir-ty/src/lower.rs | 184 |
1 files changed, 124 insertions, 60 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 3ed9c941f..532544fee 100644 --- a/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs +++ b/src/tools/rust-analyzer/crates/hir-ty/src/lower.rs @@ -1,12 +1,12 @@ //! Methods for lowering the HIR to types. There are two main cases here: //! //! - Lowering a type reference like `&usize` or `Option<foo::bar::Baz>` to a -//! type: The entry point for this is `Ty::from_hir`. -//! - Building the type for an item: This happens through the `type_for_def` query. +//! type: The entry point for this is `TyLoweringContext::lower_ty`. +//! - Building the type for an item: This happens through the `ty` query. //! //! This usually involves resolving names, collecting generic arguments etc. use std::{ - cell::{Cell, RefCell}, + cell::{Cell, RefCell, RefMut}, iter, sync::Arc, }; @@ -47,7 +47,7 @@ use crate::{ consteval::{intern_const_scalar, path_to_const, unknown_const, unknown_const_as_generic}, db::HirDatabase, make_binders, - mapping::ToChalk, + mapping::{from_chalk_trait_id, ToChalk}, static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx, utils::Generics, utils::{all_super_trait_refs, associated_type_by_name_including_super_traits, generics}, @@ -238,18 +238,7 @@ impl<'a> TyLoweringContext<'a> { }) .intern(Interner) } - TypeRef::DynTrait(bounds) => { - let self_ty = - TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(Interner); - let bounds = self.with_shifted_in(DebruijnIndex::ONE, |ctx| { - QuantifiedWhereClauses::from_iter( - Interner, - bounds.iter().flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false)), - ) - }); - let bounds = crate::make_single_type_binders(bounds); - TyKind::Dyn(DynTy { bounds, lifetime: static_lifetime() }).intern(Interner) - } + TypeRef::DynTrait(bounds) => self.lower_dyn_trait(bounds), TypeRef::ImplTrait(bounds) => { match self.impl_trait_mode { ImplTraitLoweringMode::Opaque => { @@ -341,26 +330,29 @@ impl<'a> TyLoweringContext<'a> { } } TypeRef::Macro(macro_call) => { - let (expander, recursion_start) = { - let mut expander = self.expander.borrow_mut(); - if expander.is_some() { - (Some(expander), false) - } else { - *expander = Some(Expander::new( - self.db.upcast(), - macro_call.file_id, - self.resolver.module(), - )); - (Some(expander), true) + let (mut expander, recursion_start) = { + match RefMut::filter_map(self.expander.borrow_mut(), Option::as_mut) { + // There already is an expander here, this means we are already recursing + Ok(expander) => (expander, false), + // No expander was created yet, so we are at the start of the expansion recursion + // and therefore have to create an expander. + Err(expander) => ( + RefMut::map(expander, |it| { + it.insert(Expander::new( + self.db.upcast(), + macro_call.file_id, + self.resolver.module(), + )) + }), + true, + ), } }; - let ty = if let Some(mut expander) = expander { - let expander_mut = expander.as_mut().unwrap(); + let ty = { let macro_call = macro_call.to_node(self.db.upcast()); - match expander_mut.enter_expand::<ast::Type>(self.db.upcast(), macro_call) { + match expander.enter_expand::<ast::Type>(self.db.upcast(), macro_call) { Ok(ExpandResult { value: Some((mark, expanded)), .. }) => { - let ctx = - LowerCtx::new(self.db.upcast(), expander_mut.current_file_id()); + let ctx = LowerCtx::new(self.db.upcast(), expander.current_file_id()); let type_ref = TypeRef::from_ast(&ctx, expanded); drop(expander); @@ -373,11 +365,14 @@ impl<'a> TyLoweringContext<'a> { .exit(self.db.upcast(), mark); Some(ty) } - _ => None, + _ => { + drop(expander); + None + } } - } else { - None }; + + // drop the expander, resetting it to pre-recursion state if recursion_start { *self.expander.borrow_mut() = None; } @@ -468,29 +463,10 @@ impl<'a> TyLoweringContext<'a> { } } 0 => { - let self_ty = Some( - TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)) - .intern(Interner), - ); - let trait_ref = self.with_shifted_in(DebruijnIndex::ONE, |ctx| { - ctx.lower_trait_ref_from_resolved_path( - trait_, - resolved_segment, - self_ty, - ) - }); - let dyn_ty = DynTy { - bounds: crate::make_single_type_binders( - QuantifiedWhereClauses::from_iter( - Interner, - Some(crate::wrap_empty_binders(WhereClause::Implemented( - trait_ref, - ))), - ), - ), - lifetime: static_lifetime(), - }; - TyKind::Dyn(dyn_ty).intern(Interner) + // Trait object type without dyn; this should be handled in upstream. See + // `lower_path()`. + stdx::never!("unexpected fully resolved trait path"); + TyKind::Error.intern(Interner) } _ => { // FIXME report error (ambiguous associated type) @@ -509,7 +485,14 @@ impl<'a> TyLoweringContext<'a> { TyKind::Placeholder(to_placeholder_idx(self.db, param_id.into())) } ParamLoweringMode::Variable => { - let idx = generics.param_idx(param_id.into()).expect("matching generics"); + let idx = match generics.param_idx(param_id.into()) { + None => { + never!("no matching generics"); + return (TyKind::Error.intern(Interner), None); + } + Some(idx) => idx, + }; + TyKind::BoundVar(BoundVar::new(self.in_binders, idx)) } } @@ -555,11 +538,20 @@ impl<'a> TyLoweringContext<'a> { let (ty, res) = self.lower_ty_ext(type_ref); return self.lower_ty_relative_path(ty, res, path.segments()); } + let (resolution, remaining_index) = match self.resolver.resolve_path_in_type_ns(self.db.upcast(), path.mod_path()) { Some(it) => it, None => return (TyKind::Error.intern(Interner), None), }; + + if matches!(resolution, TypeNs::TraitId(_)) && remaining_index.is_none() { + // trait object type without dyn + let bound = TypeBound::Path(path.clone(), TraitBoundModifier::None); + let ty = self.lower_dyn_trait(&[Interned::new(bound)]); + return (ty, None); + } + let (resolved_segment, remaining_segments) = match remaining_index { None => ( path.segments().last().expect("resolved path has at least one element"), @@ -987,6 +979,78 @@ 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. + let bounds = self.with_shifted_in(DebruijnIndex::ONE, |ctx| { + let mut bounds: Vec<_> = bounds + .iter() + .flat_map(|b| ctx.lower_type_bound(b, self_ty.clone(), false)) + .collect(); + + let mut multiple_regular_traits = false; + let mut multiple_same_projection = false; + bounds.sort_unstable_by(|lhs, rhs| { + use std::cmp::Ordering; + match (lhs.skip_binders(), rhs.skip_binders()) { + (WhereClause::Implemented(lhs), WhereClause::Implemented(rhs)) => { + let lhs_id = lhs.trait_id; + let lhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(lhs_id)).is_auto; + let rhs_id = rhs.trait_id; + let rhs_is_auto = ctx.db.trait_data(from_chalk_trait_id(rhs_id)).is_auto; + + if !lhs_is_auto && !rhs_is_auto { + multiple_regular_traits = true; + } + // Note that the ordering here is important; this ensures the invariant + // mentioned above. + (lhs_is_auto, lhs_id).cmp(&(rhs_is_auto, rhs_id)) + } + (WhereClause::Implemented(_), _) => Ordering::Less, + (_, WhereClause::Implemented(_)) => Ordering::Greater, + (WhereClause::AliasEq(lhs), WhereClause::AliasEq(rhs)) => { + match (&lhs.alias, &rhs.alias) { + (AliasTy::Projection(lhs_proj), AliasTy::Projection(rhs_proj)) => { + // We only compare the `associated_ty_id`s. We shouldn't have + // multiple bounds for an associated type in the correct Rust code, + // and if we do, we error out. + if lhs_proj.associated_ty_id == rhs_proj.associated_ty_id { + multiple_same_projection = true; + } + lhs_proj.associated_ty_id.cmp(&rhs_proj.associated_ty_id) + } + // We don't produce `AliasTy::Opaque`s yet. + _ => unreachable!(), + } + } + // We don't produce `WhereClause::{TypeOutlives, LifetimeOutlives}` yet. + _ => unreachable!(), + } + }); + + if multiple_regular_traits || multiple_same_projection { + 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(); + + Some(QuantifiedWhereClauses::from_iter(Interner, bounds)) + }); + + if let Some(bounds) = bounds { + 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) + TyKind::Error.intern(Interner) + } + } + fn lower_impl_trait( &self, bounds: &[Interned<TypeBound>], @@ -1126,7 +1190,7 @@ pub(crate) fn field_types_query( let ctx = TyLoweringContext::new(db, &resolver).with_type_param_mode(ParamLoweringMode::Variable); for (field_id, field_data) in var_data.fields().iter() { - res.insert(field_id, make_binders(db, &generics, ctx.lower_ty(&field_data.type_ref))) + res.insert(field_id, make_binders(db, &generics, ctx.lower_ty(&field_data.type_ref))); } Arc::new(res) } |