diff options
Diffstat (limited to 'compiler/rustc_ast_lowering/src/lib.rs')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 133 |
1 files changed, 83 insertions, 50 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 8d4f96639..429e62c4a 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1539,9 +1539,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { ); debug!(?opaque_ty_def_id); - // Contains the new lifetime definitions created for the TAIT (if any). - let mut collected_lifetimes = Vec::new(); - // If this came from a TAIT (as opposed to a function that returns an RPIT), we only want // to capture the lifetimes that appear in the bounds. So visit the bounds to find out // exactly which ones those are. @@ -1558,20 +1555,31 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }; debug!(?lifetimes_to_remap); - self.with_hir_id_owner(opaque_ty_node_id, |lctx| { - let mut new_remapping = FxHashMap::default(); + let mut new_remapping = FxHashMap::default(); - // If this opaque type is only capturing a subset of the lifetimes (those that appear - // in bounds), then create the new lifetime parameters required and create a mapping - // from the old `'a` (on the function) to the new `'a` (on the opaque type). - collected_lifetimes = lctx.create_lifetime_defs( - opaque_ty_def_id, - &lifetimes_to_remap, - &mut new_remapping, - ); - debug!(?collected_lifetimes); - debug!(?new_remapping); + // Contains the new lifetime definitions created for the TAIT (if any). + // If this opaque type is only capturing a subset of the lifetimes (those that appear in + // bounds), then create the new lifetime parameters required and create a mapping from the + // old `'a` (on the function) to the new `'a` (on the opaque type). + let collected_lifetimes = + self.create_lifetime_defs(opaque_ty_def_id, &lifetimes_to_remap, &mut new_remapping); + debug!(?collected_lifetimes); + debug!(?new_remapping); + + // This creates HIR lifetime arguments as `hir::GenericArg`, in the given example `type + // TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing `&['x]`. + let collected_lifetime_mapping: Vec<_> = collected_lifetimes + .iter() + .map(|(node_id, lifetime)| { + let id = self.next_node_id(); + let lifetime = self.new_named_lifetime(lifetime.id, id, lifetime.ident); + let def_id = self.local_def_id(*node_id); + (lifetime, def_id) + }) + .collect(); + debug!(?collected_lifetime_mapping); + self.with_hir_id_owner(opaque_ty_node_id, |lctx| { // Install the remapping from old to new (if any): lctx.with_remapping(new_remapping, |lctx| { // This creates HIR lifetime definitions as `hir::GenericParam`, in the given @@ -1610,6 +1618,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { let hir_bounds = lctx.lower_param_bounds(bounds, itctx); debug!(?hir_bounds); + let lifetime_mapping = if in_trait { + self.arena.alloc_from_iter( + collected_lifetime_mapping + .iter() + .map(|(lifetime, def_id)| (**lifetime, *def_id)), + ) + } else { + &mut [] + }; + let opaque_ty_item = hir::OpaqueTy { generics: self.arena.alloc(hir::Generics { params: lifetime_defs, @@ -1620,6 +1638,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }), bounds: hir_bounds, origin, + lifetime_mapping, in_trait, }; debug!(?opaque_ty_item); @@ -1628,20 +1647,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }) }); - // This creates HIR lifetime arguments as `hir::GenericArg`, in the given example `type - // TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing `&['x]`. - let lifetimes = - self.arena.alloc_from_iter(collected_lifetimes.into_iter().map(|(_, lifetime)| { - let id = self.next_node_id(); - let l = self.new_named_lifetime(lifetime.id, id, lifetime.ident); - hir::GenericArg::Lifetime(l) - })); - debug!(?lifetimes); - // `impl Trait` now just becomes `Foo<'a, 'b, ..>`. hir::TyKind::OpaqueDef( hir::ItemId { owner_id: hir::OwnerId { def_id: opaque_ty_def_id } }, - lifetimes, + self.arena.alloc_from_iter( + collected_lifetime_mapping + .iter() + .map(|(lifetime, _)| hir::GenericArg::Lifetime(*lifetime)), + ), in_trait, ) } @@ -1655,7 +1668,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { span: Span, opaque_ty_span: Span, ) -> hir::OwnerNode<'hir> { - let opaque_ty_item_kind = hir::ItemKind::OpaqueTy(opaque_ty_item); + let opaque_ty_item_kind = hir::ItemKind::OpaqueTy(self.arena.alloc(opaque_ty_item)); // Generate an `type Foo = impl Trait;` declaration. trace!("registering opaque type with id {:#?}", opaque_ty_id); let opaque_ty_item = hir::Item { @@ -1983,7 +1996,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { let lifetime = Lifetime { id: outer_node_id, ident }; collected_lifetimes.push((inner_node_id, lifetime, Some(inner_res))); } - debug!(?collected_lifetimes); // We only want to capture the lifetimes that appear in the bounds. So visit the bounds to @@ -1993,22 +2005,36 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { let lifetimes_to_remap = lifetime_collector::lifetimes_in_ret_ty(&self.resolver, output); debug!(?lifetimes_to_remap); - self.with_hir_id_owner(opaque_ty_node_id, |this| { - // If this opaque type is only capturing a subset of the lifetimes (those that appear - // in bounds), then create the new lifetime parameters required and create a mapping - // from the old `'a` (on the function) to the new `'a` (on the opaque type). - collected_lifetimes.extend( - this.create_lifetime_defs( - opaque_ty_def_id, - &lifetimes_to_remap, - &mut new_remapping, - ) + // If this opaque type is only capturing a subset of the lifetimes (those that appear in + // bounds), then create the new lifetime parameters required and create a mapping from the + // old `'a` (on the function) to the new `'a` (on the opaque type). + collected_lifetimes.extend( + self.create_lifetime_defs(opaque_ty_def_id, &lifetimes_to_remap, &mut new_remapping) .into_iter() .map(|(new_node_id, lifetime)| (new_node_id, lifetime, None)), - ); - debug!(?collected_lifetimes); - debug!(?new_remapping); + ); + debug!(?collected_lifetimes); + debug!(?new_remapping); + + // This creates pairs of HIR lifetimes and def_ids. In the given example `type + // TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing the + // new lifetime of the RPIT 'x and the def_id of the lifetime 'x corresponding to + // `TestReturn`. + let collected_lifetime_mapping: Vec<_> = collected_lifetimes + .iter() + .map(|(node_id, lifetime, res)| { + let id = self.next_node_id(); + let res = res.unwrap_or( + self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error), + ); + let lifetime = self.new_named_lifetime_with_res(id, lifetime.ident, res); + let def_id = self.local_def_id(*node_id); + (lifetime, def_id) + }) + .collect(); + debug!(?collected_lifetime_mapping); + self.with_hir_id_owner(opaque_ty_node_id, |this| { // Install the remapping from old to new (if any): this.with_remapping(new_remapping, |this| { // We have to be careful to get elision right here. The @@ -2063,6 +2089,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { )); debug!("lower_async_fn_ret_ty: generic_params={:#?}", generic_params); + let lifetime_mapping = if in_trait { + self.arena.alloc_from_iter( + collected_lifetime_mapping + .iter() + .map(|(lifetime, def_id)| (**lifetime, *def_id)), + ) + } else { + &mut [] + }; + let opaque_ty_item = hir::OpaqueTy { generics: this.arena.alloc(hir::Generics { params: generic_params, @@ -2073,6 +2109,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { }), bounds: arena_vec![this; future_bound], origin: hir::OpaqueTyOrigin::AsyncFn(fn_def_id), + lifetime_mapping, in_trait, }; @@ -2096,15 +2133,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // // For the "output" lifetime parameters, we just want to // generate `'_`. - let generic_args = self.arena.alloc_from_iter(collected_lifetimes.into_iter().map( - |(_, lifetime, res)| { - let id = self.next_node_id(); - let res = res.unwrap_or( - self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error), - ); - hir::GenericArg::Lifetime(self.new_named_lifetime_with_res(id, lifetime.ident, res)) - }, - )); + let generic_args = self.arena.alloc_from_iter( + collected_lifetime_mapping + .iter() + .map(|(lifetime, _)| hir::GenericArg::Lifetime(*lifetime)), + ); // Create the `Foo<...>` reference itself. Note that the `type // Foo = impl Trait` is, internally, created as a child of the |