From aa6a72f4a5f53f7e81a5cb15f1f129e697667964 Mon Sep 17 00:00:00 2001 From: Mazdak Farrokhzad Date: Thu, 7 Nov 2019 19:13:22 +0100 Subject: [PATCH] TAIT: use hack in ->HIR to avoid more changes --- src/librustc/hir/lowering.rs | 1 - src/librustc/hir/lowering/item.rs | 62 +++++++++++++++------------ src/librustc/hir/map/def_collector.rs | 5 +-- src/libsyntax/ast.rs | 9 ++++ 4 files changed, 46 insertions(+), 31 deletions(-) diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index 2c8e14f2add..9a840022a3d 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -452,7 +452,6 @@ fn visit_item(&mut self, item: &'tcx Item) { | ItemKind::Union(_, ref generics) | ItemKind::Enum(_, ref generics) | ItemKind::TyAlias(_, ref generics) - | ItemKind::OpaqueTy(_, ref generics) | ItemKind::Trait(_, _, ref generics, ..) => { let def_id = self.lctx.resolver.definitions().local_def_id(item.id); let count = generics diff --git a/src/librustc/hir/lowering/item.rs b/src/librustc/hir/lowering/item.rs index aafdd78e3e8..356adcdf2a9 100644 --- a/src/librustc/hir/lowering/item.rs +++ b/src/librustc/hir/lowering/item.rs @@ -335,20 +335,22 @@ fn lower_item_kind( ItemKind::Mod(ref m) => hir::ItemKind::Mod(self.lower_mod(m)), ItemKind::ForeignMod(ref nm) => hir::ItemKind::ForeignMod(self.lower_foreign_mod(nm)), ItemKind::GlobalAsm(ref ga) => hir::ItemKind::GlobalAsm(self.lower_global_asm(ga)), - ItemKind::TyAlias(ref t, ref generics) => hir::ItemKind::TyAlias( - self.lower_ty(t, ImplTraitContext::disallowed()), - self.lower_generics(generics, ImplTraitContext::disallowed()), - ), - ItemKind::OpaqueTy(ref b, ref generics) => hir::ItemKind::OpaqueTy( - hir::OpaqueTy { - generics: self.lower_generics(generics, - ImplTraitContext::OpaqueTy(None)), - bounds: self.lower_param_bounds(b, - ImplTraitContext::OpaqueTy(None)), - impl_trait_fn: None, - origin: hir::OpaqueTyOrigin::TypeAlias, + ItemKind::TyAlias(ref ty, ref generics) => match ty.kind.opaque_top_hack() { + None => { + let ty = self.lower_ty(ty, ImplTraitContext::disallowed()); + let generics = self.lower_generics(generics, ImplTraitContext::disallowed()); + hir::ItemKind::TyAlias(ty, generics) }, - ), + Some(bounds) => { + let ty = hir::OpaqueTy { + generics: self.lower_generics(generics, ImplTraitContext::OpaqueTy(None)), + bounds: self.lower_param_bounds(bounds, ImplTraitContext::OpaqueTy(None)), + impl_trait_fn: None, + origin: hir::OpaqueTyOrigin::TypeAlias, + }; + hir::ItemKind::OpaqueTy(ty) + } + } ItemKind::Enum(ref enum_definition, ref generics) => { hir::ItemKind::Enum( hir::EnumDef { @@ -914,16 +916,20 @@ fn lower_impl_item(&mut self, i: &ImplItem) -> hir::ImplItem { (generics, hir::ImplItemKind::Method(sig, body_id)) } - ImplItemKind::TyAlias(ref ty) => ( - self.lower_generics(&i.generics, ImplTraitContext::disallowed()), - hir::ImplItemKind::TyAlias(self.lower_ty(ty, ImplTraitContext::disallowed())), - ), - ImplItemKind::OpaqueTy(ref bounds) => ( - self.lower_generics(&i.generics, ImplTraitContext::disallowed()), - hir::ImplItemKind::OpaqueTy( - self.lower_param_bounds(bounds, ImplTraitContext::disallowed()), - ), - ), + ImplItemKind::TyAlias(ref ty) => { + let generics = self.lower_generics(&i.generics, ImplTraitContext::disallowed()); + let kind = match ty.kind.opaque_top_hack() { + None => { + let ty = self.lower_ty(ty, ImplTraitContext::disallowed()); + hir::ImplItemKind::TyAlias(ty) + } + Some(bs) => { + let bounds = self.lower_param_bounds(bs, ImplTraitContext::disallowed()); + hir::ImplItemKind::OpaqueTy(bounds) + } + }; + (generics, kind) + }, ImplItemKind::Macro(..) => bug!("`TyMac` should have been expanded by now"), }; @@ -948,11 +954,13 @@ fn lower_impl_item_ref(&mut self, i: &ImplItem) -> hir::ImplItemRef { span: i.span, vis: self.lower_visibility(&i.vis, Some(i.id)), defaultness: self.lower_defaultness(i.defaultness, true /* [1] */), - kind: match i.kind { + kind: match &i.kind { ImplItemKind::Const(..) => hir::AssocItemKind::Const, - ImplItemKind::TyAlias(..) => hir::AssocItemKind::Type, - ImplItemKind::OpaqueTy(..) => hir::AssocItemKind::OpaqueTy, - ImplItemKind::Method(ref sig, _) => hir::AssocItemKind::Method { + ImplItemKind::TyAlias(ty) => match ty.kind.opaque_top_hack() { + None => hir::AssocItemKind::Type, + Some(_) => hir::AssocItemKind::OpaqueTy, + }, + ImplItemKind::Method(sig, _) => hir::AssocItemKind::Method { has_self: sig.decl.has_self(), }, ImplItemKind::Macro(..) => unimplemented!(), diff --git a/src/librustc/hir/map/def_collector.rs b/src/librustc/hir/map/def_collector.rs index d858e00a2e9..cfd90f50b1b 100644 --- a/src/librustc/hir/map/def_collector.rs +++ b/src/librustc/hir/map/def_collector.rs @@ -107,7 +107,7 @@ fn visit_item(&mut self, i: &'a Item) { } ItemKind::Mod(..) | ItemKind::Trait(..) | ItemKind::TraitAlias(..) | ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) | - ItemKind::OpaqueTy(..) | ItemKind::ExternCrate(..) | ItemKind::ForeignMod(..) | + ItemKind::ExternCrate(..) | ItemKind::ForeignMod(..) | ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name), ItemKind::Fn(sig, generics, body) if sig.header.asyncness.node.is_async() => { return self.visit_async_fn( @@ -239,8 +239,7 @@ fn visit_impl_item(&mut self, ii: &'a ImplItem) { } ImplItemKind::Method(..) | ImplItemKind::Const(..) => DefPathData::ValueNs(ii.ident.name), - ImplItemKind::TyAlias(..) | - ImplItemKind::OpaqueTy(..) => DefPathData::TypeNs(ii.ident.name), + ImplItemKind::TyAlias(..) => DefPathData::TypeNs(ii.ident.name), ImplItemKind::Macro(..) => return self.visit_macro_invoc(ii.id), }; diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs index 4cfa9988570..d358efbe543 100644 --- a/src/libsyntax/ast.rs +++ b/src/libsyntax/ast.rs @@ -1815,6 +1815,15 @@ pub fn is_unit(&self) -> bool { false } } + + /// HACK(type_alias_impl_trait, Centril): A temporary crutch used + /// in lowering to avoid making larger changes there and beyond. + pub fn opaque_top_hack(&self) -> Option<&GenericBounds> { + match self { + Self::ImplTrait(_, bounds) => Some(bounds), + _ => None, + } + } } /// Syntax used to declare a trait object.