Auto merge of #47416 - petrochenkov:remove-impl-for-dot-dot, r=petrochenkov

Remove `impl Foo for .. {}` in favor `auto trait Foo {}`

Rebase of #46480 with restored parsing support.

Author: bors

src/libcore/marker.rs

@@ -40,15 +40,10 @@ use hash::Hasher;
 /// [ub]: ../../reference/behavior-considered-undefined.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented = "`{Self}` cannot be sent between threads safely"]
-pub unsafe trait Send {
+pub unsafe auto trait Send {
     // empty.
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-#[allow(unknown_lints)]
-#[allow(auto_impl)]
-unsafe impl Send for .. { }
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> !Send for *const T { }
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -345,15 +340,10 @@ pub trait Copy : Clone {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[lang = "sync"]
 #[rustc_on_unimplemented = "`{Self}` cannot be shared between threads safely"]
-pub unsafe trait Sync {
+pub unsafe auto trait Sync {
     // Empty
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-#[allow(unknown_lints)]
-#[allow(auto_impl)]
-unsafe impl Sync for .. { }
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> !Sync for *const T { }
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -563,11 +553,7 @@ mod impls {
 /// This affects, for example, whether a `static` of that type is
 /// placed in read-only static memory or writable static memory.
 #[lang = "freeze"]
-unsafe trait Freeze {}
-
-#[allow(unknown_lints)]
-#[allow(auto_impl)]
-unsafe impl Freeze for .. {}
+unsafe auto trait Freeze {}
 
 impl<T: ?Sized> !Freeze for UnsafeCell<T> {}
 unsafe impl<T: ?Sized> Freeze for PhantomData<T> {}

src/librustc/dep_graph/dep_node.rs

@@ -496,7 +496,6 @@ define_dep_nodes!( <'tcx>
     [] SuperPredicatesOfItem(DefId),
     [] TraitDefOfItem(DefId),
     [] AdtDefOfItem(DefId),
-    [] IsAutoImpl(DefId),
     [] ImplTraitRef(DefId),
     [] ImplPolarity(DefId),
     [] FnSignature(DefId),

src/librustc/hir/intravisit.rs

@@ -498,10 +498,6 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
             // visit_enum_def() takes care of visiting the Item's NodeId
             visitor.visit_enum_def(enum_definition, type_parameters, item.id, item.span)
         }
-        ItemAutoImpl(_, ref trait_ref) => {
-            visitor.visit_id(item.id);
-            visitor.visit_trait_ref(trait_ref)
-        }
         ItemImpl(.., ref type_parameters, ref opt_trait_reference, ref typ, ref impl_item_refs) => {
             visitor.visit_id(item.id);
             visitor.visit_generics(type_parameters);

src/librustc/hir/lowering.rs

@@ -1952,16 +1952,6 @@ impl<'a> LoweringContext<'a> {
                 let vdata = self.lower_variant_data(vdata);
                 hir::ItemUnion(vdata, self.lower_generics(generics))
             }
-            ItemKind::AutoImpl(unsafety, ref trait_ref) => {
-                let trait_ref = self.lower_trait_ref(trait_ref, ImplTraitContext::Disallowed);
-
-                if let Def::Trait(def_id) = trait_ref.path.def {
-                    self.trait_auto_impl.insert(def_id, id);
-                }
-
-                hir::ItemAutoImpl(self.lower_unsafety(unsafety),
-                                     trait_ref)
-            }
             ItemKind::Impl(unsafety,
                            polarity,
                            defaultness,

src/librustc/hir/map/def_collector.rs

@@ -104,8 +104,7 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
         // Pick the def data. This need not be unique, but the more
         // information we encapsulate into
         let def_data = match i.node {
-            ItemKind::AutoImpl(..) | ItemKind::Impl(..) =>
-                DefPathData::Impl,
+            ItemKind::Impl(..) => DefPathData::Impl,
             ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) |
             ItemKind::Trait(..) | ItemKind::TraitAlias(..) |
             ItemKind::ExternCrate(..) | ItemKind::ForeignMod(..) | ItemKind::Ty(..) =>

src/librustc/hir/map/mod.rs

@@ -1192,7 +1192,6 @@ fn node_id_to_string(map: &Map, id: NodeId, include_id: bool) -> String {
                 ItemTrait(..) => "trait",
                 ItemTraitAlias(..) => "trait alias",
                 ItemImpl(..) => "impl",
-                ItemAutoImpl(..) => "default impl",
             };
             format!("{} {}{}", item_str, path_str(), id_str)
         }

src/librustc/hir/mod.rs

@@ -1965,10 +1965,6 @@ pub enum Item_ {
     /// Represents a Trait Alias Declaration
     ItemTraitAlias(Generics, TyParamBounds),
 
-    /// Auto trait implementations
-    ///
-    /// `impl Trait for .. {}`
-    ItemAutoImpl(Unsafety, TraitRef),
     /// An implementation, eg `impl<A> Trait for Foo { .. }`
     ItemImpl(Unsafety,
              ImplPolarity,
@@ -1996,8 +1992,7 @@ impl Item_ {
             ItemUnion(..) => "union",
             ItemTrait(..) => "trait",
             ItemTraitAlias(..) => "trait alias",
-            ItemImpl(..) |
-            ItemAutoImpl(..) => "item",
+            ItemImpl(..) => "item",
         }
     }
 

src/librustc/hir/print.rs

@@ -652,18 +652,6 @@ impl<'a> State<'a> {
                 self.head(&visibility_qualified(&item.vis, "union"))?;
                 self.print_struct(struct_def, generics, item.name, item.span, true)?;
             }
-            hir::ItemAutoImpl(unsafety, ref trait_ref) => {
-                self.head("")?;
-                self.print_visibility(&item.vis)?;
-                self.print_unsafety(unsafety)?;
-                self.word_nbsp("impl")?;
-                self.print_trait_ref(trait_ref)?;
-                self.s.space()?;
-                self.word_space("for")?;
-                self.word_space("..")?;
-                self.bopen()?;
-                self.bclose(item.span)?;
-            }
             hir::ItemImpl(unsafety,
                           polarity,
                           defaultness,

src/librustc/ich/impls_hir.rs

@@ -854,7 +854,6 @@ impl_stable_hash_for!(enum hir::Item_ {
     ItemUnion(variant_data, generics),
     ItemTrait(is_auto, unsafety, generics, bounds, item_refs),
     ItemTraitAlias(generics, bounds),
-    ItemAutoImpl(unsafety, trait_ref),
     ItemImpl(unsafety, impl_polarity, impl_defaultness, generics, trait_ref, ty, impl_item_refs)
 });
 

src/librustc/middle/dead.rs

@@ -564,7 +564,6 @@ impl<'a, 'tcx> Visitor<'tcx> for DeadVisitor<'a, 'tcx> {
                 hir::ItemStruct(..) |
                 hir::ItemUnion(..) |
                 hir::ItemTrait(..) |
-                hir::ItemAutoImpl(..) |
                 hir::ItemImpl(..) => self.tcx.sess.codemap().def_span(item.span),
                 _ => item.span,
             };