Merge hir::IsAuto into ast::IsAuto.

Author: cjgillot

src/librustc/hir/lowering/item.rs

@@ -449,7 +449,7 @@ impl LoweringContext<'_> {
                     .map(|item| self.lower_trait_item_ref(item))
                     .collect();
                 hir::ItemKind::Trait(
-                    self.lower_is_auto(is_auto),
+                    is_auto,
                     unsafety,
                     self.lower_generics(generics, ImplTraitContext::disallowed()),
                     bounds,
@@ -1275,13 +1275,6 @@ impl LoweringContext<'_> {
         (generics, hir::FnSig { header, decl })
     }
 
-    fn lower_is_auto(&mut self, a: IsAuto) -> hir::IsAuto {
-        match a {
-            IsAuto::Yes => hir::IsAuto::Yes,
-            IsAuto::No => hir::IsAuto::No,
-        }
-    }
-
     fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
         hir::FnHeader {
             unsafety: h.unsafety,

src/librustc/hir/mod.rs

@@ -21,7 +21,7 @@ use syntax_pos::{Span, DUMMY_SP, MultiSpan};
 use syntax::source_map::Spanned;
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, AsmDialect};
 use syntax::ast::{Attribute, Label, LitKind, StrStyle, FloatTy, IntTy, UintTy};
-pub use syntax::ast::{Mutability, Constness, Unsafety, Movability, CaptureBy};
+pub use syntax::ast::{Mutability, Constness, Unsafety, Movability, CaptureBy, IsAuto};
 use syntax::attr::{InlineAttr, OptimizeAttr};
 use syntax::symbol::{Symbol, kw};
 use syntax::tokenstream::TokenStream;
@@ -2122,13 +2122,6 @@ impl ImplicitSelfKind {
     }
 }
 
-/// Is the trait definition an auto trait?
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable)]
-pub enum IsAuto {
-    Yes,
-    No
-}
-
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, HashStable,
          Ord, RustcEncodable, RustcDecodable, Debug)]
 pub enum IsAsync {

src/librustc/ich/impls_syntax.rs

@@ -170,6 +170,7 @@ impl_stable_hash_for!(enum ::syntax::ast::StrStyle { Cooked, Raw(pounds) });
 impl_stable_hash_for!(enum ::syntax::ast::AttrStyle { Outer, Inner });
 impl_stable_hash_for!(enum ::syntax::ast::Movability { Static, Movable });
 impl_stable_hash_for!(enum ::syntax::ast::CaptureBy { Value, Ref });
+impl_stable_hash_for!(enum ::syntax::ast::IsAuto { Yes, No });
 
 impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {