Auto merge of #51829 - petrochenkov:noideq, r=eddyb

Remove most of `PartialEq` and `Hash` impls from AST and HIR structures

Continuation of https://github.com/rust-lang/rust/pull/49326, prerequisite for removing `PartialEq` for `Ident`.

16 files changed, 186 insertions, 381 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 71ff9e8058e..209e0b6d787 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -34,7 +34,7 @@ use std::u32;
 
 pub use rustc_target::abi::FloatTy;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
 pub struct Label {
     pub ident: Ident,
 }
@@ -45,7 +45,7 @@ impl fmt::Debug for Label {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
 pub struct Lifetime {
     pub id: NodeId,
     pub ident: Ident,
@@ -63,7 +63,7 @@ impl fmt::Debug for Lifetime {
 /// along with a bunch of supporting information.
 ///
 /// E.g. `std::cmp::PartialEq`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Path {
     pub span: Span,
     /// The segments in the path: the things separated by `::`.
@@ -115,7 +115,7 @@ impl Path {
 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
 ///
 /// E.g. `std`, `String` or `Box<T>`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct PathSegment {
     /// The identifier portion of this path segment.
     pub ident: Ident,
@@ -141,7 +141,7 @@ impl PathSegment {
 /// Arguments of a path segment.
 ///
 /// E.g. `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericArgs {
     /// The `<'a, A,B,C>` in `foo::bar::baz::<'a, A,B,C>`
     AngleBracketed(AngleBracketedArgs),
@@ -158,14 +158,14 @@ impl GenericArgs {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericArg {
     Lifetime(Lifetime),
     Type(P<Ty>),
 }
 
 /// A path like `Foo<'a, T>`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Default)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
 pub struct AngleBracketedArgs {
     /// Overall span
     pub span: Span,
@@ -190,7 +190,7 @@ impl Into<Option<P<GenericArgs>>> for ParenthesisedArgs {
 }
 
 /// A path like `Foo(A,B) -> C`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct ParenthesisedArgs {
     /// Overall span
     pub span: Span,
@@ -202,7 +202,7 @@ pub struct ParenthesisedArgs {
     pub output: Option<P<Ty>>,
 }
 
-#[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 pub struct NodeId(u32);
 
 impl NodeId {
@@ -270,7 +270,7 @@ pub const DUMMY_NODE_ID: NodeId = NodeId(!0);
 
 /// A modifier on a bound, currently this is only used for `?Sized`, where the
 /// modifier is `Maybe`. Negative bounds should also be handled here.
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 pub enum TraitBoundModifier {
     None,
     Maybe,
@@ -280,7 +280,7 @@ pub enum TraitBoundModifier {
 /// typeck::collect::compute_bounds matches these against
 /// the "special" built-in traits (see middle::lang_items) and
 /// detects Copy, Send and Sync.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericBound {
     Trait(PolyTraitRef, TraitBoundModifier),
     Outlives(Lifetime)
@@ -297,7 +297,7 @@ impl GenericBound {
 
 pub type GenericBounds = Vec<GenericBound>;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericParamKind {
     /// A lifetime definition, e.g. `'a: 'b+'c+'d`.
     Lifetime,
@@ -306,7 +306,7 @@ pub enum GenericParamKind {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct GenericParam {
     pub id: NodeId,
     pub ident: Ident,
@@ -318,7 +318,7 @@ pub struct GenericParam {
 
 /// Represents lifetime, type and const parameters attached to a declaration of
 /// a function, enum, trait, etc.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Generics {
     pub params: Vec<GenericParam>,
     pub where_clause: WhereClause,
@@ -341,7 +341,7 @@ impl Default for Generics {
 }
 
 /// A `where` clause in a definition
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereClause {
     pub id: NodeId,
     pub predicates: Vec<WherePredicate>,
@@ -349,7 +349,7 @@ pub struct WhereClause {
 }
 
 /// A single predicate in a `where` clause
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum WherePredicate {
     /// A type binding, e.g. `for<'c> Foo: Send+Clone+'c`
     BoundPredicate(WhereBoundPredicate),
@@ -372,7 +372,7 @@ impl WherePredicate {
 /// A type bound.
 ///
 /// E.g. `for<'c> Foo: Send+Clone+'c`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereBoundPredicate {
     pub span: Span,
     /// Any generics from a `for` binding
@@ -386,7 +386,7 @@ pub struct WhereBoundPredicate {
 /// A lifetime predicate.
 ///
 /// E.g. `'a: 'b+'c`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereRegionPredicate {
     pub span: Span,
     pub lifetime: Lifetime,
@@ -396,7 +396,7 @@ pub struct WhereRegionPredicate {
 /// An equality predicate (unsupported).
 ///
 /// E.g. `T=int`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereEqPredicate {
     pub id: NodeId,
     pub span: Span,
@@ -408,7 +408,7 @@ pub struct WhereEqPredicate {
 /// used to drive conditional compilation
 pub type CrateConfig = HashSet<(Name, Option<Symbol>)>;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Crate {
     pub module: Mod,
     pub attrs: Vec<Attribute>,
@@ -421,7 +421,7 @@ pub type NestedMetaItem = Spanned<NestedMetaItemKind>;
 /// Possible values inside of compile-time attribute lists.
 ///
 /// E.g. the '..' in `#[name(..)]`.
-#[derive(Clone, Eq, RustcEncodable, RustcDecodable, Hash, Debug, PartialEq)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum NestedMetaItemKind {
     /// A full MetaItem, for recursive meta items.
     MetaItem(MetaItem),
@@ -434,7 +434,7 @@ pub enum NestedMetaItemKind {
 /// A spanned compile-time attribute item.
 ///
 /// E.g. `#[test]`, `#[derive(..)]`, `#[rustfmt::skip]` or `#[feature = "foo"]`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct MetaItem {
     pub ident: Path,
     pub node: MetaItemKind,
@@ -444,7 +444,7 @@ pub struct MetaItem {
 /// A compile-time attribute item.
 ///
 /// E.g. `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum MetaItemKind {
     /// Word meta item.
     ///
@@ -463,7 +463,7 @@ pub enum MetaItemKind {
 /// A Block (`{ .. }`).
 ///
 /// E.g. `{ .. }` as in `fn foo() { .. }`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Block {
     /// Statements in a block
     pub stmts: Vec<Stmt>,
@@ -474,7 +474,7 @@ pub struct Block {
     pub recovered: bool,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Pat {
     pub id: NodeId,
     pub node: PatKind,
@@ -552,7 +552,7 @@ impl Pat {
 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
 /// except is_shorthand is true
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct FieldPat {
     /// The identifier for the field
     pub ident: Ident,
@@ -562,25 +562,25 @@ pub struct FieldPat {
     pub attrs: ThinVec<Attribute>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum BindingMode {
     ByRef(Mutability),
     ByValue(Mutability),
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum RangeEnd {
     Included(RangeSyntax),
     Excluded,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum RangeSyntax {
     DotDotDot,
     DotDotEq,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum PatKind {
     /// Represents a wildcard pattern (`_`)
     Wild,
@@ -627,13 +627,13 @@ pub enum PatKind {
     Mac(Mac),
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum Mutability {
     Mutable,
     Immutable,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum BinOpKind {
     /// The `+` operator (addition)
     Add,
@@ -730,7 +730,7 @@ impl BinOpKind {
 
 pub type BinOp = Spanned<BinOpKind>;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum UnOp {
     /// The `*` operator for dereferencing
     Deref,
@@ -759,7 +759,7 @@ impl UnOp {
 }
 
 /// A statement
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Stmt {
     pub id: NodeId,
     pub node: StmtKind,
@@ -800,7 +800,7 @@ impl fmt::Debug for Stmt {
 }
 
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub enum StmtKind {
     /// A local (let) binding.
     Local(P<Local>),
@@ -816,7 +816,7 @@ pub enum StmtKind {
     Mac(P<(Mac, MacStmtStyle, ThinVec<Attribute>)>),
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum MacStmtStyle {
     /// The macro statement had a trailing semicolon, e.g. `foo! { ... };`
     /// `foo!(...);`, `foo![...];`
@@ -830,7 +830,7 @@ pub enum MacStmtStyle {
 }
 
 /// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Local {
     pub pat: P<Pat>,
     pub ty: Option<P<Ty>>,
@@ -851,7 +851,7 @@ pub struct Local {
 ///     _ => { println!("no match!") },
 /// }
 /// ```
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Arm {
     pub attrs: Vec<Attribute>,
     pub pats: Vec<P<Pat>>,
@@ -859,7 +859,7 @@ pub struct Arm {
     pub body: P<Expr>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Field {
     pub ident: Ident,
     pub expr: P<Expr>,
@@ -868,13 +868,15 @@ pub struct Field {
     pub attrs: ThinVec<Attribute>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+pub type SpannedIdent = Spanned<Ident>;
+
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum BlockCheckMode {
     Default,
     Unsafe(UnsafeSource),
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum UnsafeSource {
     CompilerGenerated,
     UserProvided,
@@ -885,7 +887,7 @@ pub enum UnsafeSource {
 /// These are usually found nested inside types (e.g. array lengths)
 /// or expressions (e.g. repeat counts), and also used to define
 /// explicit discriminant values for enum variants.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct AnonConst {
     pub id: NodeId,
     pub value: P<Expr>,
@@ -893,7 +895,7 @@ pub struct AnonConst {
 
 
 /// An expression
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash,)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Expr {
     pub id: NodeId,
     pub node: ExprKind,
@@ -1016,7 +1018,7 @@ impl fmt::Debug for Expr {
 }
 
 /// Limit types of a range (inclusive or exclusive)
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum RangeLimits {
     /// Inclusive at the beginning, exclusive at the end
     HalfOpen,
@@ -1024,7 +1026,7 @@ pub enum RangeLimits {
     Closed,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum ExprKind {
     /// A `box x` expression.
     Box(P<Expr>),
@@ -1181,7 +1183,7 @@ pub enum ExprKind {
 ///  ^~~~~    ^
 ///  ty       position = 0
 /// ```
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct QSelf {
     pub ty: P<Ty>,
 
@@ -1193,14 +1195,14 @@ pub struct QSelf {
 }
 
 /// A capture clause
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum CaptureBy {
     Value,
     Ref,
 }
 
 /// The movability of a generator / closure literal
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum Movability {
     Static,
     Movable,
@@ -1214,14 +1216,14 @@ pub type Mac = Spanned<Mac_>;
 ///
 /// NB: the additional ident for a macro_rules-style macro is actually
 /// stored in the enclosing item. Oog.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Mac_ {
     pub path: Path,
     pub delim: MacDelimiter,
     pub tts: ThinTokenStream,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 pub enum MacDelimiter {
     Parenthesis,
     Bracket,
@@ -1234,7 +1236,7 @@ impl Mac_ {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct MacroDef {
     pub tokens: ThinTokenStream,
     pub legacy: bool,
@@ -1246,7 +1248,7 @@ impl MacroDef {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum StrStyle {
     /// A regular string, like `"foo"`
     Cooked,
@@ -1259,7 +1261,7 @@ pub enum StrStyle {
 /// A literal
 pub type Lit = Spanned<LitKind>;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum LitIntType {
     Signed(IntTy),
     Unsigned(UintTy),
@@ -1269,7 +1271,7 @@ pub enum LitIntType {
 /// Literal kind.
 ///
 /// E.g. `"foo"`, `42`, `12.34` or `bool`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum LitKind {
     /// A string literal (`"foo"`)
     Str(Symbol, StrStyle),
@@ -1335,7 +1337,7 @@ impl LitKind {
 
 // NB: If you change this, you'll probably want to change the corresponding
 // type structure in middle/ty.rs as well.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct MutTy {
     pub ty: P<Ty>,
     pub mutbl: Mutability,
@@ -1343,7 +1345,7 @@ pub struct MutTy {
 
 /// Represents a method's signature in a trait declaration,
 /// or in an implementation.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct MethodSig {
     pub header: FnHeader,
     pub decl: P<FnDecl>,
@@ -1353,7 +1355,7 @@ pub struct MethodSig {
 /// possibly including a default implementation. A trait item is
 /// either required (meaning it doesn't have an implementation, just a
 /// signature) or provided (meaning it has a default implementation).
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TraitItem {
     pub id: NodeId,
     pub ident: Ident,
@@ -1365,7 +1367,7 @@ pub struct TraitItem {
     pub tokens: Option<TokenStream>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum TraitItemKind {
     Const(P<Ty>, Option<P<Expr>>),
     Method(MethodSig, Option<P<Block>>),
@@ -1373,7 +1375,7 @@ pub enum TraitItemKind {
     Macro(Mac),
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct ImplItem {
     pub id: NodeId,
     pub ident: Ident,
@@ -1387,7 +1389,7 @@ pub struct ImplItem {
     pub tokens: Option<TokenStream>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum ImplItemKind {
     Const(P<Ty>, P<Expr>),
     Method(MethodSig, P<Block>),
@@ -1395,8 +1397,7 @@ pub enum ImplItemKind {
     Macro(Mac),
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy,
-         PartialOrd, Ord)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
 pub enum IntTy {
     Isize,
     I8,
@@ -1449,8 +1450,7 @@ impl IntTy {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy,
-         PartialOrd, Ord)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
 pub enum UintTy {
     Usize,
     U8,
@@ -1501,7 +1501,7 @@ impl fmt::Display for UintTy {
 }
 
 // Bind a type to an associated type: `A=Foo`.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TypeBinding {
     pub id: NodeId,
     pub ident: Ident,
@@ -1509,7 +1509,7 @@ pub struct TypeBinding {
     pub span: Span,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Ty {
     pub id: NodeId,
     pub node: TyKind,
@@ -1522,7 +1522,7 @@ impl fmt::Debug for Ty {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct BareFnTy {
     pub unsafety: Unsafety,
     pub abi: Abi,
@@ -1531,7 +1531,7 @@ pub struct BareFnTy {
 }
 
 /// The different kinds of types recognized by the compiler
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum TyKind {
     /// A variable-length slice (`[T]`)
     Slice(P<Ty>),
@@ -1577,8 +1577,18 @@ pub enum TyKind {
     Err,
 }
 
+impl TyKind {
+    pub fn is_implicit_self(&self) -> bool {
+        if let TyKind::ImplicitSelf = *self { true } else { false }
+    }
+
+    crate fn is_unit(&self) -> bool {
+        if let TyKind::Tup(ref tys) = *self { tys.is_empty() } else { false }
+    }
+}
+
 /// Syntax used to declare a trait object.
-#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum TraitObjectSyntax {
     Dyn,
     None,
@@ -1587,7 +1597,7 @@ pub enum TraitObjectSyntax {
 /// Inline assembly dialect.
 ///
 /// E.g. `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum AsmDialect {
     Att,
     Intel,
@@ -1596,7 +1606,7 @@ pub enum AsmDialect {
 /// Inline assembly.
 ///
 /// E.g. `"={eax}"(result)` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct InlineAsmOutput {
     pub constraint: Symbol,
     pub expr: P<Expr>,
@@ -1607,7 +1617,7 @@ pub struct InlineAsmOutput {
 /// Inline assembly.
 ///
 /// E.g. `asm!("NOP");`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct InlineAsm {
     pub asm: Symbol,
     pub asm_str_style: StrStyle,
@@ -1623,7 +1633,7 @@ pub struct InlineAsm {
 /// An argument in a function header.
 ///
 /// E.g. `bar: usize` as in `fn foo(bar: usize)`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Arg {
     pub ty: P<Ty>,
     pub pat: P<Pat>,
@@ -1633,7 +1643,7 @@ pub struct Arg {
 /// Alternative representation for `Arg`s describing `self` parameter of methods.
 ///
 /// E.g. `&mut self` as in `fn foo(&mut self)`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum SelfKind {
     /// `self`, `mut self`
     Value(Mutability),
@@ -1651,7 +1661,7 @@ impl Arg {
             if ident.name == keywords::SelfValue.name() {
                 return match self.ty.node {
                     TyKind::ImplicitSelf => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
-                    TyKind::Rptr(lt, MutTy{ref ty, mutbl}) if ty.node == TyKind::ImplicitSelf => {
+                    TyKind::Rptr(lt, MutTy{ref ty, mutbl}) if ty.node.is_implicit_self() => {
                         Some(respan(self.pat.span, SelfKind::Region(lt, mutbl)))
                     }
                     _ => Some(respan(self.pat.span.to(self.ty.span),
@@ -1701,7 +1711,7 @@ impl Arg {
 /// Header (not the body) of a function declaration.
 ///
 /// E.g. `fn foo(bar: baz)`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct FnDecl {
     pub inputs: Vec<Arg>,
     pub output: FunctionRetTy,
@@ -1718,19 +1728,19 @@ impl FnDecl {
 }
 
 /// Is the trait definition an auto trait?
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum IsAuto {
     Yes,
     No
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum Unsafety {
     Unsafe,
     Normal,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum IsAsync {
     Async {
         closure_id: NodeId,
@@ -1756,13 +1766,13 @@ impl IsAsync {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum Constness {
     Const,
     NotConst,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub enum Defaultness {
     Default,
     Final,
@@ -1777,7 +1787,7 @@ impl fmt::Display for Unsafety {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum ImplPolarity {
     /// `impl Trait for Type`
     Positive,
@@ -1795,7 +1805,7 @@ impl fmt::Debug for ImplPolarity {
 }
 
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum FunctionRetTy {
     /// Return type is not specified.
     ///
@@ -1819,7 +1829,7 @@ impl FunctionRetTy {
 /// Module declaration.
 ///
 /// E.g. `mod foo;` or `mod foo { .. }`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Mod {
     /// A span from the first token past `{` to the last token until `}`.
     /// For `mod foo;`, the inner span ranges from the first token
@@ -1831,7 +1841,7 @@ pub struct Mod {
 /// Foreign module declaration.
 ///
 /// E.g. `extern { .. }` or `extern C { .. }`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct ForeignMod {
     pub abi: Abi,
     pub items: Vec<ForeignItem>,
@@ -1840,18 +1850,18 @@ pub struct ForeignMod {
 /// Global inline assembly
 ///
 /// aka module-level assembly or file-scoped assembly
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub struct GlobalAsm {
     pub asm: Symbol,
     pub ctxt: SyntaxContext,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct EnumDef {
     pub variants: Vec<Variant>,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Variant_ {
     pub ident: Ident,
     pub attrs: Vec<Attribute>,
@@ -1863,7 +1873,7 @@ pub struct Variant_ {
 pub type Variant = Spanned<Variant_>;
 
 /// Part of `use` item to the right of its prefix.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum UseTreeKind {
     /// `use prefix` or `use prefix as rename`
     ///
@@ -1878,7 +1888,7 @@ pub enum UseTreeKind {
 
 /// A tree of paths sharing common prefixes.
 /// Used in `use` items both at top-level and inside of braces in import groups.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct UseTree {
     pub prefix: Path,
     pub kind: UseTreeKind,
@@ -1899,7 +1909,7 @@ impl UseTree {
 /// Distinguishes between Attributes that decorate items and Attributes that
 /// are contained as statements within items. These two cases need to be
 /// distinguished for pretty-printing.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum AttrStyle {
     Outer,
     Inner,
@@ -1910,7 +1920,7 @@ pub struct AttrId(pub usize);
 
 /// Meta-data associated with an item
 /// Doc-comments are promoted to attributes that have is_sugared_doc = true
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Attribute {
     pub id: AttrId,
     pub style: AttrStyle,
@@ -1926,13 +1936,13 @@ pub struct Attribute {
 /// that the ref_id is for. The impl_id maps to the "self type" of this impl.
 /// If this impl is an ItemKind::Impl, the impl_id is redundant (it could be the
 /// same as the impl's node id).
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TraitRef {
     pub path: Path,
     pub ref_id: NodeId,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct PolyTraitRef {
     /// The `'a` in `<'a> Foo<&'a T>`
     pub bound_generic_params: Vec<GenericParam>,
@@ -1953,7 +1963,7 @@ impl PolyTraitRef {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum CrateSugar {
     /// Source is `pub(crate)`
     PubCrate,
@@ -1964,7 +1974,7 @@ pub enum CrateSugar {
 
 pub type Visibility = Spanned<VisibilityKind>;
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum VisibilityKind {
     Public,
     Crate(CrateSugar),
@@ -1972,10 +1982,16 @@ pub enum VisibilityKind {
     Inherited,
 }
 
+impl VisibilityKind {
+    pub fn is_pub(&self) -> bool {
+        if let VisibilityKind::Public = *self { true } else { false }
+    }
+}
+
 /// Field of a struct.
 ///
 /// E.g. `bar: usize` as in `struct Foo { bar: usize }`
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct StructField {
     pub span: Span,
     pub ident: Option<Ident>,
@@ -1996,7 +2012,7 @@ pub struct StructField {
 /// used for `Struct`-structs (but still presents). Structures don't have an analogue of "Id of
 /// the variant itself" from enum variants.
 /// Id of the whole struct lives in `Item`.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum VariantData {
     /// Struct variant.
     ///
@@ -2038,7 +2054,7 @@ impl VariantData {
 /// An item
 ///
 /// The name might be a dummy name in case of anonymous items
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Item {
     pub ident: Ident,
     pub attrs: Vec<Attribute>,
@@ -2061,7 +2077,7 @@ pub struct Item {
 ///
 /// All the information between the visibility & the name of the function is
 /// included in this struct (e.g. `async unsafe fn` or `const extern "C" fn`)
-#[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)]
 pub struct FnHeader {
     pub unsafety: Unsafety,
     pub asyncness: IsAsync,
@@ -2080,7 +2096,7 @@ impl Default for FnHeader {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum ItemKind {
     /// An `extern crate` item, with optional *original* crate name if the crate was renamed.
     ///
@@ -2179,7 +2195,7 @@ impl ItemKind {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct ForeignItem {
     pub ident: Ident,
     pub attrs: Vec<Attribute>,
@@ -2190,7 +2206,7 @@ pub struct ForeignItem {
 }
 
 /// An item within an `extern` block
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum ForeignItemKind {
     /// A foreign function
     Fn(P<FnDecl>, Generics),
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index e49a521040f..38ddb501085 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -725,7 +725,7 @@ pub trait Resolver {
     fn check_unused_macros(&self);
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, PartialEq, Debug)]
 pub enum Determinacy {
     Determined,
     Undetermined,
diff --git a/src/libsyntax/ext/tt/quoted.rs b/src/libsyntax/ext/tt/quoted.rs
index 82b0fae3e9c..d21ffabb62e 100644
--- a/src/libsyntax/ext/tt/quoted.rs
+++ b/src/libsyntax/ext/tt/quoted.rs
@@ -22,7 +22,7 @@ use rustc_data_structures::sync::Lrc;
 
 /// Contains the sub-token-trees of a "delimited" token tree, such as the contents of `(`. Note
 /// that the delimiter itself might be `NoDelim`.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub struct Delimited {
     pub delim: token::DelimToken,
     pub tts: Vec<TokenTree>,
@@ -60,7 +60,7 @@ impl Delimited {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub struct SequenceRepetition {
     /// The sequence of token trees
     pub tts: Vec<TokenTree>,
@@ -74,7 +74,7 @@ pub struct SequenceRepetition {
 
 /// A Kleene-style [repetition operator](http://en.wikipedia.org/wiki/Kleene_star)
 /// for token sequences.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum KleeneOp {
     /// Kleene star (`*`) for zero or more repetitions
     ZeroOrMore,
@@ -85,7 +85,7 @@ pub enum KleeneOp {
 
 /// Similar to `tokenstream::TokenTree`, except that `$i`, `$i:ident`, and `$(...)`
 /// are "first-class" token trees. Useful for parsing macros.
-#[derive(Debug, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Debug, Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum TokenTree {
     Token(Span, token::Token),
     Delimited(Span, Lrc<Delimited>),
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 50b2ac3369c..f033c5006c5 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -632,7 +632,7 @@ declare_features! (
 // move that documentation into the relevant place in the other docs, and
 // remove the chapter on the flag.
 
-#[derive(PartialEq, Copy, Clone, Debug)]
+#[derive(Copy, Clone, PartialEq, Debug)]
 pub enum AttributeType {
     /// Normal, builtin attribute that is consumed
     /// by the compiler before the unused_attribute check
@@ -665,7 +665,7 @@ impl AttributeGate {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(Copy, Clone, Debug)]
 pub enum Stability {
     Unstable,
     // Argument is tracking issue link.
@@ -1113,7 +1113,7 @@ const GATED_CFGS: &[(&str, &str, fn(&Features) -> bool)] = &[
     ("target_has_atomic", "cfg_target_has_atomic", cfg_fn!(cfg_target_has_atomic)),
 ];
 
-#[derive(Debug, Eq, PartialEq)]
+#[derive(Debug)]
 pub struct GatedCfg {
     span: Span,
     index: usize,
@@ -1272,7 +1272,7 @@ pub enum GateIssue {
     Library(Option<u32>)
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub enum GateStrength {
     /// A hard error. (Most feature gates should use this.)
     Hard,
@@ -1704,7 +1704,9 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
 
     fn visit_fn_ret_ty(&mut self, ret_ty: &'a ast::FunctionRetTy) {
         if let ast::FunctionRetTy::Ty(ref output_ty) = *ret_ty {
-            if output_ty.node != ast::TyKind::Never {
+            if let ast::TyKind::Never = output_ty.node {
+                // Do nothing
+            } else {
                 self.visit_ty(output_ty)
             }
         }
@@ -2046,7 +2048,7 @@ pub fn check_crate(krate: &ast::Crate,
     visit::walk_crate(visitor, krate);
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Clone, Copy, Hash)]
 pub enum UnstableFeatures {
     /// Hard errors for unstable features are active, as on
     /// beta/stable channels.
diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index 9919d910fbc..4d59f64bb6b 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -16,7 +16,7 @@ use parse::token::{self, Nonterminal};
 use parse::parser::{Parser, TokenType, PathStyle};
 use tokenstream::TokenStream;
 
-#[derive(PartialEq, Eq, Debug)]
+#[derive(Debug)]
 enum InnerAttributeParsePolicy<'a> {
     Permitted,
     NotPermitted { reason: &'a str },
@@ -94,7 +94,7 @@ impl<'a> Parser<'a> {
                 let lo = self.span;
                 self.bump();
 
-                if inner_parse_policy == InnerAttributeParsePolicy::Permitted {
+                if let InnerAttributeParsePolicy::Permitted = inner_parse_policy {
                     self.expected_tokens.push(TokenType::Token(token::Not));
                 }
                 let style = if self.token == token::Not {
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index dcc71e78778..bf790e6143a 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -26,7 +26,7 @@ pub mod comments;
 mod tokentrees;
 mod unicode_chars;
 
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, Debug)]
 pub struct TokenAndSpan {
     pub tok: token::Token,
     pub sp: Span,
@@ -1842,7 +1842,8 @@ mod tests {
                 tok: token::Ident(id, false),
                 sp: Span::new(BytePos(21), BytePos(23), NO_EXPANSION),
             };
-            assert_eq!(tok1, tok2);
+            assert_eq!(tok1.tok, tok2.tok);
+            assert_eq!(tok1.sp, tok2.sp);
             assert_eq!(string_reader.next_token().tok, token::Whitespace);
             // the 'main' id is already read:
             assert_eq!(string_reader.pos.clone(), BytePos(28));
@@ -1852,7 +1853,8 @@ mod tests {
                 tok: mk_ident("main"),
                 sp: Span::new(BytePos(24), BytePos(28), NO_EXPANSION),
             };
-            assert_eq!(tok3, tok4);
+            assert_eq!(tok3.tok, tok4.tok);
+            assert_eq!(tok3.sp, tok4.sp);
             // the lparen is already read:
             assert_eq!(string_reader.pos.clone(), BytePos(29))
         })
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index c443f240780..1754e5f1b9a 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -673,22 +673,40 @@ fn integer_lit(s: &str, suffix: Option<Symbol>, diag: Option<(Span, &Handler)>)
     })
 }
 
+/// `SeqSep` : a sequence separator (token)
+/// and whether a trailing separator is allowed.
+pub struct SeqSep {
+    pub sep: Option<token::Token>,
+    pub trailing_sep_allowed: bool,
+}
+
+impl SeqSep {
+    pub fn trailing_allowed(t: token::Token) -> SeqSep {
+        SeqSep {
+            sep: Some(t),
+            trailing_sep_allowed: true,
+        }
+    }
+
+    pub fn none() -> SeqSep {
+        SeqSep {
+            sep: None,
+            trailing_sep_allowed: false,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
-    use syntax_pos::{self, Span, BytePos, Pos, NO_EXPANSION};
-    use codemap::{respan, Spanned};
+    use syntax_pos::{Span, BytePos, Pos, NO_EXPANSION};
     use ast::{self, Ident, PatKind};
-    use rustc_target::spec::abi::Abi;
     use attr::first_attr_value_str_by_name;
     use parse;
-    use parse::parser::Parser;
     use print::pprust::item_to_string;
-    use ptr::P;
     use tokenstream::{self, TokenTree};
-    use util::parser_testing::{string_to_stream, string_to_parser};
-    use util::parser_testing::{string_to_expr, string_to_item, string_to_stmt};
-    use util::ThinVec;
+    use util::parser_testing::string_to_stream;
+    use util::parser_testing::{string_to_expr, string_to_item};
     use with_globals;
 
     // produce a syntax_pos::span
@@ -696,42 +714,6 @@ mod tests {
         Span::new(BytePos(a), BytePos(b), NO_EXPANSION)
     }
 
-    fn str2seg(s: &str, lo: u32, hi: u32) -> ast::PathSegment {
-        ast::PathSegment::from_ident(Ident::new(Symbol::intern(s), sp(lo, hi)))
-    }
-
-    #[test] fn path_exprs_1() {
-        with_globals(|| {
-            assert!(string_to_expr("a".to_string()) ==
-                    P(ast::Expr{
-                        id: ast::DUMMY_NODE_ID,
-                        node: ast::ExprKind::Path(None, ast::Path {
-                            span: sp(0, 1),
-                            segments: vec![str2seg("a", 0, 1)],
-                        }),
-                        span: sp(0, 1),
-                        attrs: ThinVec::new(),
-                    }))
-        })
-    }
-
-    #[test] fn path_exprs_2 () {
-        with_globals(|| {
-            assert!(string_to_expr("::a::b".to_string()) ==
-                    P(ast::Expr {
-                        id: ast::DUMMY_NODE_ID,
-                        node: ast::ExprKind::Path(None, ast::Path {
-                            span: sp(0, 6),
-                            segments: vec![ast::PathSegment::crate_root(sp(0, 0)),
-                                        str2seg("a", 2, 3),
-                                        str2seg("b", 5, 6)]
-                        }),
-                        span: sp(0, 6),
-                        attrs: ThinVec::new(),
-                    }))
-        })
-    }
-
     #[should_panic]
     #[test] fn bad_path_expr_1() {
         with_globals(|| {
@@ -832,143 +814,6 @@ mod tests {
         })
     }
 
-    #[test] fn ret_expr() {
-        with_globals(|| {
-            assert!(string_to_expr("return d".to_string()) ==
-                    P(ast::Expr{
-                        id: ast::DUMMY_NODE_ID,
-                        node:ast::ExprKind::Ret(Some(P(ast::Expr{
-                            id: ast::DUMMY_NODE_ID,
-                            node:ast::ExprKind::Path(None, ast::Path{
-                                span: sp(7, 8),
-                                segments: vec![str2seg("d", 7, 8)],
-                            }),
-                            span:sp(7,8),
-                            attrs: ThinVec::new(),
-                        }))),
-                        span:sp(0,8),
-                        attrs: ThinVec::new(),
-                    }))
-        })
-    }
-
-    #[test] fn parse_stmt_1 () {
-        with_globals(|| {
-            assert!(string_to_stmt("b;".to_string()) ==
-                    Some(ast::Stmt {
-                        node: ast::StmtKind::Expr(P(ast::Expr {
-                            id: ast::DUMMY_NODE_ID,
-                            node: ast::ExprKind::Path(None, ast::Path {
-                                span:sp(0,1),
-                                segments: vec![str2seg("b", 0, 1)],
-                                }),
-                            span: sp(0,1),
-                            attrs: ThinVec::new()})),
-                        id: ast::DUMMY_NODE_ID,
-                        span: sp(0,1)}))
-        })
-    }
-
-    fn parser_done(p: Parser){
-        assert_eq!(p.token.clone(), token::Eof);
-    }
-
-    #[test] fn parse_ident_pat () {
-        with_globals(|| {
-            let sess = ParseSess::new(FilePathMapping::empty());
-            let mut parser = string_to_parser(&sess, "b".to_string());
-            assert!(panictry!(parser.parse_pat())
-                    == P(ast::Pat{
-                    id: ast::DUMMY_NODE_ID,
-                    node: PatKind::Ident(ast::BindingMode::ByValue(ast::Mutability::Immutable),
-                                         Ident::new(Symbol::intern("b"), sp(0, 1)),
-                                         None),
-                    span: sp(0,1)}));
-            parser_done(parser);
-        })
-    }
-
-    // check the contents of the tt manually:
-    #[test] fn parse_fundecl () {
-        with_globals(|| {
-            // this test depends on the intern order of "fn" and "i32"
-            let item = string_to_item("fn a (b : i32) { b; }".to_string()).map(|m| {
-                m.map(|mut m| {
-                    m.tokens = None;
-                    m
-                })
-            });
-            assert_eq!(item,
-                    Some(
-                        P(ast::Item{ident:Ident::from_str("a"),
-                                attrs:Vec::new(),
-                                id: ast::DUMMY_NODE_ID,
-                                tokens: None,
-                                node: ast::ItemKind::Fn(P(ast::FnDecl {
-                                    inputs: vec![ast::Arg{
-                                        ty: P(ast::Ty{id: ast::DUMMY_NODE_ID,
-                                                    node: ast::TyKind::Path(None, ast::Path{
-                                            span:sp(10,13),
-                                            segments: vec![str2seg("i32", 10, 13)],
-                                            }),
-                                            span:sp(10,13)
-                                        }),
-                                        pat: P(ast::Pat {
-                                            id: ast::DUMMY_NODE_ID,
-                                            node: PatKind::Ident(
-                                                ast::BindingMode::ByValue(
-                                                    ast::Mutability::Immutable),
-                                                Ident::new(Symbol::intern("b"), sp(6, 7)),
-                                                None
-                                            ),
-                                            span: sp(6,7)
-                                        }),
-                                            id: ast::DUMMY_NODE_ID
-                                        }],
-                                    output: ast::FunctionRetTy::Default(sp(15, 15)),
-                                    variadic: false
-                                }),
-                                        ast::FnHeader {
-                                            unsafety: ast::Unsafety::Normal,
-                                            asyncness: ast::IsAsync::NotAsync,
-                                            constness: Spanned {
-                                                span: sp(0,2),
-                                                node: ast::Constness::NotConst,
-                                            },
-                                            abi: Abi::Rust,
-                                        },
-                                        ast::Generics{
-                                            params: Vec::new(),
-                                            where_clause: ast::WhereClause {
-                                                id: ast::DUMMY_NODE_ID,
-                                                predicates: Vec::new(),
-                                                span: syntax_pos::DUMMY_SP,
-                                            },
-                                            span: syntax_pos::DUMMY_SP,
-                                        },
-                                        P(ast::Block {
-                                            stmts: vec![ast::Stmt {
-                                                node: ast::StmtKind::Semi(P(ast::Expr{
-                                                    id: ast::DUMMY_NODE_ID,
-                                                    node: ast::ExprKind::Path(None,
-                                                        ast::Path{
-                                                            span:sp(17,18),
-                                                            segments: vec![str2seg("b", 17, 18)],
-                                                        }),
-                                                    span: sp(17,18),
-                                                    attrs: ThinVec::new()})),
-                                                id: ast::DUMMY_NODE_ID,
-                                                span: sp(17,19)}],
-                                            id: ast::DUMMY_NODE_ID,
-                                            rules: ast::BlockCheckMode::Default, // no idea
-                                            span: sp(15,21),
-                                            recovered: false,
-                                        })),
-                                vis: respan(sp(0, 0), ast::VisibilityKind::Inherited),
-                                span: sp(0,21)})));
-        })
-    }
-
     #[test] fn parse_use() {
         with_globals(|| {
             let use_s = "use foo::bar::baz;";
@@ -1133,26 +978,3 @@ mod tests {
         });
     }
 }
-
-/// `SeqSep` : a sequence separator (token)
-/// and whether a trailing separator is allowed.
-pub struct SeqSep {
-    pub sep: Option<token::Token>,
-    pub trailing_sep_allowed: bool,
-}
-
-impl SeqSep {
-    pub fn trailing_allowed(t: token::Token) -> SeqSep {
-        SeqSep {
-            sep: Some(t),
-            trailing_sep_allowed: true,
-        }
-    }
-
-    pub fn none() -> SeqSep {
-        SeqSep {
-            sep: None,
-            trailing_sep_allowed: false,
-        }
-    }
-}
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index a1b78a23b8f..62bb5fbd04f 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -95,13 +95,13 @@ pub enum PathStyle {
     Mod,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, PartialEq, Debug)]
 enum SemiColonMode {
     Break,
     Ignore,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, PartialEq, Debug)]
 enum BlockMode {
     Break,
     Ignore,
@@ -376,7 +376,7 @@ impl TokenCursor {
     }
 }
 
-#[derive(PartialEq, Eq, Clone)]
+#[derive(Clone, PartialEq)]
 crate enum TokenType {
     Token(token::Token),
     Keyword(keywords::Keyword),
@@ -522,7 +522,7 @@ fn dummy_arg(span: Span) -> Arg {
     Arg { ty: P(ty), pat: pat, id: ast::DUMMY_NODE_ID }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug)]
 enum TokenExpectType {
     Expect,
     NoExpect,
@@ -6999,7 +6999,7 @@ impl<'a> Parser<'a> {
 
         // Verify whether we have encountered a struct or method definition where the user forgot to
         // add the `struct` or `fn` keyword after writing `pub`: `pub S {}`
-        if visibility.node == VisibilityKind::Public &&
+        if visibility.node.is_pub() &&
             self.check_ident() &&
             self.look_ahead(1, |t| *t != token::Not)
         {
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 7ea047d332b..aef3beeccdf 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -30,7 +30,7 @@ use std::{cmp, fmt};
 use std::mem;
 use rustc_data_structures::sync::{Lrc, Lock};
 
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum BinOpToken {
     Plus,
     Minus,
@@ -45,7 +45,7 @@ pub enum BinOpToken {
 }
 
 /// A delimiter token
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum DelimToken {
     /// A round parenthesis: `(` or `)`
     Paren,
@@ -67,7 +67,7 @@ impl DelimToken {
     }
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum Lit {
     Byte(ast::Name),
     Char(ast::Name),
@@ -139,7 +139,7 @@ fn ident_can_begin_type(ident: ast::Ident, is_raw: bool) -> bool {
     ].contains(&ident.name)
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Debug)]
 pub enum Token {
     /* Expression-operator symbols. */
     Eq,
@@ -638,7 +638,7 @@ impl Token {
     }
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Eq, Hash)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 /// For interpolation during macro expansion.
 pub enum Nonterminal {
     NtItem(P<ast::Item>),
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index c5ba7daaeb8..b0a9003a456 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -2641,7 +2641,9 @@ impl<'a> State<'a> {
                                    |s, p| s.print_pat(p))?;
                 if let Some(ref p) = *slice {
                     if !before.is_empty() { self.word_space(",")?; }
-                    if p.node != PatKind::Wild {
+                    if let PatKind::Wild = p.node {
+                        // Print nothing
+                    } else {
                         self.print_pat(p)?;
                     }
                     self.s.word("..")?;
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index 25d916af77d..b86d19ba3ce 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -46,7 +46,7 @@ use serialize::{Encodable, Decodable, Encoder, Decoder};
 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
                                            HashStable};
 /// An owned smart pointer.
-#[derive(Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Hash, PartialEq, Eq)]
 pub struct P<T: ?Sized> {
     ptr: Box<T>
 }
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 4d5b0b327dd..d8b8d13a38c 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -329,7 +329,6 @@ fn ignored_span(cx: &TestCtxt, sp: Span) -> Span {
     sp.with_ctxt(cx.ctxt)
 }
 
-#[derive(PartialEq)]
 enum HasTestSignature {
     Yes,
     No(BadTestSignature),
@@ -354,7 +353,7 @@ fn is_test_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
                 // type implements the `Termination` trait as `libtest` enforces that.
                 let has_output = match decl.output {
                     ast::FunctionRetTy::Default(..) => false,
-                    ast::FunctionRetTy::Ty(ref t) if t.node == ast::TyKind::Tup(vec![]) => false,
+                    ast::FunctionRetTy::Ty(ref t) if t.node.is_unit() => false,
                     _ => true
                 };
 
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index 8736fcf9729..048a041f698 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -33,10 +33,9 @@ use util::RcSlice;
 
 use std::borrow::Cow;
 use std::{fmt, iter, mem};
-use std::hash::{self, Hash};
 
 /// A delimited sequence of token trees
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
 pub struct Delimited {
     /// The type of delimiter
     pub delim: token::DelimToken,
@@ -93,7 +92,7 @@ impl Delimited {
 ///
 /// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
 /// Nothing special happens to misnamed or misplaced `SubstNt`s.
-#[derive(Debug, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
+#[derive(Debug, Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum TokenTree {
     /// A single token
     Token(Span, token::Token),
@@ -605,14 +604,6 @@ impl Decodable for TokenStream {
     }
 }
 
-impl Hash for TokenStream {
-    fn hash<H: hash::Hasher>(&self, state: &mut H) {
-        for tree in self.trees() {
-            tree.hash(state);
-        }
-    }
-}
-
 impl Encodable for ThinTokenStream {
     fn encode<E: Encoder>(&self, encoder: &mut E) -> Result<(), E::Error> {
         TokenStream::from(self.clone()).encode(encoder)
@@ -625,13 +616,6 @@ impl Decodable for ThinTokenStream {
     }
 }
 
-impl Hash for ThinTokenStream {
-    fn hash<H: hash::Hasher>(&self, state: &mut H) {
-        TokenStream::from(self.clone()).hash(state);
-    }
-}
-
-
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/src/libsyntax/util/parser.rs b/src/libsyntax/util/parser.rs
index 15d910b33b0..67bc6f947b5 100644
--- a/src/libsyntax/util/parser.rs
+++ b/src/libsyntax/util/parser.rs
@@ -11,12 +11,10 @@ use parse::token::{Token, BinOpToken};
 use symbol::keywords;
 use ast::{self, BinOpKind};
 
-use std::cmp::Ordering;
-
 /// Associative operator with precedence.
 ///
 /// This is the enum which specifies operator precedence and fixity to the parser.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(PartialEq, Debug)]
 pub enum AssocOp {
     /// `+`
     Add,
@@ -70,7 +68,7 @@ pub enum AssocOp {
     Colon,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(PartialEq, Debug)]
 pub enum Fixity {
     /// The operator is left-associative
     Left,
@@ -230,7 +228,7 @@ pub const PREC_POSTFIX: i8 = 60;
 pub const PREC_PAREN: i8 = 99;
 pub const PREC_FORCE_PAREN: i8 = 100;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy)]
 pub enum ExprPrecedence {
     Closure,
     Break,
@@ -280,18 +278,6 @@ pub enum ExprPrecedence {
     Async,
 }
 
-impl PartialOrd for ExprPrecedence {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.order().cmp(&other.order()))
-    }
-}
-
-impl Ord for ExprPrecedence {
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.order().cmp(&other.order())
-    }
-}
-
 impl ExprPrecedence {
     pub fn order(self) -> i8 {
         match self {
diff --git a/src/libsyntax/util/parser_testing.rs b/src/libsyntax/util/parser_testing.rs
index 42cd7c8faa5..46b7f2d7bda 100644
--- a/src/libsyntax/util/parser_testing.rs
+++ b/src/libsyntax/util/parser_testing.rs
@@ -63,14 +63,6 @@ pub fn string_to_item (source_str : String) -> Option<P<ast::Item>> {
     })
 }
 
-/// Parse a string, return a stmt
-pub fn string_to_stmt(source_str : String) -> Option<ast::Stmt> {
-    let ps = ParseSess::new(FilePathMapping::empty());
-    with_error_checking_parse(source_str, &ps, |p| {
-        p.parse_stmt()
-    })
-}
-
 /// Parse a string, return a pat. Uses "irrefutable"... which doesn't
 /// (currently) affect parsing.
 pub fn string_to_pat(source_str: String) -> P<ast::Pat> {
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index bb35bcee438..9211a2383b6 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -28,7 +28,7 @@ use syntax_pos::Span;
 use parse::token::Token;
 use tokenstream::{TokenTree, TokenStream};
 
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone)]
 pub enum FnKind<'a> {
     /// fn foo() or extern "Abi" fn foo()
     ItemFn(Ident, FnHeader, &'a Visibility, &'a Block),