Remove TraitDef::generics.

Because it's always empty.

compiler/rustc_ast/src/ast.rs

@@ -392,15 +392,7 @@ pub struct Generics {
 impl Default for Generics {
     /// Creates an instance of `Generics`.
     fn default() -> Generics {
-        Generics {
-            params: Vec::new(),
-            where_clause: WhereClause {
-                has_where_token: false,
-                predicates: Vec::new(),
-                span: DUMMY_SP,
-            },
-            span: DUMMY_SP,
-        }
+        Generics { params: Vec::new(), where_clause: Default::default(), span: DUMMY_SP }
     }
 }
 
@@ -415,6 +407,12 @@ pub struct WhereClause {
     pub span: Span,
 }
 
+impl Default for WhereClause {
+    fn default() -> WhereClause {
+        WhereClause { has_where_token: false, predicates: Vec::new(), span: DUMMY_SP }
+    }
+}
+
 /// A single predicate in a where-clause.
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum WherePredicate {

compiler/rustc_builtin_macros/src/deriving/bounds.rs

@@ -1,4 +1,3 @@
-use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
 
@@ -18,7 +17,6 @@ pub fn expand_deriving_copy(
         path: path_std!(marker::Copy),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: true,
         methods: Vec::new(),
         associated_types: Vec::new(),

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -74,7 +74,6 @@ pub fn expand_deriving_clone(
         path: path_std!(clone::Clone),
         skip_path_as_bound: false,
         additional_bounds: bounds,
-        generics: Bounds::empty(),
         supports_unions: true,
         methods: vec![MethodDef {
             name: sym::clone,

compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs

@@ -27,7 +27,6 @@ pub fn expand_deriving_eq(
         path: path_std!(cmp::Eq),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: true,
         methods: vec![MethodDef {
             name: sym::assert_receiver_is_total_eq,

compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs

@@ -21,7 +21,6 @@ pub fn expand_deriving_ord(
         path: path_std!(cmp::Ord),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::cmp,

compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs

@@ -85,7 +85,6 @@ pub fn expand_deriving_partial_eq(
         path: path_std!(cmp::PartialEq),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods,
         associated_types: Vec::new(),

compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs

@@ -39,7 +39,6 @@ pub fn expand_deriving_partial_ord(
         path: path_std!(cmp::PartialOrd),
         skip_path_as_bound: false,
         additional_bounds: vec![],
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![partial_cmp_def],
         associated_types: Vec::new(),

compiler/rustc_builtin_macros/src/deriving/debug.rs

@@ -22,7 +22,6 @@ pub fn expand_deriving_debug(
         path: path_std!(fmt::Debug),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::fmt,

compiler/rustc_builtin_macros/src/deriving/decodable.rs

@@ -25,7 +25,6 @@ pub fn expand_deriving_rustc_decodable(
         path: Path::new_(vec![krate, sym::Decodable], vec![], PathKind::Global),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::decode,

compiler/rustc_builtin_macros/src/deriving/default.rs

@@ -26,7 +26,6 @@ pub fn expand_deriving_default(
         path: Path::new(vec![kw::Default, sym::Default]),
         skip_path_as_bound: has_a_default_variant(item),
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: kw::Default,

compiler/rustc_builtin_macros/src/deriving/encodable.rs

@@ -109,7 +109,6 @@ pub fn expand_deriving_rustc_encodable(
         path: Path::new_(vec![krate, sym::Encodable], vec![], PathKind::Global),
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::encode,

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -195,9 +195,6 @@ pub struct TraitDef<'a> {
     /// other than the current trait
     pub additional_bounds: Vec<Ty>,
 
-    /// Any extra lifetimes and/or bounds, e.g., `D: serialize::Decoder`
-    pub generics: Bounds,
-
     /// Can this trait be derived for unions?
     pub supports_unions: bool,
 
@@ -581,19 +578,21 @@ impl<'a> TraitDef<'a> {
             })
         });
 
-        let Generics { mut params, mut where_clause, .. } =
-            self.generics.to_generics(cx, self.span, type_ident, generics);
+        let mut where_clause = ast::WhereClause::default();
         where_clause.span = generics.where_clause.span;
         let ctxt = self.span.ctxt();
         let span = generics.span.with_ctxt(ctxt);
 
         // Create the generic parameters
-        params.extend(generics.params.iter().map(|param| match &param.kind {
-            GenericParamKind::Lifetime { .. } => param.clone(),
-            GenericParamKind::Type { .. } => {
-                // I don't think this can be moved out of the loop, since
-                // a GenericBound requires an ast id
-                let bounds: Vec<_> =
+        let params: Vec<_> = generics
+            .params
+            .iter()
+            .map(|param| match &param.kind {
+                GenericParamKind::Lifetime { .. } => param.clone(),
+                GenericParamKind::Type { .. } => {
+                    // I don't think this can be moved out of the loop, since
+                    // a GenericBound requires an ast id
+                    let bounds: Vec<_> =
                     // extra restrictions on the generics parameters to the
                     // type being derived upon
                     self.additional_bounds.iter().map(|p| {
@@ -606,21 +605,22 @@ impl<'a> TraitDef<'a> {
                         param.bounds.iter().cloned()
                     ).collect();
 
-                cx.typaram(param.ident.span.with_ctxt(ctxt), param.ident, bounds, None)
-            }
-            GenericParamKind::Const { ty, kw_span, .. } => {
-                let const_nodefault_kind = GenericParamKind::Const {
-                    ty: ty.clone(),
-                    kw_span: kw_span.with_ctxt(ctxt),
-
-                    // We can't have default values inside impl block
-                    default: None,
-                };
-                let mut param_clone = param.clone();
-                param_clone.kind = const_nodefault_kind;
-                param_clone
-            }
-        }));
+                    cx.typaram(param.ident.span.with_ctxt(ctxt), param.ident, bounds, None)
+                }
+                GenericParamKind::Const { ty, kw_span, .. } => {
+                    let const_nodefault_kind = GenericParamKind::Const {
+                        ty: ty.clone(),
+                        kw_span: kw_span.with_ctxt(ctxt),
+
+                        // We can't have default values inside impl block
+                        default: None,
+                    };
+                    let mut param_clone = param.clone();
+                    param_clone.kind = const_nodefault_kind;
+                    param_clone
+                }
+            })
+            .collect();
 
         // and similarly for where clauses
         where_clause.predicates.extend(generics.where_clause.predicates.iter().map(|clause| {

compiler/rustc_builtin_macros/src/deriving/hash.rs

@@ -24,7 +24,6 @@ pub fn expand_deriving_hash(
         path,
         skip_path_as_bound: false,
         additional_bounds: Vec::new(),
-        generics: Bounds::empty(),
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::hash,