libsyntax: extend generic deriving code to handle almost all possible traits.

This adds support for static methods, and arguments of most types, traits with
type parameters, methods with type parameters (and lifetimes for both), as well
as making the code more robust to support deriving on types with lifetimes (i.e.
'self).

src/libsyntax/ext/build.rs

@@ -54,43 +54,52 @@ pub fn mk_binary(cx: @ext_ctxt, sp: span, op: ast::binop,
     cx.next_id(); // see ast_util::op_expr_callee_id
     mk_expr(cx, sp, ast::expr_binary(op, lhs, rhs))
 }
+
+pub fn mk_deref(cx: @ext_ctxt, sp: span, e: @ast::expr) -> @ast::expr {
+    mk_unary(cx, sp, ast::deref, e)
+}
 pub fn mk_unary(cx: @ext_ctxt, sp: span, op: ast::unop, e: @ast::expr)
              -> @ast::expr {
     cx.next_id(); // see ast_util::op_expr_callee_id
     mk_expr(cx, sp, ast::expr_unary(op, e))
 }
 pub fn mk_raw_path(sp: span, idents: ~[ast::ident]) -> @ast::Path {
-    mk_raw_path_(sp, idents, ~[])
+    mk_raw_path_(sp, idents, None, ~[])
 }
 pub fn mk_raw_path_(sp: span,
                     idents: ~[ast::ident],
+                    rp: Option<@ast::Lifetime>,
                     types: ~[@ast::Ty])
                  -> @ast::Path {
     @ast::Path { span: sp,
                  global: false,
                  idents: idents,
-                 rp: None,
+                 rp: rp,
                  types: types }
 }
 pub fn mk_raw_path_global(sp: span, idents: ~[ast::ident]) -> @ast::Path {
-    mk_raw_path_global_(sp, idents, ~[])
+    mk_raw_path_global_(sp, idents, None, ~[])
 }
 pub fn mk_raw_path_global_(sp: span,
                            idents: ~[ast::ident],
+                           rp: Option<@ast::Lifetime>,
                            types: ~[@ast::Ty]) -> @ast::Path {
     @ast::Path { span: sp,
                  global: true,
                  idents: idents,
-                 rp: None,
+                 rp: rp,
                  types: types }
 }
+pub fn mk_path_raw(cx: @ext_ctxt, sp: span, path: @ast::Path)-> @ast::expr {
+    mk_expr(cx, sp, ast::expr_path(path))
+}
 pub fn mk_path(cx: @ext_ctxt, sp: span, idents: ~[ast::ident])
             -> @ast::expr {
-    mk_expr(cx, sp, ast::expr_path(mk_raw_path(sp, idents)))
+    mk_path_raw(cx, sp, mk_raw_path(sp, idents))
 }
 pub fn mk_path_global(cx: @ext_ctxt, sp: span, idents: ~[ast::ident])
                    -> @ast::expr {
-    mk_expr(cx, sp, ast::expr_path(mk_raw_path_global(sp, idents)))
+    mk_path_raw(cx, sp, mk_raw_path_global(sp, idents))
 }
 pub fn mk_access_(cx: @ext_ctxt, sp: span, p: @ast::expr, m: ast::ident)
                -> @ast::expr {
@@ -354,44 +363,69 @@ pub fn mk_stmt(cx: @ext_ctxt, span: span, expr: @ast::expr) -> @ast::stmt {
     let stmt_ = ast::stmt_semi(expr, cx.next_id());
     @codemap::spanned { node: stmt_, span: span }
 }
+
+pub fn mk_ty_mt(ty: @ast::Ty, mutbl: ast::mutability) -> ast::mt {
+    ast::mt {
+        ty: ty,
+        mutbl: mutbl
+    }
+}
+
+pub fn mk_ty(cx: @ext_ctxt,
+             span: span,
+             ty: ast::ty_) -> @ast::Ty {
+    @ast::Ty {
+        id: cx.next_id(),
+        span: span,
+        node: ty
+    }
+}
+
 pub fn mk_ty_path(cx: @ext_ctxt,
                   span: span,
                   idents: ~[ ast::ident ])
                -> @ast::Ty {
     let ty = build::mk_raw_path(span, idents);
-    let ty = ast::ty_path(ty, cx.next_id());
-    let ty = @ast::Ty { id: cx.next_id(), node: ty, span: span };
-    ty
+    mk_ty_path_path(cx, span, ty)
 }
+
 pub fn mk_ty_path_global(cx: @ext_ctxt,
                          span: span,
                          idents: ~[ ast::ident ])
                       -> @ast::Ty {
     let ty = build::mk_raw_path_global(span, idents);
-    let ty = ast::ty_path(ty, cx.next_id());
-    let ty = @ast::Ty { id: cx.next_id(), node: ty, span: span };
-    ty
+    mk_ty_path_path(cx, span, ty)
 }
+
+pub fn mk_ty_path_path(cx: @ext_ctxt,
+                       span: span,
+                       path: @ast::Path)
+                      -> @ast::Ty {
+    let ty = ast::ty_path(path, cx.next_id());
+    mk_ty(cx, span, ty)
+}
+
 pub fn mk_ty_rptr(cx: @ext_ctxt,
                   span: span,
                   ty: @ast::Ty,
+                  lifetime: Option<@ast::Lifetime>,
                   mutbl: ast::mutability)
                -> @ast::Ty {
-    @ast::Ty {
-        id: cx.next_id(),
-        span: span,
-        node: ast::ty_rptr(
-            None,
-            ast::mt { ty: ty, mutbl: mutbl }
-        ),
-    }
+    mk_ty(cx, span,
+          ast::ty_rptr(lifetime, mk_ty_mt(ty, mutbl)))
 }
+pub fn mk_ty_uniq(cx: @ext_ctxt, span: span, ty: @ast::Ty) -> @ast::Ty {
+    mk_ty(cx, span, ast::ty_uniq(mk_ty_mt(ty, ast::m_imm)))
+}
+pub fn mk_ty_box(cx: @ext_ctxt, span: span,
+                 ty: @ast::Ty, mutbl: ast::mutability) -> @ast::Ty {
+    mk_ty(cx, span, ast::ty_box(mk_ty_mt(ty, mutbl)))
+}
+
+
+
 pub fn mk_ty_infer(cx: @ext_ctxt, span: span) -> @ast::Ty {
-    @ast::Ty {
-        id: cx.next_id(),
-        node: ast::ty_infer,
-        span: span,
-    }
+    mk_ty(cx, span, ast::ty_infer)
 }
 pub fn mk_trait_ref_global(cx: @ext_ctxt,
                            span: span,

src/libsyntax/ext/deriving/clone.rs

@@ -13,7 +13,6 @@ use codemap::span;
 use ext::base::ext_ctxt;
 use ext::build;
 use ext::deriving::generic::*;
-use core::option::{None,Some};
 
 
 pub fn expand_deriving_clone(cx: @ext_ctxt,
@@ -22,13 +21,16 @@ pub fn expand_deriving_clone(cx: @ext_ctxt,
                              in_items: ~[@item])
                           -> ~[@item] {
     let trait_def = TraitDef {
-        path: ~[~"core", ~"clone", ~"Clone"],
+        path: Path::new(~[~"core", ~"clone", ~"Clone"]),
         additional_bounds: ~[],
+        generics: LifetimeBounds::empty(),
         methods: ~[
             MethodDef {
                 name: ~"clone",
-                nargs: 0,
-                output_type: None, // return Self
+                generics: LifetimeBounds::empty(),
+                self_ty: borrowed_explicit_self(),
+                args: ~[],
+                ret_ty: Self,
                 const_nonmatching: false,
                 combine_substructure: cs_clone
             }
@@ -66,7 +68,8 @@ fn cs_clone(cx: @ext_ctxt, span: span,
             ctor_ident = ~[ variant.node.name ];
             all_fields = af;
         },
-        EnumNonMatching(*) => cx.bug("Non-matching enum variants in `deriving(Clone)`")
+        EnumNonMatching(*) => cx.span_bug(span, "Non-matching enum variants in `deriving(Clone)`"),
+        StaticEnum(*) | StaticStruct(*) => cx.span_bug(span, "Static method in `deriving(Clone)`")
     }
 
     match all_fields {

src/libsyntax/ext/deriving/cmp/eq.rs

@@ -8,15 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 use ast::{meta_item, item, expr};
 use codemap::span;
 use ext::base::ext_ctxt;
 use ext::build;
 use ext::deriving::generic::*;
 
-use core::option::Some;
-
 pub fn expand_deriving_eq(cx: @ext_ctxt,
                           span: span,
                           mitem: @meta_item,
@@ -24,28 +21,32 @@ pub fn expand_deriving_eq(cx: @ext_ctxt,
     // structures are equal if all fields are equal, and non equal, if
     // any fields are not equal or if the enum variants are different
     fn cs_eq(cx: @ext_ctxt, span: span, substr: &Substructure) -> @expr {
-        cs_and(|cx, span, _| build::mk_bool(cx, span, false),
+        cs_and(|cx, span, _, _| build::mk_bool(cx, span, false),
                                  cx, span, substr)
     }
     fn cs_ne(cx: @ext_ctxt, span: span, substr: &Substructure) -> @expr {
-        cs_or(|cx, span, _| build::mk_bool(cx, span, true),
+        cs_or(|cx, span, _, _| build::mk_bool(cx, span, true),
               cx, span, substr)
     }
+
     macro_rules! md (
         ($name:expr, $f:ident) => {
             MethodDef {
                 name: $name,
-                output_type: Some(~[~"bool"]),
-                nargs: 1,
+                generics: LifetimeBounds::empty(),
+                self_ty: borrowed_explicit_self(),
+                args: ~[borrowed_self()],
+                ret_ty: Literal(Path::new(~[~"bool"])),
                 const_nonmatching: true,
                 combine_substructure: $f
             },
         }
-    )
+    );
 
     let trait_def = TraitDef {
-        path: ~[~"core", ~"cmp", ~"Eq"],
+        path: Path::new(~[~"core", ~"cmp", ~"Eq"]),
         additional_bounds: ~[],
+        generics: LifetimeBounds::empty(),
         methods: ~[
             md!(~"eq", cs_eq),
             md!(~"ne", cs_ne)

src/libsyntax/ext/deriving/cmp/ord.rs

@@ -14,29 +14,33 @@ use codemap::span;
 use ext::base::ext_ctxt;
 use ext::build;
 use ext::deriving::generic::*;
-use core::option::Some;
-
-macro_rules! md {
-    ($name:expr, $less:expr, $equal:expr) => {
-        MethodDef {
-            name: $name,
-            output_type: Some(~[~"bool"]),
-            nargs: 1,
-            const_nonmatching: false,
-            combine_substructure: |cx, span, substr|
-                    cs_ord($less, $equal, cx, span, substr)
-        }
-    }
-}
 
 pub fn expand_deriving_ord(cx: @ext_ctxt,
                            span: span,
                            mitem: @meta_item,
                            in_items: ~[@item]) -> ~[@item] {
+    macro_rules! md (
+        ($name:expr, $less:expr, $equal:expr) => {
+            MethodDef {
+                name: $name,
+                generics: LifetimeBounds::empty(),
+                self_ty: borrowed_explicit_self(),
+                args: ~[borrowed_self()],
+                ret_ty: Literal(Path::new(~[~"bool"])),
+                const_nonmatching: false,
+                combine_substructure: |cx, span, substr|
+                    cs_ord($less, $equal, cx, span, substr)
+            }
+        }
+    );
+
+
+
     let trait_def = TraitDef {
-        path: ~[~"core", ~"cmp", ~"Ord"],
+        path: Path::new(~[~"core", ~"cmp", ~"Ord"]),
         // XXX: Ord doesn't imply Eq yet
-        additional_bounds: ~[~[~"core", ~"cmp", ~"Eq"]],
+        additional_bounds: ~[Literal(Path::new(~[~"core", ~"cmp", ~"Eq"]))],
+        generics: LifetimeBounds::empty(),
         methods: ~[
             md!(~"lt", true,  false),
             md!(~"le", true,  true),
@@ -97,19 +101,19 @@ fn cs_ord(less: bool, equal: bool,
             }
 
             let cmp = build::mk_method_call(cx, span,
-                                            self_f, cx.ident_of(~"eq"), other_fs);
+                                            self_f, cx.ident_of(~"eq"), other_fs.to_owned());
             let subexpr = build::mk_simple_block(cx, span, subexpr);
             let elseif = expr_if(cmp, subexpr, Some(false_blk_expr));
             let elseif = build::mk_expr(cx, span, elseif);
 
             let cmp = build::mk_method_call(cx, span,
-                                            self_f, binop, other_fs);
+                                            self_f, binop, other_fs.to_owned());
             let if_ = expr_if(cmp, true_blk, Some(elseif));
 
             build::mk_expr(cx, span, if_)
         },
         base,
-        |cx, span, args| {
+        |cx, span, args, _| {
             // nonmatching enums, order by the order the variants are
             // written
             match args {

src/libsyntax/ext/deriving/cmp/totaleq.rs

@@ -15,26 +15,27 @@ use ext::base::ext_ctxt;
 use ext::build;
 use ext::deriving::generic::*;
 
-use core::option::Some;
-
 pub fn expand_deriving_totaleq(cx: @ext_ctxt,
                           span: span,
                           mitem: @meta_item,
                           in_items: ~[@item]) -> ~[@item] {
 
     fn cs_equals(cx: @ext_ctxt, span: span, substr: &Substructure) -> @expr {
-        cs_and(|cx, span, _| build::mk_bool(cx, span, false),
+        cs_and(|cx, span, _, _| build::mk_bool(cx, span, false),
                cx, span, substr)
     }
 
     let trait_def = TraitDef {
-        path: ~[~"core", ~"cmp", ~"TotalEq"],
+        path: Path::new(~[~"core", ~"cmp", ~"TotalEq"]),
         additional_bounds: ~[],
+        generics: LifetimeBounds::empty(),
         methods: ~[
             MethodDef {
                 name: ~"equals",
-                output_type: Some(~[~"bool"]),
-                nargs: 1,
+                generics: LifetimeBounds::empty(),
+                self_ty: borrowed_explicit_self(),
+                args: ~[borrowed_self()],
+                ret_ty: Literal(Path::new(~[~"bool"])),
                 const_nonmatching: true,
                 combine_substructure: cs_equals
             }

src/libsyntax/ext/deriving/cmp/totalord.rs

@@ -14,20 +14,22 @@ use ext::base::ext_ctxt;
 use ext::build;
 use ext::deriving::generic::*;
 use core::cmp::{Ordering, Equal, Less, Greater};
-use core::option::Some;
 
 pub fn expand_deriving_totalord(cx: @ext_ctxt,
                                 span: span,
                                 mitem: @meta_item,
                                 in_items: ~[@item]) -> ~[@item] {
     let trait_def = TraitDef {
-        path: ~[~"core", ~"cmp", ~"TotalOrd"],
+        path: Path::new(~[~"core", ~"cmp", ~"TotalOrd"]),
         additional_bounds: ~[],
+        generics: LifetimeBounds::empty(),
         methods: ~[
             MethodDef {
                 name: ~"cmp",
-                output_type: Some(~[~"core", ~"cmp", ~"Ordering"]),
-                nargs: 1,
+                generics: LifetimeBounds::empty(),
+                self_ty: borrowed_explicit_self(),
+                args: ~[borrowed_self()],
+                ret_ty: Literal(Path::new(~[~"core", ~"cmp", ~"Ordering"])),
                 const_nonmatching: false,
                 combine_substructure: cs_cmp
             }
@@ -64,7 +66,7 @@ pub fn cs_cmp(cx: @ext_ctxt, span: span,
             build::mk_call_global(cx, span, lexical_ord, ~[old, new])
         },
         ordering_const(cx, span, Equal),
-        |cx, span, list| {
+        |cx, span, list, _| {
             match list {
                 // an earlier nonmatching variant is Less than a
                 // later one

src/libsyntax/ext/deriving/decodable.rs

@@ -66,6 +66,7 @@ fn create_derived_decodable_impl(
             cx.ident_of(~"serialize"),
             cx.ident_of(~"Decodable")
         ],
+        None,
         ~[
             build::mk_simple_ty_path(cx, span, cx.ident_of(~"__D"))
         ]
@@ -77,7 +78,7 @@ fn create_derived_decodable_impl(
         generics,
         methods,
         trait_path,
-        generic_ty_params,
+        Generics { ty_params: generic_ty_params, lifetimes: opt_vec::Empty },
         opt_vec::Empty
     )
 }
@@ -96,6 +97,7 @@ fn create_decode_method(
         cx,
         span,
         build::mk_simple_ty_path(cx, span, cx.ident_of(~"__D")),
+        None,
         ast::m_mutbl
     );
     let d_ident = cx.ident_of(~"__d");

src/libsyntax/ext/deriving/encodable.rs

@@ -66,6 +66,7 @@ fn create_derived_encodable_impl(
             cx.ident_of(~"serialize"),
             cx.ident_of(~"Encodable")
         ],
+        None,
         ~[
             build::mk_simple_ty_path(cx, span, cx.ident_of(~"__E"))
         ]
@@ -77,7 +78,7 @@ fn create_derived_encodable_impl(
         generics,
         methods,
         trait_path,
-        generic_ty_params,
+        Generics { ty_params: generic_ty_params, lifetimes: opt_vec::Empty },
         opt_vec::Empty
     )
 }
@@ -94,6 +95,7 @@ fn create_encode_method(
         cx,
         span,
         build::mk_simple_ty_path(cx, span, cx.ident_of(~"__E")),
+        None,
         ast::m_mutbl
     );
     let e_arg = build::mk_arg(cx, span, cx.ident_of(~"__e"), e_arg_type);
@@ -303,7 +305,7 @@ fn expand_deriving_encodable_enum_method(
     // Create the arms of the match in the method body.
     let arms = do enum_definition.variants.mapi |i, variant| {
         // Create the matching pattern.
-        let pat = create_enum_variant_pattern(cx, span, variant, ~"__self");
+        let (pat, fields) = create_enum_variant_pattern(cx, span, variant, ~"__self", ast::m_imm);
 
         // Feed the discriminant to the encode function.
         let mut stmts = ~[];
@@ -311,11 +313,7 @@ fn expand_deriving_encodable_enum_method(
         // Feed each argument in this variant to the encode function
         // as well.
         let variant_arg_len = variant_arg_count(cx, span, variant);
-        for uint::range(0, variant_arg_len) |j| {
-            // Create the expression for this field.
-            let field_ident = cx.ident_of(~"__self_" + j.to_str());
-            let field = build::mk_path(cx, span, ~[ field_ident ]);
-
+        for fields.eachi |j, &(_, field)| {
             // Call the substructure method.
             let expr = call_substructure_encode_method(cx, span, field);
 

src/libsyntax/ext/deriving/mod.rs

@@ -12,14 +12,7 @@
 /// #[deriving(IterBytes)] extensions.
 
 use ast;
-use ast::{Ty, bind_by_ref, deref, enum_def};
-use ast::{expr, expr_match, ident, item, item_};
-use ast::{item_enum, item_impl, item_struct, Generics};
-use ast::{m_imm, meta_item, method};
-use ast::{named_field, pat, pat_ident, public};
-use ast::{struct_def, struct_variant_kind};
-use ast::{tuple_variant_kind};
-use ast::{ty_path, unnamed_field, variant};
+use ast::{Ty, enum_def, expr, ident, item, Generics, meta_item, struct_def};
 use ext::base::ext_ctxt;
 use ext::build;
 use codemap::{span, respan};
@@ -78,23 +71,21 @@ pub fn expand_meta_deriving(cx: @ext_ctxt,
                     meta_name_value(tname, _) |
                     meta_list(tname, _) |
                     meta_word(tname) => {
+                        macro_rules! expand(($func:path) => ($func(cx, titem.span,
+                                                                   titem, in_items)));
                         match *tname {
-                            ~"Clone" => clone::expand_deriving_clone(cx,
-                                titem.span, titem, in_items),
-                            ~"IterBytes" => iter_bytes::expand_deriving_iter_bytes(cx,
-                                titem.span, titem, in_items),
-                            ~"Encodable" => encodable::expand_deriving_encodable(cx,
-                                titem.span, titem, in_items),
-                            ~"Decodable" => decodable::expand_deriving_decodable(cx,
-                                titem.span, titem, in_items),
-                            ~"Eq" => eq::expand_deriving_eq(cx, titem.span,
-                                                             titem, in_items),
-                            ~"TotalEq" => totaleq::expand_deriving_totaleq(cx, titem.span,
-                                                                           titem, in_items),
-                            ~"Ord" => ord::expand_deriving_ord(cx, titem.span,
-                                                               titem, in_items),
-                            ~"TotalOrd" => totalord::expand_deriving_totalord(cx, titem.span,
-                                                                              titem, in_items),
+                            ~"Clone" => expand!(clone::expand_deriving_clone),
+
+                            ~"IterBytes" => expand!(iter_bytes::expand_deriving_iter_bytes),
+
+                            ~"Encodable" => expand!(encodable::expand_deriving_encodable),
+                            ~"Decodable" => expand!(decodable::expand_deriving_decodable),
+
+                            ~"Eq" => expand!(eq::expand_deriving_eq),
+                            ~"TotalEq" => expand!(totaleq::expand_deriving_totaleq),
+                            ~"Ord" => expand!(ord::expand_deriving_ord),
+                            ~"TotalOrd" => expand!(totalord::expand_deriving_totalord),
+
                             tname => {
                                 cx.span_err(titem.span, fmt!("unknown \
                                     `deriving` trait: `%s`", tname));
@@ -118,14 +109,14 @@ pub fn expand_deriving(cx: @ext_ctxt,
     for in_items.each |item| {
         result.push(copy *item);
         match item.node {
-            item_struct(struct_def, ref generics) => {
+            ast::item_struct(struct_def, ref generics) => {
                 result.push(expand_deriving_struct_def(cx,
                                                        span,
                                                        struct_def,
                                                        item.ident,
                                                        generics));
             }
-            item_enum(ref enum_definition, ref generics) => {
+            ast::item_enum(ref enum_definition, ref generics) => {
                 result.push(expand_deriving_enum_def(cx,
                                                      span,
                                                      enum_definition,
@@ -138,7 +129,7 @@ pub fn expand_deriving(cx: @ext_ctxt,
     result
 }
 
-fn create_impl_item(cx: @ext_ctxt, span: span, item: item_) -> @item {
+fn create_impl_item(cx: @ext_ctxt, span: span, item: ast::item_) -> @item {
     let doc_attr = respan(span,
                           ast::lit_str(@~"Automatically derived."));
     let doc_attr = respan(span, ast::meta_name_value(@~"doc", doc_attr));
@@ -154,7 +145,7 @@ fn create_impl_item(cx: @ext_ctxt, span: span, item: item_) -> @item {
         attrs: ~[doc_attr],
         id: cx.next_id(),
         node: item,
-        vis: public,
+        vis: ast::public,
         span: span,
     }
 }
@@ -173,22 +164,29 @@ pub fn create_self_type_with_params(cx: @ext_ctxt,
         self_ty_params.push(self_ty_param);
     }
 
+    let lifetime = if generics.lifetimes.is_empty() {
+        None
+    } else {
+        Some(@*generics.lifetimes.get(0))
+    };
+
+
     // Create the type of `self`.
     let self_type = build::mk_raw_path_(span,
                                         ~[ type_ident ],
+                                        lifetime,
                                         self_ty_params);
-    let self_type = ty_path(self_type, cx.next_id());
-    @ast::Ty { id: cx.next_id(), node: self_type, span: span }
+    build::mk_ty_path_path(cx, span, self_type)
 }
 
 pub fn create_derived_impl(cx: @ext_ctxt,
                            span: span,
                            type_ident: ident,
                            generics: &Generics,
-                           methods: &[@method],
+                           methods: &[@ast::method],
                            trait_path: @ast::Path,
-                           mut impl_ty_params: opt_vec::OptVec<ast::TyParam>,
-                           bounds_paths: opt_vec::OptVec<~[ident]>)
+                           mut impl_generics:  Generics,
+                           bounds_paths: opt_vec::OptVec<@ast::Path>)
                         -> @item {
     /*!
      *
@@ -204,21 +202,22 @@ pub fn create_derived_impl(cx: @ext_ctxt,
      */
 
     // Copy the lifetimes
-    let impl_lifetimes = generics.lifetimes.map(|l| {
-        build::mk_lifetime(cx, l.span, l.ident)
-    });
+    for generics.lifetimes.each |l| {
+        impl_generics.lifetimes.push(copy *l)
+    };
 
     // Create the type parameters.
     for generics.ty_params.each |ty_param| {
+        // extra restrictions on the generics parameters to the type being derived upon
         let mut bounds = do bounds_paths.map |&bound_path| {
-            build::mk_trait_ty_param_bound_global(cx, span, bound_path)
+            build::mk_trait_ty_param_bound_(cx, bound_path)
         };
 
         let this_trait_bound =
             build::mk_trait_ty_param_bound_(cx, trait_path);
         bounds.push(this_trait_bound);
 
-        impl_ty_params.push(build::mk_ty_param(cx, ty_param.ident, @bounds));
+        impl_generics.ty_params.push(build::mk_ty_param(cx, ty_param.ident, @bounds));
     }
 
     // Create the reference to the trait.
@@ -231,8 +230,7 @@ pub fn create_derived_impl(cx: @ext_ctxt,
                                                  generics);
 
     // Create the impl item.
-    let impl_item = item_impl(Generics {lifetimes: impl_lifetimes,
-                                        ty_params: impl_ty_params},
+    let impl_item = ast::item_impl(impl_generics,
                               Some(trait_ref),
                               self_type,
                               methods.map(|x| *x));
@@ -241,113 +239,135 @@ pub fn create_derived_impl(cx: @ext_ctxt,
 
 pub fn create_subpatterns(cx: @ext_ctxt,
                           span: span,
-                      prefix: ~str,
-                      n: uint)
-                   -> ~[@pat] {
-    let mut subpats = ~[];
-    for uint::range(0, n) |_i| {
-        // Create the subidentifier.
-        let index = subpats.len();
-        let ident = cx.ident_of(fmt!("%s_%u", prefix, index));
-
-        // Create the subpattern.
-        let subpath = build::mk_raw_path(span, ~[ ident ]);
-        let subpat = pat_ident(bind_by_ref(m_imm), subpath, None);
-        let subpat = build::mk_pat(cx, span, subpat);
-        subpats.push(subpat);
+                          field_paths: ~[@ast::Path],
+                          mutbl: ast::mutability)
+                   -> ~[@ast::pat] {
+    do field_paths.map |&path| {
+        build::mk_pat(cx, span,
+                      ast::pat_ident(ast::bind_by_ref(mutbl), path, None))
     }
-    return subpats;
 }
 
-pub fn is_struct_tuple(struct_def: &struct_def) -> bool {
-    struct_def.fields.len() > 0 && struct_def.fields.all(|f| {
-        match f.node.kind {
-            named_field(*) => false,
-            unnamed_field => true
+#[deriving(Eq)] // dogfooding!
+enum StructType {
+    Unknown, Record, Tuple
+}
+
+pub fn create_struct_pattern(cx: @ext_ctxt,
+                             span: span,
+                             struct_ident: ident,
+                             struct_def: &struct_def,
+                             prefix: ~str,
+                             mutbl: ast::mutability)
+    -> (@ast::pat, ~[(Option<ident>, @expr)]) {
+    if struct_def.fields.is_empty() {
+        return (
+            build::mk_pat_ident_with_binding_mode(
+                cx, span, struct_ident, ast::bind_infer),
+            ~[]);
     }
-    })
+
+    let matching_path = build::mk_raw_path(span, ~[ struct_ident ]);
+
+    let mut paths = ~[], ident_expr = ~[];
+
+    let mut struct_type = Unknown;
+
+    for struct_def.fields.eachi |i, struct_field| {
+        let opt_id = match struct_field.node.kind {
+            ast::named_field(ident, _, _) if (struct_type == Unknown ||
+                                              struct_type == Record) => {
+                struct_type = Record;
+                Some(ident)
+            }
+            ast::unnamed_field if (struct_type == Unknown ||
+                                   struct_type == Tuple) => {
+                struct_type = Tuple;
+                None
+            }
+            _ => {
+                cx.span_bug(span, "A struct with named and unnamed fields in `deriving`");
+            }
+        };
+        let path = build::mk_raw_path(span,
+                                      ~[ cx.ident_of(fmt!("%s_%u", prefix, i)) ]);
+        paths.push(path);
+        ident_expr.push((opt_id, build::mk_path_raw(cx, span, path)));
+    }
+
+    let subpats = create_subpatterns(cx, span, paths, mutbl);
+
+    // struct_type is definitely not Unknown, since struct_def.fields
+    // must be nonempty to reach here
+    let pattern = if struct_type == Record {
+        let field_pats = do vec::build |push| {
+            for vec::each2(subpats, ident_expr) |&pat, &(id, _)| {
+                // id is guaranteed to be Some
+                push(ast::field_pat { ident: id.get(), pat: pat })
+            }
+        };
+        build::mk_pat_struct(cx, span, matching_path, field_pats)
+    } else {
+        build::mk_pat_enum(cx, span, matching_path, subpats)
+    };
+
+    (pattern, ident_expr)
 }
 
 pub fn create_enum_variant_pattern(cx: @ext_ctxt,
                                    span: span,
-                               variant: &variant,
-                               prefix: ~str)
-                            -> @pat {
+                                   variant: &ast::variant,
+                                   prefix: ~str,
+                                   mutbl: ast::mutability)
+    -> (@ast::pat, ~[(Option<ident>, @expr)]) {
+
     let variant_ident = variant.node.name;
     match variant.node.kind {
-        tuple_variant_kind(ref variant_args) => {
-            if variant_args.len() == 0 {
-                return build::mk_pat_ident_with_binding_mode(
-                    cx, span, variant_ident, ast::bind_infer);
+        ast::tuple_variant_kind(ref variant_args) => {
+            if variant_args.is_empty() {
+                return (build::mk_pat_ident_with_binding_mode(
+                    cx, span, variant_ident, ast::bind_infer), ~[]);
             }
 
             let matching_path = build::mk_raw_path(span, ~[ variant_ident ]);
-            let subpats = create_subpatterns(cx,
-                                             span,
+
+            let mut paths = ~[], ident_expr = ~[];
+            for uint::range(0, variant_args.len()) |i| {
+                let path = build::mk_raw_path(span,
+                                              ~[ cx.ident_of(fmt!("%s_%u", prefix, i)) ]);
+
+                paths.push(path);
+                ident_expr.push((None, build::mk_path_raw(cx, span, path)));
+            }
+
+            let subpats = create_subpatterns(cx, span, paths, mutbl);
+
+            (build::mk_pat_enum(cx, span, matching_path, subpats),
+             ident_expr)
+        }
+        ast::struct_variant_kind(struct_def) => {
+            create_struct_pattern(cx, span,
+                                  variant_ident, struct_def,
                                   prefix,
-                                             variant_args.len());
-
-            return build::mk_pat_enum(cx, span, matching_path, subpats);
-        }
-        struct_variant_kind(struct_def) => {
-            let matching_path = build::mk_raw_path(span, ~[ variant_ident ]);
-            let subpats = create_subpatterns(cx,
-                                             span,
-                                             prefix,
-                                             struct_def.fields.len());
-
-            let field_pats = do struct_def.fields.mapi |i, struct_field| {
-                let ident = match struct_field.node.kind {
-                    named_field(ident, _, _) => ident,
-                    unnamed_field => {
-                        cx.span_bug(span, ~"unexpected unnamed field");
-                    }
-                };
-                ast::field_pat { ident: ident, pat: subpats[i] }
-            };
-
-            build::mk_pat_struct(cx, span, matching_path, field_pats)
+                                  mutbl)
         }
     }
 }
 
-pub fn variant_arg_count(_cx: @ext_ctxt, _span: span, variant: &variant) -> uint {
+pub fn variant_arg_count(_cx: @ext_ctxt, _span: span, variant: &ast::variant) -> uint {
     match variant.node.kind {
-        tuple_variant_kind(ref args) => args.len(),
-        struct_variant_kind(ref struct_def) => struct_def.fields.len(),
+        ast::tuple_variant_kind(ref args) => args.len(),
+        ast::struct_variant_kind(ref struct_def) => struct_def.fields.len(),
     }
 }
 
-/// Iterate through the idents of the variant arguments. The field is
-/// unnamed (i.e. it's not a struct-like enum), then `None`.
-pub fn each_variant_arg_ident(_cx: @ext_ctxt, _span: span,
-                              variant: &variant, it: &fn(uint, Option<ident>) -> bool) {
-    match variant.node.kind {
-        tuple_variant_kind(ref args) => {
-            for uint::range(0, args.len()) |i| {
-                if !it(i, None) { break }
-            }
-        }
-        struct_variant_kind(ref struct_def) => {
-            for struct_def.fields.eachi |i, f| {
-                let id = match f.node.kind {
-                    named_field(ident, _, _) => Some(ident),
-                    unnamed_field => None
-                };
-                if !it(i, id) { break }
-            }
-        }
-    }
-}
-
-
 pub fn expand_enum_or_struct_match(cx: @ext_ctxt,
                                span: span,
                                arms: ~[ ast::arm ])
                             -> @expr {
     let self_ident = cx.ident_of(~"self");
     let self_expr = build::mk_path(cx, span, ~[ self_ident ]);
-    let self_expr = build::mk_unary(cx, span, deref, self_expr);
-    let self_match_expr = expr_match(self_expr, arms);
+    let self_expr = build::mk_unary(cx, span, ast::deref, self_expr);
+    let self_match_expr = ast::expr_match(self_expr, arms);
     build::mk_expr(cx, span, self_match_expr)
 }

src/libsyntax/ext/deriving/ty.rs

@@ -0,0 +1,242 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+/*!
+A mini version of ast::Ty, which is easier to use, and features an
+explicit `Self` type to use when specifying impls to be derived.
+*/
+
+use ast;
+use ast::{expr,Generics,ident};
+use ext::base::ext_ctxt;
+use ext::build;
+use codemap::{span,respan};
+use opt_vec;
+
+/// The types of pointers
+#[deriving(Eq)]
+pub enum PtrTy {
+    Owned, // ~
+    Managed(ast::mutability), // @[mut]
+    Borrowed(Option<~str>, ast::mutability), // &['lifetime] [mut]
+}
+
+/// A path, e.g. `::core::option::Option::<int>` (global). Has support
+/// for type parameters and a lifetime.
+#[deriving(Eq)]
+pub struct Path {
+    path: ~[~str],
+    lifetime: Option<~str>,
+    params: ~[~Ty],
+    global: bool
+}
+
+pub impl Path {
+    fn new(path: ~[~str]) -> Path {
+        Path::new_(path, None, ~[], true)
+    }
+    fn new_local(path: ~str) -> Path {
+        Path::new_(~[ path ], None, ~[], false)
+    }
+    fn new_(path: ~[~str], lifetime: Option<~str>, params: ~[~Ty], global: bool) -> Path {
+        Path {
+            path: path,
+            lifetime: lifetime,
+            params: params,
+            global: global
+        }
+    }
+
+    fn to_ty(&self, cx: @ext_ctxt, span: span,
+             self_ty: ident, self_generics: &Generics) -> @ast::Ty {
+                build::mk_ty_path_path(cx, span,
+                                       self.to_path(cx, span,
+                                                    self_ty, self_generics))
+    }
+    fn to_path(&self, cx: @ext_ctxt, span: span,
+               self_ty: ident, self_generics: &Generics) -> @ast::Path {
+        let idents = self.path.map(|s| cx.ident_of(*s) );
+        let lt = mk_lifetime(cx, span, self.lifetime);
+        let tys = self.params.map(|t| t.to_ty(cx, span, self_ty, self_generics));
+
+        if self.global {
+            build::mk_raw_path_global_(span, idents, lt, tys)
+        } else {
+            build::mk_raw_path_(span, idents, lt, tys)
+        }
+    }
+}
+
+/// A type. Supports pointers (except for *), Self, and literals
+#[deriving(Eq)]
+pub enum Ty {
+    Self,
+    // &/~/@ Ty
+    Ptr(~Ty, PtrTy),
+    // mod::mod::Type<[lifetime], [Params...]>, including a plain type
+    // parameter, and things like `int`
+    Literal(Path),
+    // includes nil
+    Tuple(~[Ty])
+}
+
+pub fn borrowed_ptrty() -> PtrTy {
+    Borrowed(None, ast::m_imm)
+}
+pub fn borrowed(ty: ~Ty) -> Ty {
+    Ptr(ty, borrowed_ptrty())
+}
+
+pub fn borrowed_explicit_self() -> Option<Option<PtrTy>> {
+    Some(Some(borrowed_ptrty()))
+}
+
+pub fn borrowed_self() -> Ty {
+    borrowed(~Self)
+}
+
+pub fn nil_ty() -> Ty {
+    Tuple(~[])
+}
+
+fn mk_lifetime(cx: @ext_ctxt, span: span, lt: Option<~str>) -> Option<@ast::Lifetime> {
+    match lt {
+        Some(s) => Some(@build::mk_lifetime(cx, span, cx.ident_of(s))),
+        None => None
+    }
+}
+
+pub impl Ty {
+    fn to_ty(&self, cx: @ext_ctxt, span: span,
+             self_ty: ident, self_generics: &Generics) -> @ast::Ty {
+        match *self {
+            Ptr(ref ty, ref ptr) => {
+                let raw_ty = ty.to_ty(cx, span, self_ty, self_generics);
+                match *ptr {
+                    Owned => {
+                        build::mk_ty_uniq(cx, span, raw_ty)
+                    }
+                    Managed(copy mutbl) => {
+                        build::mk_ty_box(cx, span, raw_ty, mutbl)
+                    }
+                    Borrowed(copy lt, copy mutbl) => {
+                        let lt = mk_lifetime(cx, span, lt);
+                        build::mk_ty_rptr(cx, span, raw_ty, lt, mutbl)
+                    }
+                }
+            }
+            Literal(ref p) => { p.to_ty(cx, span, self_ty, self_generics) }
+            Self  => {
+                build::mk_ty_path_path(cx, span, self.to_path(cx, span, self_ty, self_generics))
+            }
+            Tuple(ref fields) => {
+                let ty = if fields.is_empty() {
+                    ast::ty_nil
+                } else {
+                    ast::ty_tup(fields.map(|f| f.to_ty(cx, span, self_ty, self_generics)))
+                };
+
+                build::mk_ty(cx, span, ty)
+            }
+        }
+    }
+
+    fn to_path(&self, cx: @ext_ctxt, span: span,
+               self_ty: ident, self_generics: &Generics) -> @ast::Path {
+        match *self {
+            Self => {
+                let self_params = do self_generics.ty_params.map |ty_param| {
+                    build::mk_ty_path(cx, span, ~[ ty_param.ident ])
+                };
+                let lifetime = if self_generics.lifetimes.is_empty() {
+                    None
+                } else {
+                    Some(@*self_generics.lifetimes.get(0))
+                };
+
+                build::mk_raw_path_(span, ~[self_ty], lifetime,
+                                    opt_vec::take_vec(self_params))
+            }
+            Literal(ref p) => {
+                p.to_path(cx, span, self_ty, self_generics)
+            }
+            Ptr(*) => { cx.span_bug(span, ~"Pointer in a path in generic `deriving`") }
+            Tuple(*) => { cx.span_bug(span, ~"Tuple in a path in generic `deriving`") }
+        }
+    }
+}
+
+
+fn mk_ty_param(cx: @ext_ctxt, span: span, name: ~str, bounds: ~[Path],
+               self_ident: ident, self_generics: &Generics) -> ast::TyParam {
+    let bounds = opt_vec::from(
+        do bounds.map |b| {
+            let path = b.to_path(cx, span, self_ident, self_generics);
+            build::mk_trait_ty_param_bound_(cx, path)
+        });
+    build::mk_ty_param(cx, cx.ident_of(name), @bounds)
+}
+
+fn mk_generics(lifetimes: ~[ast::Lifetime],  ty_params: ~[ast::TyParam]) -> Generics {
+    Generics {
+        lifetimes: opt_vec::from(lifetimes),
+        ty_params: opt_vec::from(ty_params)
+    }
+}
+
+/// Lifetimes and bounds on type paramers
+pub struct LifetimeBounds {
+    lifetimes: ~[~str],
+    bounds: ~[(~str, ~[Path])]
+}
+
+pub impl LifetimeBounds {
+    fn empty() -> LifetimeBounds {
+        LifetimeBounds {
+            lifetimes: ~[], bounds: ~[]
+        }
+    }
+    fn to_generics(&self, cx: @ext_ctxt, span: span,
+                   self_ty: ident, self_generics: &Generics) -> Generics {
+        let lifetimes = do self.lifetimes.map |&lt| {
+            build::mk_lifetime(cx, span, cx.ident_of(lt))
+        };
+        let ty_params = do self.bounds.map |&(name, bounds)| {
+            mk_ty_param(cx, span, name, bounds, self_ty, self_generics)
+        };
+        mk_generics(lifetimes, ty_params)
+    }
+}
+
+
+pub fn get_explicit_self(cx: @ext_ctxt, span: span, self_ptr: Option<PtrTy>)
+    -> (@expr, ast::self_ty) {
+    let self_path = build::mk_path(cx, span, ~[cx.ident_of(~"self")]);
+    match self_ptr {
+        None => {
+            (self_path, respan(span, ast::sty_value))
+        }
+        Some(ptr) => {
+            let self_ty = respan(
+                span,
+                match ptr {
+                    Owned => ast::sty_uniq(ast::m_imm),
+                    Managed(mutbl) => ast::sty_box(mutbl),
+                    Borrowed(lt, mutbl) => {
+                        let lt = lt.map(|s| @build::mk_lifetime(cx, span,
+                                                                cx.ident_of(*s)));
+                        ast::sty_region(lt, mutbl)
+                    }
+                });
+            let self_expr = build::mk_deref(cx, span, self_path);
+            (self_expr, self_ty)
+        }
+    }
+}