auto merge of #5435 : nikomatsakis/rust/issue-4846-refactor-self_info, r=nikomatsakis

Refactor the self-info so that the def-id is carried in ty_self()and the fn_ctxt doesn't need any self_info field at all. Pull out explicit self transformation into `check_method`. Step towards fixing `fn(&self)` to have a distinct lifetime. (cc #4846) 

r? @catamorphism

Author: bors

src/librustc/metadata/tydecode.rs

@@ -289,7 +289,8 @@ fn parse_ty(st: @mut PState, conv: conv_did) -> ty::t {
         return ty::mk_param(st.tcx, parse_int(st) as uint, did);
       }
       's' => {
-        return ty::mk_self(st.tcx);
+        let did = parse_def(st, TypeParameter, conv);
+        return ty::mk_self(st.tcx, did);
       }
       '@' => return ty::mk_box(st.tcx, parse_mt(st, conv)),
       '~' => return ty::mk_uniq(st.tcx, parse_mt(st, conv)),

src/librustc/metadata/tyencode.rs

@@ -312,8 +312,10 @@ fn enc_sty(w: @io::Writer, cx: @ctxt, +st: ty::sty) {
         w.write_char('|');
         w.write_str(uint::to_str(id));
       }
-      ty::ty_self => {
+      ty::ty_self(did) => {
         w.write_char('s');
+        w.write_str((cx.ds)(did));
+        w.write_char('|');
       }
       ty::ty_type => w.write_char('Y'),
       ty::ty_opaque_closure_ptr(p) => {

src/librustc/middle/trans/reflect.rs

@@ -297,7 +297,7 @@ pub impl Reflector {
               let extra = ~[self.c_uint(p.idx)];
               self.visit(~"param", extra)
           }
-          ty::ty_self => self.leaf(~"self"),
+          ty::ty_self(*) => self.leaf(~"self"),
           ty::ty_type => self.leaf(~"type"),
           ty::ty_opaque_box => self.leaf(~"opaque_box"),
           ty::ty_opaque_closure_ptr(ck) => {

src/librustc/middle/trans/type_of.rs

@@ -144,7 +144,7 @@ pub fn sizing_type_of(cx: @CrateContext, t: ty::t) -> TypeRef {
             T_struct(adt::sizing_fields_of(cx, repr))
         }
 
-        ty::ty_self | ty::ty_infer(*) | ty::ty_param(*) | ty::ty_err(*) => {
+        ty::ty_self(_) | ty::ty_infer(*) | ty::ty_param(*) | ty::ty_err(*) => {
             cx.tcx.sess.bug(
                 fmt!("fictitious type %? in sizing_type_of()",
                      ty::get(t).sty))
@@ -251,7 +251,7 @@ pub fn type_of(cx: @CrateContext, t: ty::t) -> TypeRef {
                                               did,
                                               /*bad*/ copy substs.tps))
       }
-      ty::ty_self => cx.tcx.sess.unimpl(~"type_of: ty_self"),
+      ty::ty_self(*) => cx.tcx.sess.unimpl(~"type_of: ty_self"),
       ty::ty_infer(*) => cx.tcx.sess.bug(~"type_of with ty_infer"),
       ty::ty_param(*) => cx.tcx.sess.bug(~"type_of with ty_param"),
       ty::ty_err(*) => cx.tcx.sess.bug(~"type_of with ty_err")

src/librustc/middle/ty.rs

@@ -522,7 +522,8 @@ pub enum sty {
     ty_tup(~[t]),
 
     ty_param(param_ty), // type parameter
-    ty_self, // special, implicit `self` type parameter
+    ty_self(def_id), /* special, implicit `self` type parameter;
+                      * def_id is the id of the trait */
 
     ty_infer(InferTy), // something used only during inference/typeck
     ty_err, // Also only used during inference/typeck, to represent
@@ -897,7 +898,7 @@ fn mk_t_with_id(cx: ctxt, +st: sty, o_def_id: Option<ast::def_id>) -> t {
       &ty_err => flags |= has_ty_err as uint,
       &ty_param(_) => flags |= has_params as uint,
       &ty_infer(_) => flags |= needs_infer as uint,
-      &ty_self => flags |= has_self as uint,
+      &ty_self(_) => flags |= has_self as uint,
       &ty_enum(_, ref substs) | &ty_struct(_, ref substs) |
       &ty_trait(_, ref substs, _) => {
         flags |= sflags(substs);
@@ -1082,7 +1083,7 @@ pub fn mk_float_var(cx: ctxt, v: FloatVid) -> t { mk_infer(cx, FloatVar(v)) }
 
 pub fn mk_infer(cx: ctxt, +it: InferTy) -> t { mk_t(cx, ty_infer(it)) }
 
-pub fn mk_self(cx: ctxt) -> t { mk_t(cx, ty_self) }
+pub fn mk_self(cx: ctxt, did: ast::def_id) -> t { mk_t(cx, ty_self(did)) }
 
 pub fn mk_param(cx: ctxt, n: uint, k: def_id) -> t {
     mk_t(cx, ty_param(param_ty { idx: n, def_id: k }))
@@ -1163,7 +1164,7 @@ pub fn maybe_walk_ty(ty: t, f: &fn(t) -> bool) {
     if !f(ty) { return; }
     match get(ty).sty {
       ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
-      ty_estr(_) | ty_type | ty_opaque_box | ty_self |
+      ty_estr(_) | ty_type | ty_opaque_box | ty_self(_) |
       ty_opaque_closure_ptr(_) | ty_infer(_) | ty_param(_) | ty_err => {
       }
       ty_box(ref tm) | ty_evec(ref tm, _) | ty_unboxed_vec(ref tm) |
@@ -1250,7 +1251,7 @@ fn fold_sty(sty: &sty, fldop: &fn(t) -> t) -> sty {
         }
         ty_nil | ty_bot | ty_bool | ty_int(_) | ty_uint(_) | ty_float(_) |
         ty_estr(_) | ty_type | ty_opaque_closure_ptr(_) | ty_err |
-        ty_opaque_box | ty_infer(_) | ty_param(*) | ty_self => {
+        ty_opaque_box | ty_infer(_) | ty_param(*) | ty_self(_) => {
             /*bad*/copy *sty
         }
     }
@@ -1362,7 +1363,7 @@ pub fn subst_tps(cx: ctxt, tps: &[t], self_ty_opt: Option<t>, typ: t) -> t {
     if self_ty_opt.is_none() && !tbox_has_flag(tb, has_params) { return typ; }
     match tb.sty {
         ty_param(p) => tps[p.idx],
-        ty_self => {
+        ty_self(_) => {
             match self_ty_opt {
                 None => cx.sess.bug(~"ty_self unexpected here"),
                 Some(self_ty) => {
@@ -1424,7 +1425,7 @@ pub fn subst(cx: ctxt,
         if !tbox_has_flag(tb, needs_subst) { return typ; }
         match tb.sty {
           ty_param(p) => substs.tps[p.idx],
-          ty_self => substs.self_ty.get(),
+          ty_self(_) => substs.self_ty.get(),
           _ => {
             fold_regions_and_ty(
                 cx, typ,
@@ -2002,7 +2003,7 @@ pub fn type_contents(cx: ctxt, ty: t) -> TypeContents {
                     cx, cx.ty_param_bounds.get(&p.def_id.node))
             }
 
-            ty_self => {
+            ty_self(_) => {
                 // Currently, self is not bounded, so we must assume the
                 // worst.  But in the future we should examine the super
                 // traits.
@@ -2159,7 +2160,7 @@ pub fn type_contents(cx: ctxt, ty: t) -> TypeContents {
                     v.args.foldl(0, |s, a| *s + type_size(cx, *a))))
           }
 
-          ty_param(_) | ty_self => {
+          ty_param(_) | ty_self(_) => {
             1
           }
 
@@ -2220,7 +2221,7 @@ pub fn is_instantiable(cx: ctxt, r_ty: t) -> bool {
           ty_infer(_) |
           ty_err |
           ty_param(_) |
-          ty_self |
+          ty_self(_) |
           ty_type |
           ty_opaque_box |
           ty_opaque_closure_ptr(_) |
@@ -2655,7 +2656,7 @@ impl to_bytes::IterBytes for sty {
           ty_bare_fn(ref ft) =>
           to_bytes::iter_bytes_2(&12u8, ft, lsb0, f),
 
-          ty_self => 13u8.iter_bytes(lsb0, f),
+          ty_self(ref did) => to_bytes::iter_bytes_2(&13u8, did, lsb0, f),
 
           ty_infer(ref v) =>
           to_bytes::iter_bytes_2(&14u8, v, lsb0, f),
@@ -3341,7 +3342,7 @@ pub fn ty_sort_str(cx: ctxt, t: t) -> ~str {
       ty_infer(IntVar(_)) => ~"integral variable",
       ty_infer(FloatVar(_)) => ~"floating-point variable",
       ty_param(_) => ~"type parameter",
-      ty_self => ~"self",
+      ty_self(_) => ~"self",
       ty_err => ~"type error"
     }
 }

src/librustc/middle/typeck/astconv.rs

@@ -64,7 +64,7 @@ use middle::typeck::{CrateCtxt, write_substs_to_tcx, write_ty_to_tcx};
 
 use core::result;
 use core::vec;
-use syntax::ast;
+use syntax::{ast, ast_util};
 use syntax::codemap::span;
 use syntax::print::pprust::{lifetime_to_str, path_to_str};
 use syntax::parse::token::special_idents;
@@ -400,12 +400,13 @@ pub fn ast_ty_to_ty<AC:AstConv, RS:region_scope + Copy + Durable>(
             check_path_args(tcx, path, NO_TPS | NO_REGIONS);
             ty::mk_param(tcx, n, id)
           }
-          ast::def_self_ty(_) => {
+          ast::def_self_ty(id) => {
             // n.b.: resolve guarantees that the self type only appears in a
             // trait, which we rely upon in various places when creating
             // substs
             check_path_args(tcx, path, NO_TPS | NO_REGIONS);
-            ty::mk_self(tcx)
+            let did = ast_util::local_def(id);
+            ty::mk_self(tcx, did)
           }
           _ => {
             tcx.sess.span_fatal(ast_ty.span,

src/librustc/middle/typeck/check/method.rs

@@ -307,12 +307,9 @@ pub impl LookupContext/&self {
                         self_ty, did, substs, store);
                     self.push_inherent_impl_candidates_for_type(did);
                 }
-                ty_self => {
+                ty_self(self_did) => {
                     // Call is of the form "self.foo()" and appears in one
                     // of a trait's default method implementations.
-                    let self_did = self.fcx.self_info.expect(
-                        ~"self_impl_def_id is undefined (`self` may not \
-                          be in scope here").def_id;
                     let substs = substs {
                         self_r: None,
                         self_ty: None,
@@ -932,7 +929,7 @@ pub impl LookupContext/&self {
             ty_bare_fn(*) | ty_box(*) | ty_uniq(*) | ty_rptr(*) |
             ty_infer(IntVar(_)) |
             ty_infer(FloatVar(_)) |
-            ty_self | ty_param(*) | ty_nil | ty_bot | ty_bool |
+            ty_self(_) | ty_param(*) | ty_nil | ty_bot | ty_bool |
             ty_int(*) | ty_uint(*) |
             ty_float(*) | ty_enum(*) | ty_ptr(*) | ty_struct(*) | ty_tup(*) |
             ty_estr(*) | ty_evec(*) | ty_trait(*) | ty_closure(*) => {

src/librustc/middle/typeck/check/mod.rs

@@ -144,8 +144,7 @@ pub mod method;
 pub struct SelfInfo {
     self_ty: ty::t,
     self_id: ast::node_id,
-    def_id: ast::def_id,
-    explicit_self: ast::self_ty
+    span: span
 }
 
 /// Fields that are part of a `FnCtxt` which are inherited by
@@ -183,9 +182,6 @@ pub struct FnCtxt {
     // with any nested functions that capture the environment
     // (and with any functions whose environment is being captured).
 
-    // Refers to whichever `self` is in scope, even this FnCtxt is
-    // for a nested closure that captures `self`
-    self_info: Option<SelfInfo>,
     ret_ty: ty::t,
     // Used by loop bodies that return from the outer function
     indirect_ret_ty: Option<ty::t>,
@@ -236,7 +232,6 @@ pub fn blank_fn_ctxt(ccx: @mut CrateCtxt,
 // It's kind of a kludge to manufacture a fake function context
 // and statement context, but we might as well do write the code only once
     @mut FnCtxt {
-        self_info: None,
         ret_ty: rty,
         indirect_ret_ty: None,
         purity: ast::pure_fn,
@@ -332,7 +327,6 @@ pub fn check_fn(ccx: @mut CrateCtxt,
         };
 
         @mut FnCtxt {
-            self_info: self_info,
             ret_ty: ret_ty,
             indirect_ret_ty: indirect_ret_ty,
             purity: purity,
@@ -344,25 +338,6 @@ pub fn check_fn(ccx: @mut CrateCtxt,
         }
     };
 
-    // Update the SelfInfo to contain an accurate self type (taking
-    // into account explicit self).
-    let self_info = do self_info.chain_ref |self_info| {
-        // If the self type is sty_static, we don't have a self ty.
-        if self_info.explicit_self.node == ast::sty_static {
-            None
-        } else  {
-            let in_scope_regions = fcx.in_scope_regions;
-            let self_region = in_scope_regions.find(ty::br_self);
-            let ty = method::transform_self_type_for_method(
-                fcx.tcx(),
-                self_region,
-                self_info.self_ty,
-                self_info.explicit_self.node,
-                TransformTypeNormally);
-            Some(SelfInfo { self_ty: ty,.. *self_info })
-        }
-    };
-
     gather_locals(fcx, decl, body, arg_tys, self_info);
     check_block(fcx, body);
 
@@ -500,20 +475,25 @@ pub fn check_fn(ccx: @mut CrateCtxt,
 
 pub fn check_method(ccx: @mut CrateCtxt,
                     method: @ast::method,
-                    self_ty: ty::t,
-                    self_impl_def_id: ast::def_id) {
-    let self_info = SelfInfo {
-        self_ty: self_ty,
-        self_id: method.self_id,
-        def_id: self_impl_def_id,
-        explicit_self: method.self_ty
+                    self_ty: ty::t)
+{
+    let self_info = if method.self_ty.node == ast::sty_static {None} else {
+        let ty = method::transform_self_type_for_method(
+            ccx.tcx,
+            Some(ty::re_bound(ty::br_self)),
+            self_ty,
+            method.self_ty.node,
+            TransformTypeNormally);
+        Some(SelfInfo {self_ty: ty, self_id: method.self_id,
+                       span: method.self_ty.span})
     };
+
     check_bare_fn(
         ccx,
         &method.decl,
         &method.body,
         method.id,
-        Some(self_info)
+        self_info
     );
 }
 
@@ -550,11 +530,7 @@ pub fn check_struct(ccx: @mut CrateCtxt,
         let class_t = SelfInfo {
             self_ty: self_ty,
             self_id: dtor.node.self_id,
-            def_id: local_def(id),
-            explicit_self: spanned {
-                node: ast::sty_by_ref,
-                span: codemap::dummy_sp()
-            }
+            span: dtor.span,
         };
         // typecheck the dtor
         let dtor_dec = ast_util::dtor_dec();
@@ -594,7 +570,7 @@ pub fn check_item(ccx: @mut CrateCtxt, it: @ast::item) {
                *ccx.tcx.sess.str_of(it.ident), it.id, rp);
         let self_ty = ccx.to_ty(&rscope::type_rscope(rp), ty);
         for ms.each |m| {
-            check_method(ccx, *m, self_ty, local_def(it.id));
+            check_method(ccx, *m, self_ty);
         }
       }
       ast::item_trait(_, _, ref trait_methods) => {
@@ -605,7 +581,8 @@ pub fn check_item(ccx: @mut CrateCtxt, it: @ast::item) {
                 // bodies to check.
               }
               provided(m) => {
-                check_method(ccx, m, ty::mk_self(ccx.tcx), local_def(it.id));
+                let self_ty = ty::mk_self(ccx.tcx, local_def(it.id));
+                check_method(ccx, m, self_ty);
               }
             }
         }
@@ -1699,9 +1676,7 @@ pub fn check_expr_with_unifier(fcx: @mut FnCtxt,
             ty::determine_inherited_purity(copy fcx.purity, purity,
                                            fn_ty.sigil);
 
-        // We inherit the same self info as the enclosing scope,
-        // since the function we're checking might capture `self`
-        check_fn(fcx.ccx, fcx.self_info, inherited_purity,
+        check_fn(fcx.ccx, None, inherited_purity,
                  &fn_ty.sig, decl, body, fn_kind,
                  fcx.in_scope_regions, fcx.inh);
     }

src/librustc/middle/typeck/check/regionmanip.rs

@@ -40,18 +40,8 @@ pub fn replace_bound_regions_in_fn_sig(
 
     let mut all_tys = ty::tys_in_fn_sig(fn_sig);
 
-    match self_info {
-      Some(SelfInfo {
-            explicit_self: codemap::spanned {
-                node: ast::sty_region(_, m),
-                // FIXME(#4846) ------^ Use this lifetime instead of self
-                _}, _}) => {
-        let region = ty::re_bound(ty::br_self);
-        let ty = ty::mk_rptr(tcx, region,
-                             ty::mt { ty: ty::mk_self(tcx), mutbl: m });
-        all_tys.push(ty);
-      }
-      _ => {}
+    for self_info.each |self_info| {
+        all_tys.push(self_info.self_ty);
     }
 
     for self_ty.each |t| { all_tys.push(*t) }

src/librustc/middle/typeck/check/writeback.rs

@@ -283,8 +283,8 @@ pub fn resolve_type_vars_in_fn(fcx: @mut FnCtxt,
     let visit = mk_visitor();
     (visit.visit_block)(blk, wbcx, visit);
     for self_info.each |self_info| {
-        if self_info.explicit_self.node == ast::sty_static { break; }
-        resolve_type_vars_for_node(wbcx, self_info.explicit_self.span,
+        resolve_type_vars_for_node(wbcx,
+                                   self_info.span,
                                    self_info.self_id);
     }
     for decl.inputs.each |arg| {