auto merge of #5802 : nikomatsakis/rust/issue-4183-trait-substs, r=nikomatsakis

Cleanup substitutions and treatment of generics around traits in a number of ways

- In a TraitRef, use the self type consistently to refer to the Self type:
  - trait ref in `impl Trait<A,B,C> for S` has a self type of `S`.
  - trait ref in `A:Trait` has the self type `A`
  - trait ref associated with a trait decl has self type `Self`
  - trait ref associated with a supertype has self type `Self`
  - trait ref in an object type `@Trait` has no self type

- Rewrite `each_bound_traits_and_supertraits` to perform
  substitutions as it goes, and thus yield a series of trait refs
  that are always in the same 'namespace' as the type parameter
  bound given as input.  Before, we left this to the caller, but
  this doesn't work because the caller lacks adequare information
  to perform the type substitutions correctly.

- For provided methods, substitute the generics involved in the provided
  method correctly.

- Introduce TypeParameterDef, which tracks the bounds declared on a type
  parameter and brings them together with the def_id and (in the future)
  other information (maybe even the parameter's name!).

- Introduce Subst trait, which helps to cleanup a lot of the
  repetitive code involved with doing type substitution.

- Introduce Repr trait, which makes debug printouts far more convenient.

Fixes #4183.  Needed for #5656.

r? @catamorphism

Author: bors

src/librustc/metadata/common.rs

@@ -127,7 +127,7 @@ pub enum astencode_tag { // Reserves 0x50 -- 0x6f
     tag_table_node_type_subst = 0x58,
     tag_table_freevars = 0x59,
     tag_table_tcache = 0x5a,
-    tag_table_param_bounds = 0x5b,
+    tag_table_param_defs = 0x5b,
     tag_table_inferred_modes = 0x5c,
     tag_table_mutbl = 0x5d,
     tag_table_last_use = 0x5e,

src/librustc/metadata/csearch.rs

@@ -210,7 +210,7 @@ pub fn get_field_type(tcx: ty::ctxt, class_id: ast::def_id,
     debug!("got field data %?", the_field);
     let ty = decoder::item_type(def, the_field, tcx, cdata);
     ty::ty_param_bounds_and_ty {
-        generics: ty::Generics {bounds: @~[],
+        generics: ty::Generics {type_param_defs: @~[],
                                 region_param: None},
         ty: ty
     }

src/librustc/metadata/decoder.rs

@@ -19,7 +19,8 @@ use metadata::csearch::{ProvidedTraitMethodInfo, StaticMethodInfo};
 use metadata::csearch;
 use metadata::cstore;
 use metadata::decoder;
-use metadata::tydecode::{parse_ty_data, parse_def_id, parse_bounds_data,
+use metadata::tydecode::{parse_ty_data, parse_def_id,
+                         parse_type_param_def_data,
                          parse_bare_fn_ty_data, parse_trait_ref_data};
 use middle::{ty, resolve};
 
@@ -266,13 +267,14 @@ fn item_trait_ref(doc: ebml::Doc, tcx: ty::ctxt, cdata: cmd) -> ty::TraitRef {
     doc_trait_ref(tp, tcx, cdata)
 }
 
-fn item_ty_param_bounds(item: ebml::Doc, tcx: ty::ctxt, cdata: cmd,
-                        tag: uint)
-    -> @~[ty::param_bounds] {
+fn item_ty_param_defs(item: ebml::Doc, tcx: ty::ctxt, cdata: cmd,
+                      tag: uint)
+    -> @~[ty::TypeParameterDef] {
     let mut bounds = ~[];
     for reader::tagged_docs(item, tag) |p| {
-        let bd = parse_bounds_data(p.data, p.start, cdata.cnum, tcx,
-                                   |_, did| translate_def_id(cdata, did));
+        let bd = parse_type_param_def_data(
+            p.data, p.start, cdata.cnum, tcx,
+            |_, did| translate_def_id(cdata, did));
         bounds.push(bd);
     }
     @bounds
@@ -378,11 +380,11 @@ pub fn get_trait_def(cdata: cmd,
                      tcx: ty::ctxt) -> ty::TraitDef
 {
     let item_doc = lookup_item(item_id, cdata.data);
-    let tp_bounds = item_ty_param_bounds(item_doc, tcx, cdata,
-                                         tag_items_data_item_ty_param_bounds);
+    let tp_defs = item_ty_param_defs(item_doc, tcx, cdata,
+                                     tag_items_data_item_ty_param_bounds);
     let rp = item_ty_region_param(item_doc);
     ty::TraitDef {
-        generics: ty::Generics {bounds: tp_bounds,
+        generics: ty::Generics {type_param_defs: tp_defs,
                                 region_param: rp},
         trait_ref: @item_trait_ref(item_doc, tcx, cdata)
     }
@@ -394,12 +396,12 @@ pub fn get_type(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
     let item = lookup_item(id, cdata.data);
     let t = item_type(ast::def_id { crate: cdata.cnum, node: id }, item, tcx,
                       cdata);
-    let tp_bounds = if family_has_type_params(item_family(item)) {
-        item_ty_param_bounds(item, tcx, cdata, tag_items_data_item_ty_param_bounds)
+    let tp_defs = if family_has_type_params(item_family(item)) {
+        item_ty_param_defs(item, tcx, cdata, tag_items_data_item_ty_param_bounds)
     } else { @~[] };
     let rp = item_ty_region_param(item);
     ty::ty_param_bounds_and_ty {
-        generics: ty::Generics {bounds: tp_bounds,
+        generics: ty::Generics {type_param_defs: tp_defs,
                                 region_param: rp},
         ty: t
     }
@@ -753,17 +755,16 @@ pub fn get_method(intr: @ident_interner, cdata: cmd, id: ast::node_id,
     let method_doc = lookup_item(id, cdata.data);
     let def_id = item_def_id(method_doc, cdata);
     let name = item_name(intr, method_doc);
-    let bounds =
-        item_ty_param_bounds(method_doc, tcx, cdata,
-                             tag_item_method_tps);
+    let type_param_defs = item_ty_param_defs(method_doc, tcx, cdata,
+                                             tag_item_method_tps);
     let transformed_self_ty = doc_transformed_self_ty(method_doc, tcx, cdata);
     let fty = doc_method_fty(method_doc, tcx, cdata);
     let vis = item_visibility(method_doc);
     let self_ty = get_self_ty(method_doc);
     ty::method {
         ident: name,
         generics: ty::Generics {
-            bounds: bounds,
+            type_param_defs: type_param_defs,
             region_param: None
         },
         transformed_self_ty: transformed_self_ty,
@@ -797,8 +798,9 @@ pub fn get_provided_trait_methods(intr: @ident_interner, cdata: cmd,
 
         let did = item_def_id(mth, cdata);
 
-        let bounds = item_ty_param_bounds(mth, tcx, cdata,
-                                          tag_items_data_item_ty_param_bounds);
+        let type_param_defs =
+            item_ty_param_defs(mth, tcx, cdata,
+                               tag_items_data_item_ty_param_bounds);
         let name = item_name(intr, mth);
         let ty = doc_type(mth, tcx, cdata);
 
@@ -815,7 +817,7 @@ pub fn get_provided_trait_methods(intr: @ident_interner, cdata: cmd,
         let ty_method = ty::method {
             ident: name,
             generics: ty::Generics {
-                bounds: bounds,
+                type_param_defs: type_param_defs,
                 region_param: None
             },
             transformed_self_ty: transformed_self_ty,

src/librustc/metadata/encoder.rs

@@ -179,10 +179,10 @@ fn encode_family(ebml_w: writer::Encoder, c: char) {
 
 pub fn def_to_str(did: def_id) -> ~str { fmt!("%d:%d", did.crate, did.node) }
 
-fn encode_ty_type_param_bounds(ebml_w: writer::Encoder,
-                               ecx: @EncodeContext,
-                               params: @~[ty::param_bounds],
-                               tag: uint) {
+fn encode_ty_type_param_defs(ebml_w: writer::Encoder,
+                             ecx: @EncodeContext,
+                             params: @~[ty::TypeParameterDef],
+                             tag: uint) {
     let ty_str_ctxt = @tyencode::ctxt {
         diag: ecx.diag,
         ds: def_to_str,
@@ -191,18 +191,18 @@ fn encode_ty_type_param_bounds(ebml_w: writer::Encoder,
         abbrevs: tyencode::ac_use_abbrevs(ecx.type_abbrevs)};
     for params.each |param| {
         ebml_w.start_tag(tag);
-        tyencode::enc_bounds(ebml_w.writer, ty_str_ctxt, *param);
+        tyencode::enc_type_param_def(ebml_w.writer, ty_str_ctxt, param);
         ebml_w.end_tag();
     }
 }
 
 fn encode_type_param_bounds(ebml_w: writer::Encoder,
                             ecx: @EncodeContext,
                             params: &OptVec<TyParam>) {
-    let ty_param_bounds =
-        @params.map_to_vec(|param| *ecx.tcx.ty_param_bounds.get(&param.id));
-    encode_ty_type_param_bounds(ebml_w, ecx, ty_param_bounds,
-                                tag_items_data_item_ty_param_bounds);
+    let ty_param_defs =
+        @params.map_to_vec(|param| *ecx.tcx.ty_param_defs.get(&param.id));
+    encode_ty_type_param_defs(ebml_w, ecx, ty_param_defs,
+                              tag_items_data_item_ty_param_bounds);
 }
 
 
@@ -588,8 +588,9 @@ fn encode_method_ty_fields(ecx: @EncodeContext,
 {
     encode_def_id(ebml_w, method_ty.def_id);
     encode_name(ecx, ebml_w, method_ty.ident);
-    encode_ty_type_param_bounds(ebml_w, ecx, method_ty.generics.bounds,
-                                tag_item_method_tps);
+    encode_ty_type_param_defs(ebml_w, ecx,
+                              method_ty.generics.type_param_defs,
+                              tag_item_method_tps);
     encode_transformed_self_ty(ecx, ebml_w, method_ty.transformed_self_ty);
     encode_method_fty(ecx, ebml_w, &method_ty.fty);
     encode_visibility(ebml_w, method_ty.vis);
@@ -952,8 +953,9 @@ fn encode_info_for_item(ecx: @EncodeContext, ebml_w: writer::Encoder,
                                       method_ty.fty.purity));
 
                     let tpt = ty::lookup_item_type(tcx, method_def_id);
-                    encode_ty_type_param_bounds(ebml_w, ecx, tpt.generics.bounds,
-                                                tag_items_data_item_ty_param_bounds);
+                    encode_ty_type_param_defs(ebml_w, ecx,
+                                              tpt.generics.type_param_defs,
+                                              tag_items_data_item_ty_param_bounds);
                     encode_type(ecx, ebml_w, tpt.ty);
                 }
 

src/librustc/metadata/tydecode.rs

@@ -547,11 +547,17 @@ pub fn parse_def_id(buf: &[u8]) -> ast::def_id {
     ast::def_id { crate: crate_num, node: def_num }
 }
 
-pub fn parse_bounds_data(data: @~[u8], start: uint,
-                         crate_num: int, tcx: ty::ctxt, conv: conv_did)
-                      -> @~[ty::param_bound] {
+pub fn parse_type_param_def_data(data: @~[u8], start: uint,
+                                 crate_num: int, tcx: ty::ctxt,
+                                 conv: conv_did) -> ty::TypeParameterDef
+{
     let st = parse_state_from_data(data, crate_num, start, tcx);
-    parse_bounds(st, conv)
+    parse_type_param_def(st, conv)
+}
+
+fn parse_type_param_def(st: @mut PState, conv: conv_did) -> ty::TypeParameterDef {
+    ty::TypeParameterDef {def_id: parse_def(st, NominalType, conv),
+                          bounds: parse_bounds(st, conv)}
 }
 
 fn parse_bounds(st: @mut PState, conv: conv_did) -> @~[ty::param_bound] {

src/librustc/metadata/tyencode.rs

@@ -412,7 +412,7 @@ fn enc_fn_sig(w: @io::Writer, cx: @ctxt, fsig: &ty::FnSig) {
     enc_ty(w, cx, fsig.output);
 }
 
-pub fn enc_bounds(w: @io::Writer, cx: @ctxt, bs: @~[ty::param_bound]) {
+fn enc_bounds(w: @io::Writer, cx: @ctxt, bs: @~[ty::param_bound]) {
     for vec::each(*bs) |bound| {
         match *bound {
           ty::bound_owned => w.write_char('S'),
@@ -428,6 +428,12 @@ pub fn enc_bounds(w: @io::Writer, cx: @ctxt, bs: @~[ty::param_bound]) {
     w.write_char('.');
 }
 
+pub fn enc_type_param_def(w: @io::Writer, cx: @ctxt, v: &ty::TypeParameterDef) {
+    w.write_str((cx.ds)(v.def_id));
+    w.write_char('|');
+    enc_bounds(w, cx, v.bounds);
+}
+
 //
 // Local Variables:
 // mode: rust

src/librustc/middle/astencode.rs

@@ -741,7 +741,9 @@ trait ebml_writer_helpers {
     fn emit_ty(&self, ecx: @e::EncodeContext, ty: ty::t);
     fn emit_vstore(&self, ecx: @e::EncodeContext, vstore: ty::vstore);
     fn emit_tys(&self, ecx: @e::EncodeContext, tys: ~[ty::t]);
-    fn emit_bounds(&self, ecx: @e::EncodeContext, bs: ty::param_bounds);
+    fn emit_type_param_def(&self,
+                           ecx: @e::EncodeContext,
+                           type_param_def: &ty::TypeParameterDef);
     fn emit_tpbt(&self, ecx: @e::EncodeContext,
                  tpbt: ty::ty_param_bounds_and_ty);
 }
@@ -771,9 +773,12 @@ impl ebml_writer_helpers for writer::Encoder {
         }
     }
 
-    fn emit_bounds(&self, ecx: @e::EncodeContext, bs: ty::param_bounds) {
+    fn emit_type_param_def(&self,
+                           ecx: @e::EncodeContext,
+                           type_param_def: &ty::TypeParameterDef) {
         do self.emit_opaque {
-            tyencode::enc_bounds(self.writer, ecx.ty_str_ctxt(), bs)
+            tyencode::enc_type_param_def(self.writer, ecx.ty_str_ctxt(),
+                                         type_param_def)
         }
     }
 
@@ -782,9 +787,11 @@ impl ebml_writer_helpers for writer::Encoder {
         do self.emit_struct("ty_param_bounds_and_ty", 2) {
             do self.emit_field(~"generics", 0) {
                 do self.emit_struct("Generics", 2) {
-                    do self.emit_field(~"bounds", 0) {
-                        do self.emit_from_vec(*tpbt.generics.bounds) |bs| {
-                            self.emit_bounds(ecx, *bs);
+                    do self.emit_field(~"type_param_defs", 0) {
+                        do self.emit_from_vec(*tpbt.generics.type_param_defs)
+                            |type_param_def|
+                        {
+                            self.emit_type_param_def(ecx, type_param_def);
                         }
                     }
                     do self.emit_field(~"region_param", 1) {
@@ -889,11 +896,11 @@ fn encode_side_tables_for_id(ecx: @e::EncodeContext,
         }
     }
 
-    for tcx.ty_param_bounds.find(&id).each |&pbs| {
-        do ebml_w.tag(c::tag_table_param_bounds) {
+    for tcx.ty_param_defs.find(&id).each |&type_param_def| {
+        do ebml_w.tag(c::tag_table_param_defs) {
             ebml_w.id(id);
             do ebml_w.tag(c::tag_table_val) {
-                ebml_w.emit_bounds(ecx, *pbs)
+                ebml_w.emit_type_param_def(ecx, type_param_def)
             }
         }
     }
@@ -990,7 +997,7 @@ trait ebml_decoder_decoder_helpers {
     fn read_arg(&self, xcx: @ExtendedDecodeContext) -> ty::arg;
     fn read_ty(&self, xcx: @ExtendedDecodeContext) -> ty::t;
     fn read_tys(&self, xcx: @ExtendedDecodeContext) -> ~[ty::t];
-    fn read_bounds(&self, xcx: @ExtendedDecodeContext) -> @~[ty::param_bound];
+    fn read_type_param_def(&self, xcx: @ExtendedDecodeContext) -> ty::TypeParameterDef;
     fn read_ty_param_bounds_and_ty(&self, xcx: @ExtendedDecodeContext)
                                 -> ty::ty_param_bounds_and_ty;
     fn convert_def_id(&self, xcx: @ExtendedDecodeContext,
@@ -1038,10 +1045,9 @@ impl ebml_decoder_decoder_helpers for reader::Decoder {
         self.read_to_vec(|| self.read_ty(xcx) )
     }
 
-    fn read_bounds(&self, xcx: @ExtendedDecodeContext)
-                  -> @~[ty::param_bound] {
+    fn read_type_param_def(&self, xcx: @ExtendedDecodeContext) -> ty::TypeParameterDef {
         do self.read_opaque |doc| {
-            tydecode::parse_bounds_data(
+            tydecode::parse_type_param_def_data(
                 doc.data, doc.start, xcx.dcx.cdata.cnum, xcx.dcx.tcx,
                 |s, a| self.convert_def_id(xcx, s, a))
         }
@@ -1054,8 +1060,8 @@ impl ebml_decoder_decoder_helpers for reader::Decoder {
             ty::ty_param_bounds_and_ty {
                 generics: do self.read_struct("Generics", 2) {
                     ty::Generics {
-                        bounds: self.read_field(~"bounds", 0, || {
-                            @self.read_to_vec(|| self.read_bounds(xcx) )
+                        type_param_defs: self.read_field("type_param_defs", 0, || {
+                            @self.read_to_vec(|| self.read_type_param_def(xcx))
                         }),
                         region_param: self.read_field(~"region_param", 1, || {
                             Decodable::decode(self)
@@ -1134,9 +1140,9 @@ fn decode_side_tables(xcx: @ExtendedDecodeContext,
                 let tpbt = val_dsr.read_ty_param_bounds_and_ty(xcx);
                 let lid = ast::def_id { crate: ast::local_crate, node: id };
                 dcx.tcx.tcache.insert(lid, tpbt);
-            } else if tag == (c::tag_table_param_bounds as uint) {
-                let bounds = val_dsr.read_bounds(xcx);
-                dcx.tcx.ty_param_bounds.insert(id, bounds);
+            } else if tag == (c::tag_table_param_defs as uint) {
+                let bounds = val_dsr.read_type_param_def(xcx);
+                dcx.tcx.ty_param_defs.insert(id, bounds);
             } else if tag == (c::tag_table_last_use as uint) {
                 let ids = val_dsr.read_to_vec(|| {
                     xcx.tr_id(val_dsr.read_int())

src/librustc/middle/borrowck/gather_loans.rs

@@ -29,7 +29,7 @@ use middle::pat_util;
 use middle::ty::{ty_region};
 use middle::ty;
 use util::common::indenter;
-use util::ppaux::{expr_repr, region_to_str};
+use util::ppaux::{Repr, region_to_str};
 
 use core::hashmap::{HashSet, HashMap};
 use core::vec;
@@ -282,7 +282,7 @@ pub impl GatherLoanCtxt {
                              expr: @ast::expr,
                              adjustment: &ty::AutoAdjustment) {
         debug!("guarantee_adjustments(expr=%s, adjustment=%?)",
-               expr_repr(self.tcx(), expr), adjustment);
+               expr.repr(self.tcx()), adjustment);
         let _i = indenter();
 
         match *adjustment {