Refactor so that references to traits are not represented using a type with a

bare function store (which is not in fact a kind of value) but rather
ty::TraitRef.  Removes many uses of fail!() and other telltale signs of
type-semantic mismatch.

cc #4183 (not a fix, but related)

Author: nikomatsakis

src/libcore/option.rs

@@ -46,7 +46,8 @@ use ops::Add;
 use kinds::Copy;
 use util;
 use num::Zero;
-use iter::{BaseIter, MutableIter};
+use iter::{BaseIter, MutableIter, ExtendedIter};
+use iter;
 
 #[cfg(test)] use ptr;
 #[cfg(test)] use str;
@@ -118,6 +119,31 @@ impl<T> MutableIter<T> for Option<T> {
     }
 }
 
+impl<A> ExtendedIter<A> for Option<A> {
+    pub fn eachi(&self, blk: &fn(uint, v: &A) -> bool) {
+        iter::eachi(self, blk)
+    }
+    pub fn all(&self, blk: &fn(&A) -> bool) -> bool {
+        iter::all(self, blk)
+    }
+    pub fn any(&self, blk: &fn(&A) -> bool) -> bool {
+        iter::any(self, blk)
+    }
+    pub fn foldl<B>(&self, b0: B, blk: &fn(&B, &A) -> B) -> B {
+        iter::foldl(self, b0, blk)
+    }
+    pub fn position(&self, f: &fn(&A) -> bool) -> Option<uint> {
+        iter::position(self, f)
+    }
+    fn map_to_vec<B>(&self, op: &fn(&A) -> B) -> ~[B] {
+        iter::map_to_vec(self, op)
+    }
+    fn flat_map_to_vec<B,IB:BaseIter<B>>(&self, op: &fn(&A) -> IB)
+        -> ~[B] {
+        iter::flat_map_to_vec(self, op)
+    }
+}
+
 pub impl<T> Option<T> {
     /// Returns true if the option equals `none`
     fn is_none(&const self) -> bool {

src/libcore/reflect.rs

@@ -443,9 +443,9 @@ impl<V:TyVisitor + MovePtr> TyVisitor for MovePtrAdaptor<V> {
     }
 
     fn visit_trait(&self) -> bool {
-        self.align_to::<TyVisitor>();
+        self.align_to::<@TyVisitor>();
         if ! self.inner.visit_trait() { return false; }
-        self.bump_past::<TyVisitor>();
+        self.bump_past::<@TyVisitor>();
         true
     }
 

src/libcore/run.rs

@@ -298,7 +298,7 @@ pub fn start_program(prog: &str, args: &[~str]) -> @Program {
     @ProgRes(repr) as @Program
 }
 
-fn read_all(rd: io::Reader) -> ~str {
+fn read_all(rd: @io::Reader) -> ~str {
     let buf = io::with_bytes_writer(|wr| {
         let mut bytes = [0, ..4096];
         while !rd.eof() {

src/librustc/metadata/common.rs

@@ -74,7 +74,9 @@ pub static tag_crate_dep_vers: uint = 0x2cu;
 pub static tag_mod_impl: uint = 0x30u;
 
 pub static tag_item_trait_method: uint = 0x31u;
-pub static tag_impl_trait: uint = 0x32u;
+
+pub static tag_item_trait_ref: uint = 0x32u;
+pub static tag_item_super_trait_ref: uint = 0x33u;
 
 // discriminator value for variants
 pub static tag_disr_val: uint = 0x34u;

src/librustc/metadata/csearch.rs

@@ -139,7 +139,7 @@ pub fn get_provided_trait_methods(tcx: ty::ctxt,
     decoder::get_provided_trait_methods(cstore.intr, cdata, def.node, tcx)
 }
 
-pub fn get_supertraits(tcx: ty::ctxt, def: ast::def_id) -> ~[ty::t] {
+pub fn get_supertraits(tcx: ty::ctxt, def: ast::def_id) -> ~[@ty::TraitRef] {
     let cstore = tcx.cstore;
     let cdata = cstore::get_crate_data(cstore, def.crate);
     decoder::get_supertraits(cdata, def.node, tcx)
@@ -180,6 +180,12 @@ pub fn get_type(tcx: ty::ctxt,
     decoder::get_type(cdata, def.node, tcx)
 }
 
+pub fn get_trait_def(tcx: ty::ctxt, def: ast::def_id) -> ty::TraitDef {
+    let cstore = tcx.cstore;
+    let cdata = cstore::get_crate_data(cstore, def.crate);
+    decoder::get_trait_def(cdata, def.node, tcx)
+}
+
 pub fn get_region_param(cstore: @mut metadata::cstore::CStore,
                         def: ast::def_id) -> Option<ty::region_variance> {
     let cdata = cstore::get_crate_data(cstore, def.crate);
@@ -204,16 +210,17 @@ 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 {
-        bounds: @~[],
-        region_param: None,
+        generics: ty::Generics {bounds: @~[],
+                                region_param: None},
         ty: ty
     }
 }
 
 // Given a def_id for an impl or class, return the traits it implements,
 // or the empty vector if it's not for an impl or for a class that implements
 // traits
-pub fn get_impl_traits(tcx: ty::ctxt, def: ast::def_id) -> ~[ty::t] {
+pub fn get_impl_traits(tcx: ty::ctxt,
+                       def: ast::def_id) -> ~[@ty::TraitRef] {
     let cstore = tcx.cstore;
     let cdata = cstore::get_crate_data(cstore, def.crate);
     decoder::get_impl_traits(cdata, def.node, tcx)

src/librustc/metadata/decoder.rs

@@ -20,7 +20,7 @@ use metadata::csearch;
 use metadata::cstore;
 use metadata::decoder;
 use metadata::tydecode::{parse_ty_data, parse_def_id, parse_bounds_data,
-                         parse_bare_fn_ty_data};
+                         parse_bare_fn_ty_data, parse_trait_ref_data};
 use middle::{ty, resolve};
 
 use core::hash::HashUtil;
@@ -256,12 +256,14 @@ pub fn item_type(item_id: ast::def_id, item: ebml::Doc,
     }
 }
 
-fn item_impl_traits(item: ebml::Doc, tcx: ty::ctxt, cdata: cmd) -> ~[ty::t] {
-    let mut results = ~[];
-    for reader::tagged_docs(item, tag_impl_trait) |ity| {
-        results.push(doc_type(ity, tcx, cdata));
-    };
-    results
+fn doc_trait_ref(doc: ebml::Doc, tcx: ty::ctxt, cdata: cmd) -> ty::TraitRef {
+    parse_trait_ref_data(doc.data, cdata.cnum, doc.start, tcx,
+                         |_, did| translate_def_id(cdata, did))
+}
+
+fn item_trait_ref(doc: ebml::Doc, tcx: ty::ctxt, cdata: cmd) -> ty::TraitRef {
+    let tp = reader::get_doc(doc, tag_item_trait_ref);
+    doc_trait_ref(tp, tcx, cdata)
 }
 
 fn item_ty_param_bounds(item: ebml::Doc, tcx: ty::ctxt, cdata: cmd,
@@ -371,6 +373,21 @@ pub fn lookup_def(cnum: ast::crate_num, data: @~[u8], did_: ast::def_id) ->
     return def_like_to_def(item_to_def_like(item, did, cnum));
 }
 
+pub fn get_trait_def(cdata: cmd,
+                     item_id: ast::node_id,
+                     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 rp = item_ty_region_param(item_doc);
+    ty::TraitDef {
+        generics: ty::Generics {bounds: tp_bounds,
+                                region_param: rp},
+        trait_ref: @item_trait_ref(item_doc, tcx, cdata)
+    }
+}
+
 pub fn get_type(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
     -> ty::ty_param_bounds_and_ty {
 
@@ -382,8 +399,8 @@ pub fn get_type(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
     } else { @~[] };
     let rp = item_ty_region_param(item);
     ty::ty_param_bounds_and_ty {
-        bounds: tp_bounds,
-        region_param: rp,
+        generics: ty::Generics {bounds: tp_bounds,
+                                region_param: rp},
         ty: t
     }
 }
@@ -399,9 +416,19 @@ pub fn get_type_param_count(data: @~[u8], id: ast::node_id) -> uint {
     item_ty_param_count(lookup_item(id, data))
 }
 
-pub fn get_impl_traits(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
-                    -> ~[ty::t] {
-    item_impl_traits(lookup_item(id, cdata.data), tcx, cdata)
+pub fn get_impl_traits(cdata: cmd,
+                       id: ast::node_id,
+                       tcx: ty::ctxt) -> ~[@ty::TraitRef]
+{
+    let item_doc = lookup_item(id, cdata.data);
+    let mut results = ~[];
+    for reader::tagged_docs(item_doc, tag_item_trait_ref) |tp| {
+        let trait_ref =
+            @parse_trait_ref_data(tp.data, cdata.cnum, tp.start, tcx,
+                                  |_, did| translate_def_id(cdata, did));
+        results.push(trait_ref);
+    };
+    results
 }
 
 pub fn get_impl_method(intr: @ident_interner, cdata: cmd, id: ast::node_id,
@@ -735,7 +762,10 @@ pub fn get_method(intr: @ident_interner, cdata: cmd, id: ast::node_id,
     let self_ty = get_self_ty(method_doc);
     ty::method {
         ident: name,
-        tps: bounds,
+        generics: ty::Generics {
+            bounds: bounds,
+            region_param: None
+        },
         transformed_self_ty: transformed_self_ty,
         fty: fty,
         self_ty: self_ty,
@@ -784,7 +814,10 @@ pub fn get_provided_trait_methods(intr: @ident_interner, cdata: cmd,
         let self_ty = get_self_ty(mth);
         let ty_method = ty::method {
             ident: name,
-            tps: bounds,
+            generics: ty::Generics {
+                bounds: bounds,
+                region_param: None
+            },
             transformed_self_ty: transformed_self_ty,
             fty: fty,
             self_ty: self_ty,
@@ -804,11 +837,11 @@ pub fn get_provided_trait_methods(intr: @ident_interner, cdata: cmd,
 
 /// Returns the supertraits of the given trait.
 pub fn get_supertraits(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
-                    -> ~[ty::t] {
+                    -> ~[@ty::TraitRef] {
     let mut results = ~[];
     let item_doc = lookup_item(id, cdata.data);
-    for reader::tagged_docs(item_doc, tag_impl_trait) |trait_doc| {
-        results.push(doc_type(trait_doc, tcx, cdata));
+    for reader::tagged_docs(item_doc, tag_item_super_trait_ref) |trait_doc| {
+        results.push(@doc_trait_ref(trait_doc, tcx, cdata));
     }
     return results;
 }
@@ -837,8 +870,8 @@ pub fn get_static_methods_if_impl(intr: @ident_interner,
         return None;
     }
 
-    // If this impl has a trait ref, don't consider it.
-    for reader::tagged_docs(item, tag_impl_trait) |_doc| {
+    // If this impl implements a trait, don't consider it.
+    for reader::tagged_docs(item, tag_item_trait_ref) |_doc| {
         return None;
     }
 

src/librustc/metadata/encoder.rs

@@ -153,14 +153,23 @@ fn add_to_index(ecx: @EncodeContext, ebml_w: writer::Encoder, path: &[ident],
         });
 }
 
-fn encode_trait_ref(ebml_w: writer::Encoder, ecx: @EncodeContext,
-                    t: @trait_ref) {
-    ebml_w.start_tag(tag_impl_trait);
-    encode_type(ecx, ebml_w, node_id_to_type(ecx.tcx, t.ref_id));
+fn encode_trait_ref(ebml_w: writer::Encoder,
+                    ecx: @EncodeContext,
+                    trait_ref: &ty::TraitRef,
+                    tag: uint)
+{
+    let ty_str_ctxt = @tyencode::ctxt {
+        diag: ecx.diag,
+        ds: def_to_str,
+        tcx: ecx.tcx,
+        reachable: |a| reachable(ecx, a),
+        abbrevs: tyencode::ac_use_abbrevs(ecx.type_abbrevs)};
+
+    ebml_w.start_tag(tag);
+    tyencode::enc_trait_ref(ebml_w.writer, ty_str_ctxt, trait_ref);
     ebml_w.end_tag();
 }
 
-
 // Item info table encoding
 fn encode_family(ebml_w: writer::Encoder, c: char) {
     ebml_w.start_tag(tag_items_data_item_family);
@@ -579,7 +588,7 @@ 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.tps,
+    encode_ty_type_param_bounds(ebml_w, ecx, method_ty.generics.bounds,
                                 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);
@@ -872,8 +881,9 @@ fn encode_info_for_item(ecx: @EncodeContext, ebml_w: writer::Encoder,
             ebml_w.writer.write(str::to_bytes(def_to_str(method_def_id)));
             ebml_w.end_tag();
         }
-        for opt_trait.each |associated_trait| {
-           encode_trait_ref(ebml_w, ecx, *associated_trait);
+        for opt_trait.each |ast_trait_ref| {
+            let trait_ref = ty::node_id_to_trait_ref(ecx.tcx, ast_trait_ref.ref_id);
+            encode_trait_ref(ebml_w, ecx, trait_ref, tag_item_trait_ref);
         }
         encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
         ebml_w.end_tag();
@@ -894,14 +904,15 @@ fn encode_info_for_item(ecx: @EncodeContext, ebml_w: writer::Encoder,
                                    &m.generics);
         }
       }
-      item_trait(ref generics, ref traits, ref ms) => {
+      item_trait(ref generics, ref super_traits, ref ms) => {
         add_to_index();
         ebml_w.start_tag(tag_items_data_item);
         encode_def_id(ebml_w, local_def(item.id));
         encode_family(ebml_w, 'I');
         encode_region_param(ecx, ebml_w, item);
         encode_type_param_bounds(ebml_w, ecx, &generics.ty_params);
-        encode_type(ecx, ebml_w, node_id_to_type(tcx, item.id));
+        let trait_def = ty::lookup_trait_def(tcx, local_def(item.id));
+        encode_trait_ref(ebml_w, ecx, trait_def.trait_ref, tag_item_trait_ref);
         encode_name(ecx, ebml_w, item.ident);
         encode_attributes(ebml_w, item.attrs);
         for ty::trait_method_def_ids(tcx, local_def(item.id)).each |&method_def_id| {
@@ -910,8 +921,9 @@ fn encode_info_for_item(ecx: @EncodeContext, ebml_w: writer::Encoder,
             ebml_w.end_tag();
         }
         encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
-        for traits.each |associated_trait| {
-            encode_trait_ref(ebml_w, ecx, *associated_trait);
+        for super_traits.each |ast_trait_ref| {
+            let trait_ref = ty::node_id_to_trait_ref(ecx.tcx, ast_trait_ref.ref_id);
+            encode_trait_ref(ebml_w, ecx, trait_ref, tag_item_super_trait_ref);
         }
         ebml_w.end_tag();
 
@@ -940,7 +952,7 @@ 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.bounds,
+                    encode_ty_type_param_bounds(ebml_w, ecx, tpt.generics.bounds,
                                                 tag_items_data_item_ty_param_bounds);
                     encode_type(ecx, ebml_w, tpt.ty);
                 }

src/librustc/metadata/tydecode.rs

@@ -125,6 +125,12 @@ pub fn parse_bare_fn_ty_data(data: @~[u8], crate_num: int, pos: uint, tcx: ty::c
     parse_bare_fn_ty(st, conv)
 }
 
+pub fn parse_trait_ref_data(data: @~[u8], crate_num: int, pos: uint, tcx: ty::ctxt,
+                            conv: conv_did) -> ty::TraitRef {
+    let st = parse_state_from_data(data, crate_num, pos, tcx);
+    parse_trait_ref(st, conv)
+}
+
 pub fn parse_arg_data(data: @~[u8], crate_num: int, pos: uint, tcx: ty::ctxt,
                       conv: conv_did) -> ty::arg {
     let st = parse_state_from_data(data, crate_num, pos, tcx);
@@ -183,7 +189,6 @@ fn parse_trait_store(st: @mut PState) -> ty::TraitStore {
         '~' => ty::UniqTraitStore,
         '@' => ty::BoxTraitStore,
         '&' => ty::RegionTraitStore(parse_region(st)),
-        '.' => ty::BareTraitStore,
         c => st.tcx.sess.bug(fmt!("parse_trait_store(): bad input '%c'", c))
     }
 }
@@ -265,6 +270,12 @@ fn parse_str(st: @mut PState, term: char) -> ~str {
     return result;
 }
 
+fn parse_trait_ref(st: @mut PState, conv: conv_did) -> ty::TraitRef {
+    let def = parse_def(st, NominalType, conv);
+    let substs = parse_substs(st, conv);
+    ty::TraitRef {def_id: def, substs: substs}
+}
+
 fn parse_ty(st: @mut PState, conv: conv_did) -> ty::t {
     match next(st) {
       'n' => return ty::mk_nil(st.tcx),
@@ -551,7 +562,7 @@ fn parse_bounds(st: @mut PState, conv: conv_did) -> @~[ty::param_bound] {
           'C' => ty::bound_copy,
           'K' => ty::bound_const,
           'O' => ty::bound_durable,
-          'I' => ty::bound_trait(parse_ty(st, conv)),
+          'I' => ty::bound_trait(@parse_trait_ref(st, conv)),
           '.' => break,
           _ => fail!(~"parse_bounds: bad bounds")
         });