auto merge of #14604 : nikomatsakis/rust/issue-5527-namespace-substs,…

… r=pcwalton

The current setup is to have a single vector of type parameters in
scope at any one time. We then have to concatenate the parameters from
the impl/trait with those of the method. This makes a lot of things
awkward, most notably associated fns ("static fns"). This branch
restructures the substitutions into three distinct namespaces (type,
self, fn). This makes most of the "type parameter management"
trivial. This also sets us up to support UFCS (though I haven't made
any particular changes in that direction in this patch).

Along the way, this patch fixes a few miscellaneous bits of code cleanup:

1. Patch resolve to detect references to out-of-scope type parameters,
   rather than checking for "out of bound" indices during substitution
   (fixes #14603).

2. Move def out of libsyntax into librustc where it belongs. I should have
   moved DefId too, but didn't.
   
3. Permit homogeneous tuples like `(T, T, T)` to be used as fixed-length
   vectors like `[T, ..3]`. This is awfully handy, though public facing.
   I suppose it requires an RFC.

4. Add some missing tests.

cc #5527

r? @pcwalton or @pnkfelix

src/librustc/metadata/common.rs

@@ -189,9 +189,7 @@ pub static tag_impls_impl: uint = 0x81;
 pub static tag_items_data_item_inherent_impl: uint = 0x82;
 pub static tag_items_data_item_extension_impl: uint = 0x83;
 
-pub static tag_region_param_def: uint = 0x84;
-pub static tag_region_param_def_ident: uint = 0x85;
-pub static tag_region_param_def_def_id: uint = 0x86;
+// GAP 0x84, 0x85, 0x86
 
 pub static tag_native_libraries: uint = 0x87;
 pub static tag_native_libraries_lib: uint = 0x88;
@@ -217,3 +215,9 @@ pub struct LinkMeta {
     pub crateid: CrateId,
     pub crate_hash: Svh,
 }
+
+pub static tag_region_param_def: uint = 0x90;
+pub static tag_region_param_def_ident: uint = 0x91;
+pub static tag_region_param_def_def_id: uint = 0x92;
+pub static tag_region_param_def_space: uint = 0x93;
+pub static tag_region_param_def_index: uint = 0x94;

src/librustc/metadata/csearch.rs

@@ -18,6 +18,7 @@ use metadata::decoder;
 use middle::lang_items;
 use middle::ty;
 use middle::typeck;
+use middle::subst::VecPerParamSpace;
 
 use serialize::ebml;
 use serialize::ebml::reader;
@@ -223,8 +224,8 @@ pub fn get_field_type(tcx: &ty::ctxt, class_id: ast::DefId,
         });
     let ty = decoder::item_type(def, the_field, tcx, &*cdata);
     ty::ty_param_bounds_and_ty {
-        generics: ty::Generics {type_param_defs: Rc::new(Vec::new()),
-                                region_param_defs: Rc::new(Vec::new())},
+        generics: ty::Generics {types: VecPerParamSpace::empty(),
+                                regions: VecPerParamSpace::empty()},
         ty: ty
     }
 }
@@ -240,7 +241,8 @@ pub fn get_impl_trait(tcx: &ty::ctxt,
 
 // Given a def_id for an impl, return information about its vtables
 pub fn get_impl_vtables(tcx: &ty::ctxt,
-                        def: ast::DefId) -> typeck::impl_res {
+                        def: ast::DefId)
+                        -> typeck::vtable_res {
     let cstore = &tcx.sess.cstore;
     let cdata = cstore.get_crate_data(def.krate);
     decoder::get_impl_vtables(&*cdata, def.node, tcx)

src/librustc/metadata/decoder.rs

@@ -23,6 +23,7 @@ use metadata::tydecode::{parse_ty_data, parse_def_id,
                          parse_bare_fn_ty_data, parse_trait_ref_data};
 use middle::lang_items;
 use middle::def;
+use middle::subst;
 use middle::ty::{ImplContainer, TraitContainer};
 use middle::ty;
 use middle::typeck;
@@ -257,34 +258,44 @@ fn item_ty_param_defs(item: ebml::Doc,
                       tcx: &ty::ctxt,
                       cdata: Cmd,
                       tag: uint)
-                      -> Rc<Vec<ty::TypeParameterDef> > {
-    let mut bounds = Vec::new();
+                      -> subst::VecPerParamSpace<ty::TypeParameterDef> {
+    let mut bounds = subst::VecPerParamSpace::empty();
     reader::tagged_docs(item, tag, |p| {
         let bd = parse_type_param_def_data(
             p.data, p.start, cdata.cnum, tcx,
             |_, did| translate_def_id(cdata, did));
-        bounds.push(bd);
+        bounds.push(bd.space, bd);
         true
     });
-    Rc::new(bounds)
+    bounds
 }
 
 fn item_region_param_defs(item_doc: ebml::Doc, cdata: Cmd)
-                          -> Rc<Vec<ty::RegionParameterDef> > {
-    let mut v = Vec::new();
+                          -> subst::VecPerParamSpace<ty::RegionParameterDef>
+{
+    let mut v = subst::VecPerParamSpace::empty();
     reader::tagged_docs(item_doc, tag_region_param_def, |rp_doc| {
-            let ident_str_doc = reader::get_doc(rp_doc,
-                                                tag_region_param_def_ident);
-            let ident = item_name(&*token::get_ident_interner(), ident_str_doc);
-            let def_id_doc = reader::get_doc(rp_doc,
-                                             tag_region_param_def_def_id);
-            let def_id = reader::with_doc_data(def_id_doc, parse_def_id);
-            let def_id = translate_def_id(cdata, def_id);
-            v.push(ty::RegionParameterDef { name: ident.name,
-                                            def_id: def_id });
-            true
-        });
-    Rc::new(v)
+        let ident_str_doc = reader::get_doc(rp_doc,
+                                            tag_region_param_def_ident);
+        let ident = item_name(&*token::get_ident_interner(), ident_str_doc);
+        let def_id_doc = reader::get_doc(rp_doc,
+                                         tag_region_param_def_def_id);
+        let def_id = reader::with_doc_data(def_id_doc, parse_def_id);
+        let def_id = translate_def_id(cdata, def_id);
+
+        let doc = reader::get_doc(rp_doc, tag_region_param_def_space);
+        let space = subst::ParamSpace::from_uint(reader::doc_as_u64(doc) as uint);
+
+        let doc = reader::get_doc(rp_doc, tag_region_param_def_index);
+        let index = reader::doc_as_u64(doc) as uint;
+
+        v.push(space, ty::RegionParameterDef { name: ident.name,
+                                               def_id: def_id,
+                                               space: space,
+                                               index: index });
+        true
+    });
+    v
 }
 
 fn enum_variant_ids(item: ebml::Doc, cdata: Cmd) -> Vec<ast::DefId> {
@@ -403,8 +414,8 @@ pub fn get_trait_def(cdata: Cmd,
     }
 
     ty::TraitDef {
-        generics: ty::Generics {type_param_defs: tp_defs,
-                                region_param_defs: rp_defs},
+        generics: ty::Generics {types: tp_defs,
+                                regions: rp_defs},
         bounds: bounds,
         trait_ref: Rc::new(item_trait_ref(item_doc, tcx, cdata))
     }
@@ -422,8 +433,8 @@ pub fn get_type(cdata: Cmd, id: ast::NodeId, tcx: &ty::ctxt)
     let rp_defs = item_region_param_defs(item, cdata);
 
     ty::ty_param_bounds_and_ty {
-        generics: ty::Generics {type_param_defs: tp_defs,
-                                region_param_defs: rp_defs},
+        generics: ty::Generics {types: tp_defs,
+                                regions: rp_defs},
         ty: t
     }
 }
@@ -440,16 +451,13 @@ pub fn get_impl_trait(cdata: Cmd,
 
 pub fn get_impl_vtables(cdata: Cmd,
                         id: ast::NodeId,
-                        tcx: &ty::ctxt) -> typeck::impl_res
+                        tcx: &ty::ctxt)
+                        -> typeck::vtable_res
 {
     let item_doc = lookup_item(id, cdata.data());
     let vtables_doc = reader::get_doc(item_doc, tag_item_impl_vtables);
     let mut decoder = reader::Decoder::new(vtables_doc);
-
-    typeck::impl_res {
-        trait_vtables: decoder.read_vtable_res(tcx, cdata),
-        self_vtables: decoder.read_vtable_param_res(tcx, cdata)
-    }
+    decoder.read_vtable_res(tcx, cdata)
 }
 
 
@@ -802,8 +810,8 @@ pub fn get_method(intr: Rc<IdentInterner>, cdata: Cmd, id: ast::NodeId,
     ty::Method::new(
         name,
         ty::Generics {
-            type_param_defs: type_param_defs,
-            region_param_defs: rp_defs,
+            types: type_param_defs,
+            regions: rp_defs,
         },
         fty,
         explicit_self,

src/librustc/metadata/encoder.rs

@@ -19,6 +19,7 @@ use metadata::common::*;
 use metadata::cstore;
 use metadata::decoder;
 use metadata::tyencode;
+use middle::subst::VecPerParamSpace;
 use middle::ty::{node_id_to_type, lookup_item_type};
 use middle::astencode;
 use middle::ty;
@@ -128,10 +129,9 @@ fn encode_trait_ref(ebml_w: &mut Encoder,
 
 fn encode_impl_vtables(ebml_w: &mut Encoder,
                        ecx: &EncodeContext,
-                       vtables: &typeck::impl_res) {
+                       vtables: &typeck::vtable_res) {
     ebml_w.start_tag(tag_item_impl_vtables);
-    astencode::encode_vtable_res(ecx, ebml_w, &vtables.trait_vtables);
-    astencode::encode_vtable_param_res(ecx, ebml_w, &vtables.self_vtables);
+    astencode::encode_vtable_res(ecx, ebml_w, vtables);
     ebml_w.end_tag();
 }
 
@@ -148,7 +148,7 @@ pub fn def_to_str(did: DefId) -> String {
 
 fn encode_ty_type_param_defs(ebml_w: &mut Encoder,
                              ecx: &EncodeContext,
-                             params: &[ty::TypeParameterDef],
+                             params: &VecPerParamSpace<ty::TypeParameterDef>,
                              tag: uint) {
     let ty_str_ctxt = &tyencode::ctxt {
         diag: ecx.diag,
@@ -164,7 +164,7 @@ fn encode_ty_type_param_defs(ebml_w: &mut Encoder,
 }
 
 fn encode_region_param_defs(ebml_w: &mut Encoder,
-                            params: &[ty::RegionParameterDef]) {
+                            params: &VecPerParamSpace<ty::RegionParameterDef>) {
     for param in params.iter() {
         ebml_w.start_tag(tag_region_param_def);
 
@@ -175,6 +175,12 @@ fn encode_region_param_defs(ebml_w: &mut Encoder,
         ebml_w.wr_tagged_str(tag_region_param_def_def_id,
                              def_to_str(param.def_id).as_slice());
 
+        ebml_w.wr_tagged_u64(tag_region_param_def_space,
+                             param.space.to_uint() as u64);
+
+        ebml_w.wr_tagged_u64(tag_region_param_def_index,
+                             param.index as u64);
+
         ebml_w.end_tag();
     }
 }
@@ -191,9 +197,9 @@ fn encode_item_variances(ebml_w: &mut Encoder,
 fn encode_bounds_and_type(ebml_w: &mut Encoder,
                           ecx: &EncodeContext,
                           tpt: &ty::ty_param_bounds_and_ty) {
-    encode_ty_type_param_defs(ebml_w, ecx, tpt.generics.type_param_defs(),
+    encode_ty_type_param_defs(ebml_w, ecx, &tpt.generics.types,
                               tag_items_data_item_ty_param_bounds);
-    encode_region_param_defs(ebml_w, tpt.generics.region_param_defs());
+    encode_region_param_defs(ebml_w, &tpt.generics.regions);
     encode_type(ecx, ebml_w, tpt.ty);
 }
 
@@ -725,8 +731,7 @@ fn encode_method_ty_fields(ecx: &EncodeContext,
                            method_ty: &ty::Method) {
     encode_def_id(ebml_w, method_ty.def_id);
     encode_name(ebml_w, method_ty.ident.name);
-    encode_ty_type_param_defs(ebml_w, ecx,
-                              method_ty.generics.type_param_defs(),
+    encode_ty_type_param_defs(ebml_w, ecx, &method_ty.generics.types,
                               tag_item_method_tps);
     encode_method_fty(ecx, ebml_w, &method_ty.fty);
     encode_visibility(ebml_w, method_ty.vis);
@@ -770,10 +775,8 @@ fn encode_info_for_method(ecx: &EncodeContext,
     }
 
     for &ast_method in ast_method_opt.iter() {
-        let num_params = tpt.generics.type_param_defs().len();
-        if num_params > 0u ||
-                is_default_impl ||
-                should_inline(ast_method.attrs.as_slice()) {
+        let any_types = !tpt.generics.types.is_empty();
+        if any_types || is_default_impl || should_inline(ast_method.attrs.as_slice()) {
             encode_inlined_item(ecx, ebml_w,
                                 IIMethodRef(local_def(parent_id), false,
                                             &*ast_method));
@@ -1125,9 +1128,9 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_item_variances(ebml_w, ecx, item.id);
         let trait_def = ty::lookup_trait_def(tcx, def_id);
         encode_ty_type_param_defs(ebml_w, ecx,
-                                  trait_def.generics.type_param_defs(),
+                                  &trait_def.generics.types,
                                   tag_items_data_item_ty_param_bounds);
-        encode_region_param_defs(ebml_w, trait_def.generics.region_param_defs());
+        encode_region_param_defs(ebml_w, &trait_def.generics.regions);
         encode_trait_ref(ebml_w, ecx, &*trait_def.trait_ref, tag_item_trait_ref);
         encode_name(ebml_w, item.ident.name);
         encode_attributes(ebml_w, item.attrs.as_slice());