auto merge of #7886 : msullivan/rust/default-methods, r=pcwalton

This does a bunch of cleanup on the data structures for the trait system. (Unfortunately it doesn't remove `provided_method_sources`. Maybe later.)

It also changes how cross crate methods are handled, so that information about them is exported in metadata, instead of having the methods regenerated by every crate that imports an impl.

r? @nikomatsakis, maybe?

src/librustc/metadata/common.rs

@@ -179,6 +179,8 @@ pub static tag_mod_child: uint = 0x7e;
 pub static tag_misc_info: uint = 0x7f;
 pub static tag_misc_info_crate_items: uint = 0x80;
 
+pub static tag_item_method_provided_source: uint = 0x81;
+
 pub struct LinkMeta {
     name: @str,
     vers: @str,

src/librustc/metadata/csearch.rs

@@ -15,7 +15,7 @@ use metadata::common::*;
 use metadata::cstore;
 use metadata::decoder;
 use metadata;
-use middle::{ty, resolve};
+use middle::ty;
 
 use std::vec;
 use reader = extra::ebml::reader;
@@ -97,10 +97,10 @@ pub fn get_enum_variants(tcx: ty::ctxt, def: ast::def_id)
 }
 
 /// Returns information about the given implementation.
-pub fn get_impl(cstore: @mut cstore::CStore, impl_def_id: ast::def_id)
-                -> resolve::Impl {
-    let cdata = cstore::get_crate_data(cstore, impl_def_id.crate);
-    decoder::get_impl(cstore.intr, cdata, impl_def_id.node)
+pub fn get_impl(tcx: ty::ctxt, impl_def_id: ast::def_id)
+                -> ty::Impl {
+    let cdata = cstore::get_crate_data(tcx.cstore, impl_def_id.crate);
+    decoder::get_impl(tcx.cstore.intr, cdata, impl_def_id.node, tcx)
 }
 
 pub fn get_method(tcx: ty::ctxt, def: ast::def_id) -> ty::Method {

src/librustc/metadata/decoder.rs

@@ -20,7 +20,7 @@ use metadata::decoder;
 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};
+use middle::ty;
 
 use std::hash::HashUtil;
 use std::int;
@@ -174,14 +174,6 @@ fn item_parent_item(d: ebml::Doc) -> Option<ast::def_id> {
     None
 }
 
-fn translated_parent_item_opt(cnum: ast::crate_num, d: ebml::Doc) ->
-        Option<ast::def_id> {
-    let trait_did_opt = item_parent_item(d);
-    do trait_did_opt.map |trait_did| {
-        ast::def_id { crate: cnum, node: trait_did.node }
-    }
-}
-
 fn item_reqd_and_translated_parent_item(cnum: ast::crate_num,
                                         d: ebml::Doc) -> ast::def_id {
     let trait_did = item_parent_item(d).expect("item without parent");
@@ -193,6 +185,12 @@ fn item_def_id(d: ebml::Doc, cdata: cmd) -> ast::def_id {
     return translate_def_id(cdata, reader::with_doc_data(tagdoc, parse_def_id));
 }
 
+fn get_provided_source(d: ebml::Doc, cdata: cmd) -> Option<ast::def_id> {
+    do reader::maybe_get_doc(d, tag_item_method_provided_source).map |doc| {
+        translate_def_id(cdata, reader::with_doc_data(*doc, parse_def_id))
+    }
+}
+
 fn each_reexport(d: ebml::Doc, f: &fn(ebml::Doc) -> bool) -> bool {
     for reader::tagged_docs(d, tag_items_data_item_reexport) |reexport_doc| {
         if !f(reexport_doc) {
@@ -323,13 +321,19 @@ fn item_to_def_like(item: ebml::Doc, did: ast::def_id, cnum: ast::crate_num)
         UnsafeFn  => dl_def(ast::def_fn(did, ast::unsafe_fn)),
         Fn        => dl_def(ast::def_fn(did, ast::impure_fn)),
         ForeignFn => dl_def(ast::def_fn(did, ast::extern_fn)),
-        UnsafeStaticMethod => {
-            let trait_did_opt = translated_parent_item_opt(cnum, item);
-            dl_def(ast::def_static_method(did, trait_did_opt, ast::unsafe_fn))
-        }
-        StaticMethod => {
-            let trait_did_opt = translated_parent_item_opt(cnum, item);
-            dl_def(ast::def_static_method(did, trait_did_opt, ast::impure_fn))
+        StaticMethod | UnsafeStaticMethod => {
+            let purity = if fam == UnsafeStaticMethod { ast::unsafe_fn } else
+                { ast::impure_fn };
+            // def_static_method carries an optional field of its enclosing
+            // *trait*, but not an inclosing Impl (if this is an inherent
+            // static method). So we need to detect whether this is in
+            // a trait or not, which we do through the mildly hacky
+            // way of checking whether there is a trait_method_sort.
+            let trait_did_opt = if reader::maybe_get_doc(
+                  item, tag_item_trait_method_sort).is_some() {
+                Some(item_reqd_and_translated_parent_item(cnum, item))
+            } else { None };
+            dl_def(ast::def_static_method(did, trait_did_opt, purity))
         }
         Type | ForeignType => dl_def(ast::def_ty(did)),
         Mod => dl_def(ast::def_mod(did)),
@@ -795,34 +799,29 @@ fn get_explicit_self(item: ebml::Doc) -> ast::explicit_self_ {
 }
 
 fn item_impl_methods(intr: @ident_interner, cdata: cmd, item: ebml::Doc,
-                     base_tps: uint) -> ~[@resolve::MethodInfo] {
+                     tcx: ty::ctxt) -> ~[@ty::Method] {
     let mut rslt = ~[];
     for reader::tagged_docs(item, tag_item_impl_method) |doc| {
         let m_did = reader::with_doc_data(doc, parse_def_id);
-        let mth_item = lookup_item(m_did.node, cdata.data);
-        let explicit_self = get_explicit_self(mth_item);
-        rslt.push(@resolve::MethodInfo {
-                    did: translate_def_id(cdata, m_did),
-                    n_tps: item_ty_param_count(mth_item) - base_tps,
-                    ident: item_name(intr, mth_item),
-                    explicit_self: explicit_self});
+        rslt.push(@get_method(intr, cdata, m_did.node, tcx));
     }
+
     rslt
 }
 
 /// Returns information about the given implementation.
-pub fn get_impl(intr: @ident_interner, cdata: cmd, impl_id: ast::node_id)
-                -> resolve::Impl {
+pub fn get_impl(intr: @ident_interner, cdata: cmd, impl_id: ast::node_id,
+               tcx: ty::ctxt)
+                -> ty::Impl {
     let data = cdata.data;
     let impl_item = lookup_item(impl_id, data);
-    let base_tps = item_ty_param_count(impl_item);
-    resolve::Impl {
+    ty::Impl {
         did: ast::def_id {
             crate: cdata.cnum,
             node: impl_id,
         },
         ident: item_name(intr, impl_item),
-        methods: item_impl_methods(intr, cdata, impl_item, base_tps),
+        methods: item_impl_methods(intr, cdata, impl_item, tcx),
     }
 }
 
@@ -842,13 +841,16 @@ 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 container_id = item_reqd_and_translated_parent_item(cdata.cnum,
+                                                            method_doc);
     let name = item_name(intr, method_doc);
     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 explicit_self = get_explicit_self(method_doc);
+    let provided_source = get_provided_source(method_doc, cdata);
 
     ty::Method::new(
         name,
@@ -860,7 +862,9 @@ pub fn get_method(intr: @ident_interner, cdata: cmd, id: ast::node_id,
         fty,
         explicit_self,
         vis,
-        def_id
+        def_id,
+        container_id,
+        provided_source
     )
 }