rustc: Implement and enforce instance coherence

2 files changed, 28 insertions, 0 deletions

diff --git a/src/rustc/metadata/csearch.rs b/src/rustc/metadata/csearch.rs
index 22d70f86eb8..56d6dcab106 100644
--- a/src/rustc/metadata/csearch.rs
+++ b/src/rustc/metadata/csearch.rs
@@ -10,6 +10,7 @@ import syntax::diagnostic::span_handler;
 import syntax::diagnostic::expect;
 import common::*;
 import std::map::hashmap;
+import dvec::{dvec, extensions};
 
 export class_dtor;
 export get_symbol;
@@ -23,6 +24,7 @@ export lookup_method_purity;
 export get_enum_variants;
 export get_impls_for_mod;
 export get_trait_methods;
+export get_method_names_if_trait;
 export each_path;
 export get_type;
 export get_impl_trait;
@@ -140,6 +142,13 @@ fn get_trait_methods(tcx: ty::ctxt, def: ast::def_id) -> @~[ty::method] {
     decoder::get_trait_methods(cdata, def.node, tcx)
 }
 
+fn get_method_names_if_trait(cstore: cstore::cstore, def: ast::def_id)
+                          -> option<@dvec<@~str>> {
+
+    let cdata = cstore::get_crate_data(cstore, def.crate);
+    ret decoder::get_method_names_if_trait(cdata, def.node);
+}
+
 fn get_class_fields(tcx: ty::ctxt, def: ast::def_id) -> ~[ty::field_ty] {
     let cstore = tcx.cstore;
     let cdata = cstore::get_crate_data(cstore, def.crate);
diff --git a/src/rustc/metadata/decoder.rs b/src/rustc/metadata/decoder.rs
index 45bdee06070..c9b214134a7 100644
--- a/src/rustc/metadata/decoder.rs
+++ b/src/rustc/metadata/decoder.rs
@@ -2,6 +2,7 @@
 
 import std::{ebml, map};
 import std::map::{hashmap, str_hash};
+import dvec::{dvec, extensions};
 import io::writer_util;
 import syntax::{ast, ast_util};
 import syntax::attr;
@@ -37,6 +38,7 @@ export get_crate_hash;
 export get_crate_vers;
 export get_impls_for_mod;
 export get_trait_methods;
+export get_method_names_if_trait;
 export get_crate_module_paths;
 export def_like;
 export dl_def;
@@ -640,6 +642,23 @@ fn get_trait_methods(cdata: cmd, id: ast::node_id, tcx: ty::ctxt)
     @result
 }
 
+// If the item in question is a trait, returns its set of methods. Otherwise,
+// returns none.
+fn get_method_names_if_trait(cdata: cmd, node_id: ast::node_id)
+                          -> option<@dvec<@~str>> {
+
+    let item = lookup_item(node_id, cdata.data);
+    if item_family(item) != 'I' {
+        ret none;
+    }
+
+    let resulting_method_names = @dvec();
+    do ebml::tagged_docs(item, tag_item_trait_method) |method| {
+        (*resulting_method_names).push(item_name(method));
+    }
+    ret some(resulting_method_names);
+}
+
 // Helper function that gets either fields or methods
 fn get_class_members(cdata: cmd, id: ast::node_id,
                      p: fn(char) -> bool) -> ~[ty::field_ty] {