save-analysis: emit names of items that a glob import actually imports.

There is also some work here to make resolve a bit more stable - it no longer overwrites a specific import with a glob import.

[breaking-change]

Import shadowing of single/list imports by globs is now forbidden. An interesting case is where a glob import imports a re-export (`pub use`) of a single import. This still counts as a single import for the purposes of shadowing .You can usually fix any bustage by re-ordering such imports. A single import may still shadow (override) a glob import or the prelude.

Author: nrc

src/librustc/metadata/csearch.rs

@@ -148,6 +148,13 @@ pub fn get_impl_or_trait_item<'tcx>(tcx: &ty::ctxt<'tcx>, def: ast::DefId)
                                     tcx)
 }
 
+pub fn get_trait_name(cstore: &cstore::CStore, def: ast::DefId) -> ast::Name {
+    let cdata = cstore.get_crate_data(def.krate);
+    decoder::get_trait_name(cstore.intr.clone(),
+                            &*cdata,
+                            def.node)
+}
+
 pub fn get_trait_item_name_and_kind(cstore: &cstore::CStore, def: ast::DefId)
                                     -> (ast::Name, resolve::TraitItemKind) {
     let cdata = cstore.get_crate_data(def.krate);

src/librustc/metadata/decoder.rs

@@ -784,6 +784,14 @@ pub fn get_impl_items(cdata: Cmd, impl_id: ast::NodeId)
     impl_items
 }
 
+pub fn get_trait_name(intr: Rc<IdentInterner>,
+                      cdata: Cmd,
+                      id: ast::NodeId)
+                      -> ast::Name {
+    let doc = lookup_item(id, cdata.data());
+    item_name(&*intr, doc)
+}
+
 pub fn get_trait_item_name_and_kind(intr: Rc<IdentInterner>,
                                     cdata: Cmd,
                                     id: ast::NodeId)