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

@@ -146,6 +146,13 @@ 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, def::TraitItemKind) {
     let cdata = cstore.get_crate_data(def.krate);

src/librustc/metadata/decoder.rs

@@ -781,6 +781,14 @@ 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)

src/librustc/middle/ty.rs

@@ -105,6 +105,7 @@ pub struct CrateAnalysis<'tcx> {
     pub ty_cx: ty::ctxt<'tcx>,
     pub reachable: NodeSet,
     pub name: String,
+    pub glob_map: Option<middle::resolve::GlobMap>,
 }
 
 #[deriving(Copy, PartialEq, Eq, Hash)]

src/librustc_driver/driver.rs

@@ -342,17 +342,24 @@ pub fn phase_3_run_analysis_passes<'tcx>(sess: Session,
     let lang_items = time(time_passes, "language item collection", (), |_|
                           middle::lang_items::collect_language_items(krate, &sess));
 
-    let resolve::CrateMap {
+    let make_glob_map = match save_analysis(&sess) {
+        true => middle::resolve::MakeGlobMap::Yes,
+        false => middle::resolve::MakeGlobMap::No,
+    };
         def_map,
         freevars,
         capture_mode_map,
         export_map,
         trait_map,
         external_exports,
-        last_private_map
+        last_private_map,
+        glob_map,
     } =
         time(time_passes, "resolution", (),
-             |_| resolve::resolve_crate(&sess, &lang_items, krate));
+             |_| resolve::resolve_crate(&sess,
+                                        &lang_items,
+                                        krate,
+                                        make_glob_map));
 
     // Discard MTWT tables that aren't required past resolution.
     syntax::ext::mtwt::clear_tables();
@@ -454,14 +461,19 @@ pub fn phase_3_run_analysis_passes<'tcx>(sess: Session,
         public_items: public_items,
         reachable: reachable_map,
         name: name,
+        glob_map: glob_map,
     }
 }
 
+fn save_analysis(sess: &Session) -> bool {
+    (sess.opts.debugging_opts & config::SAVE_ANALYSIS) != 0
+}
+
 pub fn phase_save_analysis(sess: &Session,
                            krate: &ast::Crate,
                            analysis: &ty::CrateAnalysis,
                            odir: &Option<Path>) {
-    if (sess.opts.debugging_opts & config::SAVE_ANALYSIS) == 0 {
+    if !save_analysis(sess) {
         return;
     }
     time(sess.time_passes(), "save analysis", krate, |krate|

src/librustc_driver/test.rs

@@ -123,7 +123,7 @@ fn test_env<F>(source_string: &str,
     // run just enough stuff to build a tcx:
     let lang_items = lang_items::collect_language_items(krate, &sess);
     let resolve::CrateMap { def_map, freevars, capture_mode_map, .. } =
-        resolve::resolve_crate(&sess, &lang_items, krate);
+        resolve::resolve_crate(&sess, &ast_map, &lang_items, krate, resolve::MakeGlobMap::No);
     let named_region_map = resolve_lifetime::krate(&sess, krate, &def_map);
     let region_map = region::resolve_crate(&sess, krate);
     let stability_index = stability::Index::build(krate);

src/librustc_resolve/check_unused.rs

@@ -28,19 +28,19 @@ use syntax::ast::{ViewPathGlob, ViewPathList, ViewPathSimple};
 use syntax::codemap::{Span, DUMMY_SP};
 use syntax::visit::{mod, Visitor};
 
-struct UnusedImportCheckVisitor<'a, 'b:'a> {
-    resolver: &'a mut Resolver<'b>
+struct UnusedImportCheckVisitor<'a, 'b:'a, 'tcx:'b> {
+    resolver: &'a mut Resolver<'b, 'tcx>
 }
 
 // Deref and DerefMut impls allow treating UnusedImportCheckVisitor as Resolver.
-impl<'a, 'b> Deref<Resolver<'b>> for UnusedImportCheckVisitor<'a, 'b> {
-    fn deref<'c>(&'c self) -> &'c Resolver<'b> {
+impl<'a, 'b, 'tcx> Deref<Resolver<'b, 'tcx>> for UnusedImportCheckVisitor<'a, 'b, 'tcx:'b> {
+    fn deref<'c>(&'c self) -> &'c Resolver<'b, 'tcx> {
         &*self.resolver
     }
 }
 
-impl<'a, 'b> DerefMut<Resolver<'b>> for UnusedImportCheckVisitor<'a, 'b> {
-    fn deref_mut<'c>(&'c mut self) -> &'c mut Resolver<'b> {
+impl<'a, 'b, 'tcx> DerefMut<Resolver<'b, 'tcx>> for UnusedImportCheckVisitor<'a, 'b, 'tcx:'b> {
+    fn deref_mut<'c>(&'c mut self) -> &'c mut Resolver<'b, 'tcx> {
         &mut *self.resolver
     }
 }
@@ -104,7 +104,7 @@ impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
     }
 }
 
-impl<'a, 'b, 'v> Visitor<'v> for UnusedImportCheckVisitor<'a, 'b> {
+impl<'a, 'b, 'v, 'tcx> Visitor<'v> for UnusedImportCheckVisitor<'a, 'b, 'tcx> {
     fn visit_view_item(&mut self, vi: &ViewItem) {
         // Ignore is_public import statements because there's no way to be sure
         // whether they're used or not. Also ignore imports with a dummy span