Fix the last known (to me) bug in import resolution. We were not properly

dropping the inner part of the environment when an intermediate item resolved
in an outer scope.

Author: cixtor

src/Makefile

@@ -448,6 +448,7 @@ TEST_XFAILS_RUSTC := $(filter-out \
                         import4.rs \
                         import5.rs \
                         import6.rs \
+                        import7.rs \
                         item-name-overload.rs \
                         large-records.rs \
                         lazy-init.rs \

src/comp/middle/resolve.rs

@@ -40,11 +40,11 @@ fn lookup_name(&env e, import_map index,
                ast.ident i) -> option.t[def] {
     auto d_ = lookup_name_wrapped(e, i);
     alt (d_) {
-        case (none[def_wrap]) {
+        case (none[tup(@env, def_wrap)]) {
             ret none[def];
         }
-        case (some[def_wrap](?d)) {
-            alt (d) {
+        case (some[tup(@env, def_wrap)](?d)) {
+            alt (d._1) {
                 case (def_wrap_use(?it)) {
                     alt (it.node) {
                         case (ast.view_item_use(_, _, ?id)) {
@@ -115,14 +115,14 @@ fn find_final_def(&env e, &span sp, vec[ident] idents) -> def_wrap {
                 auto next_i = rest_idents.(0);
                 auto next_ = lookup_name_wrapped(tmp_e, next_i);
                 alt (next_) {
-                    case (none[def_wrap]) {
+                    case (none[tup(@env, def_wrap)]) {
                         e.sess.span_err(sp, "unresolved name: " + next_i);
                         fail;
                     }
-                    case (some[def_wrap](?next)) {
+                    case (some[tup(@env, def_wrap)](?next)) {
                         auto combined_e = update_env_for_item(e, i);
                         ret found_something(combined_e, pending, sp,
-                                            rest_idents, next);
+                                            rest_idents, next._1);
                     }
                 }
             }
@@ -141,20 +141,20 @@ fn find_final_def(&env e, &span sp, vec[ident] idents) -> def_wrap {
         auto first = idents.(0);
         auto d_ = lookup_name_wrapped(e, first);
         alt (d_) {
-            case (none[def_wrap]) {
+            case (none[tup(@env, def_wrap)]) {
                 e.sess.span_err(sp, "unresolved name: " + first);
                 fail;
             }
-            case (some[def_wrap](?d)) {
-                ret found_something(e, pending, sp, idents, d);
+            case (some[tup(@env, def_wrap)](?d)) {
+                ret found_something(*d._0, pending, sp, idents, d._1);
             }
         }
     }
     auto pending = new_def_hash[bool]();
     ret inner(e, pending, sp, idents);
 }
 
-fn lookup_name_wrapped(&env e, ast.ident i) -> option.t[def_wrap] {
+fn lookup_name_wrapped(&env e, ast.ident i) -> option.t[tup(@env, def_wrap)] {
 
     // log "resolving name " + i;
 
@@ -308,8 +308,23 @@ fn lookup_name_wrapped(&env e, ast.ident i) -> option.t[def_wrap] {
         ret none[def_wrap];
     }
 
-    ret std.list.find[scope,def_wrap](e.scopes,
-                                      bind in_scope(i, _));
+    alt (e.scopes) {
+        case (nil[scope]) {
+            ret none[tup(@env, def_wrap)];
+        }
+        case (cons[scope](?hd, ?tl)) {
+            auto x = in_scope(i, hd);
+            alt (x) {
+                case (some[def_wrap](?x)) {
+                    ret some(tup(@e, x));
+                }
+                case (none[def_wrap]) {
+                    auto outer_env = rec(scopes = *tl with e);
+                    ret lookup_name_wrapped(outer_env, i);
+                }
+            }
+        }
+    }
 }
 
 fn fold_pat_tag(&env e, &span sp, import_map index, ident i,

src/test/run-pass/import7.rs

@@ -0,0 +1,19 @@
+import bar.baz;
+import foo.zed;
+mod foo {
+  mod zed {
+    fn baz() {
+      log "baz";
+    }
+  }
+}
+mod bar {
+  import zed.baz;
+  mod foo {
+    mod zed {
+    }
+  }
+}
+fn main(vec[str] args) {
+  baz();
+}