Split trans' collection in two passes. This allows us to handle tags

that are defined after use in a block.

This is really inefficient, but for now it lets us compile the included test.

Author: cixtor

src/comp/middle/trans.rs

@@ -5484,6 +5484,25 @@ fn collect_native_item(&@crate_ctxt cx, @ast.native_item i) -> @crate_ctxt {
 
 fn collect_item(&@crate_ctxt cx, @ast.item i) -> @crate_ctxt {
 
+    alt (i.node) {
+        case (ast.item_const(?name, _, _, ?cid, _)) {
+            cx.items.insert(cid, i);
+        }
+
+        case (ast.item_mod(?name, ?m, ?mid)) {
+            cx.items.insert(mid, i);
+        }
+
+        case (ast.item_tag(_, ?variants, ?tps, ?tag_id)) {
+            cx.items.insert(tag_id, i);
+        }
+
+        case (_) { /* fall through */ }
+    }
+    ret cx;
+}
+
+fn collect_item_pass2(&@crate_ctxt cx, @ast.item i) -> @crate_ctxt {
     alt (i.node) {
         case (ast.item_fn(?name, ?f, ?tps, ?fid, ?ann)) {
             cx.items.insert(fid, i);
@@ -5500,18 +5519,6 @@ fn collect_item(&@crate_ctxt cx, @ast.item i) -> @crate_ctxt {
             }
         }
 
-        case (ast.item_const(?name, _, _, ?cid, _)) {
-            cx.items.insert(cid, i);
-        }
-
-        case (ast.item_mod(?name, ?m, ?mid)) {
-            cx.items.insert(mid, i);
-        }
-
-        case (ast.item_tag(_, ?variants, ?tps, ?tag_id)) {
-            cx.items.insert(tag_id, i);
-        }
-
         case (_) { /* fall through */ }
     }
     ret cx;
@@ -5523,11 +5530,20 @@ fn collect_items(@crate_ctxt cx, @ast.crate crate) {
     let fold.ast_fold[@crate_ctxt] fld =
         fold.new_identity_fold[@crate_ctxt]();
 
-    fld = @rec( update_env_for_item = bind collect_item(_,_),
-                update_env_for_native_item = bind collect_native_item(_,_)
-                with *fld );
+    // FIXME: if ty_tag had a pointer directly to the definition instead
+    // of a def_id, we wouldn't need the second pass.
 
-    fold.fold_crate[@crate_ctxt](cx, fld, crate);
+    auto fld1 =
+        @rec( update_env_for_item = bind collect_item(_,_),
+              update_env_for_native_item = bind collect_native_item(_,_)
+              with *fld );
+
+    fold.fold_crate[@crate_ctxt](cx, fld1, crate);
+
+    auto fld2 = @rec( update_env_for_item = bind collect_item_pass2(_,_)
+                      with *fld );
+
+    fold.fold_crate[@crate_ctxt](cx, fld2, crate);
 }
 
 fn collect_tag_ctor(&@crate_ctxt cx, @ast.item i) -> @crate_ctxt {

src/test/run-pass/tag-in-block.rs

@@ -0,0 +1,13 @@
+fn foo() {
+  fn zed(bar z) {
+  }
+  tag bar {
+    nil;
+  }
+  fn baz() {
+    zed(nil);
+  }
+}
+
+fn main(vec[str] args) {
+}