Inject the view_items for core in the right place, add comment documenting why the wrong place was wrong.

Author: graydon

src/comp/driver/rustc.rs

@@ -123,12 +123,10 @@ fn inject_libcore_reference(sess: session::session,
     let vi1 = spanned(ast::view_item_use("core", [], n1));
     let vi2 = spanned(ast::view_item_import_glob(@["core"], n2));
 
-    let cd1 = spanned(ast::cdir_view_item(vi1));
-    let cd2 = spanned(ast::cdir_view_item(vi2));
+    let vis = [vi1, vi2] + crate.node.module.view_items;
 
-    let cdirs = [cd1, cd2] + crate.node.directives;
-
-    ret @{node: {directives: cdirs with crate.node} with *crate }
+    ret @{node: {module: { view_items: vis with crate.node.module }
+                 with crate.node} with *crate }
 }
 
 

src/comp/syntax/ast.rs

@@ -60,7 +60,14 @@ type crate_ =
 tag crate_directive_ {
     cdir_src_mod(ident, [attribute]);
     cdir_dir_mod(ident, [@crate_directive], [attribute]);
+
+    // NB: cdir_view_item is *not* processed by the rest of the compiler; the
+    // attached view_items are sunk into the crate's module during parsing,
+    // and processed (resolved, imported, etc.) there. This tag-variant exists
+    // only to preserve the view items in order in case we decide to
+    // pretty-print crates in the future.
     cdir_view_item(@view_item);
+
     cdir_syntax(@path);
 }