package-private visibility

TODO.md

@@ -842,13 +842,13 @@
   - this keeps package lookup shallow and deterministic and avoids overloading import aliases with
     declaration visibility
 
-36.5. explicit `hide` file-local declarations (implemented)
+36.5. explicit `hide` package-local declarations (implemented)
   - `hide name ...` gives any named top-level function, global, native/C record, union, enum,
-    opaque/distinct type, or declaration/type alias the existing file-local semantics
+    opaque/distinct type, or declaration/type alias package-local visibility across sibling files
   - declarations remain public by default; a leading underscore is an ordinary identifier and `_`
     remains the write-only sink
-  - hidden native and C declarations with the same name may coexist in separate files, while public
-    collisions are still diagnosed
+  - hidden declarations occupy the package namespace, collide with sibling declarations of the
+    same name, and remain absent from imported package namespaces
   - `hide` is reserved for named top-level declarations and is rejected on imports, locals,
     parameters, fields, and anonymous declarations