Disallow dereferencing enum types when the variant is private

If an enum type's only variant is private, disallow dereferencing
values of its type.

Due to #4082, this only applies to enums that are in the same crate.

r=pcwalton

Closes #818

2 files changed, 50 insertions, 0 deletions

diff --git a/src/libsyntax/ast_map.rs b/src/libsyntax/ast_map.rs
index 3251ea5d2e9..6e0069a649a 100644
--- a/src/libsyntax/ast_map.rs
+++ b/src/libsyntax/ast_map.rs
@@ -391,6 +391,16 @@ fn node_id_to_str(map: map, id: node_id, itr: @ident_interner) -> ~str {
       }
     }
 }
+
+fn node_item_query<Result>(items: map, id: node_id,
+                           query: fn(@item) -> Result,
+                           error_msg: ~str) -> Result {
+    match items.find(id) {
+        Some(node_item(it, _)) => query(it),
+        _ => fail(error_msg)
+    }
+}
+
 // Local Variables:
 // mode: rust
 // fill-column: 78;
diff --git a/src/libsyntax/ast_util.rs b/src/libsyntax/ast_util.rs
index 0b066b57168..e4e29d1fb45 100644
--- a/src/libsyntax/ast_util.rs
+++ b/src/libsyntax/ast_util.rs
@@ -602,6 +602,46 @@ fn struct_def_is_tuple_like(struct_def: @ast::struct_def) -> bool {
     struct_def.ctor_id.is_some()
 }
 
+
+fn visibility_to_privacy(visibility: visibility,
+                         legacy_exports: bool) -> Privacy {
+    if legacy_exports {
+        match visibility {
+            inherited | public => Public,
+            private => Private
+        }
+    } else {
+        match visibility {
+            public => Public,
+            inherited | private => Private
+        }
+    }
+}
+
+enum Privacy {
+    Private,
+    Public
+}
+
+impl Privacy : cmp::Eq {
+    pure fn eq(&self, other: &Privacy) -> bool {
+        ((*self) as uint) == ((*other) as uint)
+    }
+    pure fn ne(&self, other: &Privacy) -> bool { !(*self).eq(other) }
+}
+
+fn has_legacy_export_attr(attrs: &[attribute]) -> bool {
+    for attrs.each |attribute| {
+        match attribute.node.value.node {
+          meta_word(w) if w == ~"legacy_exports" => {
+            return true;
+          }
+          _ => {}
+        }
+    }
+    return false;
+}
+
 // Local Variables:
 // mode: rust
 // fill-column: 78;