Fixed dumping previously loaded Constant which is an alias

lib/rdoc/constant.rb

@@ -79,7 +79,9 @@ def full_name
   def is_alias_for
     case @is_alias_for
     when String then
-      @is_alias_for = @store.find_class_or_module @is_alias_for
+      found = @store.find_class_or_module @is_alias_for
+      @is_alias_for = found if found
+      @is_alias_for
     else
       @is_alias_for
     end
@@ -96,16 +98,21 @@ def inspect # :nodoc:
   # Dumps this Constant for use by ri.  See also #marshal_load
 
   def marshal_dump
+    alias_name = case found = is_alias_for
+                 when RDoc::CodeObject then found.full_name
+                 else                       found
+                 end
+
     [ MARSHAL_VERSION,
       @name,
       full_name,
       @visibility,
-      @is_alias_for ? @is_alias_for.full_name : nil,
+      alias_name,
       parse(@comment),
       @file.absolute_name,
-      @parent_name   || @parent.name,
-      @parent_class  || @parent.class,
-      @section_title || section.title,
+      parent.name,
+      parent.class,
+      section.title,
     ]
   end
 

test/test_rdoc_constant.rb

@@ -12,6 +12,23 @@ def test_full_name
     assert_equal 'C1::CONST', @const.full_name
   end
 
+  def test_is_alias_for
+    top_level = @store.add_file 'file.rb'
+
+    c = RDoc::Constant.new 'CONST', nil, 'comment'
+    top_level.add_constant c
+
+    assert_nil c.is_alias_for
+
+    c.is_alias_for = 'C1'
+
+    assert_equal @c1, c.is_alias_for
+
+    c.is_alias_for = 'unknown'
+
+    assert_equal 'unknown', c.is_alias_for
+  end
+
   def test_marshal_dump
     top_level = @store.add_file 'file.rb'
 
@@ -101,11 +118,12 @@ def test_marshal_load_version_0
     assert_equal section,        loaded.section
   end
 
-  def test_marshal_round_trip_section
+  def test_marshal_round_trip
     top_level = @store.add_file 'file.rb'
 
     c = RDoc::Constant.new 'CONST', nil, 'this is a comment'
     c.record_location top_level
+    c.is_alias_for = 'Unknown'
 
     cm = top_level.add_class RDoc::NormalClass, 'Klass'
     cm.add_constant c
@@ -118,7 +136,8 @@ def test_marshal_round_trip_section
     reloaded = Marshal.load Marshal.dump loaded
     reloaded.store = @store
 
-    assert_equal section, reloaded.section
+    assert_equal section,   reloaded.section
+    assert_equal 'Unknown', reloaded.is_alias_for
   end
 
   def test_path