diff --git a/lib/rdoc/code_object/class_module.rb b/lib/rdoc/code_object/class_module.rb
index b564059ae7..de7665a589 100644
--- a/lib/rdoc/code_object/class_module.rb
+++ b/lib/rdoc/code_object/class_module.rb
@@ -673,7 +673,7 @@ def path
   # module or class return the name of the latter.
 
   def name_for_path
-    is_alias_for ? is_alias_for.full_name : full_name
+    is_alias_for ? is_alias_for.name_for_path : full_name
   end
 
   ##
@@ -848,6 +848,13 @@ def type
   def update_aliases
     constants.each do |const|
       next unless cm = const.is_alias_for
+
+      # Resolve chained aliases (A = B = C) to the real class/module.
+      cm = @store.find_class_or_module(cm.full_name) || cm
+      while (target = cm.is_alias_for)
+        cm = target
+      end
+
       cm_alias = cm.dup
       cm_alias.name = const.name
 
diff --git a/lib/rdoc/markup/to_html_crossref.rb b/lib/rdoc/markup/to_html_crossref.rb
index 106810072b..a0e218b657 100644
--- a/lib/rdoc/markup/to_html_crossref.rb
+++ b/lib/rdoc/markup/to_html_crossref.rb
@@ -59,21 +59,24 @@ def init_link_notation_regexp_handlings
   # given it is used as the link text, otherwise +name+ is used.
 
   def cross_reference(name, text = nil, code = true, rdoc_ref: false)
-    lookup = name
+    # What to show when the reference doesn't resolve to a link:
+    # caller-provided text if any, otherwise the original name (preserving '#').
+    fallback = text || name
 
-    name = name[1..-1] unless @show_hash if name[0, 1] == '#'
+    # Strip '#' for link display text (e.g. #method shows as "method" in links)
+    display = !@show_hash && name.start_with?('#') ? name[1..] : name
 
-    if !name.end_with?('+@', '-@') && match = name.match(/(.*[^#:])?@(.*)/)
+    if !display.end_with?('+@', '-@') && match = display.match(/(.*[^#:])?@(.*)/)
       context_name = match[1]
       label = RDoc::Text.decode_legacy_label(match[2])
       text ||= "#{label} at <code>#{context_name}</code>" if context_name
       text ||= label
       code = false
     else
-      text ||= name
+      text ||= display
     end
 
-    link lookup, text, code, rdoc_ref: rdoc_ref
+    link(name, text, code, rdoc_ref: rdoc_ref) || fallback
   end
 
   ##
@@ -150,6 +153,7 @@ def gen_url(url, text)
 
   ##
   # Creates an HTML link to +name+ with the given +text+.
+  # Returns the link HTML string, or +nil+ if the reference could not be resolved.
 
   def link(name, text, code = true, rdoc_ref: false)
     if !(name.end_with?('+@', '-@')) and name =~ /(.*[^#:])?@/
@@ -162,56 +166,60 @@ def link(name, text, code = true, rdoc_ref: false)
     # Non-text source files (C, Ruby, etc.) don't get HTML pages generated,
     # so don't auto-link to them. Explicit rdoc-ref: links are still allowed.
     if !rdoc_ref && RDoc::TopLevel === ref && !ref.text?
-      return text
+      return
     end
 
     case ref
-    when String then
+    when String
       if rdoc_ref && @warn_missing_rdoc_ref
         puts "#{@from_path}: `rdoc-ref:#{name}` can't be resolved for `#{text}`"
       end
-      ref
+      return
+    when nil
+      # A bare label reference like @foo still produces a valid anchor link
+      return unless label
+      path = +""
     else
-      path = ref ? ref.as_href(@from_path) : +""
+      path = ref.as_href(@from_path)
 
       if code and RDoc::CodeObject === ref and !(RDoc::TopLevel === ref)
         text = "<code>#{CGI.escapeHTML text}</code>"
       end
+    end
 
-      if label
-        # Decode legacy labels (e.g., "What-27s+Here" -> "What's Here")
-        # then convert to GitHub-style anchor format
-        decoded_label = RDoc::Text.decode_legacy_label(label)
-        formatted_label = RDoc::Text.to_anchor(decoded_label)
-
-        # Case 1: Path already has an anchor (e.g., method link)
-        #   Input:  C1#method@label -> path="C1.html#method-i-m"
-        #   Output: C1.html#method-i-m-label
-        if path =~ /#/
-          path << "-#{formatted_label}"
-
-        # Case 2: Label matches a section title
-        #   Input:  C1@Section -> path="C1.html", section "Section" exists
-        #   Output: C1.html#section (uses section.aref for GitHub-style)
-        elsif (section = ref&.sections&.find { |s| decoded_label == s.title })
-          path << "##{section.aref}"
-
-        # Case 3: Ref has an aref (class/module context)
-        #   Input:  C1@heading -> path="C1.html", ref=C1 class
-        #   Output: C1.html#class-c1-heading
-        elsif ref.respond_to?(:aref)
-          path << "##{ref.aref}-#{formatted_label}"
-
-        # Case 4: No context, just the label (e.g., TopLevel/file)
-        #   Input:  README@section -> path="README_md.html"
-        #   Output: README_md.html#section
-        else
-          path << "##{formatted_label}"
-        end
+    if label
+      # Decode legacy labels (e.g., "What-27s+Here" -> "What's Here")
+      # then convert to GitHub-style anchor format
+      decoded_label = RDoc::Text.decode_legacy_label(label)
+      formatted_label = RDoc::Text.to_anchor(decoded_label)
+
+      # Case 1: Path already has an anchor (e.g., method link)
+      #   Input:  C1#method@label -> path="C1.html#method-i-m"
+      #   Output: C1.html#method-i-m-label
+      if path =~ /#/
+        path << "-#{formatted_label}"
+
+      # Case 2: Label matches a section title
+      #   Input:  C1@Section -> path="C1.html", section "Section" exists
+      #   Output: C1.html#section (uses section.aref for GitHub-style)
+      elsif (section = ref&.sections&.find { |s| decoded_label == s.title })
+        path << "##{section.aref}"
+
+      # Case 3: Ref has an aref (class/module context)
+      #   Input:  C1@heading -> path="C1.html", ref=C1 class
+      #   Output: C1.html#class-c1-heading
+      elsif ref.respond_to?(:aref)
+        path << "##{ref.aref}-#{formatted_label}"
+
+      # Case 4: No context, just the label (e.g., TopLevel/file)
+      #   Input:  README@section -> path="README_md.html"
+      #   Output: README_md.html#section
+      else
+        path << "##{formatted_label}"
       end
-
-      "<a href=\"#{path}\">#{text}</a>"
     end
+
+    "<a href=\"#{path}\">#{text}</a>"
   end
 
   def handle_TT(code)
diff --git a/test/rdoc/generator/darkfish_test.rb b/test/rdoc/generator/darkfish_test.rb
index bf4ec57058..dc9f7ae035 100644
--- a/test/rdoc/generator/darkfish_test.rb
+++ b/test/rdoc/generator/darkfish_test.rb
@@ -610,6 +610,43 @@ def test_canonical_url_for_classes
     assert_include(content, '<link rel="canonical" href="https://docs.ruby-lang.org/en/master/Klass/Inner.html">')
   end
 
+  def test_generate_chained_alias_sidebar_links
+    # Reproduces ruby/rdoc#1664:
+    #   class Original < Base
+    #   DirectAlias = Original           # alias of real class
+    #   ChainedAlias = DirectAlias       # alias of an alias
+    #
+    # ChainedAlias's sidebar link must point to Original.html, not DirectAlias.html
+    # (which is never generated because aliases don't get their own files).
+    parent = @top_level.add_module RDoc::NormalModule, 'Parent'
+    original = parent.add_class RDoc::NormalClass, 'Original'
+
+    direct_alias_const = RDoc::Constant.new 'DirectAlias', nil, ''
+    direct_alias_const.record_location @top_level
+    direct_alias_const.is_alias_for = original
+    parent.add_constant direct_alias_const
+    parent.update_aliases
+
+    direct_alias = @store.find_class_or_module 'Parent::DirectAlias'
+
+    chained_alias_const = RDoc::Constant.new 'ChainedAlias', nil, ''
+    chained_alias_const.record_location @top_level
+    chained_alias_const.is_alias_for = direct_alias
+    parent.add_constant chained_alias_const
+    parent.update_aliases
+
+    @store.complete :private
+    @g.generate
+
+    assert_file 'Parent/Original.html'
+    refute File.exist?('Parent/DirectAlias.html'), 'alias should not get its own file'
+    refute File.exist?('Parent/ChainedAlias.html'), 'chained alias should not get its own file'
+
+    index_html = File.binread('index.html')
+    assert_match %r{href="\./Parent/Original\.html">DirectAlias<}, index_html
+    assert_match %r{href="\./Parent/Original\.html">ChainedAlias<}, index_html
+  end
+
   def test_canonical_url_for_rdoc_files
     @store.add_file("CONTRIBUTING.rdoc", parser: RDoc::Parser::Simple)
 
diff --git a/test/rdoc/markup/to_html_crossref_test.rb b/test/rdoc/markup/to_html_crossref_test.rb
index ff243fc9e0..24e0c97e86 100644
--- a/test/rdoc/markup/to_html_crossref_test.rb
+++ b/test/rdoc/markup/to_html_crossref_test.rb
@@ -407,7 +407,7 @@ def test_convert_RDOCLINK_rdoc_ref_c_file_linked
   end
 
   def test_link
-    assert_equal 'n', @to.link('n', 'n')
+    assert_nil @to.link('n', 'n')
 
     assert_equal '<a href="C1.html#method-c-m"><code>m</code></a>', @to.link('m', 'm')
   end
@@ -423,6 +423,20 @@ def test_link_class_method_full
                  @to.link('Parent::m', 'Parent::m')
   end
 
+  def test_handle_regexp_CROSSREF_hash_preserved_for_unresolved
+    @to.show_hash = false
+
+    # #no should not lose its '#' when it doesn't resolve to a method
+    assert_equal "#no", REGEXP_HANDLING('#no')
+  end
+
+  def test_cross_reference_preserves_explicit_text_for_unresolved
+    # When explicit text is provided, it should be preserved on unresolved refs
+    assert_equal "Foo", @to.cross_reference("Missing", "Foo")
+  end
+
+  private
+
   def para(text)
     "\n<p>#{text}</p>\n"
   end