Only take overrideable stanzas into account

- This skips over stanza names that are not overrideable in `on_*`
  blocks, with the positive side effect that `on_*` blocks themselves
  aren't in the list so we can get rid of another conditional.
- Stanzas overrideable in blocks are defined in `Cask::DSL` by each of
  the methods calling `set_unique_stanza`.

Library/Homebrew/rubocops/cask/no_overrides.rb

@@ -9,6 +9,12 @@ module RuboCop
         include CaskHelp
 
         ON_SYSTEM_METHODS = RuboCop::Cask::Constants::ON_SYSTEM_METHODS
+        # These stanzas can be overridden by `on_*` blocks, so take them into account.
+        # TODO: Update this list if new stanzas are added to `Cask::DSL` that call `set_unique_stanza`.
+        OVERRIDEABLE_METHODS = [
+          :appcast, :arch, :auto_updates, :conflicts_with, :container,
+          :desc, :homepage, :sha256, :url, :version
+        ].freeze
         MESSAGE = <<~EOS
           Do not use a top-level `%<stanza>s` stanza as the default. Add it to an `on_{system}` block instead.
           Use `:or_older` or `:or_newer` to specify a range of macOS versions.
@@ -23,8 +29,8 @@ module RuboCop
           stanzas_in_blocks = on_system_stanzas(on_blocks)
 
           cask_stanzas.each do |stanza|
-            # Skip if the stanza is itself an `on_*` block.
+            # Skip if the stanza is not allowed to be overridden.
-            next if ON_SYSTEM_METHODS.include?(stanza.stanza_name)
+            next unless OVERRIDEABLE_METHODS.include?(stanza.stanza_name)
             # Skip if the stanza outside of a block is not also in an `on_*` block.
             next unless stanzas_in_blocks.include?(stanza.stanza_name)
 

Library/Homebrew/test/rubocops/cask/no_overrides_spec.rb

@@ -38,6 +38,26 @@ describe RuboCop::Cop::Cask::NoOverrides do
     include_examples "does not report any offenses"
   end
 
+  context "when there are top-level stanzas also in `on_*` blocks that should not override" do
+    let(:source) do
+      <<~CASK
+        cask 'foo' do
+          version '1.2.3'
+
+          on_arm do
+            binary "foo-\#{version}-arm64"
+          end
+
+          app "foo-\#{version}.app"
+
+          binary "foo-\#{version}"
+        end
+      CASK
+    end
+
+    include_examples "does not report any offenses"
+  end
+
   context "when there are `arch` variables in the `url` in the `on_*` blocks" do
     let(:source) do
       <<~CASK