Support passing casks in brew style.

Library/Homebrew/cli/named_args.rb

@@ -74,8 +74,33 @@ module Homebrew
       end
 
       def to_formulae_paths
-        @to_formulae_paths ||= (downcased_unique_named - homebrew_tap_cask_names).map do |name|
-          Formulary.path(name)
+        to_paths(only: :formulae)
+      end
+
+      # Keep existing paths and try to convert others to tap, formula or cask paths.
+      # If a cask and formula with the same name exist, includes both their paths
+      # unless `only` is specified.
+      def to_paths(only: nil)
+        @to_paths ||= {}
+        @to_paths[only] ||= downcased_unique_named.flat_map do |name|
+          if File.exist?(name)
+            name
+          elsif name.count("/") == 1
+            Tap.fetch(name).path
+          else
+            next Formulary.path(name) if only == :formulae
+            next Cask::CaskLoader.path(name) if only == :casks
+
+            formula_path = Formulary.path(name)
+            cask_path = Cask::CaskLoader.path(name)
+
+            paths = []
+
+            paths << formula_path if formula_path.exist?
+            paths << cask_path if cask_path.exist?
+
+            paths.empty? ? name : paths
+          end
         end.uniq.freeze
       end
 

Library/Homebrew/dev-cmd/style.rb

@@ -39,12 +39,8 @@ module Homebrew
 
     target = if args.no_named?
       nil
-    elsif args.named.any? { |file| File.exist? file }
-      args.named
-    elsif args.named.any? { |tap| tap.count("/") == 1 }
-      args.named.map { |tap| Tap.fetch(tap).path }
     else
-      args.named.to_formulae_paths
+      args.named.to_paths
     end
 
     only_cops = args.only_cops

Library/Homebrew/style.rb

@@ -126,10 +126,9 @@ module Homebrew
       when :print
         args << "--debug" if debug
 
-        if ENV["CI"]
-          # Don't show the default formatter's progress dots on CI.
-          args << "--format" << "clang"
-        end
+        # Don't show the default formatter's progress dots
+        # on CI or if only checking a single file.
+        args << "--format" << "clang" if ENV["CI"] || files.count { |f| !f.directory? } == 1
 
         args << "--color" if Tty.color?