1 files changed, 3 insertions, 5 deletions
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index dac8b8f1e..0f78e4412 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -18,12 +18,10 @@ module OS
         when "10.11" then "8.0"
         when "10.12" then "8.0"
         else
+          raise "macOS '#{MacOS.version}' is invalid" unless OS::Mac.prerelease?
+
           # Default to newest known version of Xcode for unreleased macOS versions.
-          if OS::Mac.prerelease?
-            "8.0"
-          else
-            raise "macOS '#{MacOS.version}' is invalid"
-          end
+          "8.0"
         end
       end