Rakefile in rbs-3.0.2 vs Rakefile in rbs-3.0.3

@@ -57,10 +57,20 @@
   require 'yaml'
 
   sh "#{ruby} #{rbs} validate --silent"
 
   libs = FileList["stdlib/*"].map {|path| File.basename(path).to_s }
-  libs << "rbs"
+
+  # Skip RBS validation because Ruby CI runs without rubygems
+  case skip_rbs_validation = ENV["SKIP_RBS_VALIDATION"]
+  when nil
+    libs << "rbs"
+  when "true"
+    # Skip
+  else
+    STDERR.puts "🚨🚨🚨🚨 SKIP_RBS_VALIDATION is expected to be `true` or unset, given `#{skip_rbs_validation}` 🚨🚨🚨🚨"
+    libs << "rbs"
+  end
 
   libs.each do |lib|
     sh "#{ruby} #{rbs} -r #{lib} validate --silent"
   end
 end