diff --git a/.travis.yml b/.travis.yml
index a2c4714b..fe4306dd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,10 +3,12 @@ language: ruby
 sudo: false
 
 before_install:
-  - gem update --system
+  - "if $(ruby -e 'exit(RUBY_VERSION >= \"2.3.0\")'); then gem update --system; fi"
+  - "if $(ruby -e 'exit(RUBY_VERSION <  \"2.3.0\")'); then gem update --system 2.7.8; fi"
   # bundler installation needed for jruby-head
   # https://github.com/travis-ci/travis-ci/issues/5861
-  - gem install bundler
+  - "if $(ruby -e 'exit(RUBY_VERSION >= \"2.3.0\")'); then gem install bundler; fi"
+  - "if $(ruby -e 'exit(RUBY_VERSION <  \"2.3.0\")'); then gem install bundler --version 1.17.3; fi"
 
 script: "bundle exec rubytest -Ilib test/ --verbose"
 bundler_args: --without guard
diff --git a/lib/core/facets/module/attr_setter.rb b/lib/core/facets/module/attr_setter.rb
index 9d517f56..857379b9 100644
--- a/lib/core/facets/module/attr_setter.rb
+++ b/lib/core/facets/module/attr_setter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
 
   # Create an attribute method for both getting
@@ -19,7 +20,7 @@ class Module
   # CREDIT: Trans
 
   def attr_setter(*args)
-    code, made = '', []
+    code, made = [], []
     args.each do |a|
       code << %{
         def #{a}(*args)
@@ -28,7 +29,7 @@ def #{a}(*args)
       }
       made << "#{a}".to_sym
     end
-    module_eval code
+    module_eval code.join
     made
   end