Merge pull request #20 from dry-rb/mri-2.4

Support for MRI 2.4

Author: nepalez

.travis.yml

@@ -8,6 +8,7 @@ script:
 rvm:
   - '2.2'
   - '2.3.0'
+  - '2.4.0'
   # - rbx-2
   - ruby-head
   - jruby-9.1.0.0

Gemfile

@@ -5,7 +5,13 @@ gemspec
 
 group :benchmarks do
   gem "benchmark-ips", "~> 2.5"
-  gem "activesupport", "< 5"
+
+  if RUBY_VERSION < "2.4"
+    gem "activesupport", "< 5"
+  else
+    gem "activesupport"
+  end
+
   gem "active_attr"
   gem "anima"
   gem "attr_extras"

lib/dry/initializer/plugins/type_constraint.rb

@@ -11,8 +11,10 @@ def call
       ivar = :"@#{rename}"
       lambda do |*|
         value = instance_variable_get(ivar)
-        return if value == Dry::Initializer::UNDEFINED
-        instance_variable_set ivar, type.call(value)
+
+        if value != Dry::Initializer::UNDEFINED
+          instance_variable_set ivar, type.call(value)
+        end
       end
     end
   end