Fixed toplevel constant DateTime referenced by Virtus::Attribute::DateTime

Author: u2

CHANGELOG.md

@@ -1,6 +1,6 @@
 Next Release
 ============
-
+* [#925](https://github.com/intridea/grape/pull/925): Fixed `toplevel constant DateTime referenced by Virtus::Attribute::DateTime` - [@u2](https://github.com/u2).
 * [#916](https://github.com/intridea/grape/pull/916): Added `DateTime/Date/Numeric/Boolean` type support `allow_blank` - [@u2](https://github.com/u2).
 * [#871](https://github.com/intridea/grape/pull/871): Fixed `Grape::Middleware::Base#response` - [@galathius](https://github.com/galathius).
 * [#559](https://github.com/intridea/grape/issues/559): Added support for Rack 1.6.0, which parses requests larger than 128KB - [@myitcv](https://github.com/myitcv).

lib/grape/validations/validators/coerce.rb

@@ -32,7 +32,7 @@ def _valid_single_type?(klass, val)
           val.is_a?(TrueClass) || val.is_a?(FalseClass) || (val.is_a?(String) && val.empty?)
         elsif klass == Rack::Multipart::UploadedFile
           val.is_a?(Hashie::Mash) && val.key?(:tempfile)
-        elsif [Virtus::Attribute::DateTime, Virtus::Attribute::Date, Virtus::Attribute::Numeric].any?{ |vclass| vclass >= klass }
+        elsif [DateTime, Date, Numeric].any?{ |vclass| vclass >= klass }
           return true if val.is_a?(String) && val.empty?
           val.is_a?(klass)
         else