3 files changed, 15 insertions, 6 deletions
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 36834bbd36..836201535f 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -110,7 +110,7 @@ module ActiveModel
     #   person.errors.include?(:name) # => true
     #   person.errors.include?(:age)  # => false
     def include?(attribute)
-      messages[attribute].present?
+      messages.key?(attribute) && messages[attribute].present?
     end
     alias :has_key? :include?
     alias :key? :include?
diff --git a/activemodel/lib/active_model/type/decimal.rb b/activemodel/lib/active_model/type/decimal.rb
index d19d8baada..11ea327026 100644
--- a/activemodel/lib/active_model/type/decimal.rb
+++ b/activemodel/lib/active_model/type/decimal.rb
@@ -29,12 +29,12 @@ module ActiveModel
           end
         end
 
-        scale ? casted_value.round(scale) : casted_value
+        apply_scale(casted_value)
       end
 
       def convert_float_to_big_decimal(value)
         if precision
-          BigDecimal(value, float_precision)
+          BigDecimal(apply_scale(value), float_precision)
         else
           value.to_d
         end
@@ -47,6 +47,14 @@ module ActiveModel
           precision.to_i
         end
       end
+
+      def apply_scale(value)
+        if scale
+          value.round(scale)
+        else
+          value
+        end
+      end
     end
   end
 end
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
index bad9e4f9a9..d49af603bb 100644
--- a/activemodel/lib/active_model/validations/clusivity.rb
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -30,14 +30,15 @@ module ActiveModel
         @delimiter ||= options[:in] || options[:within]
       end
 
-      # In Ruby 1.9 <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
+      # In Ruby 2.2 <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
       # possible values in the range for equality, which is slower but more accurate.
       # <tt>Range#cover?</tt> uses the previous logic of comparing a value with the range
-      # endpoints, which is fast but is only accurate on Numeric, Time, or DateTime ranges.
+      # endpoints, which is fast but is only accurate on Numeric, Time, Date,
+      # or DateTime ranges.
       def inclusion_method(enumerable)
         if enumerable.is_a? Range
           case enumerable.first
-          when Numeric, Time, DateTime
+          when Numeric, Time, DateTime, Date
             :cover?
           else
             :include?