4 files changed, 30 insertions, 12 deletions
diff --git a/activerecord/lib/arel/nodes/bind_param.rb b/activerecord/lib/arel/nodes/bind_param.rb
index f145e44ae3..344e46479f 100644
--- a/activerecord/lib/arel/nodes/bind_param.rb
+++ b/activerecord/lib/arel/nodes/bind_param.rb
@@ -28,8 +28,8 @@ module Arel # :nodoc: all
         value.respond_to?(:infinite?) && value.infinite?
       end
 
-      def boundable?
-        !value.respond_to?(:boundable?) || value.boundable?
+      def unboundable?
+        value.respond_to?(:unboundable?) && value.unboundable?
       end
     end
   end
diff --git a/activerecord/lib/arel/nodes/case.rb b/activerecord/lib/arel/nodes/case.rb
index 654a54825e..b8f83128c8 100644
--- a/activerecord/lib/arel/nodes/case.rb
+++ b/activerecord/lib/arel/nodes/case.rb
@@ -3,6 +3,8 @@
 module Arel # :nodoc: all
   module Nodes
     class Case < Arel::Nodes::Node
+      include Arel::AliasPredication
+
       attr_accessor :case, :conditions, :default
 
       def initialize(expression = nil, default = nil)
diff --git a/activerecord/lib/arel/predications.rb b/activerecord/lib/arel/predications.rb
index 2a62c53aa3..7dafde4952 100644
--- a/activerecord/lib/arel/predications.rb
+++ b/activerecord/lib/arel/predications.rb
@@ -35,15 +35,17 @@ module Arel # :nodoc: all
     end
 
     def between(other)
-      if infinity?(other.begin)
-        if other.end.nil? || infinity?(other.end)
+      if unboundable?(other.begin) == 1 || unboundable?(other.end) == -1
+        self.in([])
+      elsif open_ended?(other.begin)
+        if other.end.nil? || open_ended?(other.end)
           not_in([])
         elsif other.exclude_end?
           lt(other.end)
         else
           lteq(other.end)
         end
-      elsif other.end.nil? || infinity?(other.end)
+      elsif other.end.nil? || open_ended?(other.end)
         gteq(other.begin)
       elsif other.exclude_end?
         gteq(other.begin).and(lt(other.end))
@@ -81,15 +83,17 @@ Passing a range to `#in` is deprecated. Call `#between`, instead.
     end
 
     def not_between(other)
-      if infinity?(other.begin)
-        if other.end.nil? || infinity?(other.end)
+      if unboundable?(other.begin) == 1 || unboundable?(other.end) == -1
+        not_in([])
+      elsif open_ended?(other.begin)
+        if other.end.nil? || open_ended?(other.end)
           self.in([])
         elsif other.exclude_end?
           gteq(other.end)
         else
           gt(other.end)
         end
-      elsif other.end.nil? || infinity?(other.end)
+      elsif other.end.nil? || open_ended?(other.end)
         lt(other.begin)
       else
         left = lt(other.begin)
@@ -241,5 +245,13 @@ Passing a range to `#not_in` is deprecated. Call `#not_between`, instead.
       def infinity?(value)
         value.respond_to?(:infinite?) && value.infinite?
       end
+
+      def unboundable?(value)
+        value.respond_to?(:unboundable?) && value.unboundable?
+      end
+
+      def open_ended?(value)
+        infinity?(value) || unboundable?(value)
+      end
   end
 end
diff --git a/activerecord/lib/arel/visitors/to_sql.rb b/activerecord/lib/arel/visitors/to_sql.rb
index b5a960ce68..d0dec63860 100644
--- a/activerecord/lib/arel/visitors/to_sql.rb
+++ b/activerecord/lib/arel/visitors/to_sql.rb
@@ -576,7 +576,7 @@ module Arel # :nodoc: all
 
         def visit_Arel_Nodes_In(o, collector)
           if Array === o.right && !o.right.empty?
-            o.right.keep_if { |value| boundable?(value) }
+            o.right.delete_if { |value| unboundable?(value) }
           end
 
           if Array === o.right && o.right.empty?
@@ -590,7 +590,7 @@ module Arel # :nodoc: all
 
         def visit_Arel_Nodes_NotIn(o, collector)
           if Array === o.right && !o.right.empty?
-            o.right.keep_if { |value| boundable?(value) }
+            o.right.delete_if { |value| unboundable?(value) }
           end
 
           if Array === o.right && o.right.empty?
@@ -629,6 +629,8 @@ module Arel # :nodoc: all
         def visit_Arel_Nodes_Equality(o, collector)
           right = o.right
 
+          return collector << "1=0" if unboundable?(right)
+
           collector = visit o.left, collector
 
           if right.nil?
@@ -662,6 +664,8 @@ module Arel # :nodoc: all
         def visit_Arel_Nodes_NotEqual(o, collector)
           right = o.right
 
+          return collector << "1=1" if unboundable?(right)
+
           collector = visit o.left, collector
 
           if right.nil?
@@ -812,8 +816,8 @@ module Arel # :nodoc: all
           }
         end
 
-        def boundable?(value)
-          !value.respond_to?(:boundable?) || value.boundable?
+        def unboundable?(value)
+          value.respond_to?(:unboundable?) && value.unboundable?
         end
 
         def has_join_sources?(o)