Fix

Author: aidanharan

lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb

@@ -12,7 +12,7 @@ module Calculations
           private
 
           def build_count_subquery(relation, column_name, distinct)
-            self.model.with_connection do |connection|
+            model.with_connection do |connection|
               relation = relation.unscope(:order) if connection.sqlserver?
               super(relation, column_name, distinct)
             end

lib/active_record/connection_adapters/sqlserver/core_ext/finder_methods.rb

@@ -11,7 +11,7 @@ module FinderMethods
           private
 
           def construct_relation_for_exists(conditions)
-            klass.with_connection do |connection|
+            model.with_connection do |connection|
               if connection.sqlserver?
                 _construct_relation_for_exists(conditions)
               else