style(rubocop): Lint/UselessAssignment

app/controllers/ip_pools_controller.rb

@@ -33,7 +33,7 @@ class IPPoolsController < ApplicationController
   def destroy
     @ip_pool.destroy
     redirect_to_with_json :ip_pools, notice: "IP pool has been removed successfully."
-  rescue ActiveRecord::DeleteRestrictionError => e
+  rescue ActiveRecord::DeleteRestrictionError
     redirect_to_with_json [:edit, @ip_pool], alert: "IP pool cannot be removed because it still has associated addresses or servers."
   end
 

app/controllers/messages_controller.rb

@@ -188,7 +188,7 @@ class MessagesController < ApplicationController
             if qs[:before]
               begin
                 options[:where][:timestamp][:less_than] = get_time_from_string(qs[:before]).to_f
-              rescue TimeUndetermined => e
+              rescue TimeUndetermined
                 flash.now[:alert] = "Couldn't determine time for before from '#{qs[:before]}'"
               end
             end
@@ -196,7 +196,7 @@ class MessagesController < ApplicationController
             if qs[:after]
               begin
                 options[:where][:timestamp][:greater_than] = get_time_from_string(qs[:after]).to_f
-              rescue TimeUndetermined => e
+              rescue TimeUndetermined
                 flash.now[:alert] = "Couldn't determine time for after from '#{qs[:after]}'"
               end
             end

app/controllers/sessions_controller.rb

@@ -10,7 +10,7 @@ class SessionsController < ApplicationController
     login(User.authenticate(params[:email_address], params[:password]))
     flash[:remember_login] = true
     redirect_to_with_return_to root_path
-  rescue Postal::Errors::AuthenticationError => e
+  rescue Postal::Errors::AuthenticationError
     flash.now[:alert] = "The credentials you've provided are incorrect. Please check and try again."
     render "new"
   end

app/models/incoming_message_prototype.rb

@@ -26,7 +26,7 @@ class IncomingMessagePrototype
   def route
     @routes ||= if @to.present?
                   uname, domain = @to.split("@", 2)
-                  uname, tag = uname.split("+", 2)
+                  uname, _tag = uname.split("+", 2)
                   @server.routes.includes(:domain).where(domains: { name: domain }, name: uname).first
                 end
   end

app/models/organization.rb

@@ -50,7 +50,7 @@ class Organization < ApplicationRecord
   has_many :ip_pool_rules, dependent: :destroy, as: :owner
 
   after_create do
-    if pool = IPPool.default
+    if IPPool.default
       ip_pools << IPPool.default
     end
   end

app/models/route.rb

@@ -202,7 +202,7 @@ class Route < ApplicationRecord
       if route = Route.includes(:domain).where(domains: { name: domain.name }, name: name).where.not(id: id).first
         errors.add :name, "is configured on the #{route.server.full_permalink} mail server"
       end
-    elsif route = Route.where(name: "__returnpath__").where.not(id: id).exists?
+    elsif Route.where(name: "__returnpath__").where.not(id: id).exists?
       errors.add :base, "A return path route already exists for this server"
     end
   end

app/models/server.rb

@@ -232,8 +232,6 @@ class Server < ApplicationRecord
     return nil unless uname
     return nil unless domain_name
 
-    uname, = uname.split("+", 2)
-
     # Find a verified domain which directly matches the domain name for the given address.
     domain = Domain.verified
                    .order(owner_type: :desc)