diff --git a/.rubocop.yml b/.rubocop.yml
index 17b6b40af2..5bbdd11447 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -159,6 +159,9 @@ Style/FrozenStringLiteralComment:
     - 'actionmailbox/db/migrate/**/*.rb'
     - 'actiontext/db/migrate/**/*.rb'
 
+Style/MapToHash:
+  Enabled: true
+
 Style/RedundantFreeze:
   Enabled: true
 
diff --git a/actiontext/lib/action_text/attachment.rb b/actiontext/lib/action_text/attachment.rb
index 2e07a42171..f77e1a0965 100644
--- a/actiontext/lib/action_text/attachment.rb
+++ b/actiontext/lib/action_text/attachment.rb
@@ -91,7 +91,7 @@ module ActionText
 
     private
       def node_attributes
-        @node_attributes ||= ATTRIBUTES.map { |name| [ name.underscore, node[name] ] }.to_h.compact
+        @node_attributes ||= ATTRIBUTES.to_h { |name| [ name.underscore, node[name] ] }.compact
       end
 
       def attachable_attributes
diff --git a/actiontext/lib/action_text/trix_attachment.rb b/actiontext/lib/action_text/trix_attachment.rb
index 8b9642e95d..bff7a44665 100644
--- a/actiontext/lib/action_text/trix_attachment.rb
+++ b/actiontext/lib/action_text/trix_attachment.rb
@@ -39,10 +39,10 @@ module ActionText
         end
 
         def typecast_attribute_values(attributes)
-          attributes.map do |key, value|
+          attributes.to_h do |key, value|
             typecast = ATTRIBUTE_TYPES[key] || ATTRIBUTE_TYPES[:default]
             [key, typecast.call(value)]
-          end.to_h
+          end
         end
     end
 
diff --git a/actionview/lib/action_view/ripper_ast_parser.rb b/actionview/lib/action_view/ripper_ast_parser.rb
index 09af3b670f..eef5b56cb5 100644
--- a/actionview/lib/action_view/ripper_ast_parser.rb
+++ b/actionview/lib/action_view/ripper_ast_parser.rb
@@ -86,11 +86,11 @@ module ActionView
         end
 
         def hash_from_body(body)
-          body.map do |hash_node|
+          body.to_h do |hash_node|
             return nil if hash_node.type != :assoc_new
 
             [hash_node[0], hash_node[1]]
-          end.to_h
+          end
         end
 
         def symbol?
@@ -189,9 +189,9 @@ module ActionView
         parser = RenderCallExtractor.new(code)
         parser.parse
 
-        parser.render_calls.group_by(&:first).collect do |method, nodes|
+        parser.render_calls.group_by(&:first).to_h do |method, nodes|
           [ method.to_sym, nodes.collect { |v| v[1] } ]
-        end.to_h
+        end
       end
     end
   end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
index 6a7c50c963..9f7276e75d 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
@@ -57,9 +57,9 @@ module ActiveRecord
               orders = options.delete(:orders)
               lengths = options.delete(:lengths)
 
-              columns = index[-1].map { |name|
+              columns = index[-1].to_h { |name|
                 [ name.to_sym, expressions[name] || +quote_column_name(name) ]
-              }.to_h
+              }
 
               index[-1] = add_options_for_index_columns(
                 columns, order: orders, length: lengths
diff --git a/activerecord/lib/active_record/encryption/encryptable_record.rb b/activerecord/lib/active_record/encryption/encryptable_record.rb
index b26e6efead..cf7cede8ee 100644
--- a/activerecord/lib/active_record/encryption/encryptable_record.rb
+++ b/activerecord/lib/active_record/encryption/encryptable_record.rb
@@ -188,12 +188,12 @@ module ActiveRecord
         end
 
         def build_decrypt_attribute_assignments
-          Array(self.class.encrypted_attributes).collect do |attribute_name|
+          Array(self.class.encrypted_attributes).to_h do |attribute_name|
             type = type_for_attribute(attribute_name)
             encrypted_value = ciphertext_for(attribute_name)
             new_value = type.deserialize(encrypted_value)
             [attribute_name, new_value]
-          end.to_h
+          end
         end
 
         def cant_modify_encrypted_attributes_when_frozen
diff --git a/activestorage/test/service/mirror_service_test.rb b/activestorage/test/service/mirror_service_test.rb
index 32b3954bce..4e86aaae91 100644
--- a/activestorage/test/service/mirror_service_test.rb
+++ b/activestorage/test/service/mirror_service_test.rb
@@ -3,11 +3,11 @@
 require "service/shared_service_tests"
 
 class ActiveStorage::Service::MirrorServiceTest < ActiveSupport::TestCase
-  mirror_config = (1..3).map do |i|
+  mirror_config = (1..3).to_h do |i|
     [ "mirror_#{i}",
       service: "Disk",
       root: Dir.mktmpdir("active_storage_tests_mirror_#{i}") ]
-  end.to_h
+  end
 
   config = mirror_config.merge \
     mirror:  { service: "Mirror", primary: "primary", mirrors: mirror_config.keys },