1 files changed, 11 insertions, 48 deletions
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index af29594e54..74dfd23811 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -96,12 +96,13 @@ INFO: The predicate for strings uses the Unicode-aware character class `[:space:
 
 WARNING: Note that numbers are not mentioned. In particular, 0 and 0.0 are **not** blank.
 
-For example, this method from `ActionDispatch::Session::AbstractStore` uses `blank?` for checking whether a session key is present:
+For example, this method from `ActionController::HttpAuthentication::Token::ControllerMethods` uses `blank?` for checking whether a token is present:
 
 ```ruby
-def ensure_session_key!
-  if @key.blank?
-    raise ArgumentError, 'A key is required...'
+def authenticate(controller, &login_procedure)
+  token, options = token_and_options(controller.request)
+  unless token.blank?
+    login_procedure.call(token, options)
   end
 end
 ```
@@ -1997,7 +1998,7 @@ Produce a string representation of a number in human-readable words:
 1234567890123456.to_s(:human)  # => "1.23 Quadrillion"
 ```
 
-NOTE: Defined in `active_support/core_ext/numeric/formatting.rb`.
+NOTE: Defined in `active_support/core_ext/numeric/conversions.rb`.
 
 Extensions to `Integer`
 -----------------------
@@ -2442,7 +2443,7 @@ dup[1][2] = 4
 array[1][2] == nil   # => true
 ```
 
-NOTE: Defined in `active_support/core_ext/array/deep_dup.rb`.
+NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`.
 
 ### Grouping
 
@@ -2668,45 +2669,7 @@ hash[:b][:e] == nil      # => true
 hash[:b][:d] == [3, 4]   # => true
 ```
 
-NOTE: Defined in `active_support/core_ext/hash/deep_dup.rb`.
-
-### Diffing
-
-The method `diff` returns a hash that represents a diff of the receiver and the argument with the following logic:
-
-* Pairs `key`, `value` that exist in both hashes do not belong to the diff hash.
-
-* If both hashes have `key`, but with different values, the pair in the receiver wins.
-
-* The rest is just merged.
-
-```ruby
-{a: 1}.diff(a: 1)
-# => {}, first rule
-
-{a: 1}.diff(a: 2)
-# => {:a=>1}, second rule
-
-{a: 1}.diff(b: 2)
-# => {:a=>1, :b=>2}, third rule
-
-{a: 1, b: 2, c: 3}.diff(b: 1, c: 3, d: 4)
-# => {:a=>1, :b=>2, :d=>4}, all rules
-
-{}.diff({})        # => {}
-{a: 1}.diff({})    # => {:a=>1}
-{}.diff(a: 1)      # => {:a=>1}
-```
-
-An important property of this diff hash is that you can retrieve the original hash by applying `diff` twice:
-
-```ruby
-hash.diff(hash2).diff(hash2) == hash
-```
-
-Diffing hashes may be useful for error messages related to expected option hashes for example.
-
-NOTE: Defined in `active_support/core_ext/hash/diff.rb`.
+NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`.
 
 ### Working with Keys
 
@@ -3841,13 +3804,13 @@ def default_helper_module!
   module_path = module_name.underscore
   helper module_path
 rescue MissingSourceFile => e
-  raise e unless e.is_missing? "#{module_path}_helper"
+  raise e unless e.is_missing? "helpers/#{module_path}_helper"
 rescue NameError => e
   raise e unless e.missing_name? "#{module_name}Helper"
 end
 ```
 
-NOTE: Defined in `active_support/core_ext/name_error.rb`.
+NOTE: Defined in `actionpack/lib/abstract_controller/helpers.rb`.
 
 Extensions to `LoadError`
 -------------------------
@@ -3870,4 +3833,4 @@ rescue NameError => e
 end
 ```
 
-NOTE: Defined in `active_support/core_ext/load_error.rb`.
+NOTE: Defined in `actionpack/lib/abstract_controller/helpers.rb`.