Merge pull request #8865 from jaredbeck/docs_redundant_safe_navigation

Docs: RedundantSafeNavigation

docs/modules/ROOT/pages/cops_lint.adoc

@@ -2918,14 +2918,19 @@ require 'unloaded_feature'
 |===
 
 This cop checks for redundant safe navigation calls.
-It is marked as unsafe, because it can produce code that returns
-non `nil` while `nil` result is expected on `nil` receiver.
+
+In the example below, the safe navigation operator (`&.`) is unnecessary
+because `NilClass` has methods like `respond_to?` and `dup`.
+
+This cop is marked as unsafe, because auto-correction can change the
+return type of the expression. An offending expression that previously
+could return `nil` will be auto-corrected to never return `nil`.
 
 === Examples
 
 [source,ruby]
 ----
-# bad
+# bad, because nil has these methods
 attrs&.respond_to?(:[])
 foo&.dup&.inspect
 

lib/rubocop/cop/lint/redundant_safe_navigation.rb

@@ -4,11 +4,16 @@ module RuboCop
   module Cop
     module Lint
       # This cop checks for redundant safe navigation calls.
-      # It is marked as unsafe, because it can produce code that returns
-      # non `nil` while `nil` result is expected on `nil` receiver.
+      #
+      # In the example below, the safe navigation operator (`&.`) is unnecessary
+      # because `NilClass` has methods like `respond_to?` and `dup`.
+      #
+      # This cop is marked as unsafe, because auto-correction can change the
+      # return type of the expression. An offending expression that previously
+      # could return `nil` will be auto-corrected to never return `nil`.
       #
       # @example
-      #   # bad
+      #   # bad, because nil has these methods
       #   attrs&.respond_to?(:[])
       #   foo&.dup&.inspect
       #