Use safe_constantize where possible.

actionpack/lib/action_controller/metal/params_wrapper.rb

@@ -141,19 +141,16 @@ module ActionController
       # try to find Foo::Bar::User, Foo::User and finally User.
       def _default_wrap_model #:nodoc:
         return nil if self.anonymous?
-
         model_name = self.name.sub(/Controller$/, '').singularize
 
         begin
-          model_klass = model_name.constantize
-        rescue NameError, ArgumentError => e
-          if e.message =~ /is not missing constant|uninitialized constant #{model_name}/
+          if model_klass = model_name.safe_constantize
+            model_klass
+          else
             namespaces = model_name.split("::")
             namespaces.delete_at(-2)
             break if namespaces.last == model_name
             model_name = namespaces.join("::")
-          else
-            raise
           end
         end until model_klass
 

actionpack/lib/action_view/test_case.rb

@@ -54,10 +54,8 @@ module ActionView
         end
 
         def determine_default_helper_class(name)
-          mod = name.sub(/Test$/, '').constantize
+          mod = name.sub(/Test$/, '').safe_constantize
           mod.is_a?(Class) ? nil : mod
-        rescue NameError
-          nil
         end
 
         def helper_method(*methods)

activesupport/lib/active_support/core_ext/module/reachable.rb

@@ -3,8 +3,6 @@ require 'active_support/core_ext/string/inflections'
 
 class Module
   def reachable? #:nodoc:
-    !anonymous? && name.constantize.equal?(self)
-  rescue NameError
-    false
+    !anonymous? && name.safe_constantize.equal?(self)
   end
 end