remove the nil check from set_inverse_instance

methods that call set_inverse_instance with a record will not have to
pay the cost of a nil check on every call

activerecord/lib/active_record/associations/association.rb

@@ -104,11 +104,12 @@ def reset_scope
 
       # Set the inverse association, if possible
       def set_inverse_instance(record)
-        if record && invertible_for?(record)
+        if invertible_for?(record)
           inverse = record.association(inverse_reflection_for(record).name)
           inverse.target = owner
           inverse.inversed = true
         end
+        record
       end
 
       # Returns the class of the target. belongs_to polymorphic overrides this to look at the

activerecord/lib/active_record/associations/belongs_to_association.rb

@@ -12,7 +12,7 @@ def replace(record)
 
         update_counters(record)
         replace_keys(record)
-        set_inverse_instance(record)
+        set_inverse_instance(record) if record
 
         @updated = true if record
 

activerecord/lib/active_record/associations/preloader/singular_association.rb

@@ -11,7 +11,7 @@ def preload(preloader)
 
             association = owner.association(reflection.name)
             association.target = record
-            association.set_inverse_instance(record)
+            association.set_inverse_instance(record) if record
           end
         end
 

activerecord/lib/active_record/associations/singular_association.rb

@@ -39,7 +39,9 @@ def create_scope
         end
 
         def find_target
-          scope.first.tap { |record| set_inverse_instance(record) }
+          if record = scope.first
+            set_inverse_instance record
+          end
         end
 
         def replace(record)