diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index 070d82cf17127..da9f20990fb93 100644
--- a/actionview/lib/action_view/template.rb
+++ b/actionview/lib/action_view/template.rb
@@ -155,7 +155,7 @@ def supports_streaming?
     # This method is instrumented as "!render_template.action_view". Notice that
     # we use a bang in this instrumentation because you don't want to
     # consume this in production. This is only slow if it's being listened to.
-    def render(view, locals, buffer = nil, &block)
+    def render(view, locals, buffer = ActionView::OutputBuffer.new, &block)
       instrument_render_template do
         compile!(view)
         view.send(method_name, locals, buffer, &block)
diff --git a/actionview/lib/action_view/template/handlers/erb/erubi.rb b/actionview/lib/action_view/template/handlers/erb/erubi.rb
index db75f028edef1..d379d7ec12355 100644
--- a/actionview/lib/action_view/template/handlers/erb/erubi.rb
+++ b/actionview/lib/action_view/template/handlers/erb/erubi.rb
@@ -13,7 +13,7 @@ def initialize(input, properties = {})
 
             # Dup properties so that we don't modify argument
             properties = Hash[properties]
-            properties[:preamble]   = "@output_buffer = output_buffer || ActionView::OutputBuffer.new;"
+            properties[:preamble]   = "@output_buffer = output_buffer;"
             properties[:postamble]  = "@output_buffer.to_s"
             properties[:bufvar]     = "@output_buffer"
             properties[:escapefunc] = ""
@@ -23,6 +23,8 @@ def initialize(input, properties = {})
 
           def evaluate(action_view_erb_handler_context)
             pr = eval("proc { #{@src} }", binding, @filename || "(erubi)")
+            # Double assignment to eliminate -w warnings
+            output_buffer = output_buffer = ActionView::OutputBuffer.new
             action_view_erb_handler_context.instance_eval(&pr)
           end