Problems with SASS @import in Rails 3.1

I have some trouble with SASS imports in rails 3.1. I've tried both the branch '3-1开发者_运维技巧-stable' and the tag 'v3.1.0.rc4'.

My Error

Undefined variable: "$var1".
  (in app/assets/stylesheets/application.css.scss)

app/assets/stylesheets/application.css.scss

@import "imp"; // defines $var1

body {
  border-right:5px solid $var1;
}

app/assets/stylesheets/_imp.scss

$var1: "blue";

Can you try renaming _imp.scss to _imp.css.scss?