#### Bug, feature request, or proposal: Proposal #### What is the expected behavior? Write the expected type for `MdSnackBarRef` #### What is the current behavior? You have to define the type as `any` #### What are the steps to reproduce? This: `let snackBarRef = snackBar.open('Message archived');` cannot be written like this: `let snackBarRef: MdSnackBarRef<SimpleSnackBar> = snackBar.open('Message archived');` because there is no import for `SimpleSnackBar` #### What is the use-case or motivation for changing an existing behavior? It is more convenient for code writing in TypeScript if the variable type is known. #### Which versions of Angular, Material, OS, browsers are affected? All