GraphQL import throws

When importing other .graphql files from schema.graphql, building the server fails.

Minimal example in Codesandbox: https://codesandbox.io/s/q848mq9o1w

schema.graphql:

# import Post from "posts.graphql"

type Query {
  posts: [Post]
}

posts.graphql:

type Post {
  id: ID!
  text: String!
  tags: [String]
}

Output on the terminal:

I tried with v1.0.2 up to 1.0.8, also with "./posts.graphql", but without success. Any idea?