Function reads_anything 

pub fn reads_anything(granted: &RolePermissions, table: &Table) -> bool

Whether this role can read anything of this table at all.

The question a relationship target has to answer, and the question that decides whether the table gets a GraphQL type: a role with a write grant and no select permission keeps the table in the cache, and a type with no fields is not a legal type. Asked of an already-reduced table, so the computed fields it still carries are the granted ones.