It's not often that one gets the chance to change something as fundamental as the scoping rules of a language. Nevertheless, I would like to propose a change to Haskell's scoping rules. The change is quite simple. As it is, top level entities in a module are in the same scope as all imported entities. I suggest that this is changed to that the entities from the module are in an inner scope and do not clash with imported identifiers. Why? Consider the following snippet module M where import I foo = True Assume this compiles. Now change the module I so it exports something called foo. After this change the module M no longer compiles since (under the current scoping rules) the imported foo clashes with the foo in M. Pros: Module compilation becomes more robust under library changes. Fewer imports with hiding are necessary. Cons: There's the chance that you happen to define a module identifier with the same name as something imported. This will typically lead to a type error, but there is a remote chance it could have the same type. Implementation status: The Mu compiler has used the scoping rule for several years now and it works very well in practice. -- Lennart