Change -XTypeOperators to treat all type-operators as type-constructors.
Previously, only type operators starting with ":" were type constructors, and writing "+" in a type resulted in a type variable. Now, type variables are always ordinary identifiers, and all operators are treated as constructors. One can still write type variables in infix form though, for example, "a `fun` b" is a type expression with 3 type variables: "a", "fun", and "b". Writing (+) in an import/export list always refers to the value (+) and not the type. To refer to the type one can write either "type (+)", or provide an explicit suobrdinate list (e.g., "(+)()"). For clarity, one can also combine the two, for example "type (+)(A,B,C)" is also accepted and means the same thing as "(+)(A,B,C)" (i.e., export the type (+), with the constructors A,B,and C).
Showing with 44 additions and 17 deletions