New CAT call
Introduction
The ECMA standard introduces a new solution to the CAT call problem. Covariant redefinition of a formal argument is only possible to a detachable type:
class A feature f (a: ANY) do end end |
class B1 inherit A redefine f end feature f (a: STRING) do end -- not valid end |
class B2 inherit A redefine f end feature f (a: ?STRING) do end -- valid end |
This wiki discusses some of concerns related to this solution.