This commit introduces TypeConstructor.refine method.
It's implementation can be roughly split in three parts:
- trivial implementations which just return 'this': mostly, it used for
typeConstructors which can not be refined at all (e.g.
IntegerValueTypeConstructor and other special cases of constructors)
- delegating implementations which call 'refine' recursively for
component typeConstructors -- obviously, they are used in composite
typeConstructors (like IntersectionTypeConstructor)
- finally, the most interesting one is in 'AbstractTypeConstructor'
which returns lightweight wrapper called 'ModuleViewTypeConstructor'.
The idea here is to propagate refinement to supertypes without eagerly
computing them all.
VERY IMPORTANT CAVEAT of TypeConstructor.refine is that call to this
method CAN NOT add new supertypes, so returned supertypes are not
entirely "valid". See the KDoc for TypeConstructor.refine for details
Dmitry Savvinov
c12f5f6055