- Allow participating subtypes of functional types in conversions
- Fix several subtle inconsistencies
- Place logic about conversions at one place
Now conversions operations have two stages: before usual subtyping
check and after one. This is needed to support conversions of
subtypes (of functional types, for example). First, the compiler
checks if it possible to resolve an argument without conversion and
only then it tries to perform conversion.
Note that it'd be incorrect to perform conversion eagerly as it can
change resolve (Runnable & () -> Unit <: KRunnable), plus we can't
guess whether conversion is needed at all as it's important not to
look into supertypes if resolution doesn't actually needed it
#KT-36448 Fixed
#KT-37574 Fixed
#KT-38604 Fixed
Jinseong Jeon