This flag is true by default but is set to false for
- Java methods and constructors
- interface delegation methods that delegate to Java
The NAMED_ARGUMENTS_NOT_ALLOWED logic is mostly refactored to use the
new flag though some custom logic remains for determining the correct
message and to work around a corner case with fake overrides.
The flag is (de)serialized from/to metadata. For backward compatibility
with K1, delegated methods to Java types are deserialized as stable.
^KT-40480 Fixed
Kirill Rakhman