Skip declarations without sources in reporting, not when determining redeclaration groups:
this allows emitting informative diagnostics for incremental compilation.
Provide containing declaration with "kind", e.g., "package '<root>'", "class A", and so on.
When checking for overloads in package, consider functions and top-level class constructors as possibly conflicting between each other. NB OverloadUtil uses containing package scope from module descriptor.
Change diagnostic message for CONFLICTING_OVERLOAD: it's misleading in case of fun vs constructor conflict.
Add custom multifile test for diagnostics in IDE (probably not the best; should preprocess file content if it's required to check highlighting in multiple files, not only in the first file).
Add test for KT-10765 Incremental compilation misses overload conflict between constructor and function ...
Zalim Bashorov