For diagnostics without any parameters, the given text is simply rendered as a
String, so no symbols should be escaped.
For diagnostics with parameters, the format in java.text.MessageFormat is used,
so one single quote is erased and two single quotes become one single quote in
the rendered text.
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 ...
Michael Bogdanov