It became possible to drop it after KT-62590. Now, on a frontend, the
return type check is part of a common AbstractExpectActualChecker logic
Change in nestedAnnotationClassViaActualTypealias.fir.kt aligns the
behaviour with K1. KT-61964
Review: https://jetbrains.team/p/kt/reviews/12750/timeline
Using files turned to be a bad idea, because people often
use the same name for files with expects and with corresponding actuals.
This commits disambiguiates ambiguous message for
AMBIGUOUS_ACTUALS/AMBGIUOUS_EXPECTS diagnostics by using modules instead
of files
^KT-32582 Fixed
Also make TypeParameterUpperBounds a "strong" incompatibility, meaning
that non-actual members from platform module are _not_ going to be
matched to the expected members if this incompatibility exists between
them, and therefore NO_ACTUAL_FOR_EXPECT will be reported on the
expected declaration, instead of ACTUAL_MISSING on the platform member.
This is needed because the difference in type parameter upper bounds can
have effect on the function signature on the platform (e.g. on JVM,
Array<T> -> T[], but Array<T> -> Comparable[] if T : Comparable<T>), and
it would be incorrect to report ACTUAL_MISSING on the member that has
nothing to do with the expected declaration that happens to coincide
with it in everything except type parameter bounds
#KT-21864 Fixed
Divide incompatibility on two groups: strong and weak. Strong incompatibility means that if declaration with such incompatibility has no `actual` modifier then it's considered as usual overload and we'll not report any error on it.
#KT-20540 Fixed
#KT-20680 Fixed
Try to report most mismatch errors on the 'impl' declaration. Only
report a mismatch error on the 'header' declaration if no error would be
otherwise reported on any 'impl' declaration in the compilation unit.
Also render declaration kind in the message
#KT-18447 In Progress
For each platform declaration, there must be at least one impl declaration in
the module with the compatible signature; similarly, for each impl declaration,
there must be at least one platform declaration with the compatible signature.
Note that currently the presence of the 'impl' modifier is not checked yet.
Also, the sad fact is that if you have platform and impl declarations which are
not compatible, you get two errors: on the platform delcaration and on the impl
declaration. This needs to be addressed as well
Nikita Bobko