Before this commit, K2 always applied coercion-to-unit for
callable references if expected type was Unit, and actual non-Unit.
However, this may not work in case when actual return type is
a type parameter and it must be inferred into Unit.
In this commit we started to disallow coercion-to-unit
for references with synthetic outer call (~ top-level in K1)
AND a type parameter as a return type (both should be true to disallow).
This provides better K1 consistency,
while still keeping some broken K1 cases working in K2.
See also added comment in CallableReferenceResolution.kt.
#KT-62565 Fixed
When expected type is known, use it as expected type for branch bodies.
While it indeed becomes different from the usual select call resolution,
where expected type is applied only after completion starts,
it helps to support, e.g. callable references resolution just as powerful
as it was in K1.
Also, in some cases where diagnostics have been changed, they become
a bit more helpful since they are reported closer
to the problematic places
cannotCastToFunction.kt test has been removed because it relied
on the case erroneously supported by the hack removed from
the FirCallResolver in this commit.
^KT-45989 Fixed
^KT-55936 Fixed
^KT-56445 Fixed
^KT-54709 Related
^KT-55931 Related
Mikhail Glukhikh