Previously, PartialBodyResolveFilter didn't know about contracts and was
filtering out calls of such functions, leading to unstable completion in
cases like that:
fun test(x: Any?) {
require(x is String)
x.<caret>
}
However, PartialBodyResolveFilter works by pure PSI, while to determine
if function has a contract we have to resolve it.
To solve it, we do something very similar to what has been done with
Nothin-returning functions: introduce
KotlinProbablyContractedFunctionShortNameIndex, which collects all
function which *may* have a contract during indexing.
^KT-25275 Fixed
Dmitry Savvinov