Instead of erasing descriptors with conflicting substitution,
use invariant CapturedType(<projection>) as replacement for type parameter
within default member scope.
After substitution leave such types 'as is' everywhere except return types,
use common approximation for them.
#KT-9294 In Progress
#KT-5411 Fixed
#KT-8647 Fixed
#KT-9462 Fixed
#KT-9893 Fixed
#KT-7581 Fixed
#KT-7296 In Progress
There are two different forms of types intestion:
1. Type parameters with multiple bounds
2. Smart casts
The problem was that when member scope of type intersection contained
effective duplicates and that lead to overload resolution ambiguity in
strange cases like `x.hashCode()`
For first type we do effectively the same thing as when building member
scope for class extending several interfaces: group all descriptors by
both-way-overridability relation and then choose most-specific in each
group.
For smart casts we do basically the same thing but with special
treatments:
1. From all descriptors that _equal_ to most specific we choose
the one that works without smartcast if possible (i.e. we choose first from candidates list)
2. If smart-cast value seems to be unstable we use only member scope
of receiver type + all descriptors from smart cast possible types
that has incompatible signature. If we'd include all of them and
choose one as more specific, and it would lead to false
SMART_CAST_IMPOSIBLE (see test unstableSmartCast.kt)
#KT-3996 Fixed
#KT-10315 Fixed
If there's only one erroneous bound (vast majority of cases), report it on the
bound; otherwise (to avoid reporting it several times) report on the type
parameter declaration
It seems that all tests on that diagnostic were replaced in previous commits by
"repeated bound" and "no other bounds except a type parameter bound"
diagnostics
This check is obsolete but leads to problems.
It appears when resolving recursive calls (see sameTypeParameterUse.kt):
`foo<R>(x: R, y: R)` within call `foo<R>(x, "")` after substitution
has R as type of it's second argument, and when checking value arguments,
x is not checked because supposed to be dependent on type parameter of candidate
(that is effectively false), so there are two successful candidates
in resolution results and wrong OVERLOAD_RESOLUTION_AMBIGUITY error.
Denis Zharkov