Previously, we would ignore the candidate with the non-smartcasted
receiver if they have the same symbol.
Now we prefer them when they're visible or when the smart cast changes
the nullability.
The compiler should only report diagnostics for
comparisons over builtins and identity-less types,
other incompatibilities should be reported
via inspections.
It's ok that in `equalityChecksOnIntegerTypes`
instead of `EQUALITY_NOT_APPLICABLE_WARNING` we get
`EQUALITY_NOT_APPLICABLE`, because
`ProperEqualityChecksInBuilderInferenceCalls`
is already active by default.
This change also replaces the notion of a representative superclass
with the least upper bound.
This makes complex types like
intersection/flexible transparent to
RULES1-based compatibility checks.
One way to look at it is to think
that this is an automatic way of handling
type parameters: automatic picking of
"interesting" bounds, and checking them against one another.
Note that `TypeIntersector.intersectTypes`
for `Int` and `T` where `T` is a type parameter
may return both `{Int & T}` or `null`
depending on `T`-s bounds. At the same time,
for type parameters `T` and `K` it will
always return `{T & K}`.
`ConeTypeIntersector.intersectTypes`, on the
other hand, will always return `{Int & T}`
irrespectively of the bounds. Meaning, the two
intersectors differ in corner cases.
`lowerBoundIfFlexible` call in `isLiterallyTypeParameter` is backed by
the `equalityOfFlexibleTypeParameters` test.
^KT-35134 #fixed-in-k2
^KT-22499 #fixed-in-k2
^KT-46383 #fixed-in-k2
* Change 1.6 to 1.7 constants
* Fix SAFE_CALL_WILL_CHANGE_NULLABILITY for testData
* Change EXPOSED_PROPERTY_TYPE_IN_CONSTRUCTOR_WARNING to EXPOSED_PROPERTY_TYPE_IN_CONSTRUCTOR_ERROR
* Change NON_EXHAUSTIVE_WHEN_STATEMENT to NO_ELSE_IN_WHEN
* Fix testData for SafeCallsAreAlwaysNullable
* Change T -> T & Any in test dumps
* Change INVALID_CHARACTERS_NATIVE_WARNING -> INVALID_CHARACTERS_NATIVE_ERROR
* TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING -> TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR
Kirill Rakhman