Full completion should not be done if lower `Nothing`
is the only proper constraint when constraint with ILT type is present.
ILT will be selected as a resulting type and transformed into `Int`
without attention to possible restrictions from outer calls.
Also use updated diagnostic pattern in TreesCompareTest.
In rare cases diagnostic was cut too early on !> characters,
that were a part of diagnostic parameter:
<!DIAGNOSTIC("Type<DefinitelyNotNullTypeArgument!!>")!>
Before fix only one level of type arguments was used to determine variance of type variable to find out direction requirements.
This incorrect in general case, because outer variance affects subtyping deductions, for example:
Inv<Out<A>> <: Inv<Out<B>> => A <: B; B <: A, despite A and B are in covariant position if only one level is considered
^KT-36233 Fixed
Consider lower `Nothing` constraint non-proper only if there is a dependant not analyzed postponed atom.
Early completion to `Nothing` provides data flow info for smart casts.
KT-35668 Fixed
Fix completion of anonymous functions with expression body without expected type.
Premature completion led to losing type info from outer calls.
Also report type mismatches on empty lambda expressions.
KT-34729 In progress
Force constraint system completer to always fix variable with unknown position.
This makes inferred type for in parameters less specific, but OI infers to
subtype in such cases, so NI won't infer to less specific types than before.
Current selection of completion mode for call is not always correct in case of full mode,
and sometimes too conservative in case of partial mode. Updated algorithm checks constraints
wrt position of type variables in return type and in other related constraints.
Full completion happens if proper constraint requirements are satisfied for variables.
simon.ogorodnik