Here we introduce ONLY_IMPLICIT_RECEIVER tower level
to support extension lambda calls on local variables,
and soften extension receiver checks to make such extensions visible & applicable.
Also here we try to map arguments twice for functional types
Nullability constraints should not be chosen when proper
argument constraints for variables in contravariant position present.
^KT-32106 Fixed
^KT-33166 Fixed
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.
Update diagnostics for new inference.
'Not enough information for parameter' should not be reported for
fake calls and functions with error return type, muted in tests.
Substituting inferred type parameters with single substitutor leads
to incorrect behaviour in cases, when class' type parameters are used in constructor.
As a side effect of two-step substitution, intermediate descriptor is created,
which prevents incorrect substitution. To preserve this side effect, single
resulting substitutor was split into two substitutors: one for substituting fresh
variables and another for substituting inferred variables and known parameters.
^KT-32415 Fixed
Known type parameters appear after inheriting from class with type
parameters. Their substitution matters for inner class constructor,
because without substitution it's parameters will be type checked
against incorrect (original) parameter descriptor with unsubstituted
type parameters.
Skip creation of composite substitutor, if old substitutor is empty.
New substitutors return null in case they don't substitute a type,
but old type substitutors have explicit isEmpty method. Composite
substitutor with empty old substitutor leads to creation
of incorrect descriptor copies.
Consider the following constraint system (from the test example):
Nothing? <: V1
F!! <: V2
Inv<V1> <: S
Inv<V2> <: S
Where V1, V2, S are type variables, and F has nullable upper bound.
Type variable fixation order should be: V2 -> V1 -> S, and the problem
was that previously after fixation of type variable V2 we were trying
to fix S (before V1), so we had the following constraints on S:
Inv<F!!> <: S
Inv<V1> <: S
=> S were fixed to Inv<F!!>
And after this V1 was fixed to F!! which is contradictory as Nothing?
is not a subtype of F!!.
#KT-33033 Fixed
#KT-30297 Fixed
#KT-32168 Fixed
#KT-27722 Fixed (actually, it was fixed with addition of DefNotNullTypes, and now test was added to save this behavior)
#KT-32345 Fixed
Default type of LazySubstitutingClassDescriptor is not lazy. However, most of default types are,
and there is an optimization in KotlinTypeFactory, which uses default type for simple type without
type arguments and/or annotations. LazySubstitutingClassDescriptor's default type creates simple type
with factory, which may therefore cause recursion.
#KT-34029 Fixed
Function return type can't and should not be used during overload resolution of callable references.
Since it can be DeferredType, its substitution in CS caused exception.
The actual problem was introduced in 4f1e85b468, note how `hashCode` is implemented:
```
var currentHashCode = cachedHashCode
if (currentHashCode == 0) return currentHashCode
...
```
It's a silly bug, there should be check `if (currentHashCode != 0) ...` because `0` is used a marker for "uncomputed value".
Now, in the commit 0219b86d06 I added map with `KotlinType` as a key and because of constant `hash` for `KotlinType`, we basically got `List` instead of `Map`, which caused this performance regression
#KT-34063 Fixed
Bug was introduced in b99efb because of lack of tests.
All code in `AbstractTypeCheckerContextForConstraintSystem.extractTypeVariableForSubtype`
related to IN projection looks suspicious and needs further investigation
Denis Zharkov