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FIR: Refine inference constraints when type variable in flexible position

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That issue might be fixed via changing
TypeVariableMarker.shouldBeFlexible at ConeConstraintSystemUtilContext
but this and some other tricks have been added because of incorrect
handling of constraints where type variable has a flexible bound

^KT-51168 Fixed
This commit is contained in:
Denis.Zharkov
2022-04-12 16:30:55 +03:00
committed by teamcity
parent 853b7ec078
commit f70ae2df3a
54 changed files with 411 additions and 154 deletions
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compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/ConstraintIncorporator.kt
+5 -1
View File
@@ -59,7 +59,11 @@ class ConstraintIncorporator(
typeVariable: TypeVariableMarker,
constraint: Constraint
) {
val shouldBeTypeVariableFlexible = with(utilContext) { typeVariable.shouldBeFlexible() }
val shouldBeTypeVariableFlexible =
if (useRefinedBoundsForTypeVariableInFlexiblePosition())
false
else
with(utilContext) { typeVariable.shouldBeFlexible() }
// \alpha <: constraint.type
if (constraint.kind != ConstraintKind.LOWER) {
compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/TypeCheckerStateForConstraintSystem.kt
+47 -13
View File
@@ -174,9 +174,9 @@ abstract class TypeCheckerStateForConstraintSystem(
*
* T?
*
* Foo <: T? -- Foo & Any <: T -- Foo!! <: T
* Foo? <: T? -- Foo? & Any <: T -- Foo!! <: T
* (Foo..Bar) <: T? -- (Foo..Bar) & Any <: T -- (Foo..Bar)!! <: T
* Foo <: T? -- Foo & Any <: T
* Foo? <: T? -- Foo? & Any <: T -- Foo & Any <: T
* (Foo..Bar) <: T? -- (Foo..Bar) & Any <: T
*
* T!
*
@@ -248,12 +248,34 @@ abstract class TypeCheckerStateForConstraintSystem(
when (subType) {
is SimpleTypeMarker ->
// Foo <: T! -- (Foo!! .. Foo) <: T
subType.createConstraintPartForLowerBoundAndFlexibleTypeVariable()
when {
useRefinedBoundsForTypeVariableInFlexiblePosition() ->
// Foo <: T! -- (Foo!! .. Foo) <: T
createFlexibleType(
subType.makeSimpleTypeDefinitelyNotNullOrNotNull(),
subType.withNullability(true)
)
// In K1 (FE1.0), there is an obsolete behavior
subType.isMarkedNullable() -> subType
else -> createFlexibleType(subType, subType.withNullability(true))
}
is FlexibleTypeMarker ->
// (Foo..Bar) <: T! -- (Foo!! .. Bar) <: T
createFlexibleType(subType.lowerBound().makeSimpleTypeDefinitelyNotNullOrNotNull(), subType.upperBound())
when {
useRefinedBoundsForTypeVariableInFlexiblePosition() ->
// (Foo..Bar) <: T! -- (Foo!! .. Bar?) <: T
createFlexibleType(
subType.lowerBound().makeSimpleTypeDefinitelyNotNullOrNotNull(),
subType.upperBound().withNullability(true)
)
else ->
// (Foo..Bar) <: T! -- (Foo!! .. Bar) <: T
createFlexibleType(
subType.lowerBound().makeSimpleTypeDefinitelyNotNullOrNotNull(),
subType.upperBound()
)
}
else -> error("sealed")
}
@@ -273,17 +295,29 @@ abstract class TypeCheckerStateForConstraintSystem(
}
/**
* T! <: Foo <=> T <: Foo..Foo?
* T! <: Foo <=> T <: Foo & Any..Foo?
* T? <: Foo <=> T <: Foo && Nothing? <: Foo
* T <: Foo -- leave as is
*/
private fun simplifyUpperConstraint(typeVariable: KotlinTypeMarker, superType: KotlinTypeMarker): Boolean = with(extensionTypeContext) {
val typeVariableLowerBound = typeVariable.lowerBoundIfFlexible()
val simplifiedSuperType = if (typeVariableLowerBound.isDefinitelyNotNullType()) {
superType.withNullability(true)
} else if (typeVariable.isFlexible() && superType is SimpleTypeMarker) {
createFlexibleType(superType, superType.withNullability(true))
} else superType
val simplifiedSuperType = when {
typeVariable.isFlexible() && useRefinedBoundsForTypeVariableInFlexiblePosition() ->
createFlexibleType(
superType.lowerBoundIfFlexible().makeSimpleTypeDefinitelyNotNullOrNotNull(),
superType.upperBoundIfFlexible().withNullability(true)
)
typeVariableLowerBound.isDefinitelyNotNullType() -> {
superType.withNullability(true)
}
typeVariable.isFlexible() && superType is SimpleTypeMarker ->
createFlexibleType(superType, superType.withNullability(true))
else -> superType
}
addUpperConstraint(typeVariableLowerBound.typeConstructor(), simplifiedSuperType)