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[NI] Refactor constraints transformations, update comments

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This commit is contained in:
Mikhail Zarechenskiy
2017-11-30 12:51:08 +03:00
parent 351c592c83
commit b9d390449c
1 changed files with 29 additions and 41 deletions
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compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/TypeCheckerContextForConstraintSystem.kt
+29 -41
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@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
import org.jetbrains.kotlin.resolve.descriptorUtil.hasExactAnnotation
import org.jetbrains.kotlin.resolve.descriptorUtil.hasNoInferAnnotation
import org.jetbrains.kotlin.types.*
import org.jetbrains.kotlin.types.KotlinTypeFactory.flexibleType
import org.jetbrains.kotlin.types.checker.*
import org.jetbrains.kotlin.types.typeUtil.builtIns
import org.jetbrains.kotlin.types.typeUtil.contains
@@ -91,25 +92,25 @@ abstract class TypeCheckerContextForConstraintSystem : TypeCheckerContext(errorT
*
* T?
*
* Foo <: T? -- Foo & Any <: T
* Foo? <: T? -- Foo? & Any <: T
* (Foo..Bar) <: T? -- (Foo..Bar) & Any <: 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
*
* T!
*
* Foo <: T! --
* assert T! == (T..T?)
* Foo <: T
* Foo <: T?
* Foo <: T (optional constraint, needs to preserve nullability)
* =>
* Foo <: T
* Foo & Any <: T
* Foo <: T
* =>
* (Foo & Any .. Foo) <: T
* (Foo & Any .. Foo) <: T -- (Foo!! .. Foo) <: T
*
* => Foo <: T! -- (Foo & Any .. Foo) <: T
* => Foo <: T! -- (Foo!! .. Foo) <: T
*
* Foo? <: T! -- (Foo? & Any .. Foo?) <: T
* Foo? <: T! -- (Foo!! .. Foo?) <: T
*
*
* (Foo..Bar) <: T! --
@@ -117,52 +118,39 @@ abstract class TypeCheckerContextForConstraintSystem : TypeCheckerContext(errorT
* (Foo..Bar) <: (T..T?)
* =>
* Foo <: T?
* Bar <: T
* Bar <: T (optional constraint, needs to preserve nullability)
* =>
* (Foo & Any .. Bar) <: T
* (Foo & Any .. Bar) <: T -- (Foo!! .. Bar) <: T
*
* => (Foo..Bar) <: T! -- (Foo & Any .. Bar) <: T
* => (Foo..Bar) <: T! -- (Foo!! .. Bar) <: T
*/
private fun simplifyLowerConstraint(typeVariable: UnwrappedType, subType: UnwrappedType): Boolean {
when (typeVariable) {
val lowerConstraint = when (typeVariable) {
is SimpleType ->
addLowerConstraintForSimpleType(typeVariable, subType)
// Foo <: T or
// Foo <: T? -- Foo!! <: T
if (typeVariable.isMarkedNullable) subType.makeDefinitelyNotNullOrNotNull() else subType
is FlexibleType -> {
assertFlexibleTypeVariable(typeVariable)
is FlexibleType ->
when (subType) {
is SimpleType -> addLowerConstraintWithSimpleSubtype(typeVariable, subType)
is FlexibleType -> addLowerConstraintWithFlexibleSubtype(typeVariable, subType)
is SimpleType ->
// Foo <: T! -- (Foo!! .. Foo) <: T
flexibleType(subType.makeSimpleTypeDefinitelyNotNullOrNotNull(), subType)
is FlexibleType ->
// (Foo..Bar) <: T! -- (Foo!! .. Bar) <: T
flexibleType(subType.lowerBound.makeSimpleTypeDefinitelyNotNullOrNotNull(), subType.upperBound)
}
}
}
addLowerConstraint(typeVariable.constructor, lowerConstraint)
return true
}
// Foo <: T! -- (Foo & Any .. Foo) <: T
private fun addLowerConstraintWithSimpleSubtype(typeVariable: FlexibleType, subType: SimpleType) {
assertFlexibleTypeVariable(typeVariable)
addLowerConstraint(typeVariable.constructor, KotlinTypeFactory.flexibleType(subType.makeSimpleTypeDefinitelyNotNullOrNotNull(), subType))
}
// (Foo..Bar) <: T! -- (Foo & Any .. Bar) <: T
private fun addLowerConstraintWithFlexibleSubtype(typeVariable: FlexibleType, subType: FlexibleType) {
assertFlexibleTypeVariable(typeVariable)
val lowerBound = subType.lowerBound
val upperBound = subType.upperBound
addLowerConstraint(typeVariable.constructor, KotlinTypeFactory.flexibleType(lowerBound.makeSimpleTypeDefinitelyNotNullOrNotNull(), upperBound))
}
// Foo <: T or
// Foo <: T? -- Foo & Any <: T
private fun addLowerConstraintForSimpleType(typeVariable: SimpleType, subType: UnwrappedType) {
if (typeVariable.isMarkedNullable)
addLowerConstraint(typeVariable.constructor, subType.makeDefinitelyNotNullOrNotNull())
else
addLowerConstraint(typeVariable.constructor, subType)
}
private fun assertFlexibleTypeVariable(typeVariable: FlexibleType) {
assert(typeVariable.lowerBound.constructor == typeVariable.upperBound.constructor) {
"Flexible type variable ($typeVariable) should have bounds with the same type constructor, i.e. (T..T?)"