org.jetbrains.kotlin.load.java.sam.SingleAbstractMethodUtils.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2016 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.kotlin.load.java.sam
import org.jetbrains.kotlin.types.SimpleType
import org.jetbrains.kotlin.types.Variance
import org.jetbrains.kotlin.types.replace
import org.jetbrains.kotlin.types.typeUtil.asTypeProjection
import org.jetbrains.kotlin.types.typeUtil.contains
// If type 'samType' contains no projection, then it's non-projection parametrization is 'samType' itself
// Else each projection type argument 'out/in A_i' (but star projections) is replaced with it's bound 'A_i'
// Star projections are treated specially:
// - If first upper bound of corresponding type parameter does not contain any type parameter of 'samType' class,
// then use this upper bound instead of star projection
// - Otherwise no non-projection parametrization exists for such 'samType'
//
// See Non-wildcard parametrization in JLS 8 p.9.9 for clarification
internal fun nonProjectionParametrization(samType: SimpleType): SimpleType? {
if (samType.arguments.none { it.projectionKind != Variance.INVARIANT }) return samType
val parameters = samType.constructor.parameters
val parametersSet = parameters.toSet()
return samType.replace(
newArguments = samType.arguments.zip(parameters).map {
val (projection, parameter) = it
when {
projection.projectionKind == Variance.INVARIANT -> projection
projection.isStarProjection ->
parameter.upperBounds.first().takeUnless {
t -> t.contains { it.constructor.declarationDescriptor in parametersSet }
}?.asTypeProjection() ?: return@nonProjectionParametrization null
else -> projection.type.asTypeProjection()
}
})
}