org.jetbrains.kotlin.types.checker.utils.kt Maven / Gradle / Ivy

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/*
 * Copyright 2010-2015 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.types.checker

import org.jetbrains.kotlin.types.JetType
import org.jetbrains.kotlin.types.TypeSubstitutor
import org.jetbrains.kotlin.types.TypeUtils
import org.jetbrains.kotlin.types.Variance
import org.jetbrains.kotlin.types.checker.TypeCheckingProcedureCallbacks
import java.util.*

private class SubtypePathNode(val type: JetType, val previous: SubtypePathNode?)

public fun findCorrespondingSupertype(
        subtype: JetType, supertype: JetType,
        typeCheckingProcedureCallbacks: TypeCheckingProcedureCallbacks
): JetType? {
    val queue = ArrayDeque()
    queue.add(SubtypePathNode(subtype, null))

    val supertypeConstructor = supertype.getConstructor()

    while (!queue.isEmpty()) {
        val lastPathNode = queue.poll()
        val currentSubtype = lastPathNode.type
        val constructor = currentSubtype.getConstructor()

        if (typeCheckingProcedureCallbacks.assertEqualTypeConstructors(constructor, supertypeConstructor)) {
            var substituted = currentSubtype
            var isAnyMarkedNullable = currentSubtype.isMarkedNullable

            var currentPathNode = lastPathNode.previous

            while (currentPathNode != null) {
                substituted = TypeSubstitutor.create(currentPathNode.type).safeSubstitute(substituted, Variance.INVARIANT)
                isAnyMarkedNullable = isAnyMarkedNullable || currentPathNode.type.isMarkedNullable

                currentPathNode = currentPathNode.previous
            }

            return TypeUtils.makeNullableAsSpecified(substituted, isAnyMarkedNullable)
        }

        for (immediateSupertype in constructor.getSupertypes()) {
            queue.add(SubtypePathNode(immediateSupertype, lastPathNode))
        }
    }

    return null
}