org.jetbrains.kotlin.types.Utils.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.types
import org.jetbrains.kotlin.types.checker.ErrorTypesAreEqualToAnything
/**
* This is temporary hack for type intersector.
*
* It is almost save, because:
* - it running only if general algorithm is failed
* - returned type is subtype of all [types].
*
* But it is hack, because it can give unstable result, but it better than exception.
* See KT-11266.
*/
internal fun hackForTypeIntersector(types: Collection): KotlinType? {
if (types.size < 2) return types.firstOrNull()
return types.firstOrNull { candidate ->
types.all {
ErrorTypesAreEqualToAnything.isSubtypeOf(candidate, it)
}
}
}
fun getEffectiveVariance(parameterVariance: Variance, projectionKind: Variance): Variance {
if (parameterVariance === Variance.INVARIANT) {
return projectionKind
}
if (projectionKind === Variance.INVARIANT) {
return parameterVariance
}
if (parameterVariance === projectionKind) {
return parameterVariance
}
// In = In<*>
// Out = Out<*>
return Variance.OUT_VARIANCE
}