org.jetbrains.kotlin.types.CompositionTypeSubstitution.kt Maven / Gradle / Ivy
/*
* 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
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package org.jetbrains.kotlin.types
import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
// Composition works as it's expected: Composition(outer, inner)(type) = outer(inner(type))
// Note that when a substitution returns null it means that type shouldn't be changed (i.e. it works like the identity function in that case)
// Currently it's only works if the inner substitution is a mapping from type parameter to another type parameter.
// Otherwise composition semantics become a little bit complicated.
class CompositionTypeSubstitution(
private val outer: TypeSubstitution, private val inner: Map
) : DelegatedTypeSubstitution(outer) {
override fun get(key: KotlinType) = inner[key.constructor.declarationDescriptor]?.let { outer[it.defaultType] } ?: outer[key]
}