Implement unionTypeAttributes and replaceTypeAttributes in ConeInferenceContext

core/compiler.common/src/org/jetbrains/kotlin/types/model/TypeSystemContext.kt

@@ -134,9 +134,9 @@ interface TypeSystemCommonSuperTypesContext : TypeSystemContext, TypeSystemTypeF
      */
     fun TypeConstructorMarker.toErrorType(): SimpleTypeMarker
 
-    fun unionTypeAttributes(types: List<KotlinTypeMarker>): List<AnnotationMarker> = emptyList()
+    fun unionTypeAttributes(types: List<KotlinTypeMarker>): List<AnnotationMarker>
 
-    fun KotlinTypeMarker.replaceTypeAttributes(newAttributes: List<AnnotationMarker>): KotlinTypeMarker = this
+    fun KotlinTypeMarker.replaceTypeAttributes(newAttributes: List<AnnotationMarker>): KotlinTypeMarker
 }
 
 // This interface is only used to declare that implementing class is supposed to be used as a TypeSystemInferenceExtensionContext component

core/descriptors/build.gradle.kts

@@ -10,6 +10,8 @@ dependencies {
     api(project(":core:util.runtime"))
     api(kotlinStdlib())
     api(project(":kotlin-annotations-jvm"))
+    api(project(":compiler:util"))
+    compileOnly(intellijCoreDep()) { includeJars("intellij-core") }
 }
 
 sourceSets {

core/descriptors/src/org/jetbrains/kotlin/types/TypeAttributesTranslator.kt

@@ -9,7 +9,7 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 
 interface TypeAttributesTranslator {
     fun toAttributes(annotations: Annotations): TypeAttributes
-    fun toAnnotations(attributes: TypeAttributes): Annotations?
+    fun toAnnotations(attributes: TypeAttributes): Annotations
 }
 
 object DefaultTypeAttributesTranslator : TypeAttributesTranslator {

core/descriptors/src/org/jetbrains/kotlin/types/extensions/TypeAttributeTranslators.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.types.extensions
+
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.extensions.ProjectExtensionDescriptor
+import org.jetbrains.kotlin.types.*
+
+interface TypeAttributeTranslatorExtension : TypeAttributesTranslator
+
+class TypeAttributeTranslators(project: Project) {
+    val translators: List<TypeAttributesTranslator> =
+        getInstances(project) + DefaultTypeAttributesTranslator
+
+    fun toAttributes(annotations: Annotations): TypeAttributes {
+        val translated = translators.map { translator ->
+            translator.toAttributes(annotations)
+        }.flatten()
+        return TypeAttributes.create(translated)
+    }
+
+    fun toAnnotations(attributes: TypeAttributes): Annotations {
+        val translated = translators.map { translator ->
+            translator.toAnnotations(attributes)
+        }.flatten()
+        return Annotations.create(translated)
+    }
+
+    companion object :
+        ProjectExtensionDescriptor<TypeAttributeTranslatorExtension>(
+            "org.jetbrains.kotlin.extensions.typeAttribute",
+            TypeAttributeTranslatorExtension::class.java
+        )
+}