KT-15153 Support typeAlias extensions in completion and add import

#KT-15153 fixed

idea/idea-core/src/org/jetbrains/kotlin/idea/core/KotlinIndicesHelper.kt

@@ -49,7 +49,6 @@ import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.isHiddenInResolution
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.utils.addIfNotNull
 import org.jetbrains.kotlin.utils.addToStdlib.singletonOrEmptyList
 import java.lang.reflect.Field
 import java.lang.reflect.Modifier
@@ -175,9 +174,31 @@ class KotlinIndicesHelper(
             suitableExtensions
     }
 
+
+    private fun resolveTypeAliasesUsingIndex(type: KotlinType, originalTypeName: String, out: MutableCollection<String>) {
+        val index = KotlinTypeAliasByExpansionShortNameIndex.INSTANCE
+
+        fun searchRecursively(typeName: String) {
+            ProgressManager.checkCanceled()
+            index[typeName, project, scope].asSequence()
+                    .map { it.resolveToDescriptorIfAny() as? TypeAliasDescriptor }
+                    .filterNotNull()
+                    .filter { it.expandedType == type }
+                    .map { it.name.asString() }
+                    .filter { it !in out }
+                    .onEach(::searchRecursively)
+                    .toCollection(out)
+        }
+
+        searchRecursively(originalTypeName)
+    }
+
     private fun MutableCollection<String>.addTypeNames(type: KotlinType) {
         val constructor = type.constructor
-        addIfNotNull(constructor.declarationDescriptor?.name?.asString())
+        constructor.declarationDescriptor?.name?.asString()?.let { typeName ->
+            add(typeName)
+            resolveTypeAliasesUsingIndex(type, typeName, this)
+        }
         constructor.supertypes.forEach { addTypeNames(it) }
     }