[Commonizer] assembelCirTree: Supoprt TypeAlias -> Class commonization

native/commonizer/src/org/jetbrains/kotlin/commonizer/tree/assembelCirTree.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.commonizer.tree
 
+import org.jetbrains.kotlin.commonizer.cir.CirClass
 import org.jetbrains.kotlin.commonizer.cir.CirTypeAlias
 import org.jetbrains.kotlin.commonizer.mergedtree.*
 
@@ -22,12 +23,15 @@ internal fun CirModuleNode.assembleCirTree(): CirTreeModule? {
 }
 
 internal fun CirPackageNode.assembleCirTree(): CirTreePackage? {
+    val commonizedPackage = commonDeclaration() ?: return null
+    val commonizedTypeAliases = typeAliases.mapNotNull { (_, typeAlias) -> typeAlias.assembleCirTree() }
+
     return CirTreePackage(
-        pkg = commonDeclaration() ?: return null,
+        pkg = commonizedPackage,
         properties = properties.mapNotNull { (key, property) -> property.assembleCirTree(key) },
         functions = functions.mapNotNull { (key, function) -> function.assembleCirTree(key) },
-        typeAliases = typeAliases.mapNotNull { (_, typeAlias) -> typeAlias.assembleCirTree() },
-        classes = classes.mapNotNull { (_, clazz) -> clazz.assembleCirTree() }
+        typeAliases = commonizedTypeAliases.filterIsInstance<CirTreeTypeAlias>(),
+        classes = classes.mapNotNull { (_, clazz) -> clazz.assembleCirTree() } + commonizedTypeAliases.filterIsInstance<CirTreeClass>()
     )
 }
 
@@ -42,11 +46,12 @@ internal fun CirClassNode.assembleCirTree(): CirTreeClass? {
     )
 }
 
-internal fun CirTypeAliasNode.assembleCirTree(): CirTreeTypeAlias? {
-    return CirTreeTypeAlias(
-        id = id,
-        typeAlias = commonDeclaration() as? CirTypeAlias ?: return null
-    )
+internal fun CirTypeAliasNode.assembleCirTree(): CirTreeClassifier? {
+    return when (val commonDeclaration = commonDeclaration()) {
+        is CirTypeAlias -> CirTreeTypeAlias(id, commonDeclaration)
+        is CirClass -> CirTreeClass(id, commonDeclaration)
+        else -> null
+    }
 }
 
 internal fun CirPropertyNode.assembleCirTree(approximationKey: PropertyApproximationKey): CirTreeProperty? {

native/commonizer/tests/org/jetbrains/kotlin/commonizer/hierarchical/HierarchicalTypeAliasCommonizationTest.kt

@@ -29,4 +29,89 @@ class HierarchicalTypeAliasCommonizationTest : AbstractInlineSourcesCommonizatio
         result.assertCommonized("c", "")
         result.assertCommonized("d", "")
     }
+
+    /**
+     * See: https://youtrack.jetbrains.com/issue/KT-45992
+     */
+    fun `todo test typealias and class`() {
+        val result = commonize {
+            outputTarget("(a,b)")
+            simpleSingleSourceTarget("a", """class X """)
+            simpleSingleSourceTarget(
+                "b", """
+                class B
+                typealias X = B
+                """
+            )
+        }
+
+        result.assertCommonized("(a,b)", "expect class X")
+    }
+
+    fun `test typealias to different classes`() {
+        val result = commonize {
+            outputTarget("(((a,b), (c,d)), (e,f))")
+            simpleSingleSourceTarget(
+                "a", """
+                class AB
+                typealias x = AB
+            """
+            )
+            simpleSingleSourceTarget(
+                "b", """
+                class AB
+                typealias x = AB
+            """
+            )
+            simpleSingleSourceTarget(
+                "c", """
+                class CD
+                typealias x = CD
+            """
+            )
+            simpleSingleSourceTarget(
+                "d", """
+                class CD
+                typealias x = CD
+            """
+            )
+            simpleSingleSourceTarget("e", """class x""")
+            simpleSingleSourceTarget("f", """class x""")
+        }
+
+        result.assertCommonized("a", """class AB""")
+        result.assertCommonized("b", """class AB""")
+        result.assertCommonized("c", """class CD""")
+        result.assertCommonized("d", """class CD""")
+        result.assertCommonized("e", """class x""")
+        result.assertCommonized("f", """class x""")
+
+        result.assertCommonized(
+            "(a,b)", """
+                expect class AB expect constructor()
+                typealias x = AB
+            """
+        )
+
+        result.assertCommonized(
+            "(c,d)", """
+                expect class CD expect constructor()
+                typealias x = CD
+            """
+        )
+
+        result.assertCommonized(
+            "(c,d)", """
+                expect class CD expect constructor()
+                typealias x = CD
+            """
+        )
+
+        result.assertCommonized(
+            "(e,f)", """expect class x expect constructor()"""
+        )
+
+        result.assertCommonized("((a,b), (c,d))", """expect class x""")
+        result.assertCommonized("(((a,b), (c,d)), (e,f))", """expect class x""")
+    }
 }