jvm-abi-gen: consider private type aliases to be public API

They can be referenced from public declarations right now.

^KT-54500 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/serialization/JvmSerializerExtension.kt

@@ -73,7 +73,8 @@ class JvmSerializerExtension @JvmOverloads constructor(
     }
 
     override fun shouldSerializeTypeAlias(descriptor: TypeAliasDescriptor): Boolean {
-        return classBuilderMode != ClassBuilderMode.ABI || descriptor.visibility != DescriptorVisibilities.PRIVATE
+        // TODO: do not serialize private type aliases in ABI class builder mode once KT-17229 is fixed.
+        return true
     }
 
     override fun shouldSerializeNestedClass(descriptor: ClassDescriptor): Boolean {

compiler/fir/fir2ir/jvm-backend/src/org/jetbrains/kotlin/fir/backend/jvm/FirJvmSerializerExtension.kt

@@ -87,7 +87,8 @@ class FirJvmSerializerExtension(
     }
 
     override fun shouldSerializeTypeAlias(typeAlias: FirTypeAlias): Boolean {
-        return classBuilderMode != ClassBuilderMode.ABI || typeAlias.visibility != Visibilities.Private
+        // TODO: do not serialize private type aliases in ABI class builder mode once KT-17229 is fixed.
+        return true
     }
 
     override fun shouldSerializeNestedClass(nestedClass: FirRegularClass): Boolean {

plugins/jvm-abi-gen/src/org/jetbrains/kotlin/jvm/abi/JvmAbiMetadataProcessor.kt

@@ -155,11 +155,7 @@ private class AbiKmClassVisitor(delegate: KmClassVisitor) : KmClassVisitor(deleg
         return null
     }
 
-    override fun visitTypeAlias(flags: Flags, name: String): KmTypeAliasVisitor? {
-        if (!isPrivateDeclaration(flags))
-            return super.visitTypeAlias(flags, name)
-        return null
-    }
+    // TODO: do not serialize private type aliases once KT-17229 is fixed.
 
     override fun visitExtensions(type: KmExtensionType): KmClassExtensionVisitor? {
         val delegate = super.visitExtensions(type)
@@ -189,11 +185,7 @@ private class AbiKmPackageVisitor(delegate: KmPackageVisitor) : KmPackageVisitor
         return null
     }
 
-    override fun visitTypeAlias(flags: Flags, name: String): KmTypeAliasVisitor? {
-        if (!isPrivateDeclaration(flags))
-            return super.visitTypeAlias(flags, name)
-        return null
-    }
+    // TODO: do not serialize private type aliases once KT-17229 is fixed.
 
     override fun visitExtensions(type: KmExtensionType): KmPackageExtensionVisitor? {
         val delegate = super.visitExtensions(type)