IR: make DescriptorMetadataSource a subtype of MetadataSource

FirMetadataSource is a metadata source too.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/MetadataSource.kt

@@ -11,21 +11,27 @@ import org.jetbrains.kotlin.name.Name
 interface MetadataSource {
     val name: Name?
 
-    abstract class DescriptorBased<D : DeclarationDescriptor> internal constructor(val descriptor: D) : MetadataSource {
-        override val name: Name
-            get() = descriptor.name
-    }
-
-    class Class(descriptor: ClassDescriptor) : DescriptorBased<ClassDescriptor>(descriptor)
-
-    open class File(val descriptors: List<DeclarationDescriptor>) : MetadataSource {
-        override val name: Name?
-            get() = null
-    }
-
-    class Function(descriptor: FunctionDescriptor) : DescriptorBased<FunctionDescriptor>(descriptor)
-
-    class Property(descriptor: PropertyDescriptor) : DescriptorBased<PropertyDescriptor>(descriptor)
-
-    class LocalDelegatedProperty(descriptor: VariableDescriptorWithAccessors) : DescriptorBased<VariableDescriptorWithAccessors>(descriptor)
+    interface File : MetadataSource
+    interface Class : MetadataSource
+    interface Function : MetadataSource
+    interface Property : MetadataSource
+}
+
+sealed class DescriptorMetadataSource : MetadataSource {
+    open val descriptor: Named?
+        get() = null
+
+    override val name: Name?
+        get() = descriptor?.name
+
+    class File(val descriptors: List<DeclarationDescriptor>) : DescriptorMetadataSource(), MetadataSource.File
+
+    class Class(override val descriptor: ClassDescriptor) : DescriptorMetadataSource(), MetadataSource.Class
+
+    class Function(override val descriptor: FunctionDescriptor) : DescriptorMetadataSource(), MetadataSource.Function
+
+    class Property(override val descriptor: PropertyDescriptor) : DescriptorMetadataSource(), MetadataSource.Property
+
+    class LocalDelegatedProperty(override val descriptor: VariableDescriptorWithAccessors) : DescriptorMetadataSource(),
+        MetadataSource.Property
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt

@@ -589,7 +589,7 @@ class SymbolTable(
                 visibility ?: it.descriptor.visibility, !it.descriptor.isVar, it.descriptor.isEffectivelyExternal(),
                 it.descriptor.dispatchReceiverParameter == null
             ).apply {
-                metadata = MetadataSource.Property(it.descriptor)
+                metadata = DescriptorMetadataSource.Property(it.descriptor)
             }
         }
     ): IrField =
@@ -662,7 +662,7 @@ class SymbolTable(
                 isExternal = descriptor.isEffectivelyExternal(),
                 isExpect = descriptor.isExpect
             ).apply {
-                metadata = MetadataSource.Property(symbol.descriptor)
+                metadata = DescriptorMetadataSource.Property(symbol.descriptor)
             }
         }
     ): IrProperty =
@@ -978,7 +978,7 @@ class SymbolTable(
             { IrLocalDelegatedPropertySymbolImpl(descriptor) },
             factory
         ).apply {
-            metadata = MetadataSource.LocalDelegatedProperty(descriptor)
+            metadata = DescriptorMetadataSource.LocalDelegatedProperty(descriptor)
         }
 
     fun referenceLocalDelegatedProperty(descriptor: VariableDescriptorWithAccessors) =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/overrides.kt

@@ -7,9 +7,9 @@ package org.jetbrains.kotlin.ir.util
 
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
+import org.jetbrains.kotlin.ir.declarations.DescriptorMetadataSource
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
-import org.jetbrains.kotlin.ir.declarations.MetadataSource
 import org.jetbrains.kotlin.ir.types.impl.IrUninitializedType
 
 @ObsoleteDescriptorBasedAPI
@@ -25,7 +25,7 @@ fun SymbolTable.declareSimpleFunctionWithOverrides(
                 startOffset, endOffset, origin, it, nameProvider.nameForDeclaration(this),
                 visibility, modality, IrUninitializedType, isInline, isExternal, isTailrec, isSuspend, isOperator, isInfix, isExpect
             ).also { declaration ->
-                declaration.metadata = MetadataSource.Function(this)
+                declaration.metadata = DescriptorMetadataSource.Function(this)
             }
         }
     }.also { declaration ->