IR: slightly simplify deep copy interface

Do not pass TypeRemapper explicitly unless an instance of something
other than DeepCopyTypeRemapper is required.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/DeepCopyIrTreeWithDeclarations.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.ir
 
 import org.jetbrains.kotlin.ir.util.DeepCopyIrTreeWithSymbols
 import org.jetbrains.kotlin.ir.util.DeepCopySymbolRemapper
-import org.jetbrains.kotlin.ir.util.DeepCopyTypeRemapper
 import org.jetbrains.kotlin.ir.util.NullDescriptorsRemapper
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 
@@ -16,7 +15,5 @@ fun <T : IrElement> T.deepCopyWithVariables(): T {
     val symbolsRemapper = DeepCopySymbolRemapper(NullDescriptorsRemapper)
     acceptVoid(symbolsRemapper)
 
-    val typesRemapper = DeepCopyTypeRemapper(symbolsRemapper)
-
-    return this.transform(DeepCopyIrTreeWithSymbols(symbolsRemapper, typesRemapper), null) as T
+    return this.transform(DeepCopyIrTreeWithSymbols(symbolsRemapper), null) as T
 }

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

@@ -25,33 +25,29 @@ import org.jetbrains.kotlin.utils.memoryOptimizedMap
 
 inline fun <reified T : IrElement> T.deepCopyWithSymbols(
     initialParent: IrDeclarationParent? = null,
-    createCopier: (SymbolRemapper, TypeRemapper) -> DeepCopyIrTreeWithSymbols =
-        { symbolRemapper, typeRemapper -> DeepCopyIrTreeWithSymbols(symbolRemapper, typeRemapper) },
-): T = deepCopyWithSymbols(initialParent, DeepCopySymbolRemapper(), createCopier)
-
-inline fun <reified T : IrElement> T.deepCopyWithSymbols(
-    initialParent: IrDeclarationParent?,
-    symbolRemapper: DeepCopySymbolRemapper,
-    createCopier: (SymbolRemapper, TypeRemapper) -> DeepCopyIrTreeWithSymbols =
-        { symbolRemapper, typeRemapper -> DeepCopyIrTreeWithSymbols(symbolRemapper, typeRemapper) },
+    createTypeRemapper: (SymbolRemapper) -> TypeRemapper = ::DeepCopyTypeRemapper
 ): T {
+    val symbolRemapper = DeepCopySymbolRemapper()
     acceptVoid(symbolRemapper)
-    val typeRemapper = DeepCopyTypeRemapper(symbolRemapper)
-    return transform(createCopier(symbolRemapper, typeRemapper), null).patchDeclarationParents(initialParent) as T
+    val typeRemapper = createTypeRemapper(symbolRemapper)
+    return transform(DeepCopyIrTreeWithSymbols(symbolRemapper, typeRemapper), null).patchDeclarationParents(initialParent) as T
 }
 
 @OptIn(ObsoleteDescriptorBasedAPI::class)
 open class DeepCopyIrTreeWithSymbols(
     private val symbolRemapper: SymbolRemapper,
-    private val typeRemapper: TypeRemapper,
+    typeRemapper: TypeRemapper? = null,
     // This parameter is not used meaningfully, but is left for compatibility with compose.
     @Suppress("UNUSED_PARAMETER") symbolRenamer: SymbolRenamer? = null,
 ) : IrElementTransformerVoid() {
     private var transformedModule: IrModuleFragment? = null
+    private val typeRemapper: TypeRemapper = typeRemapper ?: DeepCopyTypeRemapper(symbolRemapper)
 
     init {
         // TODO refactor
-        (typeRemapper as? DeepCopyTypeRemapper)?.let {
+        // After removing usages of DeepCopyTypeRemapper constructor from compose, the lateinit property `DeepCopyTypeRemapper.deepCopy`
+        // can be refactored to a constructor parameter.
+        (this.typeRemapper as? DeepCopyTypeRemapper)?.let {
             it.deepCopy = this
         }
     }

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

@@ -14,14 +14,11 @@ fun <T : IrElement> T.deepCopySavingMetadata(
     symbolRemapper: DeepCopySymbolRemapper = DeepCopySymbolRemapper()
 ): T {
     acceptVoid(symbolRemapper)
-    val typeRemapper = DeepCopyTypeRemapper(symbolRemapper)
     @Suppress("UNCHECKED_CAST")
-    return transform(DeepCopySavingMetadata(symbolRemapper, typeRemapper), null)
-        .patchDeclarationParents(initialParent) as T
+    return transform(DeepCopySavingMetadata(symbolRemapper), null).patchDeclarationParents(initialParent) as T
 }
 
-private class DeepCopySavingMetadata(symbolRemapper: SymbolRemapper, typeRemapper: TypeRemapper) :
-    DeepCopyIrTreeWithSymbols(symbolRemapper, typeRemapper) {
+private class DeepCopySavingMetadata(symbolRemapper: SymbolRemapper) : DeepCopyIrTreeWithSymbols(symbolRemapper) {
     override fun visitFile(declaration: IrFile): IrFile =
         super.visitFile(declaration).apply {
             metadata = declaration.metadata
@@ -30,7 +27,6 @@ private class DeepCopySavingMetadata(symbolRemapper: SymbolRemapper, typeRemappe
     override fun visitClass(declaration: IrClass): IrClass =
         super.visitClass(declaration).apply {
             metadata = declaration.metadata
-
         }
 
     override fun visitConstructor(declaration: IrConstructor): IrConstructor =