IR: use mutable lists in IrStringConcatenation, IrTry, IrVararg

Make addArgument/addElement/putElement extension functions. This will
simplify transition to auto-generated IR.

Co-authored-by: mcpiroman <mcpiroman@gmail.com>

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/AdapterGenerator.kt

@@ -447,10 +447,9 @@ internal class AdapterGenerator(
         if (argument !is FirVarargArgumentsExpression || argument.arguments.size != elements.size) {
             return this
         }
-        val argumentMapping = this.elements.zip(argument.arguments).toMap()
+        val argumentMapping = elements.zip(argument.arguments).toMap()
         // [IrElementTransformer] is not preferred, since it's hard to visit vararg elements only.
-        val irVarargElements = elements as MutableList<IrVarargElement>
-        irVarargElements.replaceAll { irVarargElement ->
+        elements.replaceAll { irVarargElement ->
             if (irVarargElement is IrExpression) {
                 val firVarargArgument =
                     argumentMapping[irVarargElement] ?: error("Can't find the original FirExpression for ${irVarargElement.render()}")

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/handlers/StepHandler.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.expressions.IrCall
 import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.addArgument
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.types.defaultType
 import org.jetbrains.kotlin.ir.types.isInt

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrExpressions.kt

@@ -36,3 +36,15 @@ var IrDynamicOperatorExpression.right: IrExpression
 
 fun IrFunctionAccessExpression.putArgument(parameter: IrValueParameter, argument: IrExpression): Unit =
     putArgument(symbol.owner, parameter, argument)
+
+fun IrVararg.putElement(i: Int, element: IrVarargElement) {
+    elements[i] = element
+}
+
+fun IrVararg.addElement(varargElement: IrVarargElement) {
+    elements.add(varargElement)
+}
+
+fun IrStringConcatenation.addArgument(argument: IrExpression) {
+    arguments.add(argument)
+}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrStringConcatenation.kt

@@ -6,7 +6,5 @@
 package org.jetbrains.kotlin.ir.expressions
 
 abstract class IrStringConcatenation : IrExpression() {
-    abstract val arguments: List<IrExpression>
-
-    abstract fun addArgument(argument: IrExpression)
+    abstract val arguments: MutableList<IrExpression>
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrTry.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.ir.expressions
 abstract class IrTry : IrExpression() {
     abstract var tryResult: IrExpression
 
-    abstract val catches: List<IrCatch>
+    abstract val catches: MutableList<IrCatch>
 
     abstract var finallyExpression: IrExpression?
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrVararg.kt

@@ -10,7 +10,5 @@ import org.jetbrains.kotlin.ir.types.IrType
 abstract class IrVararg : IrExpression() {
     abstract var varargElementType: IrType
 
-    abstract val elements: List<IrVarargElement>
-
-    abstract fun putElement(i: Int, element: IrVarargElement)
+    abstract val elements: MutableList<IrVarargElement>
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrStringConcatenationImpl.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.ir.expressions.IrStringConcatenation
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
-import java.util.*
 
 class IrStringConcatenationImpl(
     override val startOffset: Int,
@@ -39,10 +38,6 @@ class IrStringConcatenationImpl(
 
     override val arguments: MutableList<IrExpression> = ArrayList()
 
-    override fun addArgument(argument: IrExpression) {
-        arguments.add(argument)
-    }
-
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitStringConcatenation(this, data)
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrVarargImpl.kt

@@ -41,14 +41,6 @@ class IrVarargImpl(
 
     override val elements: MutableList<IrVarargElement> = SmartList()
 
-    fun addElement(varargElement: IrVarargElement) {
-        elements.add(varargElement)
-    }
-
-    override fun putElement(i: Int, element: IrVarargElement) {
-        elements[i] = element
-    }
-
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R {
         return visitor.visitVararg(this, data)
     }

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

@@ -10,11 +10,8 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrVariableImpl
-import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
+import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
-import org.jetbrains.kotlin.ir.expressions.mapTypeParameters
-import org.jetbrains.kotlin.ir.expressions.mapValueParameters
 import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol