[IR] Push default values from base to implementation classes

The default value of those properties is a detail that should be handled
 by implementation or builder layer.

 This change will also simplify auto-generating and reasoning about
 generated implementation classes, and allow for potential further
 enhancements like intercepting all mutations.

^KT-65773 In Progress

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/IrTree.kt

@@ -443,7 +443,6 @@ object IrTree : AbstractTreeBuilder() {
         fieldsToSkipInIrFactoryMethod.add("origin")
 
         +field("symbol", symbolType, mutable = false) {
-            baseGetter = "error(\"Should never be called\")"
             skipInIrFactory()
         }
     }
@@ -495,13 +494,6 @@ object IrTree : AbstractTreeBuilder() {
         +field("name", type<Name>(), mutable = false)
         +field("irBuiltins", type(Packages.tree, "IrBuiltIns"), mutable = false)
         +listField("files", file, mutability = MutableList)
-        additionalImports += ArbitraryImportable(Packages.tree, "UNDEFINED_OFFSET")
-        +field("startOffset", int, mutable = false) {
-            baseGetter = "UNDEFINED_OFFSET"
-        }
-        +field("endOffset", int, mutable = false) {
-            baseGetter = "UNDEFINED_OFFSET"
-        }
     }
     val property: Element by element(Declaration) {
         isLeaf = true
@@ -678,14 +670,6 @@ object IrTree : AbstractTreeBuilder() {
         parent(varargElement)
         parent(attributeContainer)
 
-        +field("attributeOwnerId", attributeContainer, isChild = false) {
-            baseDefaultValue = "this"
-            skipInIrFactory()
-        }
-        +field("originalBeforeInline", attributeContainer, nullable = true, isChild = false) {
-            baseDefaultValue = "null"
-            skipInIrFactory()
-        }
         +field("type", irTypeType)
     }
     val statementContainer: Element by element(Expression) {
@@ -733,12 +717,8 @@ object IrTree : AbstractTreeBuilder() {
 
         parent(declarationReference)
 
-        +field("dispatchReceiver", expression, nullable = true) {
-            baseDefaultValue = "null"
-        }
-        +field("extensionReceiver", expression, nullable = true) {
-            baseDefaultValue = "null"
-        }
+        +field("dispatchReceiver", expression, nullable = true)
+        +field("extensionReceiver", expression, nullable = true)
         +symbol(s)
         +field("origin", statementOriginType, nullable = true)
         +listField("valueArguments", expression.copy(nullable = true), mutability = Array) {
@@ -862,9 +842,6 @@ object IrTree : AbstractTreeBuilder() {
         parent(statementContainer)
 
         +field("origin", statementOriginType, nullable = true)
-        +listField("statements", statement, mutability = MutableList) {
-            baseDefaultValue = "ArrayList(2)"
-        }
     }
     val block: Element by element(Expression) {
         needAcceptMethod()
@@ -902,9 +879,7 @@ object IrTree : AbstractTreeBuilder() {
         parent(expression)
 
         +field("loop", loop, isChild = false)
-        +field("label", string, nullable = true) {
-            baseDefaultValue = "null"
-        }
+        +field("label", string, nullable = true)
     }
     val `break` by element(Expression) {
         visitorParameterName = "jump"
@@ -1051,9 +1026,7 @@ object IrTree : AbstractTreeBuilder() {
 
         +symbol(fieldSymbolType, mutable = true)
         +field("superQualifierSymbol", classSymbolType, nullable = true)
-        +field("receiver", expression, nullable = true) {
-            baseDefaultValue = "null"
-        }
+        +field("receiver", expression, nullable = true)
         +field("origin", statementOriginType, nullable = true)
     }
     val getField: Element by element(Expression) {
@@ -1089,13 +1062,9 @@ object IrTree : AbstractTreeBuilder() {
         parent(expression)
 
         +field("origin", statementOriginType, nullable = true)
-        +field("body", expression, nullable = true) {
-            baseDefaultValue = "null"
-        }
+        +field("body", expression, nullable = true)
         +field("condition", expression)
-        +field("label", string, nullable = true) {
-            baseDefaultValue = "null"
-        }
+        +field("label", string, nullable = true)
     }
     val whileLoop: Element by element(Expression) {
         visitorParameterName = "loop"

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/model/Field.kt

@@ -11,8 +11,7 @@ import org.jetbrains.kotlin.generators.tree.ListField as AbstractListField
 sealed class Field(
     override val name: String,
     override var isMutable: Boolean,
-) : AbstractField<Field>() {
-    var baseDefaultValue: String? = null
+) : AbstractField<Field>(), AbstractFieldWithDefaultValue<Field> {
     var baseGetter: String? = null
 
     sealed class UseFieldAsParameterInIrFactoryStrategy {
@@ -32,11 +31,18 @@ sealed class Field(
                 UseFieldAsParameterInIrFactoryStrategy.Yes(null)
             }
 
-    override val withGetter: Boolean
+    override var withGetter: Boolean
         get() = baseGetter != null
+        set(value) = error("Operation not supported")
 
-    override val defaultValueInImplementation: String?
-        get() = baseGetter ?: baseDefaultValue
+    override var defaultValueInImplementation: String? by ::baseGetter
+
+    override var defaultValueInBuilder: String?
+        get() = null
+        set(_) = error("Builders are not supported")
+
+    override val origin: Field
+        get() = this
 
     override var customSetter: String? = null
 
@@ -46,7 +52,7 @@ sealed class Field(
         get() = false
 
     override val isFinal: Boolean
-        get() = defaultValueInImplementation != null
+        get() = baseGetter != null
 
     override val isParameter: Boolean
         get() = false
@@ -55,7 +61,6 @@ sealed class Field(
 
     override fun updateFieldsInCopy(copy: Field) {
         super.updateFieldsInCopy(copy)
-        copy.baseDefaultValue = baseDefaultValue
         copy.baseGetter = baseGetter
         copy.customUseInIrFactoryStrategy = customUseInIrFactoryStrategy
         copy.customSetter = customSetter