[SIR] Auto-generate the Swift IR tree

Co-authored-by: Gleb Lukianets <gleb.lukianets@jetbrains.com>

generators/tree-generator-common/src/org/jetbrains/kotlin/generators/tree/AbstractElement.kt

@@ -6,7 +6,11 @@
 package org.jetbrains.kotlin.generators.tree
 
 /**
- * A class representing a FIR or IR tree element.
+ * Represents an abstract class/interface for a tree node in the tree generator.
+ *
+ * Examples: `IrElement`, `FirRegularClass`.
+ *
+ * Subclasses may contain additional properties/logic specific to a particular tree.
  */
 abstract class AbstractElement<Element, Field, Implementation>(
     val name: String,

generators/tree-generator-common/src/org/jetbrains/kotlin/generators/tree/AbstractVisitorPrinter.kt

@@ -49,7 +49,8 @@ abstract class AbstractVisitorPrinter<Element : AbstractElement<Element, Field,
      * If `true`, visitor methods for generic tree elements will be parameterized correspondingly.
      * Otherwise, type arguments of generic tree elements will be replaced with `*`.
      */
-    abstract val allowTypeParametersInVisitorMethods: Boolean
+    open val allowTypeParametersInVisitorMethods: Boolean
+        get() = false
 
     /**
      * Allows to customize the default element to visit if the method for visiting this [element] is not overridden.