IR: make IrDeclarationWithVisibility.visibility mutable

It was mutable anyway in many subclasses. This is needed in order to
avoid depending on concrete IR implementations in the JVM IR backend
where it's necessary to be able to change visibility.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt

@@ -72,8 +72,11 @@ class Fir2IrLazySimpleFunction(
     override val name: Name
         get() = fir.name
 
-    override val visibility: Visibility
+    override var visibility: Visibility
         get() = fir.visibility
+        set(_) {
+            error("Mutating Fir2Ir lazy elements is not possible")
+        }
 
     override val modality: Modality
         get() = fir.modality!!

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/ToArrayLowering.kt

@@ -24,7 +24,6 @@ import org.jetbrains.kotlin.ir.builders.irReturn
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
-import org.jetbrains.kotlin.ir.declarations.impl.IrFunctionImpl
 import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.defaultType
@@ -97,7 +96,7 @@ private class ToArrayLowering(private val context: JvmBackendContext) : ClassLow
     }
 
     private fun IrClass.findOrCreate(indirectSubclass: Boolean, matcher: (IrSimpleFunction) -> Boolean, fallback: () -> IrSimpleFunction) {
-        val existing = functions.find(matcher) as? IrFunctionImpl
+        val existing = functions.find(matcher)
         if (existing != null) {
             // This is an explicit override of a method defined in `kotlin.collections.AbstractCollection`
             // or `java.util.Collection`. From here on, the frontend will check the existence of implementations;

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

@@ -16,7 +16,10 @@
 
 package org.jetbrains.kotlin.ir.declarations
 
-import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.SourceElement
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.IrType
@@ -28,8 +31,6 @@ interface IrClass :
     @ObsoleteDescriptorBasedAPI
     override val descriptor: ClassDescriptor
 
-    override var visibility: Visibility
-
     val kind: ClassKind
     var modality: Modality
     val isCompanion: Boolean
@@ -54,16 +55,3 @@ fun IrClass.addMember(member: IrDeclaration) {
 fun IrClass.addAll(members: List<IrDeclaration>) {
     declarations.addAll(members)
 }
-
-fun IrClass.getInstanceInitializerMembers() =
-    declarations.filter {
-        when (it) {
-            is IrAnonymousInitializer ->
-                true
-            is IrProperty ->
-                it.backingField?.initializer != null
-            is IrField ->
-                it.initializer != null
-            else -> false
-        }
-    }

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

@@ -17,17 +17,12 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
-import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 
-
 interface IrConstructor : IrFunction, IrSymbolDeclaration<IrConstructorSymbol> {
     @ObsoleteDescriptorBasedAPI
     override val descriptor: ClassConstructorDescriptor
 
-    override var visibility: Visibility
-
     val isPrimary: Boolean
 }
-

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

@@ -55,7 +55,7 @@ interface IrOverridableDeclaration<S : IrSymbol> : IrDeclaration {
 }
 
 interface IrDeclarationWithVisibility : IrDeclaration {
-    val visibility: Visibility
+    var visibility: Visibility
 }
 
 interface IrDeclarationWithName : IrDeclaration {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt

@@ -38,7 +38,7 @@ class IrFieldImpl(
     override val symbol: IrFieldSymbol,
     override val name: Name,
     override val type: IrType,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val isFinal: Boolean,
     override val isExternal: Boolean,
     override val isStatic: Boolean

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt

@@ -33,7 +33,7 @@ abstract class IrPropertyCommonImpl(
     endOffset: Int,
     origin: IrDeclarationOrigin,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val modality: Modality,
     override val isVar: Boolean,
     override val isConst: Boolean,
@@ -113,7 +113,7 @@ class IrPropertyImpl(
     origin: IrDeclarationOrigin,
     override val symbol: IrPropertySymbol,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val modality: Modality,
     override val isVar: Boolean,
     override val isConst: Boolean,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt

@@ -24,7 +24,7 @@ class IrTypeAliasImpl(
     endOffset: Int,
     override val symbol: IrTypeAliasSymbol,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val expandedType: IrType,
     override val isActual: Boolean,
     origin: IrDeclarationOrigin

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt

@@ -32,7 +32,7 @@ class IrLazyField(
     override val symbol: IrFieldSymbol,
     override val descriptor: PropertyDescriptor,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val isFinal: Boolean,
     override val isExternal: Boolean,
     override val isStatic: Boolean,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt

@@ -27,7 +27,7 @@ class IrLazyProperty(
     override val symbol: IrPropertySymbol,
     override val descriptor: PropertyDescriptor,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val modality: Modality,
     override val isVar: Boolean,
     override val isConst: Boolean,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt

@@ -29,7 +29,7 @@ class IrLazyTypeAlias(
     override val symbol: IrTypeAliasSymbol,
     override val descriptor: TypeAliasDescriptor,
     override val name: Name,
-    override val visibility: Visibility,
+    override var visibility: Visibility,
     override val isActual: Boolean,
     stubGenerator: DeclarationStubGenerator,
     typeTranslator: TypeTranslator