[IR] Fix mutable shared reference of MFVC type

Signed-off-by: Evgeniy.Zhelenskiy <Evgeniy.Zhelenskiy@jetbrains.com>

#KT-1179

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

@@ -894,7 +894,11 @@ internal class JvmMultiFieldValueClassLowering(
                 context.createJvmIrBuilder(currentScope.symbol, expression).irBlock {
                     val rootNode = replacements.getRootMfvcNode(function.constructedClass)
                     val instance = rootNode.createInstanceFromValueDeclarationsAndBoxType(
-                        this, function.constructedClassType as IrSimpleType, Name.identifier("constructor_tmp"), ::variablesSaver
+                        scope = this,
+                        type = function.constructedClassType as IrSimpleType,
+                        name = Name.identifier("constructor_tmp"),
+                        saveVariable = ::variablesSaver,
+                        isVar = false,
                     )
                     for (valueDeclaration in instance.valueDeclarations) {
                         valueDeclaration.origin = JvmLoweredDeclarationOrigin.TEMPORARY_MULTI_FIELD_VALUE_CLASS_VARIABLE
@@ -1175,7 +1179,7 @@ internal class JvmMultiFieldValueClassLowering(
             val rootNode = replacements.getRootMfvcNode(irClass)
             return context.createJvmIrBuilder(getCurrentScopeSymbol(), declaration).irBlock {
                 val instance = rootNode.createInstanceFromValueDeclarationsAndBoxType(
-                    this, declaration.type as IrSimpleType, declaration.name, ::variablesSaver
+                    this, declaration.type as IrSimpleType, declaration.name, ::variablesSaver, declaration.isVar
                 )
                 valueDeclarationsRemapper.registerReplacement(declaration, instance)
                 initializer?.let {
@@ -1201,7 +1205,8 @@ internal class JvmMultiFieldValueClassLowering(
             savableStandaloneVariable(
                 type = it.type.substitute(typeArguments),
                 origin = IrDeclarationOrigin.IR_TEMPORARY_VARIABLE,
-                saveVariable = ::variablesSaver
+                saveVariable = ::variablesSaver,
+                isVar = false,
             )
         }
         val instance = ValueDeclarationMfvcNodeInstance(rootMfvcNode, typeArguments, variables)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/MfvcNode.kt

@@ -48,18 +48,19 @@ fun MfvcNode.createInstanceFromBox(
     createInstanceFromBox(scope, makeTypeArgumentsFromType(receiver.type as IrSimpleType), receiver, accessType, saveVariable)
 
 fun MfvcNode.createInstanceFromValueDeclarationsAndBoxType(
-    scope: IrBuilderWithScope, type: IrSimpleType, name: Name, saveVariable: (IrVariable) -> Unit,
-): ValueDeclarationMfvcNodeInstance = createInstanceFromValueDeclarations(scope, makeTypeArgumentsFromType(type), name, saveVariable)
+    scope: IrBuilderWithScope, type: IrSimpleType, name: Name, saveVariable: (IrVariable) -> Unit, isVar: Boolean
+): ValueDeclarationMfvcNodeInstance = createInstanceFromValueDeclarations(scope, makeTypeArgumentsFromType(type), name, saveVariable, isVar)
 
 fun MfvcNode.createInstanceFromValueDeclarations(
-    scope: IrBuilderWithScope, typeArguments: TypeArguments, name: Name, saveVariable: (IrVariable) -> Unit,
+    scope: IrBuilderWithScope, typeArguments: TypeArguments, name: Name, saveVariable: (IrVariable) -> Unit, isVar: Boolean
 ): ValueDeclarationMfvcNodeInstance {
     val valueDeclarations = mapLeaves {
         scope.savableStandaloneVariable(
             type = it.type,
             name = listOf(name, it.fullFieldName).joinToString("-"),
             origin = JvmLoweredDeclarationOrigin.MULTI_FIELD_VALUE_CLASS_REPRESENTATION_VARIABLE,
-            saveVariable = saveVariable
+            saveVariable = saveVariable,
+            isVar = isVar,
         )
     }
     return ValueDeclarationMfvcNodeInstance(this, typeArguments, valueDeclarations)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/MfvcNodeInstance.kt

@@ -241,7 +241,7 @@ fun IrContainerExpression.unwrapBlock(): IrExpression = statements.singleOrNull(
 fun IrBuilderWithScope.savableStandaloneVariable(
     type: IrType,
     name: String? = null,
-    isMutable: Boolean = false,
+    isVar: Boolean,
     origin: IrDeclarationOrigin,
     isTemporary: Boolean = origin == IrDeclarationOrigin.IR_TEMPORARY_VARIABLE
             || origin == JvmLoweredDeclarationOrigin.TEMPORARY_MULTI_FIELD_VALUE_CLASS_VARIABLE
@@ -249,7 +249,7 @@ fun IrBuilderWithScope.savableStandaloneVariable(
     saveVariable: (IrVariable) -> Unit,
 ): IrVariable {
     val variable = if (isTemporary || name == null) scope.createTemporaryVariableDeclaration(
-        type, name, isMutable,
+        type, name, isVar,
         startOffset = startOffset,
         endOffset = endOffset,
         origin = origin,
@@ -260,7 +260,7 @@ fun IrBuilderWithScope.savableStandaloneVariable(
         symbol = IrVariableSymbolImpl(),
         name = Name.identifier(name),
         type = type,
-        isVar = isMutable,
+        isVar = isVar,
         isConst = false,
         isLateinit = false
     ).apply {