PSI2IR: generate field writes for all val property assignments

Assuming the frontend is correct, and it hopefully is, all of them are
initializations even if not done in the owner class directly.

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/AssignmentGenerator.kt

@@ -25,7 +25,6 @@ import org.jetbrains.kotlin.ir.builders.irGet
 import org.jetbrains.kotlin.ir.builders.irTemporary
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrDynamicOperatorExpressionImpl
-import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.util.referenceFunction
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
@@ -39,7 +38,6 @@ import org.jetbrains.kotlin.resolve.PropertyImportedFromObject
 import org.jetbrains.kotlin.resolve.calls.callUtil.isSafeCall
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.resolve.calls.tasks.isDynamic
-import org.jetbrains.kotlin.resolve.scopes.receivers.ThisClassReceiver
 import org.jetbrains.kotlin.types.KotlinType
 
 class AssignmentGenerator(statementGenerator: StatementGenerator) : StatementGeneratorExtension(statementGenerator) {
@@ -277,16 +275,10 @@ class AssignmentGenerator(statementGenerator: StatementGenerator) : StatementGen
                         isAssignmentReceiver = isAssignmentStatement
                     )
                 )
-            isValInitializationInConstructor(descriptor, resolvedCall) -> {
-                val thisClass = getThisClass()
-                val thisAsReceiverParameter = thisClass.thisAsReceiverParameter
-                val thisType = thisAsReceiverParameter.type.toIrType()
-                val irThis = IrGetValueImpl(
-                    ktLeft.startOffsetSkippingComments, ktLeft.endOffset,
-                    thisType,
-                    context.symbolTable.referenceValueParameter(thisAsReceiverParameter)
-                )
-                createBackingFieldLValue(ktLeft, descriptor, RematerializableValue(irThis), null)
+            origin == IrStatementOrigin.EQ && !descriptor.isVar -> {
+                // An assignment to a val property can only be its initialization in the constructor.
+                val receiver = resolvedCall.dispatchReceiver ?: descriptor.dispatchReceiverParameter?.value
+                createBackingFieldLValue(ktLeft, descriptor, statementGenerator.generateReceiverOrNull(ktLeft, receiver), null)
             }
             else -> {
                 val propertyReceiver = statementGenerator.generateCallReceiver(
@@ -356,12 +348,6 @@ class AssignmentGenerator(statementGenerator: StatementGenerator) : StatementGen
             )
     }
 
-    private fun isValInitializationInConstructor(descriptor: PropertyDescriptor, resolvedCall: ResolvedCall<*>): Boolean =
-        !descriptor.isVar &&
-                descriptor.kind != CallableMemberDescriptor.Kind.FAKE_OVERRIDE &&
-                statementGenerator.scopeOwner.let { it is ConstructorDescriptor || it is ClassDescriptor } &&
-                resolvedCall.dispatchReceiver is ThisClassReceiver
-
     private fun getThisClass(): ClassDescriptor {
         val scopeOwner = statementGenerator.scopeOwner
         return when (scopeOwner) {