FIR2IR: set dispatch receiver for companion member reference

#KT-42132 fixed

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -495,7 +495,7 @@ class Fir2IrVisitor(
 
     override fun visitCallableReferenceAccess(callableReferenceAccess: FirCallableReferenceAccess, data: Any?): IrElement {
         val explicitReceiverExpression = convertToIrReceiverExpression(
-            callableReferenceAccess.explicitReceiver, callableReferenceAccess.calleeReference, callableReferenceMode = true
+            callableReferenceAccess.explicitReceiver, callableReferenceAccess.calleeReference, callableReferenceAccess
         )
         return callGenerator.convertToIrCallableReference(callableReferenceAccess, explicitReceiverExpression)
     }
@@ -547,11 +547,11 @@ class Fir2IrVisitor(
     private fun convertToIrReceiverExpression(
         expression: FirExpression?,
         calleeReference: FirReference,
-        callableReferenceMode: Boolean = false
+        callableReferenceAccess: FirCallableReferenceAccess? = null
     ): IrExpression? {
         return when (expression) {
             null -> null
-            is FirResolvedQualifier -> callGenerator.convertToGetObject(expression, callableReferenceMode)
+            is FirResolvedQualifier -> callGenerator.convertToGetObject(expression, callableReferenceAccess)
             is FirExpressionWithSmartcast -> convertToImplicitCastExpression(expression, calleeReference)
             is FirFunctionCall, is FirThisReceiverExpression, is FirCallableReferenceAccess -> convertToIrExpression(expression)
             else -> if (expression is FirQualifiedAccessExpression && expression.explicitReceiver == null) {

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/CallAndReferenceGenerator.kt

@@ -361,14 +361,35 @@ class CallAndReferenceGenerator(
         }.applyCallArguments(annotationCall, annotationMode = true)
     }
 
-    fun convertToGetObject(qualifier: FirResolvedQualifier): IrExpression {
-        return convertToGetObject(qualifier, callableReferenceMode = false)!!
+    internal fun convertToGetObject(qualifier: FirResolvedQualifier): IrExpression {
+        return convertToGetObject(qualifier, null)!!
     }
 
-    internal fun convertToGetObject(qualifier: FirResolvedQualifier, callableReferenceMode: Boolean): IrExpression? {
+    internal fun convertToGetObject(
+        qualifier: FirResolvedQualifier,
+        callableReferenceAccess: FirCallableReferenceAccess? = null
+    ): IrExpression? {
         val classSymbol = (qualifier.typeRef.coneType as? ConeClassLikeType)?.lookupTag?.toSymbol(session)
-        if (callableReferenceMode && classSymbol is FirRegularClassSymbol) {
-            if (classSymbol.classId != qualifier.classId) {
+        if (callableReferenceAccess != null && classSymbol is FirRegularClassSymbol) {
+            val classIdMatched = classSymbol.classId == qualifier.classId
+            val companionClassIdMatched = classSymbol.fir.isCompanion && classSymbol.classId.outerClassId == qualifier.classId
+            val lastClassIfCompanion = conversionScope.lastClass()?.takeIf { it.isCompanion }
+            val callable =
+                ((callableReferenceAccess.calleeReference as FirResolvedNamedReference).resolvedSymbol as FirCallableSymbol<*>)
+            val companionMemberReferenceThatNeedsDispatchReceiver = companionClassIdMatched &&
+                    // TODO: this can't cover delegated members. See bb test kt38664.kt
+                    // Make sure the reference indeed refers to a member of that companion
+                    classSymbol.fir.declarations.contains(callable.fir) &&
+                    // Built-in extensions are stored in the companion, e.g., String.Companion.
+                    // Make sure this is not a reference to an extension function.
+                    !callable.isExtension &&
+                    // Dispatch receiver is not needed if we're converting a callable reference inside that companion, e.g.,
+                    // class Foo {
+                    //   companion object {
+                    //      val cp = Foo::member
+                    // } }
+                    lastClassIfCompanion?.classId != classSymbol.classId
+            if (!classIdMatched && !companionMemberReferenceThatNeedsDispatchReceiver) {
                 return null
             }
         }
@@ -612,7 +633,7 @@ class CallAndReferenceGenerator(
             return explicitReceiverExpression
         }
         if (firReceiver is FirResolvedQualifier) {
-            return convertToGetObject(firReceiver, callableReferenceMode = this is FirCallableReferenceAccess)
+            return convertToGetObject(firReceiver, this as? FirCallableReferenceAccess)
         }
         return firReceiver.takeIf { it !is FirNoReceiverExpression }?.let { visitor.convertToIrExpression(it) }
             ?: explicitReceiverExpression

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirCallableSymbol.kt

@@ -6,7 +6,9 @@
 package org.jetbrains.kotlin.fir.symbols.impl
 
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirFunction
 import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirProperty
 import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.CallableId
 
@@ -21,6 +23,13 @@ abstract class FirCallableSymbol<D : FirCallableDeclaration<D>> : AbstractFirBas
 
 val FirCallableSymbol<*>.isStatic: Boolean get() = (fir as? FirMemberDeclaration)?.status?.isStatic == true
 
+val FirCallableSymbol<*>.isExtension: Boolean
+    get() = when (fir) {
+        is FirFunction -> fir.receiverTypeRef != null
+        is FirProperty -> fir.receiverTypeRef != null
+        else -> false
+    }
+
 inline fun <reified E : FirCallableSymbol<*>> E.unwrapSubstitutionOverrides(): E {
     var current = this
     while (current.overriddenSymbol != null) {

compiler/testData/codegen/box/reflection/call/inlineClasses/jvmStaticFunction.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // JVM_TARGET: 1.8
 // WITH_REFLECT