[FIR2IR] Simplify generation of bound callable reference receivers

Remove a bunch of custom logic to determine when a callable reference is
bound or not (and hence mustn't have a receiver). Instead, a helper
extension is introduced to determine when a callable reference is bound
by checking if dispatch/extensionReceiver is not FirNoReceiver and the
referenced member is not static.

#KT-57253 Fixed

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

@@ -702,64 +702,11 @@ class CallAndReferenceGenerator(
         callableReferenceAccess: FirCallableReferenceAccess?
     ): IrExpression? {
         val classSymbol = (qualifier.typeRef.coneType as? ConeClassLikeType)?.lookupTag?.toSymbol(session)
-        if (callableReferenceAccess != null && classSymbol is FirRegularClassSymbol) {
-            val classId = qualifier.symbol?.fullyExpandedClass(session)?.classId
-            val classIdMatched = classSymbol.classId == classId
-            if (!classIdMatched) {
-                // Check whether we need get companion object as dispatch receiver
-                if (!classSymbol.fir.isCompanion || classSymbol.classId.outerClassId != classId) {
-                    return null
-                }
-                val resolvedReference = callableReferenceAccess.calleeReference as FirResolvedNamedReference
-                val firCallableSymbol = resolvedReference.resolvedSymbol as FirCallableSymbol<*>
-                // Make sure the reference indeed refers to a member of that companion
 
-                val receiverClassLookupTag = firCallableSymbol.dispatchReceiverClassLookupTagOrNull()
+        if (callableReferenceAccess?.isBound == false) {
-                    ?: firCallableSymbol.receiverParameter?.typeRef?.coneTypeSafe<ConeClassLikeType>()?.lookupTag
+            return null
-                    ?: return null
-
-                val callableIsDefinitelyNotMemberOfCompanion = with(session.typeContext) {
-                    !classSymbol.defaultType().anySuperTypeConstructor { it.typeConstructor() == receiverClassLookupTag }
-                }
-                if (callableIsDefinitelyNotMemberOfCompanion) {
-                    return null
-                }
-                /*
-                 * This check is supposed to distinguish cases when both companion and containing class have this function
-                 *
-                 *   open class Base {
-                 *       fun foo() {}
-                 *   }
-                 *
-                 *   class Some : Base() {
-                 *       companion object : Base() {
-                 *           fun bar()
-                 *       }
-                 *   }
-                 *
-                 *   Some::foo // reference to Some.foo
-                 *   Some::bar // reference to Some.Companion.bar
-                 */
-                val containingClass = classSymbol.getContainingClassLookupTag()?.toFirRegularClassSymbol(session) ?: return null
-                val callableIsDefinitelyMemberOfOuterClass = with(session.typeContext) {
-                    containingClass.defaultType().anySuperTypeConstructor { it.typeConstructor() == receiverClassLookupTag }
-                }
-                if (callableIsDefinitelyMemberOfOuterClass) {
-                    val expectedParameterCount = callableReferenceAccess.typeRef.coneType.typeArguments.size - 1
-
-                    val declaration = firCallableSymbol.fir
-                    val requiredParameterCount = ((declaration as? FirFunction)?.valueParameters?.size ?: 0) +
-                            (if (declaration.dispatchReceiverType != null) 1 else 0) +
-                            (if (declaration.receiverParameter != null) 1 else 0)
-
-                    // However, if the number of parameters only match, if the receiver is bound, allow using the companion as receiver.
-                    val boundCallableIsExpected = requiredParameterCount == expectedParameterCount + 1
-                    if (!boundCallableIsExpected) {
-                        return null
-                    }
-                }
-            }
         }
+
         val irType = qualifier.typeRef.toIrType()
         return qualifier.convertWithOffsets { startOffset, endOffset ->
             if (classSymbol != null) {

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.KtSourceElement
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
 import org.jetbrains.kotlin.fir.declarations.FirValueParameter
+import org.jetbrains.kotlin.fir.declarations.utils.isStatic
 import org.jetbrains.kotlin.fir.diagnostics.ConeDiagnostic
 import org.jetbrains.kotlin.fir.expressions.builder.buildConstExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildErrorExpression
@@ -17,10 +18,7 @@ import org.jetbrains.kotlin.fir.expressions.impl.FirBlockImpl
 import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.expressions.impl.FirResolvedArgumentList
 import org.jetbrains.kotlin.fir.expressions.impl.FirSingleExpressionBlock
-import org.jetbrains.kotlin.fir.references.FirReference
+import org.jetbrains.kotlin.fir.references.*
-import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
-import org.jetbrains.kotlin.fir.references.resolved
-import org.jetbrains.kotlin.fir.references.toResolvedFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
 import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
@@ -162,3 +160,12 @@ fun FirExpression.unwrapSmartcastExpression(): FirExpression =
         is FirSmartCastExpression -> originalExpression
         else -> this
     }
+
+/**
+ * A callable reference is bound iff
+ * - one of [dispatchReceiver] or [extensionReceiver] is **not** [FirNoReceiverExpression] and
+ * - it's not referring to a static member.
+ */
+val FirCallableReferenceAccess.isBound: Boolean
+    get() = (dispatchReceiver != FirNoReceiverExpression || extensionReceiver != FirNoReceiverExpression) &&
+            calleeReference.toResolvedCallableSymbol()?.isStatic != true

compiler/testData/codegen/box/callableReference/bound/companionObjectReceiverInheritsFromOuter.kt

@@ -55,6 +55,17 @@ fun box(): String {
     if (!callContext(A::instanceProp, A.Companion)) return "Fail unbound 7"
     if (!callContext(A::extProp, A.Companion)) return "Fail unbound 8"
 
+    with (A) {
+        if (!call(::instance)) return "Fail implicit bound function 1"
+        if (!call(::companion)) return "Fail implicit bound function 2"
+        if (!call(::ext)) return "Fail implicit bound function 3"
+        if (!call(::companionExt)) return "Fail implicit bound function 4"
+        if (!call(::instanceProp)) return "Fail imlicit bound prop 5"
+        if (!call(::companionProp)) return "Fail imlicit bound prop 6"
+        if (!call(::extProp)) return "Fail imlicit bound prop 7"
+        if (!call(::companionExtProp)) return "Fail imlicit bound prop 8"
+    }
+
     val instance = A::instance
     val ext = A::ext
     val instanceProp = A::instanceProp