FIR checker: report PROPERTY_AS_OPERATOR

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1145,6 +1145,9 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
             parameter<FirNamedFunctionSymbol>("functionSymbol")
             parameter<String>("operator")
         }
+        val PROPERTY_AS_OPERATOR by error<PsiElement>(PositioningStrategy.OPERATOR) {
+            parameter<FirPropertySymbol>("property")
+        }
     }
 
     val TYPE_ALIAS by object : DiagnosticGroup("Type alias") {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -596,6 +596,7 @@ object FirErrors {
     val INCOMPATIBLE_ENUM_COMPARISON_ERROR by error2<KtElement, ConeKotlinType, ConeKotlinType>()
     val INC_DEC_SHOULD_NOT_RETURN_UNIT by error0<KtExpression>(SourceElementPositioningStrategies.OPERATOR)
     val ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT by error2<KtExpression, FirNamedFunctionSymbol, String>(SourceElementPositioningStrategies.OPERATOR)
+    val PROPERTY_AS_OPERATOR by error1<PsiElement, FirPropertySymbol>(SourceElementPositioningStrategies.OPERATOR)
 
     // Type alias
     val TOPLEVEL_TYPEALIASES_ONLY by error0<KtTypeAlias>()

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirConventionFunctionCallChecker.kt

@@ -6,17 +6,26 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.expression
 
 import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
+import org.jetbrains.kotlin.fir.FirRealSourceElementKind
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.expressions.FirExpression
+import org.jetbrains.kotlin.fir.expressions.FirExpressionWithSmartcast
 import org.jetbrains.kotlin.fir.expressions.FirFunctionCall
+import org.jetbrains.kotlin.fir.expressions.FirPropertyAccessExpression
 import org.jetbrains.kotlin.fir.references.FirErrorNamedReference
+import org.jetbrains.kotlin.fir.resolve.diagnostics.ConePropertyAsOperator
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnresolvedNameError
 import org.jetbrains.kotlin.util.OperatorNameConventions
+import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 
 object FirConventionFunctionCallChecker : FirFunctionCallChecker() {
     override fun check(expression: FirFunctionCall, context: CheckerContext, reporter: DiagnosticReporter) {
+        // PROPERTY_AS_OPERATOR can only happen for function calls and it's reported on the receiver expression.
+        checkPropertyAsOperator(expression, expression.dispatchReceiver, context, reporter)
+        checkPropertyAsOperator(expression, expression.extensionReceiver, context, reporter)
         val calleeReference = expression.calleeReference as? FirErrorNamedReference ?: return
         val diagnostic = calleeReference.diagnostic as? ConeUnresolvedNameError ?: return
 
@@ -27,4 +36,24 @@ object FirConventionFunctionCallChecker : FirFunctionCallChecker() {
             }
         }
     }
+
+    private fun checkPropertyAsOperator(
+        callExpression: FirFunctionCall,
+        receiver: FirExpression,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        val sourceKind = callExpression.source?.kind
+        if (sourceKind !is FirRealSourceElementKind &&
+            sourceKind !is FirFakeSourceElementKind.GeneratedComparisonExpression &&
+            sourceKind !is FirFakeSourceElementKind.DesugaredCompoundAssignment
+        ) return
+        val unwrapped = when (receiver) {
+            is FirExpressionWithSmartcast -> receiver.originalExpression
+            else -> receiver
+        }
+        if (unwrapped !is FirPropertyAccessExpression) return
+        val diagnostic = unwrapped.nonFatalDiagnostics.firstIsInstanceOrNull<ConePropertyAsOperator>() ?: return
+        reporter.reportOn(callExpression.calleeReference.source, FirErrors.PROPERTY_AS_OPERATOR, diagnostic.symbol, context)
+    }
 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -332,6 +332,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PRIVATE_SETTER_FO
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PRIVATE_SETTER_FOR_OPEN_PROPERTY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROPERTY_AS_OPERATOR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROPERTY_INITIALIZER_IN_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROPERTY_INITIALIZER_NO_BACKING_FIELD
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.PROPERTY_TYPE_MISMATCH_BY_DELEGATION
@@ -1515,6 +1516,11 @@ class FirDefaultErrorMessages {
                 SYMBOL,
                 TO_STRING
             )
+            map.put(
+                PROPERTY_AS_OPERATOR,
+                "Property ''{0}'' cannot be used as an operator.",
+                SYMBOL
+            )
 
             // Type alias
             map.put(TOPLEVEL_TYPEALIASES_ONLY, "Nested and local type aliases are not supported")

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/FirCallResolver.kt

@@ -84,11 +84,11 @@ class FirCallResolver(
 
         return components.context.withIncrementedQualifierPartIndex {
             val name = functionCall.calleeReference.name
-            val result = collectCandidates(functionCall, name)
+            val result = collectCandidates(functionCall, name, origin = functionCall.origin)
 
             var forceCandidates: Collection<Candidate>? = null
             if (result.candidates.isEmpty()) {
-                val newResult = collectCandidates(functionCall, name, CallKind.VariableAccess)
+                val newResult = collectCandidates(functionCall, name, CallKind.VariableAccess, origin = functionCall.origin)
                 if (newResult.candidates.isNotEmpty()) {
                     forceCandidates = newResult.candidates
                 }
@@ -152,7 +152,8 @@ class FirCallResolver(
     private fun <T : FirQualifiedAccess> collectCandidates(
         qualifiedAccess: T,
         name: Name,
-        forceCallKind: CallKind? = null
+        forceCallKind: CallKind? = null,
+        origin: FirFunctionCallOrigin = FirFunctionCallOrigin.Regular
     ): ResolutionResult {
         val explicitReceiver = qualifiedAccess.explicitReceiver
         val argumentList = (qualifiedAccess as? FirFunctionCall)?.argumentList ?: FirEmptyArgumentList
@@ -172,6 +173,7 @@ class FirCallResolver(
             session,
             components.file,
             transformer.components.containingDeclarations,
+            origin = origin
         )
         towerResolver.reset()
         val result = towerResolver.runResolver(info, transformer.resolutionContext)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.fir.declarations.FirValueParameter
 import org.jetbrains.kotlin.fir.expressions.FirArgumentList
 import org.jetbrains.kotlin.fir.expressions.FirEmptyArgumentList
 import org.jetbrains.kotlin.fir.expressions.FirExpression
+import org.jetbrains.kotlin.fir.expressions.FirFunctionCallOrigin
 import org.jetbrains.kotlin.fir.expressions.builder.buildArgumentList
 import org.jetbrains.kotlin.fir.expressions.impl.FirExpressionStub
 import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
@@ -55,7 +56,8 @@ data class CallInfo(
     // Four properties for callable references only
     val expectedType: ConeKotlinType? = null,
     val outerCSBuilder: ConstraintSystemBuilder? = null,
-    val lhs: DoubleColonLHS? = null
+    val lhs: DoubleColonLHS? = null,
+    val origin: FirFunctionCallOrigin = FirFunctionCallOrigin.Regular,
 ) {
     val arguments: List<FirExpression> get() = argumentList.arguments
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CandidateFactory.kt

@@ -82,6 +82,10 @@ class CandidateFactory private constructor(
         ) {
             result.addDiagnostic(NoCompanionObject)
         }
+        if (callInfo.origin == FirFunctionCallOrigin.Operator && symbol is FirPropertySymbol) {
+            // Flag all property references that are resolved from an convention operator call.
+            result.addDiagnostic(PropertyAsOperator)
+        }
         return result
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionDiagnostic.kt

@@ -98,4 +98,6 @@ class ManyLambdaExpressionArguments(
 class InfixCallOfNonInfixFunction(val function: FirNamedFunctionSymbol) : ResolutionDiagnostic(INAPPLICABLE_MODIFIER)
 class OperatorCallOfNonOperatorFunction(val function: FirNamedFunctionSymbol) : ResolutionDiagnostic(INAPPLICABLE_MODIFIER)
 
-class Unsupported(val message: String, val source: FirSourceElement? = null) : ResolutionDiagnostic(UNSUPPORTED)
+class Unsupported(val message: String, val source: FirSourceElement? = null) : ResolutionDiagnostic(UNSUPPORTED)
+
+object PropertyAsOperator : ResolutionDiagnostic(PROPERTY_AS_OPERATOR)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirInvokeResolveTowerExtension.kt

@@ -11,14 +11,13 @@ import org.jetbrains.kotlin.fir.expressions.FirResolvedQualifier
 import org.jetbrains.kotlin.fir.expressions.builder.FirPropertyAccessExpressionBuilder
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.*
-import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.resolve.diagnostics.ConePropertyAsOperator
-import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.*
-import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
-import org.jetbrains.kotlin.fir.symbols.impl.FirTypeAliasSymbol
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
 import org.jetbrains.kotlin.fir.types.coneTypeUnsafe
 import org.jetbrains.kotlin.fir.types.isExtensionFunctionType
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
+import org.jetbrains.kotlin.resolve.calls.tower.CandidateApplicability
 import org.jetbrains.kotlin.util.OperatorNameConventions
 
 internal class FirInvokeResolveTowerExtension(
@@ -291,6 +290,10 @@ private fun BodyResolveComponents.createExplicitReceiverForInvokeByCallable(
             // NB: this should fix problem in DFA (KT-36014)
             explicitReceiver = info.explicitReceiver
         }
+
+        if (candidate.currentApplicability == CandidateApplicability.PROPERTY_AS_OPERATOR) {
+            nonFatalDiagnostics.add(ConePropertyAsOperator(candidate.symbol as FirPropertySymbol))
+        }
     }.build().let(::transformQualifiedAccessUsingSmartcastInfo)
 }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt

@@ -206,6 +206,10 @@ class ConeLocalVariableNoTypeOrInitializer(val variable: FirVariable) : ConeDiag
     override val reason: String get() = "Cannot infer variable type without initializer / getter / delegate"
 }
 
+class ConePropertyAsOperator(val symbol: FirPropertySymbol) : ConeDiagnostic {
+    override val reason: String get() = "Cannot use a property as an operator"
+}
+
 private fun describeSymbol(symbol: FirBasedSymbol<*>): String {
     return when (symbol) {
         is FirClassLikeSymbol<*> -> symbol.classId.asString()

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirCallCompletionResultsWriterTransformer.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.fir.declarations.utils.isSuspend
 import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
 import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
 import org.jetbrains.kotlin.fir.expressions.*
+import org.jetbrains.kotlin.fir.expressions.impl.FirPropertyAccessExpressionImpl
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.builder.buildErrorNamedReference
 import org.jetbrains.kotlin.fir.references.builder.buildResolvedCallableReference
@@ -26,6 +27,7 @@ import org.jetbrains.kotlin.fir.resolve.createFunctionalType
 import org.jetbrains.kotlin.fir.resolve.dfa.FirDataFlowAnalyzer
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeConstraintSystemHasContradiction
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeInapplicableCandidateError
+import org.jetbrains.kotlin.fir.resolve.diagnostics.ConePropertyAsOperator
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeTypeParameterInQualifiedAccess
 import org.jetbrains.kotlin.fir.resolve.firProvider
 import org.jetbrains.kotlin.fir.resolve.inference.*
@@ -39,6 +41,7 @@ import org.jetbrains.kotlin.fir.scopes.impl.FirIntegerOperatorCall
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirConstructorSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
@@ -48,6 +51,7 @@ import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.fir.visitors.transformSingle
+import org.jetbrains.kotlin.resolve.calls.tower.CandidateApplicability
 import org.jetbrains.kotlin.resolve.calls.tower.isSuccess
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.Variance
@@ -126,6 +130,9 @@ class FirCallCompletionResultsWriterTransformer(
             )
             .transformDispatchReceiver(StoreReceiver, subCandidate.dispatchReceiverExpression())
             .transformExtensionReceiver(StoreReceiver, subCandidate.extensionReceiverExpression()) as T
+        if (result is FirPropertyAccessExpressionImpl && calleeReference.candidate.currentApplicability == CandidateApplicability.PROPERTY_AS_OPERATOR) {
+            result.nonFatalDiagnostics.add(ConePropertyAsOperator(calleeReference.candidate.symbol as FirPropertySymbol))
+        }
 
         if (result is FirQualifiedAccessExpression) {
             result.replaceTypeRef(typeRef)

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/tower/CandidateApplicability.kt

@@ -20,6 +20,7 @@ enum class CandidateApplicability {
     UNSTABLE_SMARTCAST, // unstable smart cast
     CONVENTION_ERROR, // missing infix, operator etc
     RESOLVED_LOW_PRIORITY,
+    PROPERTY_AS_OPERATOR, // using property of functional type as an operator. From resolution perspective, this is considered successful.
     RESOLVED_NEED_PRESERVE_COMPATIBILITY, // call resolved successfully, but using new features that changes resolve
     RESOLVED_WITH_ERROR, // call has error, but it is still successful from resolution perspective
     RESOLVED, // call success or has uncompleted inference or in other words possible successful candidate

compiler/testData/diagnostics/tests/kt34857.fir.kt

@@ -1,8 +0,0 @@
-// !LANGUAGE: +NewInference
-
-val Int.plusAssign: (Int) -> Unit
-    get() = {}
-
-fun main() {
-    1 += 2
-}

compiler/testData/diagnostics/tests/kt34857.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference
 
 val Int.plusAssign: (Int) -> Unit

compiler/tests-spec/testData/diagnostics/linked/overload-resolution/building-the-overload-candidate-set-ocs/operator-call/p-4/neg/1.1.fir.kt

@@ -73,19 +73,44 @@ class Arifm() {
     operator fun invoke(i: Int) {}
 }
 
+class Contains() {
+    operator fun invoke(i: Int): Boolean = true
+}
+
+class Getter() {
+    operator fun invoke(i: Int): Int = 1
+}
+
+class Setter() {
+    operator fun invoke(i: Int, j: Int) {}
+}
+
+class Unary<B>() {
+    operator fun invoke(): B = TODO()
+}
+
 class B() {
     val plus = Arifm()
     val minus = Arifm()
     val compareTo = Comp()
+    val contains = Contains()
+    val get = Getter()
+    val set = Setter()
+    val unaryPlus = Unary<B>()
 }
 
 fun case3() {
     var b = B()
-    b + 5
+    b <!PROPERTY_AS_OPERATOR!>+<!> 5
-    b - 5
+    b <!PROPERTY_AS_OPERATOR!>-<!> 5
-    b < 5
+    b <!PROPERTY_AS_OPERATOR!><<!> 5
-    b >= 5
+    b <!PROPERTY_AS_OPERATOR!>>=<!> 5
+    1 <!PROPERTY_AS_OPERATOR!>in<!> b
+    <!PROPERTY_AS_OPERATOR!>b[2]<!>
+    <!PROPERTY_AS_OPERATOR!>b[3]<!> = 4
+    <!PROPERTY_AS_OPERATOR!>+<!>b
 }
+
 // FILE: TestCase4.kt
 /*
  * TESTCASE NUMBER: 4
@@ -102,8 +127,8 @@ class B(val minusAssign: Assign = Assign()) {
 
 fun case3() {
     var b = B()
-    b  +=  2
+    b  <!PROPERTY_AS_OPERATOR!>+=<!>  2
-    b  -=  3
+    b  <!PROPERTY_AS_OPERATOR!>-=<!>  3
 }
 
 // FILE: TestCase5.kt
@@ -142,7 +167,7 @@ class B(var a: Int = 0) {
         val plus :E =TODO()
 
         fun foo(b: B){
-            this + 1
+            this <!PROPERTY_AS_OPERATOR!>+<!> 1
         }
 
         operator fun invoke(value: Int) = B()

compiler/tests-spec/testData/diagnostics/linked/overload-resolution/building-the-overload-candidate-set-ocs/operator-call/p-4/neg/1.1.kt

@@ -82,10 +82,30 @@ class Arifm() {
     operator fun invoke(i: Int) {}
 }
 
+class Contains() {
+    operator fun invoke(i: Int): Boolean = true
+}
+
+class Getter() {
+    operator fun invoke(i: Int): Int = 1
+}
+
+class Setter() {
+    operator fun invoke(i: Int, j: Int) {}
+}
+
+class Unary<B>() {
+    operator fun invoke(): B = TODO()
+}
+
 class B() {
     val plus = Arifm()
     val minus = Arifm()
     val compareTo = Comp()
+    val contains = Contains()
+    val get = Getter()
+    val set = Setter()
+    val unaryPlus = Unary<B>()
 }
 
 fun case3() {
@@ -94,7 +114,12 @@ fun case3() {
     b <!PROPERTY_AS_OPERATOR!>-<!> 5
     b <!PROPERTY_AS_OPERATOR!><<!> 5
     b <!PROPERTY_AS_OPERATOR!>>=<!> 5
+    1 <!PROPERTY_AS_OPERATOR!>in<!> b
+    <!PROPERTY_AS_OPERATOR!>b[2]<!>
+    <!PROPERTY_AS_OPERATOR!>b[3]<!> = 4
+    <!PROPERTY_AS_OPERATOR!>+<!>b
 }
+
 // FILE: TestCase4.kt
 /*
  * TESTCASE NUMBER: 4

compiler/tests-spec/testData/diagnostics/linked/overload-resolution/building-the-overload-candidate-set-ocs/operator-call/p-4/pos/1.1.fir.kt

@@ -21,7 +21,7 @@ class B() {
     fun case7(){
         var b =B()
         <!ASSIGN_OPERATOR_AMBIGUITY!>b+=1<!> //ASSIGN_OPERATOR_AMBIGUITY
-        this += 1 //ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT, PROPERTY_AS_OPERATOR
+        this <!PROPERTY_AS_OPERATOR!>+=<!> 1 //ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT, PROPERTY_AS_OPERATOR
     }
 }
 

compiler/tests-spec/testData/diagnostics/linked/type-inference/smart-casts/smart-cast-sink-stability/p-5/neg/1.1.fir.kt

@@ -14,7 +14,7 @@ class Case1() {
     fun foo(e: E) {
 
         if (e.plus != null) {
-            run { e + 1 }
+            run { e <!PROPERTY_AS_OPERATOR!>+<!> 1 }
 
             /*
              [PROPERTY_AS_OPERATOR]  (ok)
@@ -22,7 +22,7 @@ class Case1() {
              [UNSAFE_OPERATOR_CALL]  (nok)
              Operator call corresponds to a dot-qualified call 'e.plus(1)' which is not allowed on a nullable receiver 'e'.
             */
-            e + 1
+            e <!PROPERTY_AS_OPERATOR!>+<!> 1
 
             e.plus.invoke(1) //ok
         }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -3131,6 +3131,13 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.PROPERTY_AS_OPERATOR) { firDiagnostic ->
+        PropertyAsOperatorImpl(
+            firSymbolBuilder.variableLikeBuilder.buildVariableSymbol(firDiagnostic.a.fir),
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.TOPLEVEL_TYPEALIASES_ONLY) { firDiagnostic ->
         ToplevelTypealiasesOnlyImpl(
             firDiagnostic as FirPsiDiagnostic,

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -2186,6 +2186,11 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val operator: String
     }
 
+    abstract class PropertyAsOperator : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = PropertyAsOperator::class
+        abstract val property: KtVariableSymbol
+    }
+
     abstract class ToplevelTypealiasesOnly : KtFirDiagnostic<KtTypeAlias>() {
         override val diagnosticClass get() = ToplevelTypealiasesOnly::class
     }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -3522,6 +3522,14 @@ internal class AssignmentOperatorShouldReturnUnitImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class PropertyAsOperatorImpl(
+    override val property: KtVariableSymbol,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.PropertyAsOperator(), KtAbstractFirDiagnostic<PsiElement> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class ToplevelTypealiasesOnlyImpl(
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,