[FIR] Fix arguments mapping for indexed set operator

Now processPositionArgument changes STATE as well as processNamedArgument

^KT-59386

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

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.declarations.FirValueParameter
 import org.jetbrains.kotlin.fir.declarations.utils.isOperator
 import org.jetbrains.kotlin.fir.expressions.*
-import org.jetbrains.kotlin.fir.expressions.builder.buildNamedArgumentExpression
 import org.jetbrains.kotlin.fir.isSubstitutionOrIntersectionOverride
 import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.defaultParameterResolver
@@ -95,22 +94,6 @@ fun BodyResolveComponents.mapArguments(
             && function.name == OperatorNameConventions.SET
             && function.origin !is FirDeclarationOrigin.DynamicScope
 
-    if (isIndexedSetOperator &&
-        function.valueParameters.any { it.defaultValue != null || it.isVararg }
-    ) {
-        val v = nonLambdaArguments.last()
-        if (v !is FirNamedArgumentExpression) {
-            val namedV = buildNamedArgumentExpression {
-                source = v.source
-                expression = v
-                isSpread = false
-                name = function.valueParameters.last().name
-            }
-            nonLambdaArguments.removeAt(nonLambdaArguments.size - 1)
-            nonLambdaArguments.add(namedV)
-        }
-    }
-
     val processor = FirCallArgumentsProcessor(session, function, this, originScope, isIndexedSetOperator)
     processor.processNonLambdaArguments(nonLambdaArguments)
     if (externalArgument != null) {
@@ -172,15 +155,16 @@ private class FirCallArgumentsProcessor(
         when {
             // process position argument
             argument !is FirNamedArgumentExpression -> {
-                if (processPositionArgument(argument, isLastArgument)) {
+                if (state == State.VARARG_POSITION && isIndexedSetOperator && isLastArgument) {
-                    state = State.VARARG_POSITION
+                    // The last argument of an indexed set operator should be reserved for the last argument (the assigned value).
+                    // That's why if vararg presented, they should be completed
+                    completeVarargPositionArguments()
                 }
+                processPositionArgument(argument, isLastArgument)
             }
             // process named argument
             function.origin == FirDeclarationOrigin.DynamicScope -> {
-                if (processPositionArgument(argument.expression, isLastArgument)) {
+                processPositionArgument(argument.expression, isLastArgument)
-                    state = State.VARARG_POSITION
-                }
             }
             else -> {
                 if (state == State.VARARG_POSITION) {
@@ -191,11 +175,10 @@ private class FirCallArgumentsProcessor(
         }
     }
 
-    // return true, if it was mapped to vararg parameter
+    private fun processPositionArgument(argument: FirExpression, isLastArgument: Boolean) {
-    private fun processPositionArgument(argument: FirExpression, isLastArgument: Boolean): Boolean {
         if (state == State.NAMED_ONLY_ARGUMENTS) {
             addDiagnostic(MixingNamedAndPositionArguments(argument))
-            return false
+            return
         }
 
         // The last parameter of an indexed set operator should be reserved for the last argument (the assigned value).
@@ -219,19 +202,19 @@ private class FirCallArgumentsProcessor(
         val parameter = parameters.getOrNull(assignedParameterIndex)
         if (parameter == null) {
             addDiagnostic(TooManyArguments(argument, function))
-            return false
+            return
         }
 
         return if (!parameter.isVararg) {
             currentPositionedParameterIndex++
 
             result[parameter] = ResolvedCallArgument.SimpleArgument(argument)
-            false
+            state = State.POSITION_ARGUMENTS
         }
         // all position arguments will be mapped to current vararg parameter
         else {
             addVarargArgument(argument)
-            true
+            state = State.VARARG_POSITION
         }
     }
 

compiler/testData/diagnostics/tests/checkArguments/arrayAccessSet.fir.kt

@@ -20,16 +20,23 @@ object Z {
     }
 }
 
+object W {
+    operator fun set(vararg va: Int, value: Int) {
+    }
+}
+
 fun test() {
-    A[0] = ""
+    A[0] = <!ARGUMENT_TYPE_MISMATCH!>""<!>
     A[0] = 2.72
 
-    B[0] = ""
+    B[0] = <!ARGUMENT_TYPE_MISMATCH!>""<!>
-    B[0] = 2.72
+    B[0] = <!ARGUMENT_TYPE_MISMATCH!>2.72<!>
     B[0] = true
 
-    D[0] = ""
+    D[0] = <!ARGUMENT_TYPE_MISMATCH!>""<!>
     D[0] = 2.72
 
     Z[<!TOO_MANY_ARGUMENTS!>0<!>] = <!TOO_MANY_ARGUMENTS!>""<!>
+
+    W[0] = 1
 }

compiler/testData/diagnostics/tests/checkArguments/arrayAccessSet.kt

@@ -20,6 +20,11 @@ object Z {
     }
 }
 
+object W {
+    operator fun set(vararg va: Int, value: Int) {
+    }
+}
+
 fun test() {
     A[0] = <!TYPE_MISMATCH!>""<!>
     A[0] = 2.72
@@ -32,4 +37,6 @@ fun test() {
     D[0] = 2.72
 
     Z[<!TOO_MANY_ARGUMENTS!>0<!>] = <!TOO_MANY_ARGUMENTS!>""<!>
+
+    W[0] = 1
 }

compiler/testData/diagnostics/tests/checkArguments/arrayAccessSet.txt

@@ -26,6 +26,14 @@ public object D {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
+public object W {
+    private constructor W()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final operator fun set(/*0*/ vararg va: kotlin.Int /*kotlin.IntArray*/, /*1*/ value: kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
 public object Z {
     private constructor Z()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -33,3 +41,4 @@ public object Z {
     public final operator fun set(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
+