FIR resolve: fix vararg parameter types

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

@@ -5,11 +5,14 @@
 
 package org.jetbrains.kotlin.fir.resolve.calls
 
+import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.declarations.FirNamedFunction
+import org.jetbrains.kotlin.fir.declarations.FirValueParameter
 import org.jetbrains.kotlin.fir.resolve.substitution.substitutorByMap
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.arrayElementType
 import org.jetbrains.kotlin.fir.types.coneTypeUnsafe
 import org.jetbrains.kotlin.resolve.OverloadabilitySpecificityCallbacks
 import org.jetbrains.kotlin.resolve.calls.inference.model.NewConstraintSystemImpl
@@ -60,7 +63,7 @@ class ConeOverloadConflictResolver(
         return FlatSignature(
             call,
             constructor.typeParameters.map { it.symbol },
-            call.argumentMapping!!.map { it.value.returnTypeRef.coneTypeUnsafe() },
+            call.argumentMapping!!.map {  it.value.argumentType() },
             //constructor.receiverTypeRef != null,
             false,
             constructor.valueParameters.any { it.isVararg },
@@ -70,12 +73,18 @@ class ConeOverloadConflictResolver(
         )
     }
 
+    private fun FirValueParameter.argumentType(): ConeKotlinType {
+        val type = returnTypeRef.coneTypeUnsafe<ConeKotlinType>()
+        if (isVararg) return type.arrayElementType(inferenceComponents.session)!!
+        return type
+    }
+
     private fun createFlatSignature(call: Candidate, function: FirNamedFunction): FlatSignature<Candidate> {
         return FlatSignature(
             call,
             function.typeParameters.map { it.symbol },
             listOfNotNull<ConeKotlinType>(function.receiverTypeRef?.coneTypeUnsafe()) +
-                    call.argumentMapping!!.map { it.value.returnTypeRef.coneTypeUnsafe() },
+                    call.argumentMapping!!.map { it.value.argumentType() },
             function.receiverTypeRef != null,
             function.valueParameters.any { it.isVararg },
             function.valueParameters.count { it.defaultValue != null },

compiler/fir/resolve/testData/resolve/stdlib/topLevelResolve.txt

@@ -13,7 +13,7 @@ FILE: topLevelResolve.kt
         lval setAndList: R|kotlin/collections/Set<kotlin/Int>| = R|kotlin/collections/setOf|<R|kotlin/Int|>(Int(0)).R|kotlin/collections/plus|<R|kotlin/Int|>(R|kotlin/collections/listOf|<R|kotlin/Int|>(Int(1), Int(2)))
         lval stringAndList: R|kotlin/String| = String().R|kotlin/String.plus|(R|kotlin/collections/emptyList|<R|kotlin/Boolean|>())
         lval map: R|kotlin/collections/Map<kotlin/String, kotlin/Int>| = R|kotlin/collections/mapOf|<R|kotlin/String|, R|kotlin/Int|>(String().R|kotlin/to|<R|kotlin/String|, R|kotlin/Int|>(Int(1)), String(.).R|kotlin/to|<R|kotlin/String|, R|kotlin/Int|>(Int(2))).R|kotlin/collections/plus|<R|kotlin/String|, R|kotlin/Int|>(String(..).R|kotlin/to|<R|kotlin/String|, R|kotlin/Int|>(Int(3)))
-        lval mapAndMap: <ERROR TYPE REF: Ambiguity: plus, [kotlin/plus, kotlin/plus, kotlin/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/sequences/plus, kotlin/sequences/plus, kotlin/sequences/plus, kotlin/text/plus]> = <Ambiguity: mapOf, [kotlin/collections/mapOf, kotlin/collections/mapOf]>#(String(-).R?C|kotlin/to|(Int(4))).<Ambiguity: plus, [kotlin/plus, kotlin/plus, kotlin/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/sequences/plus, kotlin/sequences/plus, kotlin/sequences/plus, kotlin/text/plus]>#(<Ambiguity: mapOf, [kotlin/collections/mapOf, kotlin/collections/mapOf]>#(String(_).R?C|kotlin/to|(Int(5))))
+        lval mapAndMap: R|kotlin/collections/Map<kotlin/String, kotlin/Int>| = R|kotlin/collections/mapOf|<R|kotlin/String|, R|kotlin/Int|>(String(-).R|kotlin/to|<R|kotlin/String|, R|kotlin/Int|>(Int(4))).R|kotlin/collections/plus|<R|kotlin/String|, R|kotlin/Int|>(R|kotlin/collections/mapOf|<R|kotlin/String|, R|kotlin/Int|>(String(_).R|kotlin/to|<R|kotlin/String|, R|kotlin/Int|>(Int(5))))
     }
     public final fun <T> id(arg: R|T|): R|T| {
         ^id R|<local>/arg|

compiler/testData/ir/irText/stubs/builtinMap.fir.txt

@@ -9,8 +9,8 @@ FILE fqName:<root> fileName:/builtinMap.kt
           BRANCH
             if: CALL 'public abstract fun isEmpty (): kotlin.Boolean declared in kotlin.collections.Map' type=kotlin.Boolean origin=null
               $this: ERROR_CALL 'Unresolved reference: this#' type=kotlin.collections.Map<out K1 of <root>.plus, V1 of <root>.plus>
-            then: ERROR_CALL 'Unresolved reference: <Ambiguity: mapOf, [kotlin/collections/mapOf, kotlin/collections/mapOf]>#' type=IrErrorType
-              GET_VAR 'pair: kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> origin=null
+            then: CALL 'public final fun mapOf (pair: kotlin.Pair<K of <uninitialized parent>, V of <uninitialized parent>>): kotlin.collections.Map<K of <uninitialized parent>, V of <uninitialized parent>> declared in kotlin.collections' type=kotlin.collections.Map<K1 of <root>.plus, V1 of <root>.plus> origin=null
+              pair: GET_VAR 'pair: kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> origin=null
           BRANCH
             if: CONST Boolean type=kotlin.Boolean value=true
             then: CALL 'public final fun apply (block: kotlin.Function1<T of <uninitialized parent>, kotlin.Unit>): T of <uninitialized parent> [inline] declared in kotlin' type=java.util.LinkedHashMap<K1 of <root>.plus, V1 of <root>.plus> origin=null