[FIR] Fix FirDuplicateParameterNameInFunctionTypeChecker

It was supposed to check only function types...

Also note that it's probably impossible
to write a simpler test right now,
because we have a massive problem that
we ignore `FirTypeRef`s with `null`
sources despite having a dedicated
family of checkers for them
specifically. This will be fixed
separately as KT-65647.

^KT-65584 Fixed
^KT-65647

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/type/FirDuplicateParameterNameInFunctionTypeChecker.kt

@@ -13,14 +13,11 @@ import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.getAnnotationByClassId
 import org.jetbrains.kotlin.fir.expressions.FirLiteralExpression
-import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
-import org.jetbrains.kotlin.fir.types.FirTypeRef
-import org.jetbrains.kotlin.fir.types.customAnnotations
-import org.jetbrains.kotlin.fir.types.type
+import org.jetbrains.kotlin.fir.types.*
 
 object FirDuplicateParameterNameInFunctionTypeChecker : FirTypeRefChecker(MppCheckerKind.Common) {
     override fun check(typeRef: FirTypeRef, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (typeRef !is FirResolvedTypeRef) return
+        if (typeRef !is FirResolvedTypeRef || !typeRef.type.isSomeFunctionType(context.session)) return
 
         val nameToArgumentProjection = typeRef.type.typeArguments.dropLast(1).groupBy {
             val type = it.type ?: return@groupBy null

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

@@ -1,41 +0,0 @@
-// ISSUE: KT-65584
-// WITH_STDLIB
-
-fun interface Flow<out T> {
-
-    suspend fun collect(collector: FlowCollector<T>)
-}
-
-fun interface FlowCollector<in T> {
-
-    suspend fun emit(value: T)
-}
-
-inline fun <T, R> Flow<T>.flatMapLatest(crossinline transform: suspend (value: T) -> Flow<R>) = Flow { collector ->
-    collect { it1 -> transform(it1).collect { it2 -> collector.emit(it2) } }
-}
-
-fun <T> flowOf(value: T): Flow<T> = Flow { collector -> collector.emit(value) }
-
-inline fun <T, R> Flow<T>.map(crossinline transform: suspend (value: T) -> R): Flow<R> = Flow { collector ->
-    collect { collector.emit(transform(it)) }
-}
-
-// ------
-
-class StationId
-class Playable
-class Entity(val stationId: StationId)
-class State(val playbackEntity: Entity)
-
-internal suspend fun init(
-    queueState: State,
-    state: Flow<Playable>
-) {
-    state
-        .flatMapLatest { playable ->
-            flowOf(playable).map { Triple(it, playable, queueState.playbackEntity.stationId) }
-        }
-        .collect { <!DUPLICATE_PARAMETER_NAME_IN_FUNCTION_TYPE!>(likeState, playable, stationId)<!> ->
-        }
-}

compiler/testData/diagnostics/tests/duplicateParameterName.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // ISSUE: KT-65584
 // WITH_STDLIB
 

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

@@ -8,7 +8,7 @@ class MyTriple<T, K, M>(val a: T, val b: K, val c: M)
 
 fun test() {
     giveItName(10) {
-        MyTriple(it, it, it).also { <!DUPLICATE_PARAMETER_NAME_IN_FUNCTION_TYPE!>self<!> -> }
+        MyTriple(it, it, it).also { self -> }
         (duplicateIt(it) { a, b -> }).also { <!DUPLICATE_PARAMETER_NAME_IN_FUNCTION_TYPE!>function<!> -> }
     }
 }