[K2] Disappeared FORBIDDEN_VARARG_PARAMETER_TYPE

^KT-59991

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirFunctionParameterChecker.kt

@@ -62,7 +62,11 @@ object FirFunctionParameterChecker : FirFunctionChecker() {
         }
 
         for (varargParameter in varargParameters) {
-            val varargParameterType = varargParameter.returnTypeRef.coneType.arrayElementType() ?: continue
+            val coneType = varargParameter.returnTypeRef.coneType
+            val varargParameterType = when (function) {
+                is FirAnonymousFunction -> coneType
+                else -> coneType.arrayElementType()
+            } ?: continue
             // LUB is checked to ensure varargParameterType may
             // never be anything except `Nothing` or `Nothing?`
             // in case it is a complex type that quantifies

compiler/testData/diagnostics/tests/inlineClasses/varargsOnParametersOfInlineClassType.fir.kt

@@ -1,21 +0,0 @@
-// !LANGUAGE: +InlineClasses, -JvmInlineValueClasses
-// !DIAGNOSTICS: -UNUSED_PARAMETER, -UNUSED_VARIABLE, -UNUSED_ANONYMOUS_PARAMETER
-
-inline class Foo(val x: Int)
-
-fun f1(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo) {}
-fun f2(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo?) {}
-
-class A {
-    fun f3(a0: Int, <!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a1: Foo) {
-        fun f4(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo) {}
-
-        val g = fun (<!USELESS_VARARG_ON_PARAMETER!>vararg v: Foo<!>) {}
-    }
-}
-
-class B(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> val s: Foo) {
-    constructor(a: Int, <!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> s: Foo) : this(*s)
-}
-
-annotation class Ann(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> val f: <!INVALID_TYPE_OF_ANNOTATION_MEMBER!>Foo<!>)

compiler/testData/diagnostics/tests/inlineClasses/varargsOnParametersOfInlineClassType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +InlineClasses, -JvmInlineValueClasses
 // !DIAGNOSTICS: -UNUSED_PARAMETER, -UNUSED_VARIABLE, -UNUSED_ANONYMOUS_PARAMETER
 

compiler/testData/diagnostics/tests/valueClasses/varargsOnParametersOfValueClassType.fir.kt

@@ -1,28 +0,0 @@
-// !SKIP_JAVAC
-// !LANGUAGE: +InlineClasses
-// ALLOW_KOTLIN_PACKAGE
-// !DIAGNOSTICS: -UNUSED_PARAMETER, -UNUSED_VARIABLE, -UNUSED_ANONYMOUS_PARAMETER
-
-package kotlin.jvm
-
-annotation class JvmInline
-
-@JvmInline
-value class Foo(val x: Int)
-
-fun f1(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo) {}
-fun f2(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo?) {}
-
-class A {
-    fun f3(a0: Int, <!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a1: Foo) {
-        fun f4(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo) {}
-
-        val g = fun (<!USELESS_VARARG_ON_PARAMETER!>vararg v: Foo<!>) {}
-    }
-}
-
-class B(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> val s: Foo) {
-    constructor(a: Int, <!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> s: Foo) : this(*s)
-}
-
-annotation class Ann(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> val f: <!INVALID_TYPE_OF_ANNOTATION_MEMBER!>Foo<!>)

compiler/testData/diagnostics/tests/valueClasses/varargsOnParametersOfValueClassType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !SKIP_JAVAC
 // !LANGUAGE: +InlineClasses
 // ALLOW_KOTLIN_PACKAGE
@@ -18,6 +19,7 @@ class A {
         fun f4(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: Foo) {}
 
         val g = fun (<!USELESS_VARARG_ON_PARAMETER!><!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> v: Foo<!>) {}
+        fun (<!USELESS_VARARG_ON_PARAMETER!><!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> v: Foo<!>) {}
     }
 }