[FIR] Fix missing receiver type if anonymous function without label

compiler/testData/diagnostics/tests/inference/regressions/kt2754.fir.kt

@@ -1,28 +0,0 @@
-// !CHECK_TYPE
-// !DIAGNOSTICS: -UNUSED_PARAMETER
-
-// T is the immutable type
-interface Builder<out T> {
-    fun build(): T
-}
-
-// T is the immutable type, U is the builder
-interface Copyable<out T, out U : Builder<T>> {
-    fun builder(): U
-}
-
-fun <T : Copyable<T, U>, U : Builder<T>> T.copy(fn: U.() -> Unit): T = throw Exception()
-
-open class Foo(val x: Int, val y: Int) : Copyable<Foo, Foo.FooBuilder> {
-    override fun builder(): FooBuilder = FooBuilder(x, y)
-
-    open class FooBuilder(var x: Int, var y: Int): Builder<Foo> {
-        override fun build(): Foo = Foo(x, y)
-    }
-}
-
-fun test() {
-    val foo1 = Foo(x = 1, y = 2)
-    val foo2 = foo1.copy { y = 3 } // this doesn't work
-    foo2 checkType { <!UNRESOLVED_REFERENCE!>_<!><Foo>() }
-}

compiler/testData/diagnostics/tests/inference/regressions/kt2754.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 

compiler/testData/diagnostics/tests/inference/regressions/kt4420.fir.kt

@@ -1,10 +0,0 @@
-// !CHECK_TYPE
-//KT-4420 Type inference with type projections
-
-class Foo<T>
-fun <T> Foo<T>.bar(): T = throw Exception()
-
-fun main() {
-    val f: Foo<out String> = Foo()
-    f.bar() checkType { <!UNRESOLVED_REFERENCE!>_<!><String>() }
-}

compiler/testData/diagnostics/tests/inference/regressions/kt4420.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 //KT-4420 Type inference with type projections