[FIR] Reproduce KT-62473

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

@@ -0,0 +1,10 @@
+// ISSUE: KT-62473
+// WITH_STDLIB
+
+class A(val list: List<*>)
+
+fun test(a: A) {
+    val result = mutableListOf<Int>()
+    @Suppress("UNCHECKED_CAST")
+    result += (a.list <!UNCHECKED_CAST!>as List<Int><!>).filter { it > 0 }
+}

compiler/testData/diagnostics/tests/suppressOnPlusAssign.kt

@@ -0,0 +1,10 @@
+// ISSUE: KT-62473
+// WITH_STDLIB
+
+class A(val list: List<*>)
+
+fun test(a: A) {
+    val result = mutableListOf<Int>()
+    @Suppress("UNCHECKED_CAST")
+    result += (a.list as List<Int>).filter { it > 0 }
+}