Mark only unreachable parts of element if it has reachable parts

like for 'return todo()' mark only 'return'

compiler/testData/diagnostics/tests/controlFlowAnalysis/deadCode/deadCodeInInnerExpressions.kt

@@ -0,0 +1,13 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun testCompound() {
+    fun Nothing.get(i: Int) {}
+    todo()<!UNREACHABLE_CODE!><!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>[12]<!>
+}
+
+fun testCompound1() {
+    fun Int.times(s: String): Array<String> = throw Exception()
+    <!UNREACHABLE_CODE!>(<!>todo() <!UNREACHABLE_CODE!>* "")[1]<!>
+}
+
+fun todo() = throw Exception()