[FIR] Bind return expression to function symbol instead of function itself

compiler/testData/codegen/box/fir/classCanNotBeCastedToVoid.kt

@@ -0,0 +1,20 @@
+class ASTNode
+class Wrap(val message: String)
+
+typealias WrappingStrategy = (childElement: ASTNode) -> Wrap?
+
+fun getWrappingStrategy(): WrappingStrategy {
+    return wrap@{ childElement ->
+        Wrap("OK").let {
+            return@wrap it
+        }
+    }
+}
+
+fun getWrapAfterAnnotation(childElement: ASTNode): Wrap? {
+    return Wrap("OK")
+}
+
+fun box(): String {
+    return getWrappingStrategy().invoke(ASTNode())?.message ?: "fail"
+}