Minor. Add tests

compiler/testData/codegen/box/inlineClasses/callableReferences/let/intGeneric.kt

@@ -0,0 +1,33 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +GenericInlineClassParameter
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class Value<T: Int>(val value: T)
+
+object Foo {
+    fun foo(value: Value<Int>) {
+        res = value.value
+    }
+
+    fun bar(value: Value<Int>?) {
+        res = value?.value
+    }
+}
+
+var res: Int? = 0
+
+fun box(): String {
+    Value(42).let(Foo::foo)
+    if (res != 42) return "FAIL 1 $res"
+    res = 0
+
+    Value(42).let(Foo::bar)
+    if (res != 42) return "FAIL 2 $res"
+    res = 0
+
+    null.let(Foo::bar)
+    if (res != null) return "FAIL 3: $res"
+
+    return "OK"
+}