RFE: issue (optional) warning when '==' is used on wrapper types

I would like that Eclipse (similar to IDEA) would issue an optional warning when one uses the following construct:

```java
Long x1 = 12345L;
Long x2 = 67890L;
if(x1 == x2)
System.out.println("Equal");
else
System.out.println("Not equal");
```
Because (as apparently we don't all know) Long is a wrapper class and using `==` only works for Long values between -127 and 127 due to caching (similarly for the other wrapper types).

This would at least uncover one such instance in our code base, of which I suspect to find a greater number alas.