JetBrains/kotlin — pull request #501 by bintree (2014-07-21 17:40:06+00:00)
Title: Assignment operations fixes (KT-4814)

Fixing of #KT-4814 with cases like:
val x = 0
x += 1L //represented as x = x + 1L and being compiled without errors.
I added a check that type of (x + 1L) can be stored in variable

Also there are some library and test changes to cope with new changes