Deprecate implicit `int` to `bool` conversion for integer literals

[Michael V. Franklin]

On Tuesday, 14 November 2017 at 13:32:52 UTC, Andrei Alexandrescu 
wrote:

>> An very similar problem exists for int and char overloads:
>> 
>> alias foo = (char c) => 1;
>> alias foo = (int i) => 4;
>> 
>> enum int e = 7;
>> static assert(foo(e) == 4); // fails
>
> Thanks. Addressing this should be part of the DIP as well. --

It doesn't appear to be related to the implicit conversion of 
integer literals to bool.  While Andrei's example is fixed by by 
deprecating implicit conversion of integral literals to bool (at 
least using this implementation: 
https://github.com/dlang/dmd/pull/7310), Nick's example isn't.

Nick, if it's not in bugzilla already, can you please add it?

Mike