[Issue 2172] statically disallow bool + bool

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=2172
Issue 2172 depends on issue 1511, which changed state.

Issue 1511 Summary: Expression T[] + T[] passes as having a type
https://issues.dlang.org/show_bug.cgi?id=1511

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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