Solution to "statement is not reachable" depending on template variables?

[tsbockman via Digitalmars-d-learn]

On Wednesday, 16 March 2016 at 11:22:02 UTC, rikki cattermole 
wrote:
> Change those static if's to just plain old ifs.

This only works (sometimes) because D's value range propagation 
doesn't understand comparisons or normal if statements very well. 
This will hopefully be fixed sooner or later:
     https://github.com/D-Programming-Language/dmd/pull/1913
     https://github.com/D-Programming-Language/dmd/pull/5229

The only future-proof way to fix the "statement is not reachable" 
warning, is to guard the potentially unreachable code with a 
`static if` whose predicate precisely describes the circumstances 
in which it becomes unreachable...

...Which itself is a terrible solution that doesn't scale well at 
all to complex generic code and violates the "DRY" principle.

We really ought to just remove the warning. It just doesn't mesh 
well with D's super-powered meta-programming features.