On Tuesday, 3 March 2026 at 14:46:56 UTC, Paul Backus wrote:
I think it's probably accidental that `is(T == U)`
short-circuits to `is(T)` if `T` does not exist. If I were to
design a "version 3.0" of the D language, starting from
scratch, I would not include this behavior.
Unfortunately, it has been around for such a long time, and is
depended on by so much existing code, that changing it is not
realistically possible, even with editions.
So if I follow your reasoning, you think it's an implementation
accident. Actually there's an aspect that makes the current D
behavior absolutly correct: that can be seen as comparing two NaN.
