On Tuesday, 12 August 2014 at 06:37:45 UTC, Jonathan M Davis via
Digitalmars-d-learn wrote:
The problem is that isNaN is now templatized, and its
constraint uses
isFloatingPoint, which requires that the type _be_ a floating
point type, not
that it implicitly convert to one. So, as it stands, isNAN
cannot work with
any type which implicitly converts to a floating point value.
Either it will
have to be instantiated with the floating point type - e.g.
isNaN!float(s) -
or you're going to have to explicitly cast s to a floating
point type.
You can open a bug report - https://issues.dlang.org - and mark
it as a
regression, and it might get changed, but the reality of the
matter is that
templates don't tend to play well with implicit conversions.
It's _far_ too
easy to allow something in due to an implicit conversion and
then have it not
actually work, because the value is never actually converted.
In general, I
would strongly advise against attempting to give types implicit
conversions
precisely because they tend to not play nicely with templates.
- Jonathan M Davis
I think this should be considered a bug. A type with alias this
should work in all cases that the aliased type would. If the
function fails to be instantiated with S!float, then it should be
forwarded to the S's val member.
