Real implicitly converts to float?

[Ali Çehreli via Digitalmars-d-learn]

On 06/23/2016 06:57 AM, Steven Schveighoffer wrote:
 > On 6/23/16 5:37 AM, Jonathan M Davis via Digitalmars-d-learn wrote:
 >> On Thursday, June 23, 2016 04:55:09 Tofu Ninja via Digitalmars-d-learn
 >> wrote:
 >
 >>> Should I make a bug report? I am not sure it's a bug, seems
 >>> intentional. Maybe a dip for a compiler flag to warn on implicit
 >>> down conversions, but it would be a pretty small dip.
 >
 > It's not a bug. Floating point is in general an approximation, so it's
 > not expected to accurately capture the value. It's not the same as a
 > narrowing conversion.
 >
 > For instance:
 >
 > int x = 1_000_000;
 > byte b = cast(byte)x;
 > assert(b == 64);
 >
 > 64 is nowhere near 1 million.
 >
 > However:
 >
 > double x = 1_000_000_000_000_000;
 > float f = x;
 > assert(f == 999_999_986_991_104);

But there is also the representable value range. The difference between 
the maximum values are worse in the case of floating point types.

void main() {
     pragma(msg, long.max / byte.max);
     pragma(msg, real.max / float.max);
}

72624976668147841L
3.49631e+4893L

So it's more nowhere near for floating point types from that point of 
view: :)

Ali