Convert double to long if lossless

[Per Nordlöw]

On Tuesday, 19 January 2021 at 16:14:17 UTC, drug wrote:
>>    https://dlang.org/phobos/std_bitmanip.html#FloatRep

Doesn't this pattern already cover all possible cases of `value` 
needed?

void f(double value)
{
     auto lvalue = cast(long)value;
     if (lvalue == value) // `value` lacks fraction and in range 
[long.min .. long.max]
     {
         // use long lvalue
         return;
     }
     // use double value
}